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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2005-2006 by Texas Instruments
4 *
5 * This file implements a DMA interface using TI's CPPI DMA.
6 * For now it's DaVinci-only, but CPPI isn't specific to DaVinci or USB.
7 * The TUSB6020, using VLYNQ, has CPPI that looks much like DaVinci.
8 */
9
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/slab.h>
13#include <linux/usb.h>
14
15#include "musb_core.h"
16#include "musb_debug.h"
17#include "cppi_dma.h"
18#include "davinci.h"
19
20
21/* CPPI DMA status 7-mar-2006:
22 *
23 * - See musb_{host,gadget}.c for more info
24 *
25 * - Correct RX DMA generally forces the engine into irq-per-packet mode,
26 * which can easily saturate the CPU under non-mass-storage loads.
27 *
28 * NOTES 24-aug-2006 (2.6.18-rc4):
29 *
30 * - peripheral RXDMA wedged in a test with packets of length 512/512/1.
31 * evidently after the 1 byte packet was received and acked, the queue
32 * of BDs got garbaged so it wouldn't empty the fifo. (rxcsr 0x2003,
33 * and RX DMA0: 4 left, 80000000 8feff880, 8feff860 8feff860; 8f321401
34 * 004001ff 00000001 .. 8feff860) Host was just getting NAKed on tx
35 * of its next (512 byte) packet. IRQ issues?
36 *
37 * REVISIT: the "transfer DMA" glue between CPPI and USB fifos will
38 * evidently also directly update the RX and TX CSRs ... so audit all
39 * host and peripheral side DMA code to avoid CSR access after DMA has
40 * been started.
41 */
42
43/* REVISIT now we can avoid preallocating these descriptors; or
44 * more simply, switch to a global freelist not per-channel ones.
45 * Note: at full speed, 64 descriptors == 4K bulk data.
46 */
47#define NUM_TXCHAN_BD 64
48#define NUM_RXCHAN_BD 64
49
50static inline void cpu_drain_writebuffer(void)
51{
52 wmb();
53#ifdef CONFIG_CPU_ARM926T
54 /* REVISIT this "should not be needed",
55 * but lack of it sure seemed to hurt ...
56 */
57 asm("mcr p15, 0, r0, c7, c10, 4 @ drain write buffer\n");
58#endif
59}
60
61static inline struct cppi_descriptor *cppi_bd_alloc(struct cppi_channel *c)
62{
63 struct cppi_descriptor *bd = c->freelist;
64
65 if (bd)
66 c->freelist = bd->next;
67 return bd;
68}
69
70static inline void
71cppi_bd_free(struct cppi_channel *c, struct cppi_descriptor *bd)
72{
73 if (!bd)
74 return;
75 bd->next = c->freelist;
76 c->freelist = bd;
77}
78
79/*
80 * Start DMA controller
81 *
82 * Initialize the DMA controller as necessary.
83 */
84
85/* zero out entire rx state RAM entry for the channel */
86static void cppi_reset_rx(struct cppi_rx_stateram __iomem *rx)
87{
88 musb_writel(&rx->rx_skipbytes, 0, 0);
89 musb_writel(&rx->rx_head, 0, 0);
90 musb_writel(&rx->rx_sop, 0, 0);
91 musb_writel(&rx->rx_current, 0, 0);
92 musb_writel(&rx->rx_buf_current, 0, 0);
93 musb_writel(&rx->rx_len_len, 0, 0);
94 musb_writel(&rx->rx_cnt_cnt, 0, 0);
95}
96
97/* zero out entire tx state RAM entry for the channel */
98static void cppi_reset_tx(struct cppi_tx_stateram __iomem *tx, u32 ptr)
99{
100 musb_writel(&tx->tx_head, 0, 0);
101 musb_writel(&tx->tx_buf, 0, 0);
102 musb_writel(&tx->tx_current, 0, 0);
103 musb_writel(&tx->tx_buf_current, 0, 0);
104 musb_writel(&tx->tx_info, 0, 0);
105 musb_writel(&tx->tx_rem_len, 0, 0);
106 /* musb_writel(&tx->tx_dummy, 0, 0); */
107 musb_writel(&tx->tx_complete, 0, ptr);
108}
109
110static void cppi_pool_init(struct cppi *cppi, struct cppi_channel *c)
111{
112 int j;
113
114 /* initialize channel fields */
115 c->head = NULL;
116 c->tail = NULL;
117 c->last_processed = NULL;
118 c->channel.status = MUSB_DMA_STATUS_UNKNOWN;
119 c->controller = cppi;
120 c->is_rndis = 0;
121 c->freelist = NULL;
122
123 /* build the BD Free list for the channel */
124 for (j = 0; j < NUM_TXCHAN_BD + 1; j++) {
125 struct cppi_descriptor *bd;
126 dma_addr_t dma;
127
128 bd = dma_pool_alloc(cppi->pool, GFP_KERNEL, &dma);
129 bd->dma = dma;
130 cppi_bd_free(c, bd);
131 }
132}
133
134static int cppi_channel_abort(struct dma_channel *);
135
136static void cppi_pool_free(struct cppi_channel *c)
137{
138 struct cppi *cppi = c->controller;
139 struct cppi_descriptor *bd;
140
141 (void) cppi_channel_abort(&c->channel);
142 c->channel.status = MUSB_DMA_STATUS_UNKNOWN;
143 c->controller = NULL;
144
145 /* free all its bds */
146 bd = c->last_processed;
147 do {
148 if (bd)
149 dma_pool_free(cppi->pool, bd, bd->dma);
150 bd = cppi_bd_alloc(c);
151 } while (bd);
152 c->last_processed = NULL;
153}
154
155static void cppi_controller_start(struct cppi *controller)
156{
157 void __iomem *tibase;
158 int i;
159
160 /* do whatever is necessary to start controller */
161 for (i = 0; i < ARRAY_SIZE(controller->tx); i++) {
162 controller->tx[i].transmit = true;
163 controller->tx[i].index = i;
164 }
165 for (i = 0; i < ARRAY_SIZE(controller->rx); i++) {
166 controller->rx[i].transmit = false;
167 controller->rx[i].index = i;
168 }
169
170 /* setup BD list on a per channel basis */
171 for (i = 0; i < ARRAY_SIZE(controller->tx); i++)
172 cppi_pool_init(controller, controller->tx + i);
173 for (i = 0; i < ARRAY_SIZE(controller->rx); i++)
174 cppi_pool_init(controller, controller->rx + i);
175
176 tibase = controller->tibase;
177 INIT_LIST_HEAD(&controller->tx_complete);
178
179 /* initialise tx/rx channel head pointers to zero */
180 for (i = 0; i < ARRAY_SIZE(controller->tx); i++) {
181 struct cppi_channel *tx_ch = controller->tx + i;
182 struct cppi_tx_stateram __iomem *tx;
183
184 INIT_LIST_HEAD(&tx_ch->tx_complete);
185
186 tx = tibase + DAVINCI_TXCPPI_STATERAM_OFFSET(i);
187 tx_ch->state_ram = tx;
188 cppi_reset_tx(tx, 0);
189 }
190 for (i = 0; i < ARRAY_SIZE(controller->rx); i++) {
191 struct cppi_channel *rx_ch = controller->rx + i;
192 struct cppi_rx_stateram __iomem *rx;
193
194 INIT_LIST_HEAD(&rx_ch->tx_complete);
195
196 rx = tibase + DAVINCI_RXCPPI_STATERAM_OFFSET(i);
197 rx_ch->state_ram = rx;
198 cppi_reset_rx(rx);
199 }
200
201 /* enable individual cppi channels */
202 musb_writel(tibase, DAVINCI_TXCPPI_INTENAB_REG,
203 DAVINCI_DMA_ALL_CHANNELS_ENABLE);
204 musb_writel(tibase, DAVINCI_RXCPPI_INTENAB_REG,
205 DAVINCI_DMA_ALL_CHANNELS_ENABLE);
206
207 /* enable tx/rx CPPI control */
208 musb_writel(tibase, DAVINCI_TXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_ENABLE);
209 musb_writel(tibase, DAVINCI_RXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_ENABLE);
210
211 /* disable RNDIS mode, also host rx RNDIS autorequest */
212 musb_writel(tibase, DAVINCI_RNDIS_REG, 0);
213 musb_writel(tibase, DAVINCI_AUTOREQ_REG, 0);
214}
215
216/*
217 * Stop DMA controller
218 *
219 * De-Init the DMA controller as necessary.
