1// SPDX-License-Identifier: GPL-2.0
   2
   3/* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
   4 * Copyright (C) 2018-2024 Linaro Ltd.
   5 */
   6
 
   7#include <linux/bits.h>
   8#include <linux/bug.h>
 
   9#include <linux/completion.h>
 
 
  10#include <linux/interrupt.h>
  11#include <linux/mutex.h>
  12#include <linux/netdevice.h>
  13#include <linux/platform_device.h>
  14#include <linux/types.h>
  15
  16#include "gsi.h"
  17#include "gsi_private.h"
  18#include "gsi_reg.h"
 
  19#include "gsi_trans.h"
  20#include "ipa_data.h"
  21#include "ipa_gsi.h"
 
  22#include "ipa_version.h"
  23#include "reg.h"
  24
  25/**
  26 * DOC: The IPA Generic Software Interface
  27 *
  28 * The generic software interface (GSI) is an integral component of the IPA,
  29 * providing a well-defined communication layer between the AP subsystem
  30 * and the IPA core.  The modem uses the GSI layer as well.
  31 *
  32 *	--------	     ---------
  33 *	|      |	     |	     |
  34 *	|  AP  +<---.	.----+ Modem |
  35 *	|      +--. |	| .->+	     |
  36 *	|      |  | |	| |  |	     |
  37 *	--------  | |	| |  ---------
  38 *		  v |	v |
  39 *		--+-+---+-+--
  40 *		|    GSI    |
  41 *		|-----------|
  42 *		|	    |
  43 *		|    IPA    |
  44 *		|	    |
  45 *		-------------
  46 *
  47 * In the above diagram, the AP and Modem represent "execution environments"
  48 * (EEs), which are independent operating environments that use the IPA for
  49 * data transfer.
  50 *
  51 * Each EE uses a set of unidirectional GSI "channels," which allow transfer
  52 * of data to or from the IPA.  A channel is implemented as a ring buffer,
  53 * with a DRAM-resident array of "transfer elements" (TREs) available to
  54 * describe transfers to or from other EEs through the IPA.  A transfer
  55 * element can also contain an immediate command, requesting the IPA perform
  56 * actions other than data transfer.
  57 *
  58 * Each TRE refers to a block of data--also located in DRAM.  After writing
  59 * one or more TREs to a channel, the writer (either the IPA or an EE) writes
  60 * a doorbell register to inform the receiving side how many elements have
  61 * been written.
  62 *
  63 * Each channel has a GSI "event ring" associated with it.  An event ring
  64 * is implemented very much like a channel ring, but is always directed from
  65 * the IPA to an EE.  The IPA notifies an EE (such as the AP) about channel
  66 * events by adding an entry to the event ring associated with the channel.
  67 * The GSI then writes its doorbell for the event ring, causing the target
  68 * EE to be interrupted.  Each entry in an event ring contains a pointer
  69 * to the channel TRE whose completion the event represents.
  70 *
  71 * Each TRE in a channel ring has a set of flags.  One flag indicates whether
  72 * the completion of the transfer operation generates an entry (and possibly
  73 * an interrupt) in the channel's event ring.  Other flags allow transfer
  74 * elements to be chained together, forming a single logical transaction.
  75 * TRE flags are used to control whether and when interrupts are generated
  76 * to signal completion of channel transfers.
  77 *
  78 * Elements in channel and event rings are completed (or consumed) strictly
  79 * in order.  Completion of one entry implies the completion of all preceding
  80 * entries.  A single completion interrupt can therefore communicate the
  81 * completion of many transfers.
  82 *
  83 * Note that all GSI registers are little-endian, which is the assumed
  84 * endianness of I/O space accesses.  The accessor functions perform byte
  85 * swapping if needed (i.e., for a big endian CPU).
  86 */
  87
  88/* Delay period for interrupt moderation (in 32KHz IPA internal timer ticks) */
  89#define GSI_EVT_RING_INT_MODT		(32 * 1) /* 1ms under 32KHz clock */
  90
  91#define GSI_CMD_TIMEOUT			50	/* milliseconds */
  92
  93#define GSI_CHANNEL_STOP_RETRIES	10
  94#define GSI_CHANNEL_MODEM_HALT_RETRIES	10
  95#define GSI_CHANNEL_MODEM_FLOW_RETRIES	5	/* disable flow control only */
  96
  97#define GSI_MHI_EVENT_ID_START		10	/* 1st reserved event id */
  98#define GSI_MHI_EVENT_ID_END		16	/* Last reserved event id */
  99
 100#define GSI_ISR_MAX_ITER		50	/* Detect interrupt storms */
 101
 102/* An entry in an event ring */
 103struct gsi_event {
 104	__le64 xfer_ptr;
 105	__le16 len;
 106	u8 reserved1;
 107	u8 code;
 108	__le16 reserved2;
 109	u8 type;
 110	u8 chid;
 111};
 112
 113/** gsi_channel_scratch_gpi - GPI protocol scratch register
 114 * @max_outstanding_tre:
 115 *	Defines the maximum number of TREs allowed in a single transaction
 116 *	on a channel (in bytes).  This determines the amount of prefetch
 117 *	performed by the hardware.  We configure this to equal the size of
 118 *	the TLV FIFO for the channel.
 119 * @outstanding_threshold:
 120 *	Defines the threshold (in bytes) determining when the sequencer
 121 *	should update the channel doorbell.  We configure this to equal
 122 *	the size of two TREs.
 123 */
 124struct gsi_channel_scratch_gpi {
 125	u64 reserved1;
 126	u16 reserved2;
 127	u16 max_outstanding_tre;
 128	u16 reserved3;
 129	u16 outstanding_threshold;
 130};
 131
 132/** gsi_channel_scratch - channel scratch configuration area
 133 *
 134 * The exact interpretation of this register is protocol-specific.
 135 * We only use GPI channels; see struct gsi_channel_scratch_gpi, above.
 136 */
 137union gsi_channel_scratch {
 138	struct gsi_channel_scratch_gpi gpi;
 139	struct {
 140		u32 word1;
 141		u32 word2;
 142		u32 word3;
 143		u32 word4;
 144	} data;
 145};
 146
 147/* Check things that can be validated at build time. */
 148static void gsi_validate_build(void)
 149{
 150	/* This is used as a divisor */
 151	BUILD_BUG_ON(!GSI_RING_ELEMENT_SIZE);
 152
 153	/* Code assumes the size of channel and event ring element are
 154	 * the same (and fixed).  Make sure the size of an event ring
 155	 * element is what's expected.
 156	 */
 157	BUILD_BUG_ON(sizeof(struct gsi_event) != GSI_RING_ELEMENT_SIZE);
 158
 159	/* Hardware requires a 2^n ring size.  We ensure the number of
 160	 * elements in an event ring is a power of 2 elsewhere; this
 161	 * ensure the elements themselves meet the requirement.
 162	 */
 163	BUILD_BUG_ON(!is_power_of_2(GSI_RING_ELEMENT_SIZE));
 164}
 165
 166/* Return the channel id associated with a given channel */
 167static u32 gsi_channel_id(struct gsi_channel *channel)
 168{
 169	return channel - &channel->gsi->channel[0];
 170}
 171
 172/* An initialized channel has a non-null GSI pointer */
 173static bool gsi_channel_initialized(struct gsi_channel *channel)
 174{
 175	return !!channel->gsi;
 176}
 177
 178/* Encode the channel protocol for the CH_C_CNTXT_0 register */
 179static u32 ch_c_cntxt_0_type_encode(enum ipa_version version,
 180				    const struct reg *reg,
 181				    enum gsi_channel_type type)
 182{
 183	u32 val;
 184
 185	val = reg_encode(reg, CHTYPE_PROTOCOL, type);
 186	if (version < IPA_VERSION_4_5 || version >= IPA_VERSION_5_0)
 187		return val;
 188
 189	type >>= hweight32(reg_fmask(reg, CHTYPE_PROTOCOL));
 190
 191	return val | reg_encode(reg, CHTYPE_PROTOCOL_MSB, type);
 192}
 193
 194/* Update the GSI IRQ type register with the cached value */
 195static void gsi_irq_type_update(struct gsi *gsi, u32 val)
 196{
 197	const struct reg *reg = gsi_reg(gsi, CNTXT_TYPE_IRQ_MSK);
 198
 199	gsi->type_enabled_bitmap = val;
 200	iowrite32(val, gsi->virt + reg_offset(reg));
 201}
 202
 203static void gsi_irq_type_enable(struct gsi *gsi, enum gsi_irq_type_id type_id)
 204{
 205	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap | type_id);
 206}
 207
 208static void gsi_irq_type_disable(struct gsi *gsi, enum gsi_irq_type_id type_id)
 209{
 210	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap & ~type_id);
 211}
 212
 213/* Event ring commands are performed one at a time.  Their completion
 214 * is signaled by the event ring control GSI interrupt type, which is
 215 * only enabled when we issue an event ring command.  Only the event
 216 * ring being operated on has this interrupt enabled.
 217 */
 218static void gsi_irq_ev_ctrl_enable(struct gsi *gsi, u32 evt_ring_id)
 219{
 220	u32 val = BIT(evt_ring_id);
 221	const struct reg *reg;
 222
 223	/* There's a small chance that a previous command completed
 224	 * after the interrupt was disabled, so make sure we have no
 225	 * pending interrupts before we enable them.
 226	 */
 227	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_CLR);
 228	iowrite32(~0, gsi->virt + reg_offset(reg));
 229
 230	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_MSK);
 231	iowrite32(val, gsi->virt + reg_offset(reg));
 232	gsi_irq_type_enable(gsi, GSI_EV_CTRL);
 233}
 234
 235/* Disable event ring control interrupts */
 236static void gsi_irq_ev_ctrl_disable(struct gsi *gsi)
 237{
 238	const struct reg *reg;
 239
 240	gsi_irq_type_disable(gsi, GSI_EV_CTRL);
 241
 242	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_MSK);
 243	iowrite32(0, gsi->virt + reg_offset(reg));
 244}
 245
 246/* Channel commands are performed one at a time.  Their completion is
 247 * signaled by the channel control GSI interrupt type, which is only
 248 * enabled when we issue a channel command.  Only the channel being
 249 * operated on has this interrupt enabled.
 250 */
 251static void gsi_irq_ch_ctrl_enable(struct gsi *gsi, u32 channel_id)
 252{
 253	u32 val = BIT(channel_id);
 254	const struct reg *reg;
 255
 256	/* There's a small chance that a previous command completed
 257	 * after the interrupt was disabled, so make sure we have no
 258	 * pending interrupts before we enable them.
 259	 */
 260	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_CLR);
 261	iowrite32(~0, gsi->virt + reg_offset(reg));
 262
 263	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_MSK);
 264	iowrite32(val, gsi->virt + reg_offset(reg));
 265
 266	gsi_irq_type_enable(gsi, GSI_CH_CTRL);
 267}
 268
 269/* Disable channel control interrupts */
 270static void gsi_irq_ch_ctrl_disable(struct gsi *gsi)
 271{
 272	const struct reg *reg;
 273
 274	gsi_irq_type_disable(gsi, GSI_CH_CTRL);
 275
 276	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_MSK);
 277	iowrite32(0, gsi->virt + reg_offset(reg));
 278}
 279
 280static void gsi_irq_ieob_enable_one(struct gsi *gsi, u32 evt_ring_id)
 281{
 282	bool enable_ieob = !gsi->ieob_enabled_bitmap;
 283	const struct reg *reg;
 284	u32 val;
 285
 286	gsi->ieob_enabled_bitmap |= BIT(evt_ring_id);
 287
 288	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_MSK);
 289	val = gsi->ieob_enabled_bitmap;
 290	iowrite32(val, gsi->virt + reg_offset(reg));
 291
 292	/* Enable the interrupt type if this is the first channel enabled */
 293	if (enable_ieob)
 294		gsi_irq_type_enable(gsi, GSI_IEOB);
 295}
 296
 297static void gsi_irq_ieob_disable(struct gsi *gsi, u32 event_mask)
 298{
 299	const struct reg *reg;
 300	u32 val;
 301
 302	gsi->ieob_enabled_bitmap &= ~event_mask;
 303
 304	/* Disable the interrupt type if this was the last enabled channel */
 305	if (!gsi->ieob_enabled_bitmap)
 306		gsi_irq_type_disable(gsi, GSI_IEOB);
 307
 308	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_MSK);
 309	val = gsi->ieob_enabled_bitmap;
 310	iowrite32(val, gsi->virt + reg_offset(reg));
 311}
 312
 313static void gsi_irq_ieob_disable_one(struct gsi *gsi, u32 evt_ring_id)
 314{
 315	gsi_irq_ieob_disable(gsi, BIT(evt_ring_id));
 316}
 317
 318/* Enable all GSI_interrupt types */
 319static void gsi_irq_enable(struct gsi *gsi)
 320{
 321	const struct reg *reg;
 322	u32 val;
 323
 324	/* Global interrupts include hardware error reports.  Enable
 325	 * that so we can at least report the error should it occur.
