1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2016 Broadcom
   4 */
   5
   6/*
   7 * Broadcom PDC Mailbox Driver
   8 * The PDC provides a ring based programming interface to one or more hardware
   9 * offload engines. For example, the PDC driver works with both SPU-M and SPU2
  10 * cryptographic offload hardware. In some chips the PDC is referred to as MDE,
  11 * and in others the FA2/FA+ hardware is used with this PDC driver.
  12 *
  13 * The PDC driver registers with the Linux mailbox framework as a mailbox
  14 * controller, once for each PDC instance. Ring 0 for each PDC is registered as
  15 * a mailbox channel. The PDC driver uses interrupts to determine when data
  16 * transfers to and from an offload engine are complete. The PDC driver uses
  17 * threaded IRQs so that response messages are handled outside of interrupt
  18 * context.
  19 *
  20 * The PDC driver allows multiple messages to be pending in the descriptor
  21 * rings. The tx_msg_start descriptor index indicates where the last message
  22 * starts. The txin_numd value at this index indicates how many descriptor
  23 * indexes make up the message. Similar state is kept on the receive side. When
  24 * an rx interrupt indicates a response is ready, the PDC driver processes numd
  25 * descriptors from the tx and rx ring, thus processing one response at a time.
  26 */
  27
  28#include <linux/errno.h>
  29#include <linux/module.h>
  30#include <linux/init.h>
  31#include <linux/slab.h>
  32#include <linux/debugfs.h>
  33#include <linux/interrupt.h>
  34#include <linux/wait.h>
  35#include <linux/platform_device.h>
  36#include <linux/io.h>
  37#include <linux/of.h>
  38#include <linux/of_device.h>
  39#include <linux/of_address.h>
  40#include <linux/of_irq.h>
  41#include <linux/mailbox_controller.h>
  42#include <linux/mailbox/brcm-message.h>
  43#include <linux/scatterlist.h>
  44#include <linux/dma-direction.h>
  45#include <linux/dma-mapping.h>
  46#include <linux/dmapool.h>
  47
  48#define PDC_SUCCESS  0
  49
  50#define RING_ENTRY_SIZE   sizeof(struct dma64dd)
  51
  52/* # entries in PDC dma ring */
  53#define PDC_RING_ENTRIES  512
  54/*
  55 * Minimum number of ring descriptor entries that must be free to tell mailbox
  56 * framework that it can submit another request
  57 */
  58#define PDC_RING_SPACE_MIN  15
  59
  60#define PDC_RING_SIZE    (PDC_RING_ENTRIES * RING_ENTRY_SIZE)
  61/* Rings are 8k aligned */
  62#define RING_ALIGN_ORDER  13
  63#define RING_ALIGN        BIT(RING_ALIGN_ORDER)
  64
  65#define RX_BUF_ALIGN_ORDER  5
  66#define RX_BUF_ALIGN	    BIT(RX_BUF_ALIGN_ORDER)
  67
  68/* descriptor bumping macros */
  69#define XXD(x, max_mask)              ((x) & (max_mask))
  70#define TXD(x, max_mask)              XXD((x), (max_mask))
  71#define RXD(x, max_mask)              XXD((x), (max_mask))
  72#define NEXTTXD(i, max_mask)          TXD((i) + 1, (max_mask))
  73#define PREVTXD(i, max_mask)          TXD((i) - 1, (max_mask))
  74#define NEXTRXD(i, max_mask)          RXD((i) + 1, (max_mask))
  75#define PREVRXD(i, max_mask)          RXD((i) - 1, (max_mask))
  76#define NTXDACTIVE(h, t, max_mask)    TXD((t) - (h), (max_mask))
  77#define NRXDACTIVE(h, t, max_mask)    RXD((t) - (h), (max_mask))
  78
  79/* Length of BCM header at start of SPU msg, in bytes */
  80#define BCM_HDR_LEN  8
  81
  82/*
  83 * PDC driver reserves ringset 0 on each SPU for its own use. The driver does
  84 * not currently support use of multiple ringsets on a single PDC engine.
  85 */
  86#define PDC_RINGSET  0
  87
  88/*
  89 * Interrupt mask and status definitions. Enable interrupts for tx and rx on
  90 * ring 0
  91 */
  92#define PDC_RCVINT_0         (16 + PDC_RINGSET)
  93#define PDC_RCVINTEN_0       BIT(PDC_RCVINT_0)
  94#define PDC_INTMASK	     (PDC_RCVINTEN_0)
  95#define PDC_LAZY_FRAMECOUNT  1
  96#define PDC_LAZY_TIMEOUT     10000
  97#define PDC_LAZY_INT  (PDC_LAZY_TIMEOUT | (PDC_LAZY_FRAMECOUNT << 24))
  98#define PDC_INTMASK_OFFSET   0x24
  99#define PDC_INTSTATUS_OFFSET 0x20
 100#define PDC_RCVLAZY0_OFFSET  (0x30 + 4 * PDC_RINGSET)
 101#define FA_RCVLAZY0_OFFSET   0x100
 102
 103/*
 104 * For SPU2, configure MDE_CKSUM_CONTROL to write 17 bytes of metadata
 105 * before frame
 106 */
 107#define PDC_SPU2_RESP_HDR_LEN  17
 108#define PDC_CKSUM_CTRL         BIT(27)
 109#define PDC_CKSUM_CTRL_OFFSET  0x400
 110
 111#define PDC_SPUM_RESP_HDR_LEN  32
 112
 113/*
 114 * Sets the following bits for write to transmit control reg:
 115 * 11    - PtyChkDisable - parity check is disabled
 116 * 20:18 - BurstLen = 3 -> 2^7 = 128 byte data reads from memory
 117 */
 118#define PDC_TX_CTL		0x000C0800
 119
 120/* Bit in tx control reg to enable tx channel */
 121#define PDC_TX_ENABLE		0x1
 122
 123/*
 124 * Sets the following bits for write to receive control reg:
 125 * 7:1   - RcvOffset - size in bytes of status region at start of rx frame buf
 126 * 9     - SepRxHdrDescEn - place start of new frames only in descriptors
 127 *                          that have StartOfFrame set
 128 * 10    - OflowContinue - on rx FIFO overflow, clear rx fifo, discard all
 129 *                         remaining bytes in current frame, report error
 130 *                         in rx frame status for current frame
 131 * 11    - PtyChkDisable - parity check is disabled
 132 * 20:18 - BurstLen = 3 -> 2^7 = 128 byte data reads from memory
 133 */
 134#define PDC_RX_CTL		0x000C0E00
 135
 136/* Bit in rx control reg to enable rx channel */
 137#define PDC_RX_ENABLE		0x1
 138
 139#define CRYPTO_D64_RS0_CD_MASK   ((PDC_RING_ENTRIES * RING_ENTRY_SIZE) - 1)
 140
 141/* descriptor flags */
 142#define D64_CTRL1_EOT   BIT(28)	/* end of descriptor table */
 143#define D64_CTRL1_IOC   BIT(29)	/* interrupt on complete */
 144#define D64_CTRL1_EOF   BIT(30)	/* end of frame */
 145#define D64_CTRL1_SOF   BIT(31)	/* start of frame */
 146
 147#define RX_STATUS_OVERFLOW       0x00800000
 148#define RX_STATUS_LEN            0x0000FFFF
 149
 150#define PDC_TXREGS_OFFSET  0x200
 151#define PDC_RXREGS_OFFSET  0x220
 152
 153/* Maximum size buffer the DMA engine can handle */
 154#define PDC_DMA_BUF_MAX 16384
 155
 156enum pdc_hw {
 157	FA_HW,		/* FA2/FA+ hardware (i.e. Northstar Plus) */
 158	PDC_HW		/* PDC/MDE hardware (i.e. Northstar 2, Pegasus) */
 159};
 160
 161struct pdc_dma_map {
 162	void *ctx;          /* opaque context associated with frame */
 163};
 164
 165/* dma descriptor */
 166struct dma64dd {
 167	u32 ctrl1;      /* misc control bits */
 168	u32 ctrl2;      /* buffer count and address extension */
 169	u32 addrlow;    /* memory address of the date buffer, bits 31:0 */
 170	u32 addrhigh;   /* memory address of the date buffer, bits 63:32 */
 171};
 172
 173/* dma registers per channel(xmt or rcv) */
 174struct dma64_regs {
 175	u32  control;   /* enable, et al */
 176	u32  ptr;       /* last descriptor posted to chip */
 177	u32  addrlow;   /* descriptor ring base address low 32-bits */
 178	u32  addrhigh;  /* descriptor ring base address bits 63:32 */
 179	u32  status0;   /* last rx descriptor written by hw */
 180	u32  status1;   /* driver does not use */
 181};
 182
 183/* cpp contortions to concatenate w/arg prescan */