220 */
221
222static void cppi_controller_stop(struct cppi *controller)
223{
224 void __iomem *tibase;
225 int i;
226 struct musb *musb;
227
228 musb = controller->controller.musb;
229
230 tibase = controller->tibase;
231 /* DISABLE INDIVIDUAL CHANNEL Interrupts */
232 musb_writel(tibase, DAVINCI_TXCPPI_INTCLR_REG,
233 DAVINCI_DMA_ALL_CHANNELS_ENABLE);
234 musb_writel(tibase, DAVINCI_RXCPPI_INTCLR_REG,
235 DAVINCI_DMA_ALL_CHANNELS_ENABLE);
236
237 musb_dbg(musb, "Tearing down RX and TX Channels");
238 for (i = 0; i < ARRAY_SIZE(controller->tx); i++) {
239 /* FIXME restructure of txdma to use bds like rxdma */
240 controller->tx[i].last_processed = NULL;
241 cppi_pool_free(controller->tx + i);
242 }
243 for (i = 0; i < ARRAY_SIZE(controller->rx); i++)
244 cppi_pool_free(controller->rx + i);
245
246 /* in Tx Case proper teardown is supported. We resort to disabling
247 * Tx/Rx CPPI after cleanup of Tx channels. Before TX teardown is
248 * complete TX CPPI cannot be disabled.
249 */
250 /*disable tx/rx cppi */
251 musb_writel(tibase, DAVINCI_TXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_DISABLE);
252 musb_writel(tibase, DAVINCI_RXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_DISABLE);
253}
254
255/* While dma channel is allocated, we only want the core irqs active
256 * for fault reports, otherwise we'd get irqs that we don't care about.
257 * Except for TX irqs, where dma done != fifo empty and reusable ...
258 *
259 * NOTE: docs don't say either way, but irq masking **enables** irqs.
260 *
261 * REVISIT same issue applies to pure PIO usage too, and non-cppi dma...
262 */
263static inline void core_rxirq_disable(void __iomem *tibase, unsigned epnum)
264{
265 musb_writel(tibase, DAVINCI_USB_INT_MASK_CLR_REG, 1 << (epnum + 8));
266}
267
268static inline void core_rxirq_enable(void __iomem *tibase, unsigned epnum)
269{
270 musb_writel(tibase, DAVINCI_USB_INT_MASK_SET_REG, 1 << (epnum + 8));
271}
272
273
274/*
275 * Allocate a CPPI Channel for DMA. With CPPI, channels are bound to
276 * each transfer direction of a non-control endpoint, so allocating
277 * (and deallocating) is mostly a way to notice bad housekeeping on
278 * the software side. We assume the irqs are always active.
279 */
280static struct dma_channel *
281cppi_channel_allocate(struct dma_controller *c,
282 struct musb_hw_ep *ep, u8 transmit)
283{
284 struct cppi *controller;
285 u8 index;
286 struct cppi_channel *cppi_ch;
287 void __iomem *tibase;
288 struct musb *musb;
289
290 controller = container_of(c, struct cppi, controller);
291 tibase = controller->tibase;
292 musb = c->musb;
293
294 /* ep0 doesn't use DMA; remember cppi indices are 0..N-1 */
295 index = ep->epnum - 1;
296
297 /* return the corresponding CPPI Channel Handle, and
298 * probably disable the non-CPPI irq until we need it.
299 */
300 if (transmit) {
301 if (index >= ARRAY_SIZE(controller->tx)) {
302 musb_dbg(musb, "no %cX%d CPPI channel", 'T', index);
303 return NULL;
304 }
305 cppi_ch = controller->tx + index;
306 } else {
307 if (index >= ARRAY_SIZE(controller->rx)) {
308 musb_dbg(musb, "no %cX%d CPPI channel", 'R', index);
309 return NULL;
310 }
311 cppi_ch = controller->rx + index;
312 core_rxirq_disable(tibase, ep->epnum);
313 }
314
315 /* REVISIT make this an error later once the same driver code works
316 * with the other DMA engine too
317 */
318 if (cppi_ch->hw_ep)
319 musb_dbg(musb, "re-allocating DMA%d %cX channel %p",
320 index, transmit ? 'T' : 'R', cppi_ch);
321 cppi_ch->hw_ep = ep;
322 cppi_ch->channel.status = MUSB_DMA_STATUS_FREE;
323 cppi_ch->channel.max_len = 0x7fffffff;
324
325 musb_dbg(musb, "Allocate CPPI%d %cX", index, transmit ? 'T' : 'R');
326 return &cppi_ch->channel;
327}
328
329/* Release a CPPI Channel. */
330static void cppi_channel_release(struct dma_channel *channel)
331{
332 struct cppi_channel *c;
333 void __iomem *tibase;
334
335 /* REVISIT: for paranoia, check state and abort if needed... */
336
337 c = container_of(channel, struct cppi_channel, channel);
338 tibase = c->controller->tibase;
339 if (!c->hw_ep)
340 musb_dbg(c->controller->controller.musb,
341 "releasing idle DMA channel %p", c);
342 else if (!c->transmit)
343 core_rxirq_enable(tibase, c->index + 1);
344
345 /* for now, leave its cppi IRQ enabled (we won't trigger it) */
346 c->hw_ep = NULL;
347 channel->status = MUSB_DMA_STATUS_UNKNOWN;
348}
349
350/* Context: controller irqlocked */
351static void
352cppi_dump_rx(int level, struct cppi_channel *c, const char *tag)
353{
354 void __iomem *base = c->controller->mregs;
355 struct cppi_rx_stateram __iomem *rx = c->state_ram;
356
357 musb_ep_select(base, c->index + 1);
358
359 musb_dbg(c->controller->controller.musb,
360 "RX DMA%d%s: %d left, csr %04x, "
361 "%08x H%08x S%08x C%08x, "
362 "B%08x L%08x %08x .. %08x",
363 c->index, tag,
364 musb_readl(c->controller->tibase,
365 DAVINCI_RXCPPI_BUFCNT0_REG + 4 * c->index),
366 musb_readw(c->hw_ep->regs, MUSB_RXCSR),
367
368 musb_readl(&rx->rx_skipbytes, 0),
369 musb_readl(&rx->rx_head, 0),
370 musb_readl(&rx->rx_sop, 0),
371 musb_readl(&rx->rx_current, 0),
372
373 musb_readl(&rx->rx_buf_current, 0),
374 musb_readl(&rx->rx_len_len, 0),
375 musb_readl(&rx->rx_cnt_cnt, 0),
376 musb_readl(&rx->rx_complete, 0)
377 );
378}
379
380/* Context: controller irqlocked */
381static void
382cppi_dump_tx(int level, struct cppi_channel *c, const char *tag)
383{
384 void __iomem *base = c->controller->mregs;
385 struct cppi_tx_stateram __iomem *tx = c->state_ram;
386
387 musb_ep_select(base, c->index + 1);