 326	 */
 327	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
 328	iowrite32(ERROR_INT, gsi->virt + reg_offset(reg));
 329
 330	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap | GSI_GLOB_EE);
 331
 332	/* General GSI interrupts are reported to all EEs; if they occur
 333	 * they are unrecoverable (without reset).  A breakpoint interrupt
 334	 * also exists, but we don't support that.  We want to be notified
 335	 * of errors so we can report them, even if they can't be handled.
 336	 */
 337	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_EN);
 338	val = BUS_ERROR;
 339	val |= CMD_FIFO_OVRFLOW;
 340	val |= MCS_STACK_OVRFLOW;
 341	iowrite32(val, gsi->virt + reg_offset(reg));
 342
 343	gsi_irq_type_update(gsi, gsi->type_enabled_bitmap | GSI_GENERAL);
 344}
 345
 346/* Disable all GSI interrupt types */
 347static void gsi_irq_disable(struct gsi *gsi)
 348{
 349	const struct reg *reg;
 350
 351	gsi_irq_type_update(gsi, 0);
 352
 353	/* Clear the type-specific interrupt masks set by gsi_irq_enable() */
 354	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_EN);
 355	iowrite32(0, gsi->virt + reg_offset(reg));
 356
 357	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
 358	iowrite32(0, gsi->virt + reg_offset(reg));
 359}
 360
 361/* Return the virtual address associated with a ring index */
 362void *gsi_ring_virt(struct gsi_ring *ring, u32 index)
 363{
 364	/* Note: index *must* be used modulo the ring count here */
 365	return ring->virt + (index % ring->count) * GSI_RING_ELEMENT_SIZE;
 366}
 367
 368/* Return the 32-bit DMA address associated with a ring index */
 369static u32 gsi_ring_addr(struct gsi_ring *ring, u32 index)
 370{
 371	return lower_32_bits(ring->addr) + index * GSI_RING_ELEMENT_SIZE;
 372}
 373
 374/* Return the ring index of a 32-bit ring offset */
 375static u32 gsi_ring_index(struct gsi_ring *ring, u32 offset)
 376{
 377	return (offset - gsi_ring_addr(ring, 0)) / GSI_RING_ELEMENT_SIZE;
 378}
 379
 380/* Issue a GSI command by writing a value to a register, then wait for
 381 * completion to be signaled.  Returns true if the command completes
 382 * or false if it times out.
 383 */
 384static bool gsi_command(struct gsi *gsi, u32 reg, u32 val)
 385{
 386	unsigned long timeout = msecs_to_jiffies(GSI_CMD_TIMEOUT);
 387	struct completion *completion = &gsi->completion;
 388
 389	reinit_completion(completion);
 390
 391	iowrite32(val, gsi->virt + reg);
 392
 393	return !!wait_for_completion_timeout(completion, timeout);
 394}
 395
 396/* Return the hardware's notion of the current state of an event ring */
 397static enum gsi_evt_ring_state
 398gsi_evt_ring_state(struct gsi *gsi, u32 evt_ring_id)
 399{
 400	const struct reg *reg = gsi_reg(gsi, EV_CH_E_CNTXT_0);
 401	u32 val;
 402
 403	val = ioread32(gsi->virt + reg_n_offset(reg, evt_ring_id));
 404
 405	return reg_decode(reg, EV_CHSTATE, val);
 406}
 407
 408/* Issue an event ring command and wait for it to complete */
 409static void gsi_evt_ring_command(struct gsi *gsi, u32 evt_ring_id,
 410				 enum gsi_evt_cmd_opcode opcode)
 411{
 412	struct device *dev = gsi->dev;
 413	const struct reg *reg;
 414	bool timeout;
 415	u32 val;
 416
 417	/* Enable the completion interrupt for the command */
 418	gsi_irq_ev_ctrl_enable(gsi, evt_ring_id);
 419
 420	reg = gsi_reg(gsi, EV_CH_CMD);
 421	val = reg_encode(reg, EV_CHID, evt_ring_id);
 422	val |= reg_encode(reg, EV_OPCODE, opcode);
 423
 424	timeout = !gsi_command(gsi, reg_offset(reg), val);
 425
 426	gsi_irq_ev_ctrl_disable(gsi);
 427
 428	if (!timeout)
 429		return;
 430
 431	dev_err(dev, "GSI command %u for event ring %u timed out, state %u\n",
 432		opcode, evt_ring_id, gsi_evt_ring_state(gsi, evt_ring_id));
 433}
 434
 435/* Allocate an event ring in NOT_ALLOCATED state */
 436static int gsi_evt_ring_alloc_command(struct gsi *gsi, u32 evt_ring_id)
 437{
 438	enum gsi_evt_ring_state state;
 439
 440	/* Get initial event ring state */
 441	state = gsi_evt_ring_state(gsi, evt_ring_id);
 442	if (state != GSI_EVT_RING_STATE_NOT_ALLOCATED) {
 443		dev_err(gsi->dev, "event ring %u bad state %u before alloc\n",
 444			evt_ring_id, state);
 445		return -EINVAL;
 446	}
 447
 448	gsi_evt_ring_command(gsi, evt_ring_id, GSI_EVT_ALLOCATE);
 449
 450	/* If successful the event ring state will have changed */
 451	state = gsi_evt_ring_state(gsi, evt_ring_id);
 452	if (state == GSI_EVT_RING_STATE_ALLOCATED)
 453		return 0;
 454
 455	dev_err(gsi->dev, "event ring %u bad state %u after alloc\n",
 456		evt_ring_id, state);
 457
 458	return -EIO;
 459}
 460
 461/* Reset a GSI event ring in ALLOCATED or ERROR state. */
 462static void gsi_evt_ring_reset_command(struct gsi *gsi, u32 evt_ring_id)
 463{
 464	enum gsi_evt_ring_state state;
 465
 466	state = gsi_evt_ring_state(gsi, evt_ring_id);
 467	if (state != GSI_EVT_RING_STATE_ALLOCATED &&
 468	    state != GSI_EVT_RING_STATE_ERROR) {
 469		dev_err(gsi->dev, "event ring %u bad state %u before reset\n",
 470			evt_ring_id, state);
 471		return;
 472	}
 473
 474	gsi_evt_ring_command(gsi, evt_ring_id, GSI_EVT_RESET);
 475
 476	/* If successful the event ring state will have changed */
 477	state = gsi_evt_ring_state(gsi, evt_ring_id);
 478	if (state == GSI_EVT_RING_STATE_ALLOCATED)
 479		return;
 480
 481	dev_err(gsi->dev, "event ring %u bad state %u after reset\n",
 482		evt_ring_id, state);
 483}
 484
 485/* Issue a hardware de-allocation request for an allocated event ring */
 486static void gsi_evt_ring_de_alloc_command(struct gsi *gsi, u32 evt_ring_id)
 487{
 488	enum gsi_evt_ring_state state;
 489
 490	state = gsi_evt_ring_state(gsi, evt_ring_id);
 491	if (state != GSI_EVT_RING_STATE_ALLOCATED) {
 492		dev_err(gsi->dev, "event ring %u state %u before dealloc\n",
 493			evt_ring_id, state);
 494		return;
 495	}
 496
 497	gsi_evt_ring_command(gsi, evt_ring_id, GSI_EVT_DE_ALLOC);
 498
 499	/* If successful the event ring state will have changed */
 500	state = gsi_evt_ring_state(gsi, evt_ring_id);
 501	if (state == GSI_EVT_RING_STATE_NOT_ALLOCATED)
 502		return;
 503
 504	dev_err(gsi->dev, "event ring %u bad state %u after dealloc\n",
 505		evt_ring_id, state);
 506}
 507
 508/* Fetch the current state of a channel from hardware */
 509static enum gsi_channel_state gsi_channel_state(struct gsi_channel *channel)
 510{
 511	const struct reg *reg = gsi_reg(channel->gsi, CH_C_CNTXT_0);
 512	u32 channel_id = gsi_channel_id(channel);
 513	struct gsi *gsi = channel->gsi;
 514	void __iomem *virt = gsi->virt;
 515	u32 val;
 516
 517	reg = gsi_reg(gsi, CH_C_CNTXT_0);
 518	val = ioread32(virt + reg_n_offset(reg, channel_id));
 519
 520	return reg_decode(reg, CHSTATE, val);
 521}
 522
 523/* Issue a channel command and wait for it to complete */
 524static void
 525gsi_channel_command(struct gsi_channel *channel, enum gsi_ch_cmd_opcode opcode)
 526{
 527	u32 channel_id = gsi_channel_id(channel);
 528	struct gsi *gsi = channel->gsi;
 529	struct device *dev = gsi->dev;
 530	const struct reg *reg;
 531	bool timeout;
 532	u32 val;
 533
 534	/* Enable the completion interrupt for the command */
 535	gsi_irq_ch_ctrl_enable(gsi, channel_id);
 536
 537	reg = gsi_reg(gsi, CH_CMD);
 538	val = reg_encode(reg, CH_CHID, channel_id);
 539	val |= reg_encode(reg, CH_OPCODE, opcode);
 540
 541	timeout = !gsi_command(gsi, reg_offset(reg), val);
 542
 543	gsi_irq_ch_ctrl_disable(gsi);
 544
 545	if (!timeout)
 546		return;
 547
 548	dev_err(dev, "GSI command %u for channel %u timed out, state %u\n",
 549		opcode, channel_id, gsi_channel_state(channel));
 550}
 551
 552/* Allocate GSI channel in NOT_ALLOCATED state */
 553static int gsi_channel_alloc_command(struct gsi *gsi, u32 channel_id)
 554{
 555	struct gsi_channel *channel = &gsi->channel[channel_id];
 556	struct device *dev = gsi->dev;
 557	enum gsi_channel_state state;
 558
 559	/* Get initial channel state */
 560	state = gsi_channel_state(channel);
 561	if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED) {
 562		dev_err(dev, "channel %u bad state %u before alloc\n",
 563			channel_id, state);
 564		return -EINVAL;
 565	}
 566
 567	gsi_channel_command(channel, GSI_CH_ALLOCATE);
 568
 569	/* If successful the channel state will have changed */
 570	state = gsi_channel_state(channel);
 571	if (state == GSI_CHANNEL_STATE_ALLOCATED)
 572		return 0;
 573
 574	dev_err(dev, "channel %u bad state %u after alloc\n",
 575		channel_id, state);
 576
 577	return -EIO;
 578}
 579
 580/* Start an ALLOCATED channel */
 581static int gsi_channel_start_command(struct gsi_channel *channel)
 582{
 583	struct device *dev = channel->gsi->dev;
 584	enum gsi_channel_state state;
 585
 586	state = gsi_channel_state(channel);
 587	if (state != GSI_CHANNEL_STATE_ALLOCATED &&
 588	    state != GSI_CHANNEL_STATE_STOPPED) {
 589		dev_err(dev, "channel %u bad state %u before start\n",
 590			gsi_channel_id(channel), state);
 591		return -EINVAL;
 592	}
 593
 594	gsi_channel_command(channel, GSI_CH_START);
 595
 596	/* If successful the channel state will have changed */
 597	state = gsi_channel_state(channel);
 598	if (state == GSI_CHANNEL_STATE_STARTED)
 599		return 0;
 600
 601	dev_err(dev, "channel %u bad state %u after start\n",
 602		gsi_channel_id(channel), state);
 603
 604	return -EIO;
 605}
 606
 607/* Stop a GSI channel in STARTED state */
 608static int gsi_channel_stop_command(struct gsi_channel *channel)
 609{
 610	struct device *dev = channel->gsi->dev;
 611	enum gsi_channel_state state;
 612
 613	state = gsi_channel_state(channel);
 614
 615	/* Channel could have entered STOPPED state since last call
 616	 * if it timed out.  If so, we're done.