 184#ifndef PAD
 185#define _PADLINE(line)  pad ## line
 186#define _XSTR(line)     _PADLINE(line)
 187#define PAD             _XSTR(__LINE__)
 188#endif  /* PAD */
 189
 190/* dma registers. matches hw layout. */
 191struct dma64 {
 192	struct dma64_regs dmaxmt;  /* dma tx */
 193	u32          PAD[2];
 194	struct dma64_regs dmarcv;  /* dma rx */
 195	u32          PAD[2];
 196};
 197
 198/* PDC registers */
 199struct pdc_regs {
 200	u32  devcontrol;             /* 0x000 */
 201	u32  devstatus;              /* 0x004 */
 202	u32  PAD;
 203	u32  biststatus;             /* 0x00c */
 204	u32  PAD[4];
 205	u32  intstatus;              /* 0x020 */
 206	u32  intmask;                /* 0x024 */
 207	u32  gptimer;                /* 0x028 */
 208
 209	u32  PAD;
 210	u32  intrcvlazy_0;           /* 0x030 (Only in PDC, not FA2) */
 211	u32  intrcvlazy_1;           /* 0x034 (Only in PDC, not FA2) */
 212	u32  intrcvlazy_2;           /* 0x038 (Only in PDC, not FA2) */
 213	u32  intrcvlazy_3;           /* 0x03c (Only in PDC, not FA2) */
 214
 215	u32  PAD[48];
 216	u32  fa_intrecvlazy;         /* 0x100 (Only in FA2, not PDC) */
 217	u32  flowctlthresh;          /* 0x104 */
 218	u32  wrrthresh;              /* 0x108 */
 219	u32  gmac_idle_cnt_thresh;   /* 0x10c */
 220
 221	u32  PAD[4];
 222	u32  ifioaccessaddr;         /* 0x120 */
 223	u32  ifioaccessbyte;         /* 0x124 */
 224	u32  ifioaccessdata;         /* 0x128 */
 225
 226	u32  PAD[21];
 227	u32  phyaccess;              /* 0x180 */
 228	u32  PAD;
 229	u32  phycontrol;             /* 0x188 */
 230	u32  txqctl;                 /* 0x18c */
 231	u32  rxqctl;                 /* 0x190 */
 232	u32  gpioselect;             /* 0x194 */
 233	u32  gpio_output_en;         /* 0x198 */
 234	u32  PAD;                    /* 0x19c */
 235	u32  txq_rxq_mem_ctl;        /* 0x1a0 */
 236	u32  memory_ecc_status;      /* 0x1a4 */
 237	u32  serdes_ctl;             /* 0x1a8 */
 238	u32  serdes_status0;         /* 0x1ac */
 239	u32  serdes_status1;         /* 0x1b0 */
 240	u32  PAD[11];                /* 0x1b4-1dc */
 241	u32  clk_ctl_st;             /* 0x1e0 */
 242	u32  hw_war;                 /* 0x1e4 (Only in PDC, not FA2) */
 243	u32  pwrctl;                 /* 0x1e8 */
 244	u32  PAD[5];
 245
 246#define PDC_NUM_DMA_RINGS   4
 247	struct dma64 dmaregs[PDC_NUM_DMA_RINGS];  /* 0x0200 - 0x2fc */
 248
 249	/* more registers follow, but we don't use them */
 250};
 251
 252/* structure for allocating/freeing DMA rings */
 253struct pdc_ring_alloc {
 254	dma_addr_t  dmabase; /* DMA address of start of ring */
 255	void	   *vbase;   /* base kernel virtual address of ring */
 256	u32	    size;    /* ring allocation size in bytes */
 257};
 258
 259/*
 260 * context associated with a receive descriptor.
 261 * @rxp_ctx: opaque context associated with frame that starts at each
 262 *           rx ring index.
 263 * @dst_sg:  Scatterlist used to form reply frames beginning at a given ring
 264 *           index. Retained in order to unmap each sg after reply is processed.
 265 * @rxin_numd: Number of rx descriptors associated with the message that starts
 266 *             at a descriptor index. Not set for every index. For example,
 267 *             if descriptor index i points to a scatterlist with 4 entries,
 268 *             then the next three descriptor indexes don't have a value set.
 269 * @resp_hdr: Virtual address of buffer used to catch DMA rx status
 270 * @resp_hdr_daddr: physical address of DMA rx status buffer
 271 */
 272struct pdc_rx_ctx {
 273	void *rxp_ctx;
 274	struct scatterlist *dst_sg;
 275	u32  rxin_numd;
 276	void *resp_hdr;
 277	dma_addr_t resp_hdr_daddr;
 278};
 279
 280/* PDC state structure */
 281struct pdc_state {
 282	/* Index of the PDC whose state is in this structure instance */
 283	u8 pdc_idx;
 284
 285	/* Platform device for this PDC instance */
 286	struct platform_device *pdev;
 287
 288	/*
 289	 * Each PDC instance has a mailbox controller. PDC receives request
 290	 * messages through mailboxes, and sends response messages through the
 291	 * mailbox framework.
 292	 */
 293	struct mbox_controller mbc;
 294
 295	unsigned int pdc_irq;
 296
 297	/* tasklet for deferred processing after DMA rx interrupt */
 298	struct tasklet_struct rx_tasklet;
 299
 300	/* Number of bytes of receive status prior to each rx frame */
 301	u32 rx_status_len;
 302	/* Whether a BCM header is prepended to each frame */
 303	bool use_bcm_hdr;
 304	/* Sum of length of BCM header and rx status header */
 305	u32 pdc_resp_hdr_len;
 306
 307	/* The base virtual address of DMA hw registers */
 308	void __iomem *pdc_reg_vbase;
 309
 310	/* Pool for allocation of DMA rings */
 311	struct dma_pool *ring_pool;
 312
 313	/* Pool for allocation of metadata buffers for response messages */
 314	struct dma_pool *rx_buf_pool;
 315
 316	/*
 317	 * The base virtual address of DMA tx/rx descriptor rings. Corresponding
 318	 * DMA address and size of ring allocation.
 319	 */
 320	struct pdc_ring_alloc tx_ring_alloc;
 321	struct pdc_ring_alloc rx_ring_alloc;
 322
 323	struct pdc_regs *regs;    /* start of PDC registers */
 324
 325	struct dma64_regs *txregs_64; /* dma tx engine registers */
 326	struct dma64_regs *rxregs_64; /* dma rx engine registers */
 327
 328	/*
 329	 * Arrays of PDC_RING_ENTRIES descriptors
 330	 * To use multiple ringsets, this needs to be extended
 331	 */
 332	struct dma64dd   *txd_64;  /* tx descriptor ring */
 333	struct dma64dd   *rxd_64;  /* rx descriptor ring */
 334
 335	/* descriptor ring sizes */
 336	u32      ntxd;       /* # tx descriptors */
 337	u32      nrxd;       /* # rx descriptors */
 338	u32      nrxpost;    /* # rx buffers to keep posted */
 339	u32      ntxpost;    /* max number of tx buffers that can be posted */
 340
 341	/*
 342	 * Index of next tx descriptor to reclaim. That is, the descriptor
 343	 * index of the oldest tx buffer for which the host has yet to process
 344	 * the corresponding response.
 345	 */
 346	u32  txin;
 347
 348	/*
 349	 * Index of the first receive descriptor for the sequence of
 350	 * message fragments currently under construction. Used to build up
 351	 * the rxin_numd count for a message. Updated to rxout when the host
 352	 * starts a new sequence of rx buffers for a new message.
 353	 */
 354	u32  tx_msg_start;
 355
 356	/* Index of next tx descriptor to post. */
 357	u32  txout;
 358
 359	/*
 360	 * Number of tx descriptors associated with the message that starts
 361	 * at this tx descriptor index.
 362	 */
 363	u32      txin_numd[PDC_RING_ENTRIES];
 364
 365	/*
 366	 * Index of next rx descriptor to reclaim. This is the index of
 367	 * the next descriptor whose data has yet to be processed by the host.
 368	 */
 369	u32  rxin;
 370
 371	/*
 372	 * Index of the first receive descriptor for the sequence of
 373	 * message fragments currently under construction. Used to build up
 374	 * the rxin_numd count for a message. Updated to rxout when the host
 375	 * starts a new sequence of rx buffers for a new message.
 376	 */
 377	u32  rx_msg_start;
 378
 379	/*
 380	 * Saved value of current hardware rx descriptor index.
 381	 * The last rx buffer written by the hw is the index previous to
 382	 * this one.