388
389 musb_dbg(c->controller->controller.musb,
390 "TX DMA%d%s: csr %04x, "
391 "H%08x S%08x C%08x %08x, "
392 "F%08x L%08x .. %08x",
393 c->index, tag,
394 musb_readw(c->hw_ep->regs, MUSB_TXCSR),
395
396 musb_readl(&tx->tx_head, 0),
397 musb_readl(&tx->tx_buf, 0),
398 musb_readl(&tx->tx_current, 0),
399 musb_readl(&tx->tx_buf_current, 0),
400
401 musb_readl(&tx->tx_info, 0),
402 musb_readl(&tx->tx_rem_len, 0),
403 /* dummy/unused word 6 */
404 musb_readl(&tx->tx_complete, 0)
405 );
406}
407
408/* Context: controller irqlocked */
409static inline void
410cppi_rndis_update(struct cppi_channel *c, int is_rx,
411 void __iomem *tibase, int is_rndis)
412{
413 /* we may need to change the rndis flag for this cppi channel */
414 if (c->is_rndis != is_rndis) {
415 u32 value = musb_readl(tibase, DAVINCI_RNDIS_REG);
416 u32 temp = 1 << (c->index);
417
418 if (is_rx)
419 temp <<= 16;
420 if (is_rndis)
421 value |= temp;
422 else
423 value &= ~temp;
424 musb_writel(tibase, DAVINCI_RNDIS_REG, value);
425 c->is_rndis = is_rndis;
426 }
427}
428
429static void cppi_dump_rxbd(const char *tag, struct cppi_descriptor *bd)
430{
431 pr_debug("RXBD/%s %08x: "
432 "nxt %08x buf %08x off.blen %08x opt.plen %08x\n",
433 tag, bd->dma,
434 bd->hw_next, bd->hw_bufp, bd->hw_off_len,
435 bd->hw_options);
436}
437
438static void cppi_dump_rxq(int level, const char *tag, struct cppi_channel *rx)
439{
440 struct cppi_descriptor *bd;
441
442 cppi_dump_rx(level, rx, tag);
443 if (rx->last_processed)
444 cppi_dump_rxbd("last", rx->last_processed);
445 for (bd = rx->head; bd; bd = bd->next)
446 cppi_dump_rxbd("active", bd);
447}
448
449
450/* NOTE: DaVinci autoreq is ignored except for host side "RNDIS" mode RX;
451 * so we won't ever use it (see "CPPI RX Woes" below).
452 */
453static inline int cppi_autoreq_update(struct cppi_channel *rx,
454 void __iomem *tibase, int onepacket, unsigned n_bds)
455{
456 u32 val;
457
458#ifdef RNDIS_RX_IS_USABLE
459 u32 tmp;
460 /* assert(is_host_active(musb)) */
461
462 /* start from "AutoReq never" */
463 tmp = musb_readl(tibase, DAVINCI_AUTOREQ_REG);
464 val = tmp & ~((0x3) << (rx->index * 2));
465
466 /* HCD arranged reqpkt for packet #1. we arrange int
467 * for all but the last one, maybe in two segments.
468 */
469 if (!onepacket) {
470#if 0
471 /* use two segments, autoreq "all" then the last "never" */
472 val |= ((0x3) << (rx->index * 2));
473 n_bds--;
474#else
475 /* one segment, autoreq "all-but-last" */
476 val |= ((0x1) << (rx->index * 2));
477#endif
478 }
479
480 if (val != tmp) {
481 int n = 100;
482
483 /* make sure that autoreq is updated before continuing */
484 musb_writel(tibase, DAVINCI_AUTOREQ_REG, val);
485 do {
486 tmp = musb_readl(tibase, DAVINCI_AUTOREQ_REG);
487 if (tmp == val)
488 break;
489 cpu_relax();
490 } while (n-- > 0);
491 }
492#endif
493
494 /* REQPKT is turned off after each segment */
495 if (n_bds && rx->channel.actual_len) {
496 void __iomem *regs = rx->hw_ep->regs;
497
498 val = musb_readw(regs, MUSB_RXCSR);
499 if (!(val & MUSB_RXCSR_H_REQPKT)) {
500 val |= MUSB_RXCSR_H_REQPKT | MUSB_RXCSR_H_WZC_BITS;
501 musb_writew(regs, MUSB_RXCSR, val);
502 /* flush writebuffer */
503 val = musb_readw(regs, MUSB_RXCSR);
504 }
505 }
506 return n_bds;
507}
508
509
510/* Buffer enqueuing Logic:
511 *
512 * - RX builds new queues each time, to help handle routine "early
513 * termination" cases (faults, including errors and short reads)
514 * more correctly.
515 *
516 * - for now, TX reuses the same queue of BDs every time
517 *
518 * REVISIT long term, we want a normal dynamic model.
519 * ... the goal will be to append to the
520 * existing queue, processing completed "dma buffers" (segments) on the fly.
521 *
522 * Otherwise we force an IRQ latency between requests, which slows us a lot
523 * (especially in "transparent" dma). Unfortunately that model seems to be
524 * inherent in the DMA model from the Mentor code, except in the rare case
525 * of transfers big enough (~128+ KB) that we could append "middle" segments
526 * in the TX paths. (RX can't do this, see below.)
527 *
528 * That's true even in the CPPI- friendly iso case, where most urbs have
529 * several small segments provided in a group and where the "packet at a time"
530 * "transparent" DMA model is always correct, even on the RX side.
531 */
532
533/*
534 * CPPI TX:
535 * ========
536 * TX is a lot more reasonable than RX; it doesn't need to run in
537 * irq-per-packet mode very often. RNDIS mode seems to behave too
538 * (except how it handles the exactly-N-packets case). Building a
539 * txdma queue with multiple requests (urb or usb_request) looks
540 * like it would work ... but fault handling would need much testing.
541 *
542 * The main issue with TX mode RNDIS relates to transfer lengths that
543 * are an exact multiple of the packet length. It appears that there's
544 * a hiccup in that case (maybe the DMA completes before the ZLP gets
545 * written?) boiling down to not being able to rely on CPPI writing any
546 * terminating zero length packet before the next transfer is written.
547 * So that's punted to PIO; better yet, gadget drivers can avoid it.
548 *
549 * Plus, there's allegedly an undocumented constraint that rndis transfer
550 * length be a multiple of 64 bytes ... but the chip doesn't act that
551 * way, and we really don't _want_ that behavior anyway.
552 *
553 * On TX, "transparent" mode works ... although experiments have shown
554 * problems trying to use the SOP/EOP bits in different USB packets.