 617	 */
 618	if (state == GSI_CHANNEL_STATE_STOPPED)
 619		return 0;
 620
 621	if (state != GSI_CHANNEL_STATE_STARTED &&
 622	    state != GSI_CHANNEL_STATE_STOP_IN_PROC) {
 623		dev_err(dev, "channel %u bad state %u before stop\n",
 624			gsi_channel_id(channel), state);
 625		return -EINVAL;
 626	}
 627
 628	gsi_channel_command(channel, GSI_CH_STOP);
 629
 630	/* If successful the channel state will have changed */
 631	state = gsi_channel_state(channel);
 632	if (state == GSI_CHANNEL_STATE_STOPPED)
 633		return 0;
 634
 635	/* We may have to try again if stop is in progress */
 636	if (state == GSI_CHANNEL_STATE_STOP_IN_PROC)
 637		return -EAGAIN;
 638
 639	dev_err(dev, "channel %u bad state %u after stop\n",
 640		gsi_channel_id(channel), state);
 641
 642	return -EIO;
 643}
 644
 645/* Reset a GSI channel in ALLOCATED or ERROR state. */
 646static void gsi_channel_reset_command(struct gsi_channel *channel)
 647{
 648	struct device *dev = channel->gsi->dev;
 649	enum gsi_channel_state state;
 650
 651	/* A short delay is required before a RESET command */
 652	usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 653
 654	state = gsi_channel_state(channel);
 655	if (state != GSI_CHANNEL_STATE_STOPPED &&
 656	    state != GSI_CHANNEL_STATE_ERROR) {
 657		/* No need to reset a channel already in ALLOCATED state */
 658		if (state != GSI_CHANNEL_STATE_ALLOCATED)
 659			dev_err(dev, "channel %u bad state %u before reset\n",
 660				gsi_channel_id(channel), state);
 661		return;
 662	}
 663
 664	gsi_channel_command(channel, GSI_CH_RESET);
 665
 666	/* If successful the channel state will have changed */
 667	state = gsi_channel_state(channel);
 668	if (state != GSI_CHANNEL_STATE_ALLOCATED)
 669		dev_err(dev, "channel %u bad state %u after reset\n",
 670			gsi_channel_id(channel), state);
 671}
 672
 673/* Deallocate an ALLOCATED GSI channel */
 674static void gsi_channel_de_alloc_command(struct gsi *gsi, u32 channel_id)
 675{
 676	struct gsi_channel *channel = &gsi->channel[channel_id];
 677	struct device *dev = gsi->dev;
 678	enum gsi_channel_state state;
 679
 680	state = gsi_channel_state(channel);
 681	if (state != GSI_CHANNEL_STATE_ALLOCATED) {
 682		dev_err(dev, "channel %u bad state %u before dealloc\n",
 683			channel_id, state);
 684		return;
 685	}
 686
 687	gsi_channel_command(channel, GSI_CH_DE_ALLOC);
 688
 689	/* If successful the channel state will have changed */
 690	state = gsi_channel_state(channel);
 691
 692	if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED)
 693		dev_err(dev, "channel %u bad state %u after dealloc\n",
 694			channel_id, state);
 695}
 696
 697/* Ring an event ring doorbell, reporting the last entry processed by the AP.
 698 * The index argument (modulo the ring count) is the first unfilled entry, so
 699 * we supply one less than that with the doorbell.  Update the event ring
 700 * index field with the value provided.
 701 */
 702static void gsi_evt_ring_doorbell(struct gsi *gsi, u32 evt_ring_id, u32 index)
 703{
 704	const struct reg *reg = gsi_reg(gsi, EV_CH_E_DOORBELL_0);
 705	struct gsi_ring *ring = &gsi->evt_ring[evt_ring_id].ring;
 706	u32 val;
 707
 708	ring->index = index;	/* Next unused entry */
 709
 710	/* Note: index *must* be used modulo the ring count here */
 711	val = gsi_ring_addr(ring, (index - 1) % ring->count);
 712	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
 713}
 714
 715/* Program an event ring for use */
 716static void gsi_evt_ring_program(struct gsi *gsi, u32 evt_ring_id)
 717{
 718	struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
 719	struct gsi_ring *ring = &evt_ring->ring;
 720	const struct reg *reg;
 721	u32 val;
 722
 723	reg = gsi_reg(gsi, EV_CH_E_CNTXT_0);
 724	/* We program all event rings as GPI type/protocol */
 725	val = reg_encode(reg, EV_CHTYPE, GSI_CHANNEL_TYPE_GPI);
 726	/* EV_EE field is 0 (GSI_EE_AP) */
 727	val |= reg_bit(reg, EV_INTYPE);
 728	val |= reg_encode(reg, EV_ELEMENT_SIZE, GSI_RING_ELEMENT_SIZE);
 729	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
 730
 731	reg = gsi_reg(gsi, EV_CH_E_CNTXT_1);
 732	val = reg_encode(reg, R_LENGTH, ring->count * GSI_RING_ELEMENT_SIZE);
 733	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
 734
 735	/* The context 2 and 3 registers store the low-order and
 736	 * high-order 32 bits of the address of the event ring,
 737	 * respectively.
 738	 */
 739	reg = gsi_reg(gsi, EV_CH_E_CNTXT_2);
 740	val = lower_32_bits(ring->addr);
 741	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
 742
 743	reg = gsi_reg(gsi, EV_CH_E_CNTXT_3);
 744	val = upper_32_bits(ring->addr);
 745	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
 746
 747	/* Enable interrupt moderation by setting the moderation delay */
 748	reg = gsi_reg(gsi, EV_CH_E_CNTXT_8);
 749	val = reg_encode(reg, EV_MODT, GSI_EVT_RING_INT_MODT);
 750	val |= reg_encode(reg, EV_MODC, 1);	/* comes from channel */
 751	/* EV_MOD_CNT is 0 (no counter-based interrupt coalescing) */
 752	iowrite32(val, gsi->virt + reg_n_offset(reg, evt_ring_id));
 753
 754	/* No MSI write data, and MSI high and low address is 0 */
 755	reg = gsi_reg(gsi, EV_CH_E_CNTXT_9);
 756	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
 757
 758	reg = gsi_reg(gsi, EV_CH_E_CNTXT_10);
 759	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
 760
 761	reg = gsi_reg(gsi, EV_CH_E_CNTXT_11);
 762	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
 763
 764	/* We don't need to get event read pointer updates */
 765	reg = gsi_reg(gsi, EV_CH_E_CNTXT_12);
 766	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
 767
 768	reg = gsi_reg(gsi, EV_CH_E_CNTXT_13);
 769	iowrite32(0, gsi->virt + reg_n_offset(reg, evt_ring_id));
 770
 771	/* Finally, tell the hardware our "last processed" event (arbitrary) */
 772	gsi_evt_ring_doorbell(gsi, evt_ring_id, ring->index);
 773}
 774
 775/* Find the transaction whose completion indicates a channel is quiesced */
 776static struct gsi_trans *gsi_channel_trans_last(struct gsi_channel *channel)
 777{
 778	struct gsi_trans_info *trans_info = &channel->trans_info;
 779	u32 pending_id = trans_info->pending_id;
 780	struct gsi_trans *trans;
 781	u16 trans_id;
 782
 783	if (channel->toward_ipa && pending_id != trans_info->free_id) {
 784		/* There is a small chance a TX transaction got allocated
 785		 * just before we disabled transmits, so check for that.
 786		 * The last allocated, committed, or pending transaction
 787		 * precedes the first free transaction.
 788		 */
 789		trans_id = trans_info->free_id - 1;
 790	} else if (trans_info->polled_id != pending_id) {
 791		/* Otherwise (TX or RX) we want to wait for anything that
 792		 * has completed, or has been polled but not released yet.
 793		 *
 794		 * The last completed or polled transaction precedes the
 795		 * first pending transaction.
 796		 */
 797		trans_id = pending_id - 1;
 798	} else {
 799		return NULL;
 800	}
 801
 802	/* Caller will wait for this, so take a reference */
 803	trans = &trans_info->trans[trans_id % channel->tre_count];
 804	refcount_inc(&trans->refcount);
 805
 806	return trans;
 807}
 808
 809/* Wait for transaction activity on a channel to complete */
 810static void gsi_channel_trans_quiesce(struct gsi_channel *channel)
 811{
 812	struct gsi_trans *trans;
 813
 814	/* Get the last transaction, and wait for it to complete */
 815	trans = gsi_channel_trans_last(channel);
 816	if (trans) {
 817		wait_for_completion(&trans->completion);
 818		gsi_trans_free(trans);
 819	}
 820}
 821
 822/* Program a channel for use; there is no gsi_channel_deprogram() */
 823static void gsi_channel_program(struct gsi_channel *channel, bool doorbell)
 824{
 825	size_t size = channel->tre_ring.count * GSI_RING_ELEMENT_SIZE;
 826	u32 channel_id = gsi_channel_id(channel);
 827	union gsi_channel_scratch scr = { };
 828	struct gsi_channel_scratch_gpi *gpi;
 829	struct gsi *gsi = channel->gsi;
 830	const struct reg *reg;
 831	u32 wrr_weight = 0;
 832	u32 offset;
 833	u32 val;
 834
 835	reg = gsi_reg(gsi, CH_C_CNTXT_0);
 836
 837	/* We program all channels as GPI type/protocol */
 838	val = ch_c_cntxt_0_type_encode(gsi->version, reg, GSI_CHANNEL_TYPE_GPI);
 839	if (channel->toward_ipa)
 840		val |= reg_bit(reg, CHTYPE_DIR);
 841	if (gsi->version < IPA_VERSION_5_0)
 842		val |= reg_encode(reg, ERINDEX, channel->evt_ring_id);
 843	val |= reg_encode(reg, ELEMENT_SIZE, GSI_RING_ELEMENT_SIZE);
 844	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 845
 846	reg = gsi_reg(gsi, CH_C_CNTXT_1);
 847	val = reg_encode(reg, CH_R_LENGTH, size);
 848	if (gsi->version >= IPA_VERSION_5_0)
 849		val |= reg_encode(reg, CH_ERINDEX, channel->evt_ring_id);
 850	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 851
 852	/* The context 2 and 3 registers store the low-order and
 853	 * high-order 32 bits of the address of the channel ring,
 854	 * respectively.