 383	 */
 384	u32  last_rx_curr;
 385
 386	/* Index of next rx descriptor to post. */
 387	u32  rxout;
 388
 389	struct pdc_rx_ctx rx_ctx[PDC_RING_ENTRIES];
 390
 391	/*
 392	 * Scatterlists used to form request and reply frames beginning at a
 393	 * given ring index. Retained in order to unmap each sg after reply
 394	 * is processed
 395	 */
 396	struct scatterlist *src_sg[PDC_RING_ENTRIES];
 397
 398	/* counters */
 399	u32  pdc_requests;     /* number of request messages submitted */
 400	u32  pdc_replies;      /* number of reply messages received */
 401	u32  last_tx_not_done; /* too few tx descriptors to indicate done */
 402	u32  tx_ring_full;     /* unable to accept msg because tx ring full */
 403	u32  rx_ring_full;     /* unable to accept msg because rx ring full */
 404	u32  txnobuf;          /* unable to create tx descriptor */
 405	u32  rxnobuf;          /* unable to create rx descriptor */
 406	u32  rx_oflow;         /* count of rx overflows */
 407
 408	/* hardware type - FA2 or PDC/MDE */
 409	enum pdc_hw hw_type;
 410};
 411
 412/* Global variables */
 413
 414struct pdc_globals {
 415	/* Actual number of SPUs in hardware, as reported by device tree */
 416	u32 num_spu;
 417};
 418
 419static struct pdc_globals pdcg;
 420
 421/* top level debug FS directory for PDC driver */
 422static struct dentry *debugfs_dir;
 423
 424static ssize_t pdc_debugfs_read(struct file *filp, char __user *ubuf,
 425				size_t count, loff_t *offp)
 426{
 427	struct pdc_state *pdcs;
 428	char *buf;
 429	ssize_t ret, out_offset, out_count;
 430
 431	out_count = 512;
 432
 433	buf = kmalloc(out_count, GFP_KERNEL);
 434	if (!buf)
 435		return -ENOMEM;
 436
 437	pdcs = filp->private_data;
 438	out_offset = 0;
 439	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 440			       "SPU %u stats:\n", pdcs->pdc_idx);
 441	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 442			       "PDC requests....................%u\n",
 443			       pdcs->pdc_requests);
 444	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 445			       "PDC responses...................%u\n",
 446			       pdcs->pdc_replies);
 447	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 448			       "Tx not done.....................%u\n",
 449			       pdcs->last_tx_not_done);
 450	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 451			       "Tx ring full....................%u\n",
 452			       pdcs->tx_ring_full);
 453	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 454			       "Rx ring full....................%u\n",
 455			       pdcs->rx_ring_full);
 456	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 457			       "Tx desc write fail. Ring full...%u\n",
 458			       pdcs->txnobuf);
 459	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 460			       "Rx desc write fail. Ring full...%u\n",
 461			       pdcs->rxnobuf);
 462	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 463			       "Receive overflow................%u\n",
 464			       pdcs->rx_oflow);
 465	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
 466			       "Num frags in rx ring............%u\n",
 467			       NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr,
 468					  pdcs->nrxpost));
 469
 470	if (out_offset > out_count)
 471		out_offset = out_count;
 472
 473	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 474	kfree(buf);
 475	return ret;
 476}
 477
 478static const struct file_operations pdc_debugfs_stats = {
 479	.owner = THIS_MODULE,
 480	.open = simple_open,
 481	.read = pdc_debugfs_read,
 482};
 483
 484/**
 485 * pdc_setup_debugfs() - Create the debug FS directories. If the top-level
 486 * directory has not yet been created, create it now. Create a stats file in
 487 * this directory for a SPU.
 488 * @pdcs: PDC state structure
 489 */
 490static void pdc_setup_debugfs(struct pdc_state *pdcs)
 491{
 492	char spu_stats_name[16];
 493
 494	if (!debugfs_initialized())
 495		return;
 496
 497	snprintf(spu_stats_name, 16, "pdc%d_stats", pdcs->pdc_idx);
 498	if (!debugfs_dir)
 499		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 500
 501	/* S_IRUSR == 0400 */
 502	debugfs_create_file(spu_stats_name, 0400, debugfs_dir, pdcs,
 503			    &pdc_debugfs_stats);
 504}
 505
 506static void pdc_free_debugfs(void)
 507{
 508	debugfs_remove_recursive(debugfs_dir);
 509	debugfs_dir = NULL;
 510}
 511
 512/**
 513 * pdc_build_rxd() - Build DMA descriptor to receive SPU result.
 514 * @pdcs:      PDC state for SPU that will generate result
 515 * @dma_addr:  DMA address of buffer that descriptor is being built for
 516 * @buf_len:   Length of the receive buffer, in bytes
 517 * @flags:     Flags to be stored in descriptor
 518 */
 519static inline void
 520pdc_build_rxd(struct pdc_state *pdcs, dma_addr_t dma_addr,
 521	      u32 buf_len, u32 flags)
 522{
 523	struct device *dev = &pdcs->pdev->dev;
 524	struct dma64dd *rxd = &pdcs->rxd_64[pdcs->rxout];
 525
 526	dev_dbg(dev,
 527		"Writing rx descriptor for PDC %u at index %u with length %u. flags %#x\n",
 528		pdcs->pdc_idx, pdcs->rxout, buf_len, flags);
 529
 530	rxd->addrlow = cpu_to_le32(lower_32_bits(dma_addr));
 531	rxd->addrhigh = cpu_to_le32(upper_32_bits(dma_addr));
 532	rxd->ctrl1 = cpu_to_le32(flags);
 533	rxd->ctrl2 = cpu_to_le32(buf_len);
 534
 535	/* bump ring index and return */
 536	pdcs->rxout = NEXTRXD(pdcs->rxout, pdcs->nrxpost);
 537}
 538
 539/**
 540 * pdc_build_txd() - Build a DMA descriptor to transmit a SPU request to
 541 * hardware.
 542 * @pdcs:        PDC state for the SPU that will process this request
 543 * @dma_addr:    DMA address of packet to be transmitted
 544 * @buf_len:     Length of tx buffer, in bytes
 545 * @flags:       Flags to be stored in descriptor
 546 */
 547static inline void
 548pdc_build_txd(struct pdc_state *pdcs, dma_addr_t dma_addr, u32 buf_len,
 549	      u32 flags)
 550{
 551	struct device *dev = &pdcs->pdev->dev;
 552	struct dma64dd *txd = &pdcs->txd_64[pdcs->txout];
 553
 554	dev_dbg(dev,
 555		"Writing tx descriptor for PDC %u at index %u with length %u, flags %#x\n",
 556		pdcs->pdc_idx, pdcs->txout, buf_len, flags);
 557
 558	txd->addrlow = cpu_to_le32(lower_32_bits(dma_addr));
 559	txd->addrhigh = cpu_to_le32(upper_32_bits(dma_addr));
 560	txd->ctrl1 = cpu_to_le32(flags);
 561	txd->ctrl2 = cpu_to_le32(buf_len);
 562
 563	/* bump ring index and return */
 564	pdcs->txout = NEXTTXD(pdcs->txout, pdcs->ntxpost);
 565}
 566
 567/**
 568 * pdc_receive_one() - Receive a response message from a given SPU.
 569 * @pdcs:    PDC state for the SPU to receive from
 570 *
 571 * When the return code indicates success, the response message is available in
 572 * the receive buffers provided prior to submission of the request.
 573 *
 574 * Return:  PDC_SUCCESS if one or more receive descriptors was processed
 575 *          -EAGAIN indicates that no response message is available
 576 *          -EIO an error occurred
 577 */
 578static int
 579pdc_receive_one(struct pdc_state *pdcs)
 580{
 581	struct device *dev = &pdcs->pdev->dev;
 582	struct mbox_controller *mbc;
 583	struct mbox_chan *chan;
 584	struct brcm_message mssg;
 585	u32 len, rx_status;
 586	u32 num_frags;
 587	u8 *resp_hdr;    /* virtual addr of start of resp message DMA header */
 588	u32 frags_rdy;   /* number of fragments ready to read */
 589	u32 rx_idx;      /* ring index of start of receive frame */
 590	dma_addr_t resp_hdr_daddr;
 591	struct pdc_rx_ctx *rx_ctx;
 592
 593	mbc = &pdcs->mbc;
 594	chan = &mbc->chans[0];
 595	mssg.type = BRCM_MESSAGE_SPU;
 596
 597	/*
 598	 * return if a complete response message is not yet ready.
 599	 * rxin_numd[rxin] is the number of fragments in the next msg
 600	 * to read.