555 *
556 * REVISIT try to handle terminating zero length packets using CPPI
557 * instead of doing it by PIO after an IRQ. (Meanwhile, make Ethernet
558 * links avoid that issue by forcing them to avoid zlps.)
559 */
560static void
561cppi_next_tx_segment(struct musb *musb, struct cppi_channel *tx)
562{
563 unsigned maxpacket = tx->maxpacket;
564 dma_addr_t addr = tx->buf_dma + tx->offset;
565 size_t length = tx->buf_len - tx->offset;
566 struct cppi_descriptor *bd;
567 unsigned n_bds;
568 unsigned i;
569 struct cppi_tx_stateram __iomem *tx_ram = tx->state_ram;
570 int rndis;
571
572 /* TX can use the CPPI "rndis" mode, where we can probably fit this
573 * transfer in one BD and one IRQ. The only time we would NOT want
574 * to use it is when hardware constraints prevent it, or if we'd
575 * trigger the "send a ZLP?" confusion.
576 */
577 rndis = (maxpacket & 0x3f) == 0
578 && length > maxpacket
579 && length < 0xffff
580 && (length % maxpacket) != 0;
581
582 if (rndis) {
583 maxpacket = length;
584 n_bds = 1;
585 } else {
586 if (length)
587 n_bds = DIV_ROUND_UP(length, maxpacket);
588 else
589 n_bds = 1;
590 n_bds = min(n_bds, (unsigned) NUM_TXCHAN_BD);
591 length = min(n_bds * maxpacket, length);
592 }
593
594 musb_dbg(musb, "TX DMA%d, pktSz %d %s bds %d dma 0x%llx len %u",
595 tx->index,
596 maxpacket,
597 rndis ? "rndis" : "transparent",
598 n_bds,
599 (unsigned long long)addr, length);
600
601 cppi_rndis_update(tx, 0, musb->ctrl_base, rndis);
602
603 /* assuming here that channel_program is called during
604 * transfer initiation ... current code maintains state
605 * for one outstanding request only (no queues, not even
606 * the implicit ones of an iso urb).
607 */
608
609 bd = tx->freelist;
610 tx->head = bd;
611 tx->last_processed = NULL;
612
613 /* FIXME use BD pool like RX side does, and just queue
614 * the minimum number for this request.
615 */
616
617 /* Prepare queue of BDs first, then hand it to hardware.
618 * All BDs except maybe the last should be of full packet
619 * size; for RNDIS there _is_ only that last packet.
620 */
621 for (i = 0; i < n_bds; ) {
622 if (++i < n_bds && bd->next)
623 bd->hw_next = bd->next->dma;
624 else
625 bd->hw_next = 0;
626
627 bd->hw_bufp = tx->buf_dma + tx->offset;
628
629 /* FIXME set EOP only on the last packet,
630 * SOP only on the first ... avoid IRQs
631 */
632 if ((tx->offset + maxpacket) <= tx->buf_len) {
633 tx->offset += maxpacket;
634 bd->hw_off_len = maxpacket;
635 bd->hw_options = CPPI_SOP_SET | CPPI_EOP_SET
636 | CPPI_OWN_SET | maxpacket;
637 } else {
638 /* only this one may be a partial USB Packet */
639 u32 partial_len;
640
641 partial_len = tx->buf_len - tx->offset;
642 tx->offset = tx->buf_len;
643 bd->hw_off_len = partial_len;
644
645 bd->hw_options = CPPI_SOP_SET | CPPI_EOP_SET
646 | CPPI_OWN_SET | partial_len;
647 if (partial_len == 0)
648 bd->hw_options |= CPPI_ZERO_SET;
649 }
650
651 musb_dbg(musb, "TXBD %p: nxt %08x buf %08x len %04x opt %08x",
652 bd, bd->hw_next, bd->hw_bufp,
653 bd->hw_off_len, bd->hw_options);
654
655 /* update the last BD enqueued to the list */
656 tx->tail = bd;
657 bd = bd->next;
658 }
659
660 /* BDs live in DMA-coherent memory, but writes might be pending */
661 cpu_drain_writebuffer();
662
663 /* Write to the HeadPtr in state RAM to trigger */
664 musb_writel(&tx_ram->tx_head, 0, (u32)tx->freelist->dma);
665
666 cppi_dump_tx(5, tx, "/S");
667}
668
669/*
670 * CPPI RX Woes:
671 * =============
672 * Consider a 1KB bulk RX buffer in two scenarios: (a) it's fed two 300 byte
673 * packets back-to-back, and (b) it's fed two 512 byte packets back-to-back.
674 * (Full speed transfers have similar scenarios.)
675 *
676 * The correct behavior for Linux is that (a) fills the buffer with 300 bytes,
677 * and the next packet goes into a buffer that's queued later; while (b) fills
678 * the buffer with 1024 bytes. How to do that with CPPI?
679 *
680 * - RX queues in "rndis" mode -- one single BD -- handle (a) correctly, but
681 * (b) loses **BADLY** because nothing (!) happens when that second packet
682 * fills the buffer, much less when a third one arrives. (Which makes this
683 * not a "true" RNDIS mode. In the RNDIS protocol short-packet termination
684 * is optional, and it's fine if peripherals -- not hosts! -- pad messages
685 * out to end-of-buffer. Standard PCI host controller DMA descriptors
686 * implement that mode by default ... which is no accident.)
687 *
688 * - RX queues in "transparent" mode -- two BDs with 512 bytes each -- have
689 * converse problems: (b) is handled right, but (a) loses badly. CPPI RX
690 * ignores SOP/EOP markings and processes both of those BDs; so both packets
691 * are loaded into the buffer (with a 212 byte gap between them), and the next
692 * buffer queued will NOT get its 300 bytes of data. (It seems like SOP/EOP
693 * are intended as outputs for RX queues, not inputs...)
694 *
695 * - A variant of "transparent" mode -- one BD at a time -- is the only way to
696 * reliably make both cases work, with software handling both cases correctly
697 * and at the significant penalty of needing an IRQ per packet. (The lack of
698 * I/O overlap can be slightly ameliorated by enabling double buffering.)
699 *
700 * So how to get rid of IRQ-per-packet? The transparent multi-BD case could
701 * be used in special cases like mass storage, which sets URB_SHORT_NOT_OK
702 * (or maybe its peripheral side counterpart) to flag (a) scenarios as errors
703 * with guaranteed driver level fault recovery and scrubbing out what's left
704 * of that garbaged datastream.
705 *
706 * But there seems to be no way to identify the cases where CPPI RNDIS mode
707 * is appropriate -- which do NOT include RNDIS host drivers, but do include
708 * the CDC Ethernet driver! -- and the documentation is incomplete/wrong.
709 * So we can't _ever_ use RX RNDIS mode ... except by using a heuristic
710 * that applies best on the peripheral side (and which could fail rudely).
711 *
712 * Leaving only "transparent" mode; we avoid multi-bd modes in almost all
713 * cases other than mass storage class. Otherwise we're correct but slow,
714 * since CPPI penalizes our need for a "true RNDIS" default mode.