 855	 */
 856	reg = gsi_reg(gsi, CH_C_CNTXT_2);
 857	val = lower_32_bits(channel->tre_ring.addr);
 858	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 859
 860	reg = gsi_reg(gsi, CH_C_CNTXT_3);
 861	val = upper_32_bits(channel->tre_ring.addr);
 862	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 863
 864	reg = gsi_reg(gsi, CH_C_QOS);
 865
 866	/* Command channel gets low weighted round-robin priority */
 867	if (channel->command)
 868		wrr_weight = reg_field_max(reg, WRR_WEIGHT);
 869	val = reg_encode(reg, WRR_WEIGHT, wrr_weight);
 870
 871	/* Max prefetch is 1 segment (do not set MAX_PREFETCH_FMASK) */
 872
 873	/* No need to use the doorbell engine starting at IPA v4.0 */
 874	if (gsi->version < IPA_VERSION_4_0 && doorbell)
 875		val |= reg_bit(reg, USE_DB_ENG);
 876
 877	/* v4.0 introduces an escape buffer for prefetch.  We use it
 878	 * on all but the AP command channel.
 879	 */
 880	if (gsi->version >= IPA_VERSION_4_0 && !channel->command) {
 881		/* If not otherwise set, prefetch buffers are used */
 882		if (gsi->version < IPA_VERSION_4_5)
 883			val |= reg_bit(reg, USE_ESCAPE_BUF_ONLY);
 884		else
 885			val |= reg_encode(reg, PREFETCH_MODE, ESCAPE_BUF_ONLY);
 886	}
 887	/* All channels set DB_IN_BYTES */
 888	if (gsi->version >= IPA_VERSION_4_9)
 889		val |= reg_bit(reg, DB_IN_BYTES);
 890
 891	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 892
 893	/* Now update the scratch registers for GPI protocol */
 894	gpi = &scr.gpi;
 895	gpi->max_outstanding_tre = channel->trans_tre_max *
 896					GSI_RING_ELEMENT_SIZE;
 897	gpi->outstanding_threshold = 2 * GSI_RING_ELEMENT_SIZE;
 898
 899	reg = gsi_reg(gsi, CH_C_SCRATCH_0);
 900	val = scr.data.word1;
 901	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 902
 903	reg = gsi_reg(gsi, CH_C_SCRATCH_1);
 904	val = scr.data.word2;
 905	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 906
 907	reg = gsi_reg(gsi, CH_C_SCRATCH_2);
 908	val = scr.data.word3;
 909	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
 910
 911	/* We must preserve the upper 16 bits of the last scratch register.
 912	 * The next sequence assumes those bits remain unchanged between the
 913	 * read and the write.
 914	 */
 915	reg = gsi_reg(gsi, CH_C_SCRATCH_3);
 916	offset = reg_n_offset(reg, channel_id);
 917	val = ioread32(gsi->virt + offset);
 918	val = (scr.data.word4 & GENMASK(31, 16)) | (val & GENMASK(15, 0));
 919	iowrite32(val, gsi->virt + offset);
 920
 921	/* All done! */
 922}
 923
 924static int __gsi_channel_start(struct gsi_channel *channel, bool resume)
 925{
 926	struct gsi *gsi = channel->gsi;
 927	int ret;
 928
 929	/* Prior to IPA v4.0 suspend/resume is not implemented by GSI */
 930	if (resume && gsi->version < IPA_VERSION_4_0)
 931		return 0;
 932
 933	mutex_lock(&gsi->mutex);
 934
 935	ret = gsi_channel_start_command(channel);
 936
 937	mutex_unlock(&gsi->mutex);
 938
 939	return ret;
 940}
 941
 942/* Start an allocated GSI channel */
 943int gsi_channel_start(struct gsi *gsi, u32 channel_id)
 944{
 945	struct gsi_channel *channel = &gsi->channel[channel_id];
 946	int ret;
 947
 948	/* Enable NAPI and the completion interrupt */
 949	napi_enable(&channel->napi);
 950	gsi_irq_ieob_enable_one(gsi, channel->evt_ring_id);
 951
 952	ret = __gsi_channel_start(channel, false);
 953	if (ret) {
 954		gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
 955		napi_disable(&channel->napi);
 956	}
 957
 958	return ret;
 959}
 960
 961static int gsi_channel_stop_retry(struct gsi_channel *channel)
 962{
 963	u32 retries = GSI_CHANNEL_STOP_RETRIES;
 964	int ret;
 965
 966	do {
 967		ret = gsi_channel_stop_command(channel);
 968		if (ret != -EAGAIN)
 969			break;
 970		usleep_range(3 * USEC_PER_MSEC, 5 * USEC_PER_MSEC);
 971	} while (retries--);
 972
 973	return ret;
 974}
 975
 976static int __gsi_channel_stop(struct gsi_channel *channel, bool suspend)
 977{
 978	struct gsi *gsi = channel->gsi;
 979	int ret;
 980
 981	/* Wait for any underway transactions to complete before stopping. */
 982	gsi_channel_trans_quiesce(channel);
 983
 984	/* Prior to IPA v4.0 suspend/resume is not implemented by GSI */
 985	if (suspend && gsi->version < IPA_VERSION_4_0)
 986		return 0;
 987
 988	mutex_lock(&gsi->mutex);
 989
 990	ret = gsi_channel_stop_retry(channel);
 991
 992	mutex_unlock(&gsi->mutex);
 993
 994	return ret;
 995}
 996
 997/* Stop a started channel */
 998int gsi_channel_stop(struct gsi *gsi, u32 channel_id)
 999{
1000	struct gsi_channel *channel = &gsi->channel[channel_id];
1001	int ret;
1002
1003	ret = __gsi_channel_stop(channel, false);
1004	if (ret)
1005		return ret;
1006
1007	/* Disable the completion interrupt and NAPI if successful */
1008	gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
1009	napi_disable(&channel->napi);
1010
1011	return 0;
1012}
1013
1014/* Reset and reconfigure a channel, (possibly) enabling the doorbell engine */
1015void gsi_channel_reset(struct gsi *gsi, u32 channel_id, bool doorbell)
1016{
1017	struct gsi_channel *channel = &gsi->channel[channel_id];
1018
1019	mutex_lock(&gsi->mutex);
1020
1021	gsi_channel_reset_command(channel);
1022	/* Due to a hardware quirk we may need to reset RX channels twice. */
1023	if (gsi->version < IPA_VERSION_4_0 && !channel->toward_ipa)
1024		gsi_channel_reset_command(channel);
1025
1026	/* Hardware assumes this is 0 following reset */
1027	channel->tre_ring.index = 0;
1028	gsi_channel_program(channel, doorbell);
1029	gsi_channel_trans_cancel_pending(channel);
1030
1031	mutex_unlock(&gsi->mutex);
1032}
1033
1034/* Stop a started channel for suspend */
1035int gsi_channel_suspend(struct gsi *gsi, u32 channel_id)
1036{
1037	struct gsi_channel *channel = &gsi->channel[channel_id];
1038	int ret;
1039
1040	ret = __gsi_channel_stop(channel, true);
1041	if (ret)
1042		return ret;
1043
1044	/* Ensure NAPI polling has finished. */
1045	napi_synchronize(&channel->napi);
1046
1047	return 0;
1048}
1049
1050/* Resume a suspended channel (starting if stopped) */
1051int gsi_channel_resume(struct gsi *gsi, u32 channel_id)
1052{
1053	struct gsi_channel *channel = &gsi->channel[channel_id];
1054
1055	return __gsi_channel_start(channel, true);
1056}
1057
1058/* Prevent all GSI interrupts while suspended */
1059void gsi_suspend(struct gsi *gsi)
1060{
1061	disable_irq(gsi->irq);
1062}
1063
1064/* Allow all GSI interrupts again when resuming */
1065void gsi_resume(struct gsi *gsi)
1066{
1067	enable_irq(gsi->irq);
1068}
1069
1070void gsi_trans_tx_committed(struct gsi_trans *trans)
1071{
1072	struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id];
1073
1074	channel->trans_count++;
1075	channel->byte_count += trans->len;
1076
1077	trans->trans_count = channel->trans_count;
1078	trans->byte_count = channel->byte_count;
1079}
1080
1081void gsi_trans_tx_queued(struct gsi_trans *trans)
1082{
1083	u32 channel_id = trans->channel_id;
1084	struct gsi *gsi = trans->gsi;
1085	struct gsi_channel *channel;
1086	u32 trans_count;
1087	u32 byte_count;
1088
1089	channel = &gsi->channel[channel_id];
1090
1091	byte_count = channel->byte_count - channel->queued_byte_count;
1092	trans_count = channel->trans_count - channel->queued_trans_count;
1093	channel->queued_byte_count = channel->byte_count;
1094	channel->queued_trans_count = channel->trans_count;
1095
1096	ipa_gsi_channel_tx_queued(gsi, channel_id, trans_count, byte_count);
1097}
1098
1099/**
1100 * gsi_trans_tx_completed() - Report completed TX transactions
1101 * @trans:	TX channel transaction that has completed
1102 *
1103 * Report that a transaction on a TX channel has completed.  At the time a
1104 * transaction is committed, we record *in the transaction* its channel's
1105 * committed transaction and byte counts.  Transactions are completed in
1106 * order, and the difference between the channel's byte/transaction count
1107 * when the transaction was committed and when it completes tells us
1108 * exactly how much data has been transferred while the transaction was
1109 * pending.
1110 *
1111 * We report this information to the network stack, which uses it to manage
1112 * the rate at which data is sent to hardware.
1113 */
1114static void gsi_trans_tx_completed(struct gsi_trans *trans)
1115{
1116	u32 channel_id = trans->channel_id;
1117	struct gsi *gsi = trans->gsi;
1118	struct gsi_channel *channel;
1119	u32 trans_count;
1120	u32 byte_count;
1121
1122	channel = &gsi->channel[channel_id];
1123	trans_count = trans->trans_count - channel->compl_trans_count;
1124	byte_count = trans->byte_count - channel->compl_byte_count;
1125
1126	channel->compl_trans_count += trans_count;
1127	channel->compl_byte_count += byte_count;
1128
1129	ipa_gsi_channel_tx_completed(gsi, channel_id, trans_count, byte_count);
1130}
1131
1132/* Channel control interrupt handler */
1133static void gsi_isr_chan_ctrl(struct gsi *gsi)
1134{
1135	const struct reg *reg;
1136	u32 channel_mask;
1137
1138	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ);
1139	channel_mask = ioread32(gsi->virt + reg_offset(reg));
1140
1141	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_CLR);
1142	iowrite32(channel_mask, gsi->virt + reg_offset(reg));
1143
1144	while (channel_mask) {
1145		u32 channel_id = __ffs(channel_mask);
1146
1147		channel_mask ^= BIT(channel_id);
1148
1149		complete(&gsi->completion);
1150	}
1151}
1152
1153/* Event ring control interrupt handler */
1154static void gsi_isr_evt_ctrl(struct gsi *gsi)
1155{
1156	const struct reg *reg;
1157	u32 event_mask;
1158
1159	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ);
1160	event_mask = ioread32(gsi->virt + reg_offset(reg));
1161
1162	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_CLR);
1163	iowrite32(event_mask, gsi->virt + reg_offset(reg));
1164
1165	while (event_mask) {
1166		u32 evt_ring_id = __ffs(event_mask);
1167
1168		event_mask ^= BIT(evt_ring_id);
1169
1170		complete(&gsi->completion);
1171	}
1172}
1173
1174/* Global channel error interrupt handler */
1175static void
1176gsi_isr_glob_chan_err(struct gsi *gsi, u32 err_ee, u32 channel_id, u32 code)
1177{
1178	if (code == GSI_OUT_OF_RESOURCES) {
1179		dev_err(gsi->dev, "channel %u out of resources\n", channel_id);
1180		complete(&gsi->completion);
1181		return;
1182	}
1183
1184	/* Report, but otherwise ignore all other error codes */
1185	dev_err(gsi->dev, "channel %u global error ee 0x%08x code 0x%08x\n",
1186		channel_id, err_ee, code);
1187}
1188
1189/* Global event error interrupt handler */
1190static void
1191gsi_isr_glob_evt_err(struct gsi *gsi, u32 err_ee, u32 evt_ring_id, u32 code)
1192{
1193	if (code == GSI_OUT_OF_RESOURCES) {
1194		struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
1195		u32 channel_id = gsi_channel_id(evt_ring->channel);
1196
1197		complete(&gsi->completion);
1198		dev_err(gsi->dev, "evt_ring for channel %u out of resources\n",
1199			channel_id);
1200		return;
1201	}
1202
1203	/* Report, but otherwise ignore all other error codes */
1204	dev_err(gsi->dev, "event ring %u global error ee %u code 0x%08x\n",
1205		evt_ring_id, err_ee, code);
1206}
1207
1208/* Global error interrupt handler */
1209static void gsi_isr_glob_err(struct gsi *gsi)
1210{
1211	const struct reg *log_reg;
1212	const struct reg *clr_reg;
1213	enum gsi_err_type type;
1214	enum gsi_err_code code;
1215	u32 offset;
1216	u32 which;
1217	u32 val;
1218	u32 ee;
1219
1220	/* Get the logged error, then reinitialize the log */
1221	log_reg = gsi_reg(gsi, ERROR_LOG);
1222	offset = reg_offset(log_reg);
1223	val = ioread32(gsi->virt + offset);
1224	iowrite32(0, gsi->virt + offset);
1225
1226	clr_reg = gsi_reg(gsi, ERROR_LOG_CLR);
1227	iowrite32(~0, gsi->virt + reg_offset(clr_reg));
1228
1229	/* Parse the error value */
1230	ee = reg_decode(log_reg, ERR_EE, val);
1231	type = reg_decode(log_reg, ERR_TYPE, val);
1232	which = reg_decode(log_reg, ERR_VIRT_IDX, val);
1233	code = reg_decode(log_reg, ERR_CODE, val);
1234
1235	if (type == GSI_ERR_TYPE_CHAN)
1236		gsi_isr_glob_chan_err(gsi, ee, which, code);
1237	else if (type == GSI_ERR_TYPE_EVT)
1238		gsi_isr_glob_evt_err(gsi, ee, which, code);
1239	else	/* type GSI_ERR_TYPE_GLOB should be fatal */
1240		dev_err(gsi->dev, "unexpected global error 0x%08x\n", type);
1241}
1242
1243/* Generic EE interrupt handler */
1244static void gsi_isr_gp_int1(struct gsi *gsi)
1245{
1246	const struct reg *reg;
1247	u32 result;
1248	u32 val;
1249
1250	/* This interrupt is used to handle completions of GENERIC GSI
1251	 * commands.  We use these to allocate and halt channels on the
1252	 * modem's behalf due to a hardware quirk on IPA v4.2.  The modem
1253	 * "owns" channels even when the AP allocates them, and have no
1254	 * way of knowing whether a modem channel's state has been changed.