 601	 */
 602	frags_rdy = NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr, pdcs->nrxpost);
 603	if ((frags_rdy == 0) ||
 604	    (frags_rdy < pdcs->rx_ctx[pdcs->rxin].rxin_numd))
 605		/* No response ready */
 606		return -EAGAIN;
 607
 608	num_frags = pdcs->txin_numd[pdcs->txin];
 609	WARN_ON(num_frags == 0);
 610
 611	dma_unmap_sg(dev, pdcs->src_sg[pdcs->txin],
 612		     sg_nents(pdcs->src_sg[pdcs->txin]), DMA_TO_DEVICE);
 613
 614	pdcs->txin = (pdcs->txin + num_frags) & pdcs->ntxpost;
 615
 616	dev_dbg(dev, "PDC %u reclaimed %d tx descriptors",
 617		pdcs->pdc_idx, num_frags);
 618
 619	rx_idx = pdcs->rxin;
 620	rx_ctx = &pdcs->rx_ctx[rx_idx];
 621	num_frags = rx_ctx->rxin_numd;
 622	/* Return opaque context with result */
 623	mssg.ctx = rx_ctx->rxp_ctx;
 624	rx_ctx->rxp_ctx = NULL;
 625	resp_hdr = rx_ctx->resp_hdr;
 626	resp_hdr_daddr = rx_ctx->resp_hdr_daddr;
 627	dma_unmap_sg(dev, rx_ctx->dst_sg, sg_nents(rx_ctx->dst_sg),
 628		     DMA_FROM_DEVICE);
 629
 630	pdcs->rxin = (pdcs->rxin + num_frags) & pdcs->nrxpost;
 631
 632	dev_dbg(dev, "PDC %u reclaimed %d rx descriptors",
 633		pdcs->pdc_idx, num_frags);
 634
 635	dev_dbg(dev,
 636		"PDC %u txin %u, txout %u, rxin %u, rxout %u, last_rx_curr %u\n",
 637		pdcs->pdc_idx, pdcs->txin, pdcs->txout, pdcs->rxin,
 638		pdcs->rxout, pdcs->last_rx_curr);
 639
 640	if (pdcs->pdc_resp_hdr_len == PDC_SPUM_RESP_HDR_LEN) {
 641		/*
 642		 * For SPU-M, get length of response msg and rx overflow status.
 643		 */
 644		rx_status = *((u32 *)resp_hdr);
 645		len = rx_status & RX_STATUS_LEN;
 646		dev_dbg(dev,
 647			"SPU response length %u bytes", len);
 648		if (unlikely(((rx_status & RX_STATUS_OVERFLOW) || (!len)))) {
 649			if (rx_status & RX_STATUS_OVERFLOW) {
 650				dev_err_ratelimited(dev,
 651						    "crypto receive overflow");
 652				pdcs->rx_oflow++;
 653			} else {
 654				dev_info_ratelimited(dev, "crypto rx len = 0");
 655			}
 656			return -EIO;
 657		}
 658	}
 659
 660	dma_pool_free(pdcs->rx_buf_pool, resp_hdr, resp_hdr_daddr);
 661
 662	mbox_chan_received_data(chan, &mssg);
 663
 664	pdcs->pdc_replies++;
 665	return PDC_SUCCESS;
 666}
 667
 668/**
 669 * pdc_receive() - Process as many responses as are available in the rx ring.
 670 * @pdcs:  PDC state
 671 *
 672 * Called within the hard IRQ.
 673 * Return:
 674 */
 675static int
 676pdc_receive(struct pdc_state *pdcs)
 677{
 678	int rx_status;
 679
 680	/* read last_rx_curr from register once */
 681	pdcs->last_rx_curr =
 682	    (ioread32((const void __iomem *)&pdcs->rxregs_64->status0) &
 683	     CRYPTO_D64_RS0_CD_MASK) / RING_ENTRY_SIZE;
 684
 685	do {
 686		/* Could be many frames ready */
 687		rx_status = pdc_receive_one(pdcs);
 688	} while (rx_status == PDC_SUCCESS);
 689
 690	return 0;
 691}
 692
 693/**
 694 * pdc_tx_list_sg_add() - Add the buffers in a scatterlist to the transmit
 695 * descriptors for a given SPU. The scatterlist buffers contain the data for a
 696 * SPU request message.
 697 * @spu_idx:   The index of the SPU to submit the request to, [0, max_spu)
 698 * @sg:        Scatterlist whose buffers contain part of the SPU request
 699 *
 700 * If a scatterlist buffer is larger than PDC_DMA_BUF_MAX, multiple descriptors
 701 * are written for that buffer, each <= PDC_DMA_BUF_MAX byte in length.
 702 *
 703 * Return: PDC_SUCCESS if successful
 704 *         < 0 otherwise
 705 */
 706static int pdc_tx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
 707{
 708	u32 flags = 0;
 709	u32 eot;
 710	u32 tx_avail;
 711
 712	/*
 713	 * Num descriptors needed. Conservatively assume we need a descriptor
 714	 * for every entry in sg.
 715	 */
 716	u32 num_desc;
 717	u32 desc_w = 0;	/* Number of tx descriptors written */
 718	u32 bufcnt;	/* Number of bytes of buffer pointed to by descriptor */
 719	dma_addr_t databufptr;	/* DMA address to put in descriptor */
 720
 721	num_desc = (u32)sg_nents(sg);
 722
 723	/* check whether enough tx descriptors are available */
 724	tx_avail = pdcs->ntxpost - NTXDACTIVE(pdcs->txin, pdcs->txout,
 725					      pdcs->ntxpost);
 726	if (unlikely(num_desc > tx_avail)) {
 727		pdcs->txnobuf++;
 728		return -ENOSPC;
 729	}
 730
 731	/* build tx descriptors */
 732	if (pdcs->tx_msg_start == pdcs->txout) {
 733		/* Start of frame */
 734		pdcs->txin_numd[pdcs->tx_msg_start] = 0;
 735		pdcs->src_sg[pdcs->txout] = sg;
 736		flags = D64_CTRL1_SOF;
 737	}
 738
 739	while (sg) {
 740		if (unlikely(pdcs->txout == (pdcs->ntxd - 1)))
 741			eot = D64_CTRL1_EOT;
 742		else
 743			eot = 0;
 744
 745		/*
 746		 * If sg buffer larger than PDC limit, split across
 747		 * multiple descriptors
 748		 */
 749		bufcnt = sg_dma_len(sg);
 750		databufptr = sg_dma_address(sg);
 751		while (bufcnt > PDC_DMA_BUF_MAX) {
 752			pdc_build_txd(pdcs, databufptr, PDC_DMA_BUF_MAX,
 753				      flags | eot);
 754			desc_w++;
 755			bufcnt -= PDC_DMA_BUF_MAX;
 756			databufptr += PDC_DMA_BUF_MAX;
 757			if (unlikely(pdcs->txout == (pdcs->ntxd - 1)))
 758				eot = D64_CTRL1_EOT;
 759			else
 760				eot = 0;
 761		}
 762		sg = sg_next(sg);
 763		if (!sg)
 764			/* Writing last descriptor for frame */
 765			flags |= (D64_CTRL1_EOF | D64_CTRL1_IOC);
 766		pdc_build_txd(pdcs, databufptr, bufcnt, flags | eot);
 767		desc_w++;
 768		/* Clear start of frame after first descriptor */
 769		flags &= ~D64_CTRL1_SOF;
 770	}
 771	pdcs->txin_numd[pdcs->tx_msg_start] += desc_w;
 772
 773	return PDC_SUCCESS;
 774}
 775
 776/**
 777 * pdc_tx_list_final() - Initiate DMA transfer of last frame written to tx
 778 * ring.
 779 * @pdcs:  PDC state for SPU to process the request
 780 *
 781 * Sets the index of the last descriptor written in both the rx and tx ring.
 782 *
 783 * Return: PDC_SUCCESS
 784 */
 785static int pdc_tx_list_final(struct pdc_state *pdcs)
 786{
 787	/*
 788	 * write barrier to ensure all register writes are complete
 789	 * before chip starts to process new request
 790	 */
 791	wmb();
 792	iowrite32(pdcs->rxout << 4, &pdcs->rxregs_64->ptr);
 793	iowrite32(pdcs->txout << 4, &pdcs->txregs_64->ptr);
 794	pdcs->pdc_requests++;
 795
 796	return PDC_SUCCESS;
 797}
 798
 799/**
 800 * pdc_rx_list_init() - Start a new receive descriptor list for a given PDC.
 801 * @pdcs:   PDC state for SPU handling request
 802 * @dst_sg: scatterlist providing rx buffers for response to be returned to
 803 *	    mailbox client
 804 * @ctx:    Opaque context for this request
 805 *
 806 * Posts a single receive descriptor to hold the metadata that precedes a
 807 * response. For example, with SPU-M, the metadata is a 32-byte DMA header and
 808 * an 8-byte BCM header. Moves the msg_start descriptor indexes for both tx and
 809 * rx to indicate the start of a new message.