715 */
716
717
718/* Heuristic, intended to kick in for ethernet/rndis peripheral ONLY
719 *
720 * IFF
721 * (a) peripheral mode ... since rndis peripherals could pad their
722 * writes to hosts, causing i/o failure; or we'd have to cope with
723 * a largely unknowable variety of host side protocol variants
724 * (b) and short reads are NOT errors ... since full reads would
725 * cause those same i/o failures
726 * (c) and read length is
727 * - less than 64KB (max per cppi descriptor)
728 * - not a multiple of 4096 (g_zero default, full reads typical)
729 * - N (>1) packets long, ditto (full reads not EXPECTED)
730 * THEN
731 * try rx rndis mode
732 *
733 * Cost of heuristic failing: RXDMA wedges at the end of transfers that
734 * fill out the whole buffer. Buggy host side usb network drivers could
735 * trigger that, but "in the field" such bugs seem to be all but unknown.
736 *
737 * So this module parameter lets the heuristic be disabled. When using
738 * gadgetfs, the heuristic will probably need to be disabled.
739 */
740static bool cppi_rx_rndis = 1;
741
742module_param(cppi_rx_rndis, bool, 0);
743MODULE_PARM_DESC(cppi_rx_rndis, "enable/disable RX RNDIS heuristic");
744
745
746/**
747 * cppi_next_rx_segment - dma read for the next chunk of a buffer
748 * @musb: the controller
749 * @rx: dma channel
750 * @onepacket: true unless caller treats short reads as errors, and
751 * performs fault recovery above usbcore.
752 * Context: controller irqlocked
753 *
754 * See above notes about why we can't use multi-BD RX queues except in
755 * rare cases (mass storage class), and can never use the hardware "rndis"
756 * mode (since it's not a "true" RNDIS mode) with complete safety..
757 *
758 * It's ESSENTIAL that callers specify "onepacket" mode unless they kick in
759 * code to recover from corrupted datastreams after each short transfer.
760 */
761static void
762cppi_next_rx_segment(struct musb *musb, struct cppi_channel *rx, int onepacket)
763{
764 unsigned maxpacket = rx->maxpacket;
765 dma_addr_t addr = rx->buf_dma + rx->offset;
766 size_t length = rx->buf_len - rx->offset;
767 struct cppi_descriptor *bd, *tail;
768 unsigned n_bds;
769 unsigned i;
770 void __iomem *tibase = musb->ctrl_base;
771 int is_rndis = 0;
772 struct cppi_rx_stateram __iomem *rx_ram = rx->state_ram;
773 struct cppi_descriptor *d;
774
775 if (onepacket) {
776 /* almost every USB driver, host or peripheral side */
777 n_bds = 1;
778
779 /* maybe apply the heuristic above */
780 if (cppi_rx_rndis
781 && is_peripheral_active(musb)
782 && length > maxpacket
783 && (length & ~0xffff) == 0
784 && (length & 0x0fff) != 0
785 && (length & (maxpacket - 1)) == 0) {
786 maxpacket = length;
787 is_rndis = 1;
788 }
789 } else {
790 /* virtually nothing except mass storage class */
791 if (length > 0xffff) {
792 n_bds = 0xffff / maxpacket;
793 length = n_bds * maxpacket;
794 } else {
795 n_bds = DIV_ROUND_UP(length, maxpacket);
796 }
797 if (n_bds == 1)
798 onepacket = 1;
799 else
800 n_bds = min(n_bds, (unsigned) NUM_RXCHAN_BD);
801 }
802
803 /* In host mode, autorequest logic can generate some IN tokens; it's
804 * tricky since we can't leave REQPKT set in RXCSR after the transfer
805 * finishes. So: multipacket transfers involve two or more segments.
806 * And always at least two IRQs ... RNDIS mode is not an option.
807 */
808 if (is_host_active(musb))
809 n_bds = cppi_autoreq_update(rx, tibase, onepacket, n_bds);
810
811 cppi_rndis_update(rx, 1, musb->ctrl_base, is_rndis);
812
813 length = min(n_bds * maxpacket, length);
814
815 musb_dbg(musb, "RX DMA%d seg, maxp %d %s bds %d (cnt %d) "
816 "dma 0x%llx len %u %u/%u",
817 rx->index, maxpacket,
818 onepacket
819 ? (is_rndis ? "rndis" : "onepacket")
820 : "multipacket",
821 n_bds,
822 musb_readl(tibase,
823 DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4))
824 & 0xffff,
825 (unsigned long long)addr, length,
826 rx->channel.actual_len, rx->buf_len);
827
828 /* only queue one segment at a time, since the hardware prevents
829 * correct queue shutdown after unexpected short packets
830 */
831 bd = cppi_bd_alloc(rx);
832 rx->head = bd;
833
834 /* Build BDs for all packets in this segment */
835 for (i = 0, tail = NULL; bd && i < n_bds; i++, tail = bd) {
836 u32 bd_len;
837
838 if (i) {
839 bd = cppi_bd_alloc(rx);
840 if (!bd)
841 break;
842 tail->next = bd;
843 tail->hw_next = bd->dma;
844 }
845 bd->hw_next = 0;
846
847 /* all but the last packet will be maxpacket size */
848 if (maxpacket < length)
849 bd_len = maxpacket;
850 else
851 bd_len = length;
852
853 bd->hw_bufp = addr;
854 addr += bd_len;
855 rx->offset += bd_len;
856
857 bd->hw_off_len = (0 /*offset*/ << 16) + bd_len;
858 bd->buflen = bd_len;
859
860 bd->hw_options = CPPI_OWN_SET | (i == 0 ? length : 0);
861 length -= bd_len;
862 }
863
864 /* we always expect at least one reusable BD! */
865 if (!tail) {
866 WARNING("rx dma%d -- no BDs? need %d\n", rx->index, n_bds);
867 return;
868 } else if (i < n_bds)
869 WARNING("rx dma%d -- only %d of %d BDs\n", rx->index, i, n_bds);
870
871 tail->next = NULL;
872 tail->hw_next = 0;
873
874 bd = rx->head;
875 rx->tail = tail;
876
877 /* short reads and other faults should terminate this entire
878 * dma segment. we want one "dma packet" per dma segment, not
879 * one per USB packet, terminating the whole queue at once...
880 * NOTE that current hardware seems to ignore SOP and EOP.
881 */
882 bd->hw_options |= CPPI_SOP_SET;
883 tail->hw_options |= CPPI_EOP_SET;
884
885 for (d = rx->head; d; d = d->next)
886 cppi_dump_rxbd("S", d);
887
888 /* in case the preceding transfer left some state... */
889 tail = rx->last_processed;
890 if (tail) {
891 tail->next = bd;
892 tail->hw_next = bd->dma;
893 }
894
895 core_rxirq_enable(tibase, rx->index + 1);
896
897 /* BDs live in DMA-coherent memory, but writes might be pending */
898 cpu_drain_writebuffer();
899
900 /* REVISIT specs say to write this AFTER the BUFCNT register
901 * below ... but that loses badly.
902 */
903 musb_writel(&rx_ram->rx_head, 0, bd->dma);
904
905 /* bufferCount must be at least 3, and zeroes on completion
906 * unless it underflows below zero, or stops at two, or keeps
907 * growing ... grr.