1255	 *
1256	 * We also use GENERIC commands to enable/disable channel flow
1257	 * control for IPA v4.2+.
1258	 *
1259	 * It is recommended that we halt the modem channels we allocated
1260	 * when shutting down, but it's possible the channel isn't running
1261	 * at the time we issue the HALT command.  We'll get an error in
1262	 * that case, but it's harmless (the channel is already halted).
1263	 * Similarly, we could get an error back when updating flow control
1264	 * on a channel because it's not in the proper state.
1265	 *
1266	 * In either case, we silently ignore a INCORRECT_CHANNEL_STATE
1267	 * error if we receive it.
1268	 */
1269	reg = gsi_reg(gsi, CNTXT_SCRATCH_0);
1270	val = ioread32(gsi->virt + reg_offset(reg));
1271	result = reg_decode(reg, GENERIC_EE_RESULT, val);
1272
1273	switch (result) {
1274	case GENERIC_EE_SUCCESS:
1275	case GENERIC_EE_INCORRECT_CHANNEL_STATE:
1276		gsi->result = 0;
1277		break;
1278
1279	case GENERIC_EE_RETRY:
1280		gsi->result = -EAGAIN;
1281		break;
1282
1283	default:
1284		dev_err(gsi->dev, "global INT1 generic result %u\n", result);
1285		gsi->result = -EIO;
1286		break;
1287	}
1288
1289	complete(&gsi->completion);
1290}
1291
1292/* Inter-EE interrupt handler */
1293static void gsi_isr_glob_ee(struct gsi *gsi)
1294{
1295	const struct reg *reg;
1296	u32 val;
1297
1298	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_STTS);
1299	val = ioread32(gsi->virt + reg_offset(reg));
1300
1301	if (val & ERROR_INT)
1302		gsi_isr_glob_err(gsi);
1303
1304	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_CLR);
1305	iowrite32(val, gsi->virt + reg_offset(reg));
1306
1307	val &= ~ERROR_INT;
1308
1309	if (val & GP_INT1) {
1310		val ^= GP_INT1;
1311		gsi_isr_gp_int1(gsi);
1312	}
1313
1314	if (val)
1315		dev_err(gsi->dev, "unexpected global interrupt 0x%08x\n", val);
1316}
1317
1318/* I/O completion interrupt event */
1319static void gsi_isr_ieob(struct gsi *gsi)
1320{
1321	const struct reg *reg;
1322	u32 event_mask;
1323
1324	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ);
1325	event_mask = ioread32(gsi->virt + reg_offset(reg));
1326
1327	gsi_irq_ieob_disable(gsi, event_mask);
1328
1329	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_CLR);
1330	iowrite32(event_mask, gsi->virt + reg_offset(reg));
1331
1332	while (event_mask) {
1333		u32 evt_ring_id = __ffs(event_mask);
1334
1335		event_mask ^= BIT(evt_ring_id);
1336
1337		napi_schedule(&gsi->evt_ring[evt_ring_id].channel->napi);
1338	}
1339}
1340
1341/* General event interrupts represent serious problems, so report them */
1342static void gsi_isr_general(struct gsi *gsi)
1343{
1344	struct device *dev = gsi->dev;
1345	const struct reg *reg;
1346	u32 val;
1347
1348	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_STTS);
1349	val = ioread32(gsi->virt + reg_offset(reg));
1350
1351	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_CLR);
1352	iowrite32(val, gsi->virt + reg_offset(reg));
1353
1354	dev_err(dev, "unexpected general interrupt 0x%08x\n", val);
1355}
1356
1357/**
1358 * gsi_isr() - Top level GSI interrupt service routine
1359 * @irq:	Interrupt number (ignored)
1360 * @dev_id:	GSI pointer supplied to request_irq()
1361 *
1362 * This is the main handler function registered for the GSI IRQ. Each type
1363 * of interrupt has a separate handler function that is called from here.
1364 */
1365static irqreturn_t gsi_isr(int irq, void *dev_id)
1366{
1367	struct gsi *gsi = dev_id;
1368	const struct reg *reg;
1369	u32 intr_mask;
1370	u32 cnt = 0;
1371	u32 offset;
1372
1373	reg = gsi_reg(gsi, CNTXT_TYPE_IRQ);
1374	offset = reg_offset(reg);
1375
1376	/* enum gsi_irq_type_id defines GSI interrupt types */
1377	while ((intr_mask = ioread32(gsi->virt + offset))) {
1378		/* intr_mask contains bitmask of pending GSI interrupts */
1379		do {
1380			u32 gsi_intr = BIT(__ffs(intr_mask));
1381
1382			intr_mask ^= gsi_intr;
1383
1384			/* Note: the IRQ condition for each type is cleared
1385			 * when the type-specific register is updated.
1386			 */
1387			switch (gsi_intr) {
1388			case GSI_CH_CTRL:
1389				gsi_isr_chan_ctrl(gsi);
1390				break;
1391			case GSI_EV_CTRL:
1392				gsi_isr_evt_ctrl(gsi);
1393				break;
1394			case GSI_GLOB_EE:
1395				gsi_isr_glob_ee(gsi);
1396				break;
1397			case GSI_IEOB:
1398				gsi_isr_ieob(gsi);
1399				break;
1400			case GSI_GENERAL:
1401				gsi_isr_general(gsi);
1402				break;
1403			default:
1404				dev_err(gsi->dev,
1405					"unrecognized interrupt type 0x%08x\n",
1406					gsi_intr);
1407				break;
1408			}
1409		} while (intr_mask);
1410
1411		if (++cnt > GSI_ISR_MAX_ITER) {
1412			dev_err(gsi->dev, "interrupt flood\n");
1413			break;
1414		}
1415	}
1416
1417	return IRQ_HANDLED;
1418}
1419
1420/* Init function for GSI IRQ lookup; there is no gsi_irq_exit() */
1421static int gsi_irq_init(struct gsi *gsi, struct platform_device *pdev)
1422{
1423	int ret;
1424
1425	ret = platform_get_irq_byname(pdev, "gsi");
1426	if (ret <= 0)
1427		return ret ? : -EINVAL;
1428
1429	gsi->irq = ret;
1430
1431	return 0;
1432}
1433
1434/* Return the transaction associated with a transfer completion event */
1435static struct gsi_trans *
1436gsi_event_trans(struct gsi *gsi, struct gsi_event *event)
1437{
1438	u32 channel_id = event->chid;
1439	struct gsi_channel *channel;
1440	struct gsi_trans *trans;
1441	u32 tre_offset;
1442	u32 tre_index;
1443
1444	channel = &gsi->channel[channel_id];
1445	if (WARN(!channel->gsi, "event has bad channel %u\n", channel_id))
1446		return NULL;
1447
1448	/* Event xfer_ptr records the TRE it's associated with */
1449	tre_offset = lower_32_bits(le64_to_cpu(event->xfer_ptr));
1450	tre_index = gsi_ring_index(&channel->tre_ring, tre_offset);
1451
1452	trans = gsi_channel_trans_mapped(channel, tre_index);
1453
1454	if (WARN(!trans, "channel %u event with no transaction\n", channel_id))
1455		return NULL;
1456
1457	return trans;
1458}
1459
1460/**
1461 * gsi_evt_ring_update() - Update transaction state from hardware
1462 * @gsi:		GSI pointer
1463 * @evt_ring_id:	Event ring ID
1464 * @index:		Event index in ring reported by hardware
1465 *
1466 * Events for RX channels contain the actual number of bytes received into
1467 * the buffer.  Every event has a transaction associated with it, and here
1468 * we update transactions to record their actual received lengths.
1469 *
1470 * When an event for a TX channel arrives we use information in the
1471 * transaction to report the number of requests and bytes that have
1472 * been transferred.
1473 *
1474 * This function is called whenever we learn that the GSI hardware has filled
1475 * new events since the last time we checked.  The ring's index field tells
1476 * the first entry in need of processing.  The index provided is the
1477 * first *unfilled* event in the ring (following the last filled one).
1478 *
1479 * Events are sequential within the event ring, and transactions are
1480 * sequential within the transaction array.
1481 *
1482 * Note that @index always refers to an element *within* the event ring.
1483 */
1484static void gsi_evt_ring_update(struct gsi *gsi, u32 evt_ring_id, u32 index)
1485{
1486	struct gsi_evt_ring *evt_ring = &gsi->evt_ring[evt_ring_id];
1487	struct gsi_ring *ring = &evt_ring->ring;
1488	struct gsi_event *event_done;
1489	struct gsi_event *event;
1490	u32 event_avail;
1491	u32 old_index;
1492
1493	/* Starting with the oldest un-processed event, determine which
1494	 * transaction (and which channel) is associated with the event.
1495	 * For RX channels, update each completed transaction with the
1496	 * number of bytes that were actually received.  For TX channels
1497	 * associated with a network device, report to the network stack
1498	 * the number of transfers and bytes this completion represents.
1499	 */
1500	old_index = ring->index;
1501	event = gsi_ring_virt(ring, old_index);
1502
1503	/* Compute the number of events to process before we wrap,
1504	 * and determine when we'll be done processing events.