 810 *
 811 * Return:  PDC_SUCCESS if successful
 812 *          < 0 if an error (e.g., rx ring is full)
 813 */
 814static int pdc_rx_list_init(struct pdc_state *pdcs, struct scatterlist *dst_sg,
 815			    void *ctx)
 816{
 817	u32 flags = 0;
 818	u32 rx_avail;
 819	u32 rx_pkt_cnt = 1;	/* Adding a single rx buffer */
 820	dma_addr_t daddr;
 821	void *vaddr;
 822	struct pdc_rx_ctx *rx_ctx;
 823
 824	rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
 825					      pdcs->nrxpost);
 826	if (unlikely(rx_pkt_cnt > rx_avail)) {
 827		pdcs->rxnobuf++;
 828		return -ENOSPC;
 829	}
 830
 831	/* allocate a buffer for the dma rx status */
 832	vaddr = dma_pool_zalloc(pdcs->rx_buf_pool, GFP_ATOMIC, &daddr);
 833	if (unlikely(!vaddr))
 834		return -ENOMEM;
 835
 836	/*
 837	 * Update msg_start indexes for both tx and rx to indicate the start
 838	 * of a new sequence of descriptor indexes that contain the fragments
 839	 * of the same message.
 840	 */
 841	pdcs->rx_msg_start = pdcs->rxout;
 842	pdcs->tx_msg_start = pdcs->txout;
 843
 844	/* This is always the first descriptor in the receive sequence */
 845	flags = D64_CTRL1_SOF;
 846	pdcs->rx_ctx[pdcs->rx_msg_start].rxin_numd = 1;
 847
 848	if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
 849		flags |= D64_CTRL1_EOT;
 850
 851	rx_ctx = &pdcs->rx_ctx[pdcs->rxout];
 852	rx_ctx->rxp_ctx = ctx;
 853	rx_ctx->dst_sg = dst_sg;
 854	rx_ctx->resp_hdr = vaddr;
 855	rx_ctx->resp_hdr_daddr = daddr;
 856	pdc_build_rxd(pdcs, daddr, pdcs->pdc_resp_hdr_len, flags);
 857	return PDC_SUCCESS;
 858}
 859
 860/**
 861 * pdc_rx_list_sg_add() - Add the buffers in a scatterlist to the receive
 862 * descriptors for a given SPU. The caller must have already DMA mapped the
 863 * scatterlist.
 864 * @spu_idx:    Indicates which SPU the buffers are for
 865 * @sg:         Scatterlist whose buffers are added to the receive ring
 866 *
 867 * If a receive buffer in the scatterlist is larger than PDC_DMA_BUF_MAX,
 868 * multiple receive descriptors are written, each with a buffer <=
 869 * PDC_DMA_BUF_MAX.
 870 *
 871 * Return: PDC_SUCCESS if successful
 872 *         < 0 otherwise (e.g., receive ring is full)
 873 */
 874static int pdc_rx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
 875{
 876	u32 flags = 0;
 877	u32 rx_avail;
 878
 879	/*
 880	 * Num descriptors needed. Conservatively assume we need a descriptor
 881	 * for every entry from our starting point in the scatterlist.
 882	 */
 883	u32 num_desc;
 884	u32 desc_w = 0;	/* Number of tx descriptors written */
 885	u32 bufcnt;	/* Number of bytes of buffer pointed to by descriptor */
 886	dma_addr_t databufptr;	/* DMA address to put in descriptor */
 887
 888	num_desc = (u32)sg_nents(sg);
 889
 890	rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
 891					      pdcs->nrxpost);
 892	if (unlikely(num_desc > rx_avail)) {
 893		pdcs->rxnobuf++;
 894		return -ENOSPC;
 895	}
 896
 897	while (sg) {
 898		if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
 899			flags = D64_CTRL1_EOT;
 900		else
 901			flags = 0;
 902
 903		/*
 904		 * If sg buffer larger than PDC limit, split across
 905		 * multiple descriptors
 906		 */
 907		bufcnt = sg_dma_len(sg);
 908		databufptr = sg_dma_address(sg);
 909		while (bufcnt > PDC_DMA_BUF_MAX) {
 910			pdc_build_rxd(pdcs, databufptr, PDC_DMA_BUF_MAX, flags);
 911			desc_w++;
 912			bufcnt -= PDC_DMA_BUF_MAX;
 913			databufptr += PDC_DMA_BUF_MAX;
 914			if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
 915				flags = D64_CTRL1_EOT;
 916			else
 917				flags = 0;
 918		}
 919		pdc_build_rxd(pdcs, databufptr, bufcnt, flags);
 920		desc_w++;
 921		sg = sg_next(sg);
 922	}
 923	pdcs->rx_ctx[pdcs->rx_msg_start].rxin_numd += desc_w;
 924
 925	return PDC_SUCCESS;
 926}
 927
 928/**
 929 * pdc_irq_handler() - Interrupt handler called in interrupt context.
 930 * @irq:      Interrupt number that has fired
 931 * @data:     device struct for DMA engine that generated the interrupt
 932 *
 933 * We have to clear the device interrupt status flags here. So cache the
 934 * status for later use in the thread function. Other than that, just return
 935 * WAKE_THREAD to invoke the thread function.
 936 *
 937 * Return: IRQ_WAKE_THREAD if interrupt is ours
 938 *         IRQ_NONE otherwise
 939 */
 940static irqreturn_t pdc_irq_handler(int irq, void *data)
 941{
 942	struct device *dev = (struct device *)data;
 943	struct pdc_state *pdcs = dev_get_drvdata(dev);
 944	u32 intstatus = ioread32(pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
 945
 946	if (unlikely(intstatus == 0))
 947		return IRQ_NONE;
 948
 949	/* Disable interrupts until soft handler runs */
 950	iowrite32(0, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
 951
 952	/* Clear interrupt flags in device */
 953	iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
 954
 955	/* Wakeup IRQ thread */
 956	tasklet_schedule(&pdcs->rx_tasklet);
 957	return IRQ_HANDLED;
 958}
 959
 960/**
 961 * pdc_tasklet_cb() - Tasklet callback that runs the deferred processing after
 962 * a DMA receive interrupt. Reenables the receive interrupt.
 963 * @data: PDC state structure
 964 */
 965static void pdc_tasklet_cb(struct tasklet_struct *t)
 966{
 967	struct pdc_state *pdcs = from_tasklet(pdcs, t, rx_tasklet);
 968
 969	pdc_receive(pdcs);
 970
 971	/* reenable interrupts */
 972	iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
 973}
 974
 975/**
 976 * pdc_ring_init() - Allocate DMA rings and initialize constant fields of
 977 * descriptors in one ringset.