908 */
909 i = musb_readl(tibase,
910 DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4))
911 & 0xffff;
912
913 if (!i)
914 musb_writel(tibase,
915 DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4),
916 n_bds + 2);
917 else if (n_bds > (i - 3))
918 musb_writel(tibase,
919 DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4),
920 n_bds - (i - 3));
921
922 i = musb_readl(tibase,
923 DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4))
924 & 0xffff;
925 if (i < (2 + n_bds)) {
926 musb_dbg(musb, "bufcnt%d underrun - %d (for %d)",
927 rx->index, i, n_bds);
928 musb_writel(tibase,
929 DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4),
930 n_bds + 2);
931 }
932
933 cppi_dump_rx(4, rx, "/S");
934}
935
936/**
937 * cppi_channel_program - program channel for data transfer
938 * @ch: the channel
939 * @maxpacket: max packet size
940 * @mode: For RX, 1 unless the usb protocol driver promised to treat
941 * all short reads as errors and kick in high level fault recovery.
942 * For TX, ignored because of RNDIS mode races/glitches.
943 * @dma_addr: dma address of buffer
944 * @len: length of buffer
945 * Context: controller irqlocked
946 */
947static int cppi_channel_program(struct dma_channel *ch,
948 u16 maxpacket, u8 mode,
949 dma_addr_t dma_addr, u32 len)
950{
951 struct cppi_channel *cppi_ch;
952 struct cppi *controller;
953 struct musb *musb;
954
955 cppi_ch = container_of(ch, struct cppi_channel, channel);
956 controller = cppi_ch->controller;
957 musb = controller->controller.musb;
958
959 switch (ch->status) {
960 case MUSB_DMA_STATUS_BUS_ABORT:
961 case MUSB_DMA_STATUS_CORE_ABORT:
962 /* fault irq handler should have handled cleanup */
963 WARNING("%cX DMA%d not cleaned up after abort!\n",
964 cppi_ch->transmit ? 'T' : 'R',
965 cppi_ch->index);
966 /* WARN_ON(1); */
967 break;
968 case MUSB_DMA_STATUS_BUSY:
969 WARNING("program active channel? %cX DMA%d\n",
970 cppi_ch->transmit ? 'T' : 'R',
971 cppi_ch->index);
972 /* WARN_ON(1); */
973 break;
974 case MUSB_DMA_STATUS_UNKNOWN:
975 musb_dbg(musb, "%cX DMA%d not allocated!",
976 cppi_ch->transmit ? 'T' : 'R',
977 cppi_ch->index);
978 fallthrough;
979 case MUSB_DMA_STATUS_FREE:
980 break;
981 }
982
983 ch->status = MUSB_DMA_STATUS_BUSY;
984
985 /* set transfer parameters, then queue up its first segment */
986 cppi_ch->buf_dma = dma_addr;
987 cppi_ch->offset = 0;
988 cppi_ch->maxpacket = maxpacket;
989 cppi_ch->buf_len = len;
990 cppi_ch->channel.actual_len = 0;
991
992 /* TX channel? or RX? */
993 if (cppi_ch->transmit)
994 cppi_next_tx_segment(musb, cppi_ch);
995 else
996 cppi_next_rx_segment(musb, cppi_ch, mode);
997
998 return true;
999}
1000
1001static bool cppi_rx_scan(struct cppi *cppi, unsigned ch)
1002{
1003 struct cppi_channel *rx = &cppi->rx[ch];
1004 struct cppi_rx_stateram __iomem *state = rx->state_ram;
1005 struct cppi_descriptor *bd;
1006 struct cppi_descriptor *last = rx->last_processed;
1007 bool completed = false;
1008 bool acked = false;
1009 int i;
1010 dma_addr_t safe2ack;
1011 void __iomem *regs = rx->hw_ep->regs;
1012 struct musb *musb = cppi->controller.musb;
1013
1014 cppi_dump_rx(6, rx, "/K");
1015
1016 bd = last ? last->next : rx->head;
1017 if (!bd)
1018 return false;
1019
1020 /* run through all completed BDs */
1021 for (i = 0, safe2ack = musb_readl(&state->rx_complete, 0);
1022 (safe2ack || completed) && bd && i < NUM_RXCHAN_BD;
1023 i++, bd = bd->next) {
1024 u16 len;
1025
1026 /* catch latest BD writes from CPPI */
1027 rmb();
1028 if (!completed && (bd->hw_options & CPPI_OWN_SET))
1029 break;
1030
1031 musb_dbg(musb, "C/RXBD %llx: nxt %08x buf %08x "
1032 "off.len %08x opt.len %08x (%d)",
1033 (unsigned long long)bd->dma, bd->hw_next, bd->hw_bufp,
1034 bd->hw_off_len, bd->hw_options,
1035 rx->channel.actual_len);
1036
1037 /* actual packet received length */
1038 if ((bd->hw_options & CPPI_SOP_SET) && !completed)
1039 len = bd->hw_off_len & CPPI_RECV_PKTLEN_MASK;
1040 else
1041 len = 0;
1042
1043 if (bd->hw_options & CPPI_EOQ_MASK)
1044 completed = true;
1045
1046 if (!completed && len < bd->buflen) {
1047 /* NOTE: when we get a short packet, RXCSR_H_REQPKT
1048 * must have been cleared, and no more DMA packets may
1049 * active be in the queue... TI docs didn't say, but
1050 * CPPI ignores those BDs even though OWN is still set.
1051 */
1052 completed = true;
1053 musb_dbg(musb, "rx short %d/%d (%d)",
1054 len, bd->buflen,
1055 rx->channel.actual_len);
1056 }
1057
1058 /* If we got here, we expect to ack at least one BD; meanwhile
1059 * CPPI may completing other BDs while we scan this list...
1060 *
1061 * RACE: we can notice OWN cleared before CPPI raises the
1062 * matching irq by writing that BD as the completion pointer.
1063 * In such cases, stop scanning and wait for the irq, avoiding
1064 * lost acks and states where BD ownership is unclear.
1065 */
1066 if (bd->dma == safe2ack) {
1067 musb_writel(&state->rx_complete, 0, safe2ack);
1068 safe2ack = musb_readl(&state->rx_complete, 0);
1069 acked = true;
1070 if (bd->dma == safe2ack)
1071 safe2ack = 0;
1072 }
1073
1074 rx->channel.actual_len += len;
1075
1076 cppi_bd_free(rx, last);
1077 last = bd;
1078
1079 /* stop scanning on end-of-segment */
1080 if (bd->hw_next == 0)
1081 completed = true;
1082 }
1083 rx->last_processed = last;
1084
1085 /* dma abort, lost ack, or ... */
1086 if (!acked && last) {
1087 int csr;
1088
1089 if (safe2ack == 0 || safe2ack == rx->last_processed->dma)
1090 musb_writel(&state->rx_complete, 0, safe2ack);
1091 if (safe2ack == 0) {
1092 cppi_bd_free(rx, last);
1093 rx->last_processed = NULL;
1094
1095 /* if we land here on the host side, H_REQPKT will
1096 * be clear and we need to restart the queue...
1097 */
1098 WARN_ON(rx->head);
1099 }
1100 musb_ep_select(cppi->mregs, rx->index + 1);
1101 csr = musb_readw(regs, MUSB_RXCSR);
1102 if (csr & MUSB_RXCSR_DMAENAB) {
1103 musb_dbg(musb, "list%d %p/%p, last %llx%s, csr %04x",
1104 rx->index,
1105 rx->head, rx->tail,
1106 rx->last_processed
1107 ? (unsigned long long)
1108 rx->last_processed->dma
1109 : 0,
1110 completed ? ", completed" : "",
1111 csr);
1112 cppi_dump_rxq(4, "/what?", rx);
1113 }
1114 }
1115 if (!completed) {
1116 int csr;
1117
1118 rx->head = bd;
1119
1120 /* REVISIT seems like "autoreq all but EOP" doesn't...