1505	 */
1506	event_avail = ring->count - old_index % ring->count;
1507	event_done = gsi_ring_virt(ring, index);
1508	do {
1509		struct gsi_trans *trans;
1510
1511		trans = gsi_event_trans(gsi, event);
1512		if (!trans)
1513			return;
1514
1515		if (trans->direction == DMA_FROM_DEVICE)
1516			trans->len = __le16_to_cpu(event->len);
1517		else
1518			gsi_trans_tx_completed(trans);
1519
1520		gsi_trans_move_complete(trans);
1521
1522		/* Move on to the next event and transaction */
1523		if (--event_avail)
1524			event++;
1525		else
1526			event = gsi_ring_virt(ring, 0);
1527	} while (event != event_done);
1528
1529	/* Tell the hardware we've handled these events */
1530	gsi_evt_ring_doorbell(gsi, evt_ring_id, index);
1531}
1532
1533/* Initialize a ring, including allocating DMA memory for its entries */
1534static int gsi_ring_alloc(struct gsi *gsi, struct gsi_ring *ring, u32 count)
1535{
1536	u32 size = count * GSI_RING_ELEMENT_SIZE;
1537	struct device *dev = gsi->dev;
1538	dma_addr_t addr;
1539
1540	/* Hardware requires a 2^n ring size, with alignment equal to size.
1541	 * The DMA address returned by dma_alloc_coherent() is guaranteed to
1542	 * be a power-of-2 number of pages, which satisfies the requirement.
1543	 */
1544	ring->virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
1545	if (!ring->virt)
1546		return -ENOMEM;
1547
1548	ring->addr = addr;
1549	ring->count = count;
1550	ring->index = 0;
1551
1552	return 0;
1553}
1554
1555/* Free a previously-allocated ring */
1556static void gsi_ring_free(struct gsi *gsi, struct gsi_ring *ring)
1557{
1558	size_t size = ring->count * GSI_RING_ELEMENT_SIZE;
1559
1560	dma_free_coherent(gsi->dev, size, ring->virt, ring->addr);
1561}
1562
1563/* Allocate an available event ring id */
1564static int gsi_evt_ring_id_alloc(struct gsi *gsi)
1565{
1566	u32 evt_ring_id;
1567
1568	if (gsi->event_bitmap == ~0U) {
1569		dev_err(gsi->dev, "event rings exhausted\n");
1570		return -ENOSPC;
1571	}
1572
1573	evt_ring_id = ffz(gsi->event_bitmap);
1574	gsi->event_bitmap |= BIT(evt_ring_id);
1575
1576	return (int)evt_ring_id;
1577}
1578
1579/* Free a previously-allocated event ring id */
1580static void gsi_evt_ring_id_free(struct gsi *gsi, u32 evt_ring_id)
1581{
1582	gsi->event_bitmap &= ~BIT(evt_ring_id);
1583}
1584
1585/* Ring a channel doorbell, reporting the first un-filled entry */
1586void gsi_channel_doorbell(struct gsi_channel *channel)
1587{
1588	struct gsi_ring *tre_ring = &channel->tre_ring;
1589	u32 channel_id = gsi_channel_id(channel);
1590	struct gsi *gsi = channel->gsi;
1591	const struct reg *reg;
1592	u32 val;
1593
1594	reg = gsi_reg(gsi, CH_C_DOORBELL_0);
1595	/* Note: index *must* be used modulo the ring count here */
1596	val = gsi_ring_addr(tre_ring, tre_ring->index % tre_ring->count);
1597	iowrite32(val, gsi->virt + reg_n_offset(reg, channel_id));
1598}
1599
1600/* Consult hardware, move newly completed transactions to completed state */
1601void gsi_channel_update(struct gsi_channel *channel)
1602{
1603	u32 evt_ring_id = channel->evt_ring_id;
1604	struct gsi *gsi = channel->gsi;
1605	struct gsi_evt_ring *evt_ring;
1606	struct gsi_trans *trans;
1607	struct gsi_ring *ring;
1608	const struct reg *reg;
1609	u32 offset;
1610	u32 index;
1611
1612	evt_ring = &gsi->evt_ring[evt_ring_id];
1613	ring = &evt_ring->ring;
1614
1615	/* See if there's anything new to process; if not, we're done.  Note
1616	 * that index always refers to an entry *within* the event ring.
1617	 */
1618	reg = gsi_reg(gsi, EV_CH_E_CNTXT_4);
1619	offset = reg_n_offset(reg, evt_ring_id);
1620	index = gsi_ring_index(ring, ioread32(gsi->virt + offset));
1621	if (index == ring->index % ring->count)
1622		return;
1623
1624	/* Get the transaction for the latest completed event. */
1625	trans = gsi_event_trans(gsi, gsi_ring_virt(ring, index - 1));
1626	if (!trans)
1627		return;
1628
1629	/* For RX channels, update each completed transaction with the number
1630	 * of bytes that were actually received.  For TX channels, report
1631	 * the number of transactions and bytes this completion represents
1632	 * up the network stack.
1633	 */
1634	gsi_evt_ring_update(gsi, evt_ring_id, index);
1635}
1636
1637/**
1638 * gsi_channel_poll_one() - Return a single completed transaction on a channel
1639 * @channel:	Channel to be polled
1640 *
1641 * Return:	Transaction pointer, or null if none are available
1642 *
1643 * This function returns the first of a channel's completed transactions.
1644 * If no transactions are in completed state, the hardware is consulted to
1645 * determine whether any new transactions have completed.  If so, they're
1646 * moved to completed state and the first such transaction is returned.
1647 * If there are no more completed transactions, a null pointer is returned.
1648 */
1649static struct gsi_trans *gsi_channel_poll_one(struct gsi_channel *channel)
1650{
1651	struct gsi_trans *trans;
1652
1653	/* Get the first completed transaction */
1654	trans = gsi_channel_trans_complete(channel);
1655	if (trans)
1656		gsi_trans_move_polled(trans);
1657
1658	return trans;
1659}
1660
1661/**
1662 * gsi_channel_poll() - NAPI poll function for a channel
1663 * @napi:	NAPI structure for the channel
1664 * @budget:	Budget supplied by NAPI core
1665 *
1666 * Return:	Number of items polled (<= budget)
1667 *
1668 * Single transactions completed by hardware are polled until either
1669 * the budget is exhausted, or there are no more.  Each transaction
1670 * polled is passed to gsi_trans_complete(), to perform remaining
1671 * completion processing and retire/free the transaction.
1672 */
1673static int gsi_channel_poll(struct napi_struct *napi, int budget)
1674{
1675	struct gsi_channel *channel;
1676	int count;
1677
1678	channel = container_of(napi, struct gsi_channel, napi);
1679	for (count = 0; count < budget; count++) {
1680		struct gsi_trans *trans;
1681
1682		trans = gsi_channel_poll_one(channel);
1683		if (!trans)
1684			break;
1685		gsi_trans_complete(trans);
1686	}
1687
1688	if (count < budget && napi_complete(napi))
1689		gsi_irq_ieob_enable_one(channel->gsi, channel->evt_ring_id);
1690
1691	return count;
1692}
1693
1694/* The event bitmap represents which event ids are available for allocation.
1695 * Set bits are not available, clear bits can be used.  This function
1696 * initializes the map so all events supported by the hardware are available,
1697 * then precludes any reserved events from being allocated.
1698 */
1699static u32 gsi_event_bitmap_init(u32 evt_ring_max)
1700{
1701	u32 event_bitmap = GENMASK(BITS_PER_LONG - 1, evt_ring_max);
1702
1703	event_bitmap |= GENMASK(GSI_MHI_EVENT_ID_END, GSI_MHI_EVENT_ID_START);
1704
1705	return event_bitmap;
1706}
1707
1708/* Setup function for a single channel */
1709static int gsi_channel_setup_one(struct gsi *gsi, u32 channel_id)
1710{
1711	struct gsi_channel *channel = &gsi->channel[channel_id];
1712	u32 evt_ring_id = channel->evt_ring_id;
1713	int ret;
1714
1715	if (!gsi_channel_initialized(channel))
1716		return 0;
1717
1718	ret = gsi_evt_ring_alloc_command(gsi, evt_ring_id);
1719	if (ret)
1720		return ret;
1721
1722	gsi_evt_ring_program(gsi, evt_ring_id);
1723
1724	ret = gsi_channel_alloc_command(gsi, channel_id);
1725	if (ret)
1726		goto err_evt_ring_de_alloc;
1727
1728	gsi_channel_program(channel, true);
1729
1730	if (channel->toward_ipa)
1731		netif_napi_add_tx(gsi->dummy_dev, &channel->napi,
1732				  gsi_channel_poll);
1733	else
1734		netif_napi_add(gsi->dummy_dev, &channel->napi,
1735			       gsi_channel_poll);
1736
1737	return 0;
1738
1739err_evt_ring_de_alloc:
1740	/* We've done nothing with the event ring yet so don't reset */
1741	gsi_evt_ring_de_alloc_command(gsi, evt_ring_id);
1742
1743	return ret;
1744}
1745
1746/* Inverse of gsi_channel_setup_one() */
1747static void gsi_channel_teardown_one(struct gsi *gsi, u32 channel_id)
1748{
1749	struct gsi_channel *channel = &gsi->channel[channel_id];
1750	u32 evt_ring_id = channel->evt_ring_id;
1751
1752	if (!gsi_channel_initialized(channel))
1753		return;
1754
1755	netif_napi_del(&channel->napi);
1756
1757	gsi_channel_de_alloc_command(gsi, channel_id);
1758	gsi_evt_ring_reset_command(gsi, evt_ring_id);
1759	gsi_evt_ring_de_alloc_command(gsi, evt_ring_id);
1760}
1761
1762/* We use generic commands only to operate on modem channels.  We don't have
1763 * the ability to determine channel state for a modem channel, so we simply
1764 * issue the command and wait for it to complete.
1765 */
1766static int gsi_generic_command(struct gsi *gsi, u32 channel_id,
1767			       enum gsi_generic_cmd_opcode opcode,
1768			       u8 params)
1769{
1770	const struct reg *reg;
1771	bool timeout;
1772	u32 offset;
1773	u32 val;
1774
1775	/* The error global interrupt type is always enabled (until we tear
1776	 * down), so we will keep it enabled.
1777	 *
1778	 * A generic EE command completes with a GSI global interrupt of
1779	 * type GP_INT1.  We only perform one generic command at a time
1780	 * (to allocate, halt, or enable/disable flow control on a modem
1781	 * channel), and only from this function.  So we enable the GP_INT1
1782	 * IRQ type here, and disable it again after the command completes.