 978 * @pdcs:    PDC instance state
 979 * @ringset: index of ringset being used
 980 *
 981 * Return: PDC_SUCCESS if ring initialized
 982 *         < 0 otherwise
 983 */
 984static int pdc_ring_init(struct pdc_state *pdcs, int ringset)
 985{
 986	int i;
 987	int err = PDC_SUCCESS;
 988	struct dma64 *dma_reg;
 989	struct device *dev = &pdcs->pdev->dev;
 990	struct pdc_ring_alloc tx;
 991	struct pdc_ring_alloc rx;
 992
 993	/* Allocate tx ring */
 994	tx.vbase = dma_pool_zalloc(pdcs->ring_pool, GFP_KERNEL, &tx.dmabase);
 995	if (unlikely(!tx.vbase)) {
 996		err = -ENOMEM;
 997		goto done;
 998	}
 999
1000	/* Allocate rx ring */
1001	rx.vbase = dma_pool_zalloc(pdcs->ring_pool, GFP_KERNEL, &rx.dmabase);
1002	if (unlikely(!rx.vbase)) {
1003		err = -ENOMEM;
1004		goto fail_dealloc;
1005	}
1006
1007	dev_dbg(dev, " - base DMA addr of tx ring      %pad", &tx.dmabase);
1008	dev_dbg(dev, " - base virtual addr of tx ring  %p", tx.vbase);
1009	dev_dbg(dev, " - base DMA addr of rx ring      %pad", &rx.dmabase);
1010	dev_dbg(dev, " - base virtual addr of rx ring  %p", rx.vbase);
1011
1012	memcpy(&pdcs->tx_ring_alloc, &tx, sizeof(tx));
1013	memcpy(&pdcs->rx_ring_alloc, &rx, sizeof(rx));
1014
1015	pdcs->rxin = 0;
1016	pdcs->rx_msg_start = 0;
1017	pdcs->last_rx_curr = 0;
1018	pdcs->rxout = 0;
1019	pdcs->txin = 0;
1020	pdcs->tx_msg_start = 0;
1021	pdcs->txout = 0;
1022
1023	/* Set descriptor array base addresses */
1024	pdcs->txd_64 = (struct dma64dd *)pdcs->tx_ring_alloc.vbase;
1025	pdcs->rxd_64 = (struct dma64dd *)pdcs->rx_ring_alloc.vbase;
1026
1027	/* Tell device the base DMA address of each ring */
1028	dma_reg = &pdcs->regs->dmaregs[ringset];
1029
1030	/* But first disable DMA and set curptr to 0 for both TX & RX */
1031	iowrite32(PDC_TX_CTL, &dma_reg->dmaxmt.control);
1032	iowrite32((PDC_RX_CTL + (pdcs->rx_status_len << 1)),
1033		  &dma_reg->dmarcv.control);
1034	iowrite32(0, &dma_reg->dmaxmt.ptr);
1035	iowrite32(0, &dma_reg->dmarcv.ptr);
1036
1037	/* Set base DMA addresses */
1038	iowrite32(lower_32_bits(pdcs->tx_ring_alloc.dmabase),
1039		  &dma_reg->dmaxmt.addrlow);
1040	iowrite32(upper_32_bits(pdcs->tx_ring_alloc.dmabase),
1041		  &dma_reg->dmaxmt.addrhigh);
1042
1043	iowrite32(lower_32_bits(pdcs->rx_ring_alloc.dmabase),
1044		  &dma_reg->dmarcv.addrlow);
1045	iowrite32(upper_32_bits(pdcs->rx_ring_alloc.dmabase),
1046		  &dma_reg->dmarcv.addrhigh);
1047
1048	/* Re-enable DMA */
1049	iowrite32(PDC_TX_CTL | PDC_TX_ENABLE, &dma_reg->dmaxmt.control);
1050	iowrite32((PDC_RX_CTL | PDC_RX_ENABLE | (pdcs->rx_status_len << 1)),
1051		  &dma_reg->dmarcv.control);
1052
1053	/* Initialize descriptors */
1054	for (i = 0; i < PDC_RING_ENTRIES; i++) {
1055		/* Every tx descriptor can be used for start of frame. */
1056		if (i != pdcs->ntxpost) {
1057			iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOF,
1058				  &pdcs->txd_64[i].ctrl1);
1059		} else {
1060			/* Last descriptor in ringset. Set End of Table. */
1061			iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOF |
1062				  D64_CTRL1_EOT, &pdcs->txd_64[i].ctrl1);
1063		}
1064
1065		/* Every rx descriptor can be used for start of frame */
1066		if (i != pdcs->nrxpost) {
1067			iowrite32(D64_CTRL1_SOF,
1068				  &pdcs->rxd_64[i].ctrl1);
1069		} else {
1070			/* Last descriptor in ringset. Set End of Table. */
1071			iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOT,
1072				  &pdcs->rxd_64[i].ctrl1);
1073		}
1074	}
1075	return PDC_SUCCESS;
1076
1077fail_dealloc:
1078	dma_pool_free(pdcs->ring_pool, tx.vbase, tx.dmabase);
1079done:
1080	return err;
1081}
1082
1083static void pdc_ring_free(struct pdc_state *pdcs)
1084{
1085	if (pdcs->tx_ring_alloc.vbase) {
1086		dma_pool_free(pdcs->ring_pool, pdcs->tx_ring_alloc.vbase,
1087			      pdcs->tx_ring_alloc.dmabase);
1088		pdcs->tx_ring_alloc.vbase = NULL;
1089	}
1090
1091	if (pdcs->rx_ring_alloc.vbase) {
1092		dma_pool_free(pdcs->ring_pool, pdcs->rx_ring_alloc.vbase,
1093			      pdcs->rx_ring_alloc.dmabase);
1094		pdcs->rx_ring_alloc.vbase = NULL;
1095	}
1096}
1097
1098/**
1099 * pdc_desc_count() - Count the number of DMA descriptors that will be required
1100 * for a given scatterlist. Account for the max length of a DMA buffer.
1101 * @sg:    Scatterlist to be DMA'd
1102 * Return: Number of descriptors required
1103 */
1104static u32 pdc_desc_count(struct scatterlist *sg)
1105{
1106	u32 cnt = 0;
1107
1108	while (sg) {
1109		cnt += ((sg->length / PDC_DMA_BUF_MAX) + 1);
1110		sg = sg_next(sg);
1111	}
1112	return cnt;
1113}
1114
1115/**
1116 * pdc_rings_full() - Check whether the tx ring has room for tx_cnt descriptors
1117 * and the rx ring has room for rx_cnt descriptors.
1118 * @pdcs:  PDC state
1119 * @tx_cnt: The number of descriptors required in the tx ring
1120 * @rx_cnt: The number of descriptors required i the rx ring
1121 *
1122 * Return: true if one of the rings does not have enough space
1123 *         false if sufficient space is available in both rings
1124 */
1125static bool pdc_rings_full(struct pdc_state *pdcs, int tx_cnt, int rx_cnt)
1126{
1127	u32 rx_avail;
1128	u32 tx_avail;
1129	bool full = false;
1130
1131	/* Check if the tx and rx rings are likely to have enough space */
1132	rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
1133					      pdcs->nrxpost);
1134	if (unlikely(rx_cnt > rx_avail)) {
1135		pdcs->rx_ring_full++;
1136		full = true;
1137	}
1138
1139	if (likely(!full)) {
1140		tx_avail = pdcs->ntxpost - NTXDACTIVE(pdcs->txin, pdcs->txout,
1141						      pdcs->ntxpost);
1142		if (unlikely(tx_cnt > tx_avail)) {
1143			pdcs->tx_ring_full++;
1144			full = true;
1145		}
1146	}
1147	return full;
1148}
1149
1150/**
1151 * pdc_last_tx_done() - If both the tx and rx rings have at least
1152 * PDC_RING_SPACE_MIN descriptors available, then indicate that the mailbox
1153 * framework can submit another message.
1154 * @chan:  mailbox channel to check
1155 * Return: true if PDC can accept another message on this channel
1156 */
1157static bool pdc_last_tx_done(struct mbox_chan *chan)
1158{
1159	struct pdc_state *pdcs = chan->con_priv;
1160	bool ret;
1161
1162	if (unlikely(pdc_rings_full(pdcs, PDC_RING_SPACE_MIN,
1163				    PDC_RING_SPACE_MIN))) {
1164		pdcs->last_tx_not_done++;
1165		ret = false;
1166	} else {
1167		ret = true;
1168	}
1169	return ret;
1170}
1171
1172/**
1173 * pdc_send_data() - mailbox send_data function
1174 * @chan:	The mailbox channel on which the data is sent. The channel
1175 *              corresponds to a DMA ringset.
1176 * @data:	The mailbox message to be sent. The message must be a
1177 *              brcm_message structure.
1178 *
1179 * This function is registered as the send_data function for the mailbox
1180 * controller. From the destination scatterlist in the mailbox message, it
1181 * creates a sequence of receive descriptors in the rx ring. From the source
1182 * scatterlist, it creates a sequence of transmit descriptors in the tx ring.
1183 * After creating the descriptors, it writes the rx ptr and tx ptr registers to
1184 * initiate the DMA transfer.
1185 *
1186 * This function does the DMA map and unmap of the src and dst scatterlists in
1187 * the mailbox message.
1188 *
1189 * Return: 0 if successful
1190 *	   -ENOTSUPP if the mailbox message is a type this driver does not
1191 *			support
1192 *         < 0 if an error
1193 */
1194static int pdc_send_data(struct mbox_chan *chan, void *data)
1195{
1196	struct pdc_state *pdcs = chan->con_priv;
1197	struct device *dev = &pdcs->pdev->dev;
1198	struct brcm_message *mssg = data;
1199	int err = PDC_SUCCESS;
1200	int src_nent;
1201	int dst_nent;
1202	int nent;
1203	u32 tx_desc_req;
1204	u32 rx_desc_req;
1205
1206	if (unlikely(mssg->type != BRCM_MESSAGE_SPU))
1207		return -ENOTSUPP;
1208
1209	src_nent = sg_nents(mssg->spu.src);
1210	if (likely(src_nent)) {
1211		nent = dma_map_sg(dev, mssg->spu.src, src_nent, DMA_TO_DEVICE);
1212		if (unlikely(nent == 0))
1213			return -EIO;
1214	}
1215
1216	dst_nent = sg_nents(mssg->spu.dst);
1217	if (likely(dst_nent)) {
1218		nent = dma_map_sg(dev, mssg->spu.dst, dst_nent,
1219				  DMA_FROM_DEVICE);
1220		if (unlikely(nent == 0)) {
1221			dma_unmap_sg(dev, mssg->spu.src, src_nent,
1222				     DMA_TO_DEVICE);
1223			return -EIO;
1224		}
1225	}
1226
1227	/*
1228	 * Check if the tx and rx rings have enough space. Do this prior to
1229	 * writing any tx or rx descriptors. Need to ensure that we do not write
1230	 * a partial set of descriptors, or write just rx descriptors but
1231	 * corresponding tx descriptors don't fit. Note that we want this check
1232	 * and the entire sequence of descriptor to happen without another
1233	 * thread getting in. The channel spin lock in the mailbox framework
1234	 * ensures this.