1121 * setting it here "should" be racey, but seems to work
1122 */
1123 csr = musb_readw(rx->hw_ep->regs, MUSB_RXCSR);
1124 if (is_host_active(cppi->controller.musb)
1125 && bd
1126 && !(csr & MUSB_RXCSR_H_REQPKT)) {
1127 csr |= MUSB_RXCSR_H_REQPKT;
1128 musb_writew(regs, MUSB_RXCSR,
1129 MUSB_RXCSR_H_WZC_BITS | csr);
1130 csr = musb_readw(rx->hw_ep->regs, MUSB_RXCSR);
1131 }
1132 } else {
1133 rx->head = NULL;
1134 rx->tail = NULL;
1135 }
1136
1137 cppi_dump_rx(6, rx, completed ? "/completed" : "/cleaned");
1138 return completed;
1139}
1140
1141irqreturn_t cppi_interrupt(int irq, void *dev_id)
1142{
1143 struct musb *musb = dev_id;
1144 struct cppi *cppi;
1145 void __iomem *tibase;
1146 struct musb_hw_ep *hw_ep = NULL;
1147 u32 rx, tx;
1148 int i, index;
1149 unsigned long flags;
1150
1151 cppi = container_of(musb->dma_controller, struct cppi, controller);
1152 if (cppi->irq)
1153 spin_lock_irqsave(&musb->lock, flags);
1154
1155 tibase = musb->ctrl_base;
1156
1157 tx = musb_readl(tibase, DAVINCI_TXCPPI_MASKED_REG);
1158 rx = musb_readl(tibase, DAVINCI_RXCPPI_MASKED_REG);
1159
1160 if (!tx && !rx) {
1161 if (cppi->irq)
1162 spin_unlock_irqrestore(&musb->lock, flags);
1163 return IRQ_NONE;
1164 }
1165
1166 musb_dbg(musb, "CPPI IRQ Tx%x Rx%x", tx, rx);
1167
1168 /* process TX channels */
1169 for (index = 0; tx; tx = tx >> 1, index++) {
1170 struct cppi_channel *tx_ch;
1171 struct cppi_tx_stateram __iomem *tx_ram;
1172 bool completed = false;
1173 struct cppi_descriptor *bd;
1174
1175 if (!(tx & 1))
1176 continue;
1177
1178 tx_ch = cppi->tx + index;
1179 tx_ram = tx_ch->state_ram;
1180
1181 /* FIXME need a cppi_tx_scan() routine, which
1182 * can also be called from abort code
1183 */
1184
1185 cppi_dump_tx(5, tx_ch, "/E");
1186
1187 bd = tx_ch->head;
1188
1189 /*
1190 * If Head is null then this could mean that a abort interrupt
1191 * that needs to be acknowledged.
1192 */
1193 if (NULL == bd) {
1194 musb_dbg(musb, "null BD");
1195 musb_writel(&tx_ram->tx_complete, 0, 0);
1196 continue;
1197 }
1198
1199 /* run through all completed BDs */
1200 for (i = 0; !completed && bd && i < NUM_TXCHAN_BD;
1201 i++, bd = bd->next) {
1202 u16 len;
1203
1204 /* catch latest BD writes from CPPI */
1205 rmb();
1206 if (bd->hw_options & CPPI_OWN_SET)
1207 break;
1208
1209 musb_dbg(musb, "C/TXBD %p n %x b %x off %x opt %x",
1210 bd, bd->hw_next, bd->hw_bufp,
1211 bd->hw_off_len, bd->hw_options);
1212
1213 len = bd->hw_off_len & CPPI_BUFFER_LEN_MASK;
1214 tx_ch->channel.actual_len += len;
1215
1216 tx_ch->last_processed = bd;
1217
1218 /* write completion register to acknowledge
1219 * processing of completed BDs, and possibly
1220 * release the IRQ; EOQ might not be set ...
1221 *
1222 * REVISIT use the same ack strategy as rx
1223 *
1224 * REVISIT have observed bit 18 set; huh??
1225 */
1226 /* if ((bd->hw_options & CPPI_EOQ_MASK)) */
1227 musb_writel(&tx_ram->tx_complete, 0, bd->dma);
1228
1229 /* stop scanning on end-of-segment */
1230 if (bd->hw_next == 0)
1231 completed = true;
1232 }
1233
1234 /* on end of segment, maybe go to next one */
1235 if (completed) {
1236 /* cppi_dump_tx(4, tx_ch, "/complete"); */
1237
1238 /* transfer more, or report completion */
1239 if (tx_ch->offset >= tx_ch->buf_len) {
1240 tx_ch->head = NULL;
1241 tx_ch->tail = NULL;
1242 tx_ch->channel.status = MUSB_DMA_STATUS_FREE;
1243
1244 hw_ep = tx_ch->hw_ep;
1245
1246 musb_dma_completion(musb, index + 1, 1);
1247
1248 } else {
1249 /* Bigger transfer than we could fit in
1250 * that first batch of descriptors...
1251 */
1252 cppi_next_tx_segment(musb, tx_ch);
1253 }
1254 } else
1255 tx_ch->head = bd;
1256 }
1257
1258 /* Start processing the RX block */
1259 for (index = 0; rx; rx = rx >> 1, index++) {
1260
1261 if (rx & 1) {
1262 struct cppi_channel *rx_ch;
1263
1264 rx_ch = cppi->rx + index;
1265
1266 /* let incomplete dma segments finish */
1267 if (!cppi_rx_scan(cppi, index))
1268 continue;
1269
1270 /* start another dma segment if needed */
1271 if (rx_ch->channel.actual_len != rx_ch->buf_len
1272 && rx_ch->channel.actual_len
1273 == rx_ch->offset) {
1274 cppi_next_rx_segment(musb, rx_ch, 1);
1275 continue;
1276 }
1277
1278 /* all segments completed! */
1279 rx_ch->channel.status = MUSB_DMA_STATUS_FREE;
1280
1281 hw_ep = rx_ch->hw_ep;
1282
1283 core_rxirq_disable(tibase, index + 1);
1284 musb_dma_completion(musb, index + 1, 0);
1285 }
1286 }
1287
1288 /* write to CPPI EOI register to re-enable interrupts */
1289 musb_writel(tibase, DAVINCI_CPPI_EOI_REG, 0);
1290
1291 if (cppi->irq)
1292 spin_unlock_irqrestore(&musb->lock, flags);
1293
1294 return IRQ_HANDLED;
1295}
1296EXPORT_SYMBOL_GPL(cppi_interrupt);
1297
1298/* Instantiate a software object representing a DMA controller. */
1299struct dma_controller *
1300cppi_dma_controller_create(struct musb *musb, void __iomem *mregs)
1301{
1302 struct cppi *controller;
1303 struct device *dev = musb->controller;
1304 struct platform_device *pdev = to_platform_device(dev);
1305 int irq = platform_get_irq_byname(pdev, "dma");
1306
1307 controller = kzalloc(sizeof *controller, GFP_KERNEL);
1308 if (!controller)
1309 return NULL;
1310
1311 controller->mregs = mregs;
1312 controller->tibase = mregs - DAVINCI_BASE_OFFSET;
1313
1314 controller->controller.musb = musb;
1315 controller->controller.channel_alloc = cppi_channel_allocate;
1316 controller->controller.channel_release = cppi_channel_release;
1317 controller->controller.channel_program = cppi_channel_program;
1318 controller->controller.channel_abort = cppi_channel_abort;
1319
1320 /* NOTE: allocating from on-chip SRAM would give the least
1321 * contention for memory access, if that ever matters here.