1783	 */
1784	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
1785	val = ERROR_INT | GP_INT1;
1786	iowrite32(val, gsi->virt + reg_offset(reg));
1787
1788	/* First zero the result code field */
1789	reg = gsi_reg(gsi, CNTXT_SCRATCH_0);
1790	offset = reg_offset(reg);
1791	val = ioread32(gsi->virt + offset);
1792
1793	val &= ~reg_fmask(reg, GENERIC_EE_RESULT);
1794	iowrite32(val, gsi->virt + offset);
1795
1796	/* Now issue the command */
1797	reg = gsi_reg(gsi, GENERIC_CMD);
1798	val = reg_encode(reg, GENERIC_OPCODE, opcode);
1799	val |= reg_encode(reg, GENERIC_CHID, channel_id);
1800	val |= reg_encode(reg, GENERIC_EE, GSI_EE_MODEM);
1801	if (gsi->version >= IPA_VERSION_4_11)
1802		val |= reg_encode(reg, GENERIC_PARAMS, params);
1803
1804	timeout = !gsi_command(gsi, reg_offset(reg), val);
1805
1806	/* Disable the GP_INT1 IRQ type again */
1807	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
1808	iowrite32(ERROR_INT, gsi->virt + reg_offset(reg));
1809
1810	if (!timeout)
1811		return gsi->result;
1812
1813	dev_err(gsi->dev, "GSI generic command %u to channel %u timed out\n",
1814		opcode, channel_id);
1815
1816	return -ETIMEDOUT;
1817}
1818
1819static int gsi_modem_channel_alloc(struct gsi *gsi, u32 channel_id)
1820{
1821	return gsi_generic_command(gsi, channel_id,
1822				   GSI_GENERIC_ALLOCATE_CHANNEL, 0);
1823}
1824
1825static void gsi_modem_channel_halt(struct gsi *gsi, u32 channel_id)
1826{
1827	u32 retries = GSI_CHANNEL_MODEM_HALT_RETRIES;
1828	int ret;
1829
1830	do
1831		ret = gsi_generic_command(gsi, channel_id,
1832					  GSI_GENERIC_HALT_CHANNEL, 0);
1833	while (ret == -EAGAIN && retries--);
1834
1835	if (ret)
1836		dev_err(gsi->dev, "error %d halting modem channel %u\n",
1837			ret, channel_id);
1838}
1839
1840/* Enable or disable flow control for a modem GSI TX channel (IPA v4.2+) */
1841void
1842gsi_modem_channel_flow_control(struct gsi *gsi, u32 channel_id, bool enable)
1843{
1844	u32 retries = 0;
1845	u32 command;
1846	int ret;
1847
1848	command = enable ? GSI_GENERIC_ENABLE_FLOW_CONTROL
1849			 : GSI_GENERIC_DISABLE_FLOW_CONTROL;
1850	/* Disabling flow control on IPA v4.11+ can return -EAGAIN if enable
1851	 * is underway.  In this case we need to retry the command.
1852	 */
1853	if (!enable && gsi->version >= IPA_VERSION_4_11)
1854		retries = GSI_CHANNEL_MODEM_FLOW_RETRIES;
1855
1856	do
1857		ret = gsi_generic_command(gsi, channel_id, command, 0);
1858	while (ret == -EAGAIN && retries--);
1859
1860	if (ret)
1861		dev_err(gsi->dev,
1862			"error %d %sabling mode channel %u flow control\n",
1863			ret, enable ? "en" : "dis", channel_id);
1864}
1865
1866/* Setup function for channels */
1867static int gsi_channel_setup(struct gsi *gsi)
1868{
1869	u32 channel_id = 0;
1870	u32 mask;
1871	int ret;
1872
1873	gsi_irq_enable(gsi);
1874
1875	mutex_lock(&gsi->mutex);
1876
1877	do {
1878		ret = gsi_channel_setup_one(gsi, channel_id);
1879		if (ret)
1880			goto err_unwind;
1881	} while (++channel_id < gsi->channel_count);
1882
1883	/* Make sure no channels were defined that hardware does not support */
1884	while (channel_id < GSI_CHANNEL_COUNT_MAX) {
1885		struct gsi_channel *channel = &gsi->channel[channel_id++];
1886
1887		if (!gsi_channel_initialized(channel))
1888			continue;
1889
1890		ret = -EINVAL;
1891		dev_err(gsi->dev, "channel %u not supported by hardware\n",
1892			channel_id - 1);
1893		channel_id = gsi->channel_count;
1894		goto err_unwind;
1895	}
1896
1897	/* Allocate modem channels if necessary */
1898	mask = gsi->modem_channel_bitmap;
1899	while (mask) {
1900		u32 modem_channel_id = __ffs(mask);
1901
1902		ret = gsi_modem_channel_alloc(gsi, modem_channel_id);
1903		if (ret)
1904			goto err_unwind_modem;
1905
1906		/* Clear bit from mask only after success (for unwind) */
1907		mask ^= BIT(modem_channel_id);
1908	}
1909
1910	mutex_unlock(&gsi->mutex);
1911
1912	return 0;
1913
1914err_unwind_modem:
1915	/* Compute which modem channels need to be deallocated */
1916	mask ^= gsi->modem_channel_bitmap;
1917	while (mask) {
1918		channel_id = __fls(mask);
1919
1920		mask ^= BIT(channel_id);
1921
1922		gsi_modem_channel_halt(gsi, channel_id);
1923	}
1924
1925err_unwind:
1926	while (channel_id--)
1927		gsi_channel_teardown_one(gsi, channel_id);
1928
1929	mutex_unlock(&gsi->mutex);
1930
1931	gsi_irq_disable(gsi);
1932
1933	return ret;
1934}
1935
1936/* Inverse of gsi_channel_setup() */
1937static void gsi_channel_teardown(struct gsi *gsi)
1938{
1939	u32 mask = gsi->modem_channel_bitmap;
1940	u32 channel_id;
1941
1942	mutex_lock(&gsi->mutex);
1943
1944	while (mask) {
1945		channel_id = __fls(mask);
1946
1947		mask ^= BIT(channel_id);
1948
1949		gsi_modem_channel_halt(gsi, channel_id);
1950	}
1951
1952	channel_id = gsi->channel_count - 1;
1953	do
1954		gsi_channel_teardown_one(gsi, channel_id);
1955	while (channel_id--);
1956
1957	mutex_unlock(&gsi->mutex);
1958
1959	gsi_irq_disable(gsi);
1960}
1961
1962/* Turn off all GSI interrupts initially */
1963static int gsi_irq_setup(struct gsi *gsi)
1964{
1965	const struct reg *reg;
1966	int ret;
1967
1968	/* Writing 1 indicates IRQ interrupts; 0 would be MSI */
1969	reg = gsi_reg(gsi, CNTXT_INTSET);
1970	iowrite32(reg_bit(reg, INTYPE), gsi->virt + reg_offset(reg));
1971
1972	/* Disable all interrupt types */
1973	gsi_irq_type_update(gsi, 0);
1974
1975	/* Clear all type-specific interrupt masks */
1976	reg = gsi_reg(gsi, CNTXT_SRC_CH_IRQ_MSK);
1977	iowrite32(0, gsi->virt + reg_offset(reg));
1978
1979	reg = gsi_reg(gsi, CNTXT_SRC_EV_CH_IRQ_MSK);
1980	iowrite32(0, gsi->virt + reg_offset(reg));
1981
1982	reg = gsi_reg(gsi, CNTXT_GLOB_IRQ_EN);
1983	iowrite32(0, gsi->virt + reg_offset(reg));
1984
1985	reg = gsi_reg(gsi, CNTXT_SRC_IEOB_IRQ_MSK);
1986	iowrite32(0, gsi->virt + reg_offset(reg));
1987
1988	/* The inter-EE interrupts are not supported for IPA v3.0-v3.1 */
1989	if (gsi->version > IPA_VERSION_3_1) {
1990		reg = gsi_reg(gsi, INTER_EE_SRC_CH_IRQ_MSK);
1991		iowrite32(0, gsi->virt + reg_offset(reg));
1992
1993		reg = gsi_reg(gsi, INTER_EE_SRC_EV_CH_IRQ_MSK);
1994		iowrite32(0, gsi->virt + reg_offset(reg));
1995	}
1996
1997	reg = gsi_reg(gsi, CNTXT_GSI_IRQ_EN);
1998	iowrite32(0, gsi->virt + reg_offset(reg));
1999
2000	ret = request_irq(gsi->irq, gsi_isr, 0, "gsi", gsi);
2001	if (ret)
2002		dev_err(gsi->dev, "error %d requesting \"gsi\" IRQ\n", ret);
2003
2004	return ret;
2005}
2006
2007static void gsi_irq_teardown(struct gsi *gsi)
2008{
2009	free_irq(gsi->irq, gsi);
2010}
2011
2012/* Get # supported channel and event rings; there is no gsi_ring_teardown() */
2013static int gsi_ring_setup(struct gsi *gsi)
2014{
2015	struct device *dev = gsi->dev;
2016	const struct reg *reg;
2017	u32 count;
2018	u32 val;
2019
2020	if (gsi->version < IPA_VERSION_3_5_1) {
2021		/* No HW_PARAM_2 register prior to IPA v3.5.1, assume the max */
2022		gsi->channel_count = GSI_CHANNEL_COUNT_MAX;
2023		gsi->evt_ring_count = GSI_EVT_RING_COUNT_MAX;
2024
2025		return 0;
2026	}
2027
2028	reg = gsi_reg(gsi, HW_PARAM_2);
2029	val = ioread32(gsi->virt + reg_offset(reg));
2030
2031	count = reg_decode(reg, NUM_CH_PER_EE, val);
2032	if (!count) {
2033		dev_err(dev, "GSI reports zero channels supported\n");
2034		return -EINVAL;
2035	}
2036	if (count > GSI_CHANNEL_COUNT_MAX) {
2037		dev_warn(dev, "limiting to %u channels; hardware supports %u\n",
2038			 GSI_CHANNEL_COUNT_MAX, count);
2039		count = GSI_CHANNEL_COUNT_MAX;
2040	}
2041	gsi->channel_count = count;
2042
2043	if (gsi->version < IPA_VERSION_5_0) {
2044		count = reg_decode(reg, NUM_EV_PER_EE, val);
2045	} else {
2046		reg = gsi_reg(gsi, HW_PARAM_4);
2047		count = reg_decode(reg, EV_PER_EE, val);
2048	}
2049	if (!count) {
2050		dev_err(dev, "GSI reports zero event rings supported\n");
2051		return -EINVAL;
2052	}
2053	if (count > GSI_EVT_RING_COUNT_MAX) {
2054		dev_warn(dev,
2055			 "limiting to %u event rings; hardware supports %u\n",
2056			 GSI_EVT_RING_COUNT_MAX, count);
2057		count = GSI_EVT_RING_COUNT_MAX;
2058	}
2059	gsi->evt_ring_count = count;
2060
2061	return 0;
2062}
2063
2064/* Setup function for GSI.  GSI firmware must be loaded and initialized */
2065int gsi_setup(struct gsi *gsi)
2066{
2067	const struct reg *reg;
2068	u32 val;
2069	int ret;
2070
2071	/* Here is where we first touch the GSI hardware */
2072	reg = gsi_reg(gsi, GSI_STATUS);
2073	val = ioread32(gsi->virt + reg_offset(reg));
2074	if (!(val & reg_bit(reg, ENABLED))) {
2075		dev_err(gsi->dev, "GSI has not been enabled\n");
2076		return -EIO;
2077	}
2078
2079	ret = gsi_irq_setup(gsi);
2080	if (ret)
2081		return ret;
2082
2083	ret = gsi_ring_setup(gsi);	/* No matching teardown required */
2084	if (ret)
2085		goto err_irq_teardown;
2086
2087	/* Initialize the error log */
2088	reg = gsi_reg(gsi, ERROR_LOG);
2089	iowrite32(0, gsi->virt + reg_offset(reg));
2090
2091	ret = gsi_channel_setup(gsi);
2092	if (ret)
2093		goto err_irq_teardown;
2094
2095	return 0;
2096
2097err_irq_teardown:
2098	gsi_irq_teardown(gsi);
2099
2100	return ret;
2101}
2102
2103/* Inverse of gsi_setup() */
2104void gsi_teardown(struct gsi *gsi)
2105{
2106	gsi_channel_teardown(gsi);
2107	gsi_irq_teardown(gsi);
2108}
2109
2110/* Initialize a channel's event ring */
2111static int gsi_channel_evt_ring_init(struct gsi_channel *channel)
2112{
2113	struct gsi *gsi = channel->gsi;
2114	struct gsi_evt_ring *evt_ring;
2115	int ret;
2116
2117	ret = gsi_evt_ring_id_alloc(gsi);
2118	if (ret < 0)
2119		return ret;
2120	channel->evt_ring_id = ret;
2121
2122	evt_ring = &gsi->evt_ring[channel->evt_ring_id];
2123	evt_ring->channel = channel;
2124
2125	ret = gsi_ring_alloc(gsi, &evt_ring->ring, channel->event_count);
2126	if (!ret)
2127		return 0;	/* Success! */
2128
2129	dev_err(gsi->dev, "error %d allocating channel %u event ring\n",
2130		ret, gsi_channel_id(channel));
2131
2132	gsi_evt_ring_id_free(gsi, channel->evt_ring_id);
2133
2134	return ret;
2135}
2136
2137/* Inverse of gsi_channel_evt_ring_init() */
2138static void gsi_channel_evt_ring_exit(struct gsi_channel *channel)
2139{
2140	u32 evt_ring_id = channel->evt_ring_id;
2141	struct gsi *gsi = channel->gsi;
2142	struct gsi_evt_ring *evt_ring;
2143
2144	evt_ring = &gsi->evt_ring[evt_ring_id];
2145	gsi_ring_free(gsi, &evt_ring->ring);
2146	gsi_evt_ring_id_free(gsi, evt_ring_id);
2147}
2148
2149static bool gsi_channel_data_valid(struct gsi *gsi, bool command,
2150				   const struct ipa_gsi_endpoint_data *data)
2151{
2152	const struct gsi_channel_data *channel_data;
2153	u32 channel_id = data->channel_id;
2154	struct device *dev = gsi->dev;
2155
2156	/* Make sure channel ids are in the range driver supports */
2157	if (channel_id >= GSI_CHANNEL_COUNT_MAX) {
2158		dev_err(dev, "bad channel id %u; must be less than %u\n",
2159			channel_id, GSI_CHANNEL_COUNT_MAX);
2160		return false;
2161	}
2162
2163	if (data->ee_id != GSI_EE_AP && data->ee_id != GSI_EE_MODEM) {
2164		dev_err(dev, "bad EE id %u; not AP or modem\n", data->ee_id);
2165		return false;
2166	}
2167
2168	if (command && !data->toward_ipa) {
2169		dev_err(dev, "command channel %u is not TX\n", channel_id);
2170		return false;
2171	}
2172
2173	channel_data = &data->channel;
2174
2175	if (!channel_data->tlv_count ||
2176	    channel_data->tlv_count > GSI_TLV_MAX) {
2177		dev_err(dev, "channel %u bad tlv_count %u; must be 1..%u\n",
2178			channel_id, channel_data->tlv_count, GSI_TLV_MAX);
2179		return false;
2180	}
2181
2182	if (command && IPA_COMMAND_TRANS_TRE_MAX > channel_data->tlv_count) {
2183		dev_err(dev, "command TRE max too big for channel %u (%u > %u)\n",
2184			channel_id, IPA_COMMAND_TRANS_TRE_MAX,
2185			channel_data->tlv_count);
2186		return false;
2187	}
2188
2189	/* We have to allow at least one maximally-sized transaction to
2190	 * be outstanding (which would use tlv_count TREs).  Given how
2191	 * gsi_channel_tre_max() is computed, tre_count has to be almost
2192	 * twice the TLV FIFO size to satisfy this requirement.