1235	 */
1236	tx_desc_req = pdc_desc_count(mssg->spu.src);
1237	rx_desc_req = pdc_desc_count(mssg->spu.dst);
1238	if (unlikely(pdc_rings_full(pdcs, tx_desc_req, rx_desc_req + 1)))
1239		return -ENOSPC;
1240
1241	/* Create rx descriptors to SPU catch response */
1242	err = pdc_rx_list_init(pdcs, mssg->spu.dst, mssg->ctx);
1243	err |= pdc_rx_list_sg_add(pdcs, mssg->spu.dst);
1244
1245	/* Create tx descriptors to submit SPU request */
1246	err |= pdc_tx_list_sg_add(pdcs, mssg->spu.src);
1247	err |= pdc_tx_list_final(pdcs);	/* initiate transfer */
1248
1249	if (unlikely(err))
1250		dev_err(&pdcs->pdev->dev,
1251			"%s failed with error %d", __func__, err);
1252
1253	return err;
1254}
1255
1256static int pdc_startup(struct mbox_chan *chan)
1257{
1258	return pdc_ring_init(chan->con_priv, PDC_RINGSET);
1259}
1260
1261static void pdc_shutdown(struct mbox_chan *chan)
1262{
1263	struct pdc_state *pdcs = chan->con_priv;
1264
1265	if (!pdcs)
1266		return;
1267
1268	dev_dbg(&pdcs->pdev->dev,
1269		"Shutdown mailbox channel for PDC %u", pdcs->pdc_idx);
1270	pdc_ring_free(pdcs);
1271}
1272
1273/**
1274 * pdc_hw_init() - Use the given initialization parameters to initialize the
1275 * state for one of the PDCs.
1276 * @pdcs:  state of the PDC
1277 */
1278static
1279void pdc_hw_init(struct pdc_state *pdcs)
1280{
1281	struct platform_device *pdev;
1282	struct device *dev;
1283	struct dma64 *dma_reg;
1284	int ringset = PDC_RINGSET;
1285
1286	pdev = pdcs->pdev;
1287	dev = &pdev->dev;
1288
1289	dev_dbg(dev, "PDC %u initial values:", pdcs->pdc_idx);
1290	dev_dbg(dev, "state structure:                   %p",
1291		pdcs);
1292	dev_dbg(dev, " - base virtual addr of hw regs    %p",
1293		pdcs->pdc_reg_vbase);
1294
1295	/* initialize data structures */
1296	pdcs->regs = (struct pdc_regs *)pdcs->pdc_reg_vbase;
1297	pdcs->txregs_64 = (struct dma64_regs *)
1298	    (((u8 *)pdcs->pdc_reg_vbase) +
1299		     PDC_TXREGS_OFFSET + (sizeof(struct dma64) * ringset));
1300	pdcs->rxregs_64 = (struct dma64_regs *)
1301	    (((u8 *)pdcs->pdc_reg_vbase) +
1302		     PDC_RXREGS_OFFSET + (sizeof(struct dma64) * ringset));
1303
1304	pdcs->ntxd = PDC_RING_ENTRIES;
1305	pdcs->nrxd = PDC_RING_ENTRIES;
1306	pdcs->ntxpost = PDC_RING_ENTRIES - 1;
1307	pdcs->nrxpost = PDC_RING_ENTRIES - 1;
1308	iowrite32(0, &pdcs->regs->intmask);
1309
1310	dma_reg = &pdcs->regs->dmaregs[ringset];
1311
1312	/* Configure DMA but will enable later in pdc_ring_init() */
1313	iowrite32(PDC_TX_CTL, &dma_reg->dmaxmt.control);
1314
1315	iowrite32(PDC_RX_CTL + (pdcs->rx_status_len << 1),
1316		  &dma_reg->dmarcv.control);
1317
1318	/* Reset current index pointers after making sure DMA is disabled */
1319	iowrite32(0, &dma_reg->dmaxmt.ptr);
1320	iowrite32(0, &dma_reg->dmarcv.ptr);
1321
1322	if (pdcs->pdc_resp_hdr_len == PDC_SPU2_RESP_HDR_LEN)
1323		iowrite32(PDC_CKSUM_CTRL,
1324			  pdcs->pdc_reg_vbase + PDC_CKSUM_CTRL_OFFSET);
1325}
1326
1327/**
1328 * pdc_hw_disable() - Disable the tx and rx control in the hw.
1329 * @pdcs: PDC state structure
1330 *
1331 */
1332static void pdc_hw_disable(struct pdc_state *pdcs)
1333{
1334	struct dma64 *dma_reg;
1335
1336	dma_reg = &pdcs->regs->dmaregs[PDC_RINGSET];
1337	iowrite32(PDC_TX_CTL, &dma_reg->dmaxmt.control);
1338	iowrite32(PDC_RX_CTL + (pdcs->rx_status_len << 1),
1339		  &dma_reg->dmarcv.control);
1340}
1341
1342/**
1343 * pdc_rx_buf_pool_create() - Pool of receive buffers used to catch the metadata
1344 * header returned with each response message.
1345 * @pdcs: PDC state structure
1346 *
1347 * The metadata is not returned to the mailbox client. So the PDC driver
1348 * manages these buffers.
1349 *
1350 * Return: PDC_SUCCESS
1351 *         -ENOMEM if pool creation fails
1352 */
1353static int pdc_rx_buf_pool_create(struct pdc_state *pdcs)
1354{
1355	struct platform_device *pdev;
1356	struct device *dev;
1357
1358	pdev = pdcs->pdev;
1359	dev = &pdev->dev;
1360
1361	pdcs->pdc_resp_hdr_len = pdcs->rx_status_len;
1362	if (pdcs->use_bcm_hdr)
1363		pdcs->pdc_resp_hdr_len += BCM_HDR_LEN;
1364
1365	pdcs->rx_buf_pool = dma_pool_create("pdc rx bufs", dev,
1366					    pdcs->pdc_resp_hdr_len,
1367					    RX_BUF_ALIGN, 0);
1368	if (!pdcs->rx_buf_pool)
1369		return -ENOMEM;
1370
1371	return PDC_SUCCESS;
1372}
1373
1374/**
1375 * pdc_interrupts_init() - Initialize the interrupt configuration for a PDC and
1376 * specify a threaded IRQ handler for deferred handling of interrupts outside of
1377 * interrupt context.
1378 * @pdcs:   PDC state
1379 *
1380 * Set the interrupt mask for transmit and receive done.
1381 * Set the lazy interrupt frame count to generate an interrupt for just one pkt.
1382 *
1383 * Return:  PDC_SUCCESS
1384 *          <0 if threaded irq request fails
1385 */
1386static int pdc_interrupts_init(struct pdc_state *pdcs)
1387{
1388	struct platform_device *pdev = pdcs->pdev;
1389	struct device *dev = &pdev->dev;
1390	struct device_node *dn = pdev->dev.of_node;
1391	int err;
1392
1393	/* interrupt configuration */
1394	iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
1395
1396	if (pdcs->hw_type == FA_HW)
1397		iowrite32(PDC_LAZY_INT, pdcs->pdc_reg_vbase +
1398			  FA_RCVLAZY0_OFFSET);
1399	else
1400		iowrite32(PDC_LAZY_INT, pdcs->pdc_reg_vbase +
1401			  PDC_RCVLAZY0_OFFSET);
1402
1403	/* read irq from device tree */
1404	pdcs->pdc_irq = irq_of_parse_and_map(dn, 0);
1405	dev_dbg(dev, "pdc device %s irq %u for pdcs %p",
1406		dev_name(dev), pdcs->pdc_irq, pdcs);
1407
1408	err = devm_request_irq(dev, pdcs->pdc_irq, pdc_irq_handler, 0,
1409			       dev_name(dev), dev);
1410	if (err) {
1411		dev_err(dev, "IRQ %u request failed with err %d\n",
1412			pdcs->pdc_irq, err);
1413		return err;
1414	}
1415	return PDC_SUCCESS;
1416}
1417
1418static const struct mbox_chan_ops pdc_mbox_chan_ops = {
1419	.send_data = pdc_send_data,
1420	.last_tx_done = pdc_last_tx_done,
1421	.startup = pdc_startup,
1422	.shutdown = pdc_shutdown
1423};
1424
1425/**
1426 * pdc_mb_init() - Initialize the mailbox controller.