2193	 */
2194	if (channel_data->tre_count < 2 * channel_data->tlv_count - 1) {
2195		dev_err(dev, "channel %u TLV count %u exceeds TRE count %u\n",
2196			channel_id, channel_data->tlv_count,
2197			channel_data->tre_count);
2198		return false;
2199	}
2200
2201	if (!is_power_of_2(channel_data->tre_count)) {
2202		dev_err(dev, "channel %u bad tre_count %u; not power of 2\n",
2203			channel_id, channel_data->tre_count);
2204		return false;
2205	}
2206
2207	if (!is_power_of_2(channel_data->event_count)) {
2208		dev_err(dev, "channel %u bad event_count %u; not power of 2\n",
2209			channel_id, channel_data->event_count);
2210		return false;
2211	}
2212
2213	return true;
2214}
2215
2216/* Init function for a single channel */
2217static int gsi_channel_init_one(struct gsi *gsi,
2218				const struct ipa_gsi_endpoint_data *data,
2219				bool command)
2220{
2221	struct gsi_channel *channel;
2222	u32 tre_count;
2223	int ret;
2224
2225	if (!gsi_channel_data_valid(gsi, command, data))
2226		return -EINVAL;
2227
2228	/* Worst case we need an event for every outstanding TRE */
2229	if (data->channel.tre_count > data->channel.event_count) {
2230		tre_count = data->channel.event_count;
2231		dev_warn(gsi->dev, "channel %u limited to %u TREs\n",
2232			 data->channel_id, tre_count);
2233	} else {
2234		tre_count = data->channel.tre_count;
2235	}
2236
2237	channel = &gsi->channel[data->channel_id];
2238	memset(channel, 0, sizeof(*channel));
2239
2240	channel->gsi = gsi;
2241	channel->toward_ipa = data->toward_ipa;
2242	channel->command = command;
2243	channel->trans_tre_max = data->channel.tlv_count;
2244	channel->tre_count = tre_count;
2245	channel->event_count = data->channel.event_count;
2246
2247	ret = gsi_channel_evt_ring_init(channel);
2248	if (ret)
2249		goto err_clear_gsi;
2250
2251	ret = gsi_ring_alloc(gsi, &channel->tre_ring, data->channel.tre_count);
2252	if (ret) {
2253		dev_err(gsi->dev, "error %d allocating channel %u ring\n",
2254			ret, data->channel_id);
2255		goto err_channel_evt_ring_exit;
2256	}
2257
2258	ret = gsi_channel_trans_init(gsi, data->channel_id);
2259	if (ret)
2260		goto err_ring_free;
2261
2262	if (command) {
2263		u32 tre_max = gsi_channel_tre_max(gsi, data->channel_id);
2264
2265		ret = ipa_cmd_pool_init(channel, tre_max);
2266	}
2267	if (!ret)
2268		return 0;	/* Success! */
2269
2270	gsi_channel_trans_exit(channel);
2271err_ring_free:
2272	gsi_ring_free(gsi, &channel->tre_ring);
2273err_channel_evt_ring_exit:
2274	gsi_channel_evt_ring_exit(channel);
2275err_clear_gsi:
2276	channel->gsi = NULL;	/* Mark it not (fully) initialized */
2277
2278	return ret;
2279}
2280
2281/* Inverse of gsi_channel_init_one() */
2282static void gsi_channel_exit_one(struct gsi_channel *channel)
2283{
2284	if (!gsi_channel_initialized(channel))
2285		return;
2286
2287	if (channel->command)
2288		ipa_cmd_pool_exit(channel);
2289	gsi_channel_trans_exit(channel);
2290	gsi_ring_free(channel->gsi, &channel->tre_ring);
2291	gsi_channel_evt_ring_exit(channel);
2292}
2293
2294/* Init function for channels */
2295static int gsi_channel_init(struct gsi *gsi, u32 count,
2296			    const struct ipa_gsi_endpoint_data *data)
2297{
2298	bool modem_alloc;
2299	int ret = 0;
2300	u32 i;
2301
2302	/* IPA v4.2 requires the AP to allocate channels for the modem */
2303	modem_alloc = gsi->version == IPA_VERSION_4_2;
2304
2305	gsi->event_bitmap = gsi_event_bitmap_init(GSI_EVT_RING_COUNT_MAX);
2306	gsi->ieob_enabled_bitmap = 0;
2307
2308	/* The endpoint data array is indexed by endpoint name */
2309	for (i = 0; i < count; i++) {
2310		bool command = i == IPA_ENDPOINT_AP_COMMAND_TX;
2311
2312		if (ipa_gsi_endpoint_data_empty(&data[i]))
2313			continue;	/* Skip over empty slots */
2314
2315		/* Mark modem channels to be allocated (hardware workaround) */
2316		if (data[i].ee_id == GSI_EE_MODEM) {
2317			if (modem_alloc)
2318				gsi->modem_channel_bitmap |=
2319						BIT(data[i].channel_id);
2320			continue;
2321		}
2322
2323		ret = gsi_channel_init_one(gsi, &data[i], command);
2324		if (ret)
2325			goto err_unwind;
2326	}
2327
2328	return ret;
2329
2330err_unwind:
2331	while (i--) {
2332		if (ipa_gsi_endpoint_data_empty(&data[i]))
2333			continue;
2334		if (modem_alloc && data[i].ee_id == GSI_EE_MODEM) {
2335			gsi->modem_channel_bitmap &= ~BIT(data[i].channel_id);
2336			continue;
2337		}
2338		gsi_channel_exit_one(&gsi->channel[data->channel_id]);
2339	}
2340
2341	return ret;
2342}
2343
2344/* Inverse of gsi_channel_init() */
2345static void gsi_channel_exit(struct gsi *gsi)
2346{
2347	u32 channel_id = GSI_CHANNEL_COUNT_MAX - 1;
2348
2349	do
2350		gsi_channel_exit_one(&gsi->channel[channel_id]);
2351	while (channel_id--);
2352	gsi->modem_channel_bitmap = 0;
2353}
2354
2355/* Init function for GSI.  GSI hardware does not need to be "ready" */
2356int gsi_init(struct gsi *gsi, struct platform_device *pdev,
2357	     enum ipa_version version, u32 count,
2358	     const struct ipa_gsi_endpoint_data *data)
2359{
2360	int ret;
2361
2362	gsi_validate_build();
2363
2364	gsi->dev = &pdev->dev;
2365	gsi->version = version;
2366
2367	/* GSI uses NAPI on all channels.  Create a dummy network device
2368	 * for the channel NAPI contexts to be associated with.
2369	 */
2370	gsi->dummy_dev = alloc_netdev_dummy(0);
2371	if (!gsi->dummy_dev)
2372		return -ENOMEM;
2373	init_completion(&gsi->completion);
2374
2375	ret = gsi_reg_init(gsi, pdev);
2376	if (ret)
2377		goto err_reg_exit;
2378
2379	ret = gsi_irq_init(gsi, pdev);	/* No matching exit required */
2380	if (ret)
2381		goto err_reg_exit;
2382
2383	ret = gsi_channel_init(gsi, count, data);
2384	if (ret)
2385		goto err_reg_exit;
2386
2387	mutex_init(&gsi->mutex);
2388
2389	return 0;
2390
2391err_reg_exit:
2392	free_netdev(gsi->dummy_dev);
2393	gsi_reg_exit(gsi);
2394
2395	return ret;
2396}
2397
2398/* Inverse of gsi_init() */
2399void gsi_exit(struct gsi *gsi)
2400{
2401	mutex_destroy(&gsi->mutex);
2402	gsi_channel_exit(gsi);
2403	free_netdev(gsi->dummy_dev);
2404	gsi_reg_exit(gsi);
2405}
2406
2407/* The maximum number of outstanding TREs on a channel.  This limits
2408 * a channel's maximum number of transactions outstanding (worst case
2409 * is one TRE per transaction).
2410 *
2411 * The absolute limit is the number of TREs in the channel's TRE ring,
2412 * and in theory we should be able use all of them.  But in practice,
2413 * doing that led to the hardware reporting exhaustion of event ring
2414 * slots for writing completion information.  So the hardware limit
2415 * would be (tre_count - 1).
2416 *
2417 * We reduce it a bit further though.  Transaction resource pools are
2418 * sized to be a little larger than this maximum, to allow resource
2419 * allocations to always be contiguous.  The number of entries in a
2420 * TRE ring buffer is a power of 2, and the extra resources in a pool
2421 * tends to nearly double the memory allocated for it.  Reducing the
2422 * maximum number of outstanding TREs allows the number of entries in
2423 * a pool to avoid crossing that power-of-2 boundary, and this can
2424 * substantially reduce pool memory requirements.  The number we
2425 * reduce it by matches the number added in gsi_trans_pool_init().
2426 */
2427u32 gsi_channel_tre_max(struct gsi *gsi, u32 channel_id)
2428{
2429	struct gsi_channel *channel = &gsi->channel[channel_id];
2430
2431	/* Hardware limit is channel->tre_count - 1 */
2432	return channel->tre_count - (channel->trans_tre_max - 1);
2433}