1427 * @pdcs:  PDC state
1428 *
1429 * Each PDC is a mailbox controller. Each ringset is a mailbox channel. Kernel
1430 * driver only uses one ringset and thus one mb channel. PDC uses the transmit
1431 * complete interrupt to determine when a mailbox message has successfully been
1432 * transmitted.
1433 *
1434 * Return: 0 on success
1435 *         < 0 if there is an allocation or registration failure
1436 */
1437static int pdc_mb_init(struct pdc_state *pdcs)
1438{
1439	struct device *dev = &pdcs->pdev->dev;
1440	struct mbox_controller *mbc;
1441	int chan_index;
1442	int err;
1443
1444	mbc = &pdcs->mbc;
1445	mbc->dev = dev;
1446	mbc->ops = &pdc_mbox_chan_ops;
1447	mbc->num_chans = 1;
1448	mbc->chans = devm_kcalloc(dev, mbc->num_chans, sizeof(*mbc->chans),
1449				  GFP_KERNEL);
1450	if (!mbc->chans)
1451		return -ENOMEM;
1452
1453	mbc->txdone_irq = false;
1454	mbc->txdone_poll = true;
1455	mbc->txpoll_period = 1;
1456	for (chan_index = 0; chan_index < mbc->num_chans; chan_index++)
1457		mbc->chans[chan_index].con_priv = pdcs;
1458
1459	/* Register mailbox controller */
1460	err = devm_mbox_controller_register(dev, mbc);
1461	if (err) {
1462		dev_crit(dev,
1463			 "Failed to register PDC mailbox controller. Error %d.",
1464			 err);
1465		return err;
1466	}
1467	return 0;
1468}
1469
1470/* Device tree API */
1471static const int pdc_hw = PDC_HW;
1472static const int fa_hw = FA_HW;
1473
1474static const struct of_device_id pdc_mbox_of_match[] = {
1475	{.compatible = "brcm,iproc-pdc-mbox", .data = &pdc_hw},
1476	{.compatible = "brcm,iproc-fa2-mbox", .data = &fa_hw},
1477	{ /* sentinel */ }
1478};
1479MODULE_DEVICE_TABLE(of, pdc_mbox_of_match);
1480
1481/**
1482 * pdc_dt_read() - Read application-specific data from device tree.
1483 * @pdev:  Platform device
1484 * @pdcs:  PDC state
1485 *
1486 * Reads the number of bytes of receive status that precede each received frame.
1487 * Reads whether transmit and received frames should be preceded by an 8-byte
1488 * BCM header.
1489 *
1490 * Return: 0 if successful
1491 *         -ENODEV if device not available
1492 */
1493static int pdc_dt_read(struct platform_device *pdev, struct pdc_state *pdcs)
1494{
1495	struct device *dev = &pdev->dev;
1496	struct device_node *dn = pdev->dev.of_node;
1497	const struct of_device_id *match;
1498	const int *hw_type;
1499	int err;
1500
1501	err = of_property_read_u32(dn, "brcm,rx-status-len",
1502				   &pdcs->rx_status_len);
1503	if (err < 0)
1504		dev_err(dev,
1505			"%s failed to get DMA receive status length from device tree",
1506			__func__);
1507
1508	pdcs->use_bcm_hdr = of_property_read_bool(dn, "brcm,use-bcm-hdr");
1509
1510	pdcs->hw_type = PDC_HW;
1511
1512	match = of_match_device(of_match_ptr(pdc_mbox_of_match), dev);
1513	if (match != NULL) {
1514		hw_type = match->data;
1515		pdcs->hw_type = *hw_type;
1516	}
1517
1518	return 0;
1519}
1520
1521/**
1522 * pdc_probe() - Probe function for PDC driver.
1523 * @pdev:   PDC platform device
1524 *
1525 * Reserve and map register regions defined in device tree.
1526 * Allocate and initialize tx and rx DMA rings.
1527 * Initialize a mailbox controller for each PDC.
1528 *
1529 * Return: 0 if successful
1530 *         < 0 if an error
1531 */
1532static int pdc_probe(struct platform_device *pdev)
1533{
1534	int err = 0;
1535	struct device *dev = &pdev->dev;
1536	struct resource *pdc_regs;
1537	struct pdc_state *pdcs;
1538
1539	/* PDC state for one SPU */
1540	pdcs = devm_kzalloc(dev, sizeof(*pdcs), GFP_KERNEL);
1541	if (!pdcs) {
1542		err = -ENOMEM;
1543		goto cleanup;
1544	}
1545
1546	pdcs->pdev = pdev;
1547	platform_set_drvdata(pdev, pdcs);
1548	pdcs->pdc_idx = pdcg.num_spu;
1549	pdcg.num_spu++;
1550
1551	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(39));
1552	if (err) {
1553		dev_warn(dev, "PDC device cannot perform DMA. Error %d.", err);
1554		goto cleanup;
1555	}
1556
1557	/* Create DMA pool for tx ring */
1558	pdcs->ring_pool = dma_pool_create("pdc rings", dev, PDC_RING_SIZE,
1559					  RING_ALIGN, 0);
1560	if (!pdcs->ring_pool) {
1561		err = -ENOMEM;
1562		goto cleanup;
1563	}
1564
1565	err = pdc_dt_read(pdev, pdcs);
1566	if (err)
1567		goto cleanup_ring_pool;
1568
1569	pdc_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1570	if (!pdc_regs) {
1571		err = -ENODEV;
1572		goto cleanup_ring_pool;
1573	}
1574	dev_dbg(dev, "PDC register region res.start = %pa, res.end = %pa",
1575		&pdc_regs->start, &pdc_regs->end);
1576
1577	pdcs->pdc_reg_vbase = devm_ioremap_resource(&pdev->dev, pdc_regs);
1578	if (IS_ERR(pdcs->pdc_reg_vbase)) {
1579		err = PTR_ERR(pdcs->pdc_reg_vbase);
 
1580		goto cleanup_ring_pool;
1581	}
1582
1583	/* create rx buffer pool after dt read to know how big buffers are */
1584	err = pdc_rx_buf_pool_create(pdcs);
1585	if (err)
1586		goto cleanup_ring_pool;
1587
1588	pdc_hw_init(pdcs);
1589
1590	/* Init tasklet for deferred DMA rx processing */
1591	tasklet_setup(&pdcs->rx_tasklet, pdc_tasklet_cb);
1592
1593	err = pdc_interrupts_init(pdcs);
1594	if (err)
1595		goto cleanup_buf_pool;
1596
1597	/* Initialize mailbox controller */
1598	err = pdc_mb_init(pdcs);
1599	if (err)
1600		goto cleanup_buf_pool;
1601
1602	pdc_setup_debugfs(pdcs);
1603
1604	dev_dbg(dev, "pdc_probe() successful");
1605	return PDC_SUCCESS;
1606
1607cleanup_buf_pool:
1608	tasklet_kill(&pdcs->rx_tasklet);
1609	dma_pool_destroy(pdcs->rx_buf_pool);
1610
1611cleanup_ring_pool:
1612	dma_pool_destroy(pdcs->ring_pool);
1613
1614cleanup:
1615	return err;
1616}
1617
1618static int pdc_remove(struct platform_device *pdev)
1619{
1620	struct pdc_state *pdcs = platform_get_drvdata(pdev);
1621
1622	pdc_free_debugfs();
1623
1624	tasklet_kill(&pdcs->rx_tasklet);
1625
1626	pdc_hw_disable(pdcs);
1627
1628	dma_pool_destroy(pdcs->rx_buf_pool);
1629	dma_pool_destroy(pdcs->ring_pool);
1630	return 0;
1631}
1632
1633static struct platform_driver pdc_mbox_driver = {
1634	.probe = pdc_probe,
1635	.remove = pdc_remove,
1636	.driver = {
1637		   .name = "brcm-iproc-pdc-mbox",
1638		   .of_match_table = of_match_ptr(pdc_mbox_of_match),
1639		   },
1640};
1641module_platform_driver(pdc_mbox_driver);
1642
1643MODULE_AUTHOR("Rob Rice <rob.rice@broadcom.com>");
1644MODULE_DESCRIPTION("Broadcom PDC mailbox driver");
1645MODULE_LICENSE("GPL v2");