1322 */
1323
1324 /* setup BufferPool */
1325 controller->pool = dma_pool_create("cppi",
1326 controller->controller.musb->controller,
1327 sizeof(struct cppi_descriptor),
1328 CPPI_DESCRIPTOR_ALIGN, 0);
1329 if (!controller->pool) {
1330 kfree(controller);
1331 return NULL;
1332 }
1333
1334 if (irq > 0) {
1335 if (request_irq(irq, cppi_interrupt, 0, "cppi-dma", musb)) {
1336 dev_err(dev, "request_irq %d failed!\n", irq);
1337 musb_dma_controller_destroy(&controller->controller);
1338 return NULL;
1339 }
1340 controller->irq = irq;
1341 }
1342
1343 cppi_controller_start(controller);
1344 return &controller->controller;
1345}
1346EXPORT_SYMBOL_GPL(cppi_dma_controller_create);
1347
1348/*
1349 * Destroy a previously-instantiated DMA controller.
1350 */
1351void cppi_dma_controller_destroy(struct dma_controller *c)
1352{
1353 struct cppi *cppi;
1354
1355 cppi = container_of(c, struct cppi, controller);
1356
1357 cppi_controller_stop(cppi);
1358
1359 if (cppi->irq)
1360 free_irq(cppi->irq, cppi->controller.musb);
1361
1362 /* assert: caller stopped the controller first */
1363 dma_pool_destroy(cppi->pool);
1364
1365 kfree(cppi);
1366}
1367EXPORT_SYMBOL_GPL(cppi_dma_controller_destroy);
1368
1369/*
1370 * Context: controller irqlocked, endpoint selected
1371 */
1372static int cppi_channel_abort(struct dma_channel *channel)
1373{
1374 struct cppi_channel *cppi_ch;
1375 struct cppi *controller;
1376 void __iomem *mbase;
1377 void __iomem *tibase;
1378 void __iomem *regs;
1379 u32 value;
1380 struct cppi_descriptor *queue;
1381
1382 cppi_ch = container_of(channel, struct cppi_channel, channel);
1383
1384 controller = cppi_ch->controller;
1385
1386 switch (channel->status) {
1387 case MUSB_DMA_STATUS_BUS_ABORT:
1388 case MUSB_DMA_STATUS_CORE_ABORT:
1389 /* from RX or TX fault irq handler */
1390 case MUSB_DMA_STATUS_BUSY:
1391 /* the hardware needs shutting down */
1392 regs = cppi_ch->hw_ep->regs;
1393 break;
1394 case MUSB_DMA_STATUS_UNKNOWN:
1395 case MUSB_DMA_STATUS_FREE:
1396 return 0;
1397 default:
1398 return -EINVAL;
1399 }
1400
1401 if (!cppi_ch->transmit && cppi_ch->head)
1402 cppi_dump_rxq(3, "/abort", cppi_ch);
1403
1404 mbase = controller->mregs;
1405 tibase = controller->tibase;
1406
1407 queue = cppi_ch->head;
1408 cppi_ch->head = NULL;
1409 cppi_ch->tail = NULL;
1410
1411 /* REVISIT should rely on caller having done this,
1412 * and caller should rely on us not changing it.
1413 * peripheral code is safe ... check host too.
1414 */
1415 musb_ep_select(mbase, cppi_ch->index + 1);
1416
1417 if (cppi_ch->transmit) {
1418 struct cppi_tx_stateram __iomem *tx_ram;
1419 /* REVISIT put timeouts on these controller handshakes */
1420
1421 cppi_dump_tx(6, cppi_ch, " (teardown)");
1422
1423 /* teardown DMA engine then usb core */
1424 do {
1425 value = musb_readl(tibase, DAVINCI_TXCPPI_TEAR_REG);
1426 } while (!(value & CPPI_TEAR_READY));
1427 musb_writel(tibase, DAVINCI_TXCPPI_TEAR_REG, cppi_ch->index);
1428
1429 tx_ram = cppi_ch->state_ram;
1430 do {
1431 value = musb_readl(&tx_ram->tx_complete, 0);
1432 } while (0xFFFFFFFC != value);
1433
1434 /* FIXME clean up the transfer state ... here?
1435 * the completion routine should get called with
1436 * an appropriate status code.
1437 */
1438
1439 value = musb_readw(regs, MUSB_TXCSR);
1440 value &= ~MUSB_TXCSR_DMAENAB;
1441 value |= MUSB_TXCSR_FLUSHFIFO;
1442 musb_writew(regs, MUSB_TXCSR, value);
1443 musb_writew(regs, MUSB_TXCSR, value);
1444
1445 /*
1446 * 1. Write to completion Ptr value 0x1(bit 0 set)
1447 * (write back mode)
1448 * 2. Wait for abort interrupt and then put the channel in
1449 * compare mode by writing 1 to the tx_complete register.
1450 */
1451 cppi_reset_tx(tx_ram, 1);
1452 cppi_ch->head = NULL;
1453 musb_writel(&tx_ram->tx_complete, 0, 1);
1454 cppi_dump_tx(5, cppi_ch, " (done teardown)");
1455
1456 /* REVISIT tx side _should_ clean up the same way
1457 * as the RX side ... this does no cleanup at all!
1458 */
1459
1460 } else /* RX */ {
1461 u16 csr;
1462
1463 /* NOTE: docs don't guarantee any of this works ... we
1464 * expect that if the usb core stops telling the cppi core
1465 * to pull more data from it, then it'll be safe to flush
1466 * current RX DMA state iff any pending fifo transfer is done.
1467 */
1468
1469 core_rxirq_disable(tibase, cppi_ch->index + 1);
1470
1471 /* for host, ensure ReqPkt is never set again */
1472 if (is_host_active(cppi_ch->controller->controller.musb)) {
1473 value = musb_readl(tibase, DAVINCI_AUTOREQ_REG);
1474 value &= ~((0x3) << (cppi_ch->index * 2));
1475 musb_writel(tibase, DAVINCI_AUTOREQ_REG, value);
1476 }
1477
1478 csr = musb_readw(regs, MUSB_RXCSR);
1479
1480 /* for host, clear (just) ReqPkt at end of current packet(s) */
1481 if (is_host_active(cppi_ch->controller->controller.musb)) {
1482 csr |= MUSB_RXCSR_H_WZC_BITS;
1483 csr &= ~MUSB_RXCSR_H_REQPKT;
1484 } else
1485 csr |= MUSB_RXCSR_P_WZC_BITS;
1486
1487 /* clear dma enable */
1488 csr &= ~(MUSB_RXCSR_DMAENAB);
1489 musb_writew(regs, MUSB_RXCSR, csr);
1490 csr = musb_readw(regs, MUSB_RXCSR);
1491
1492 /* Quiesce: wait for current dma to finish (if not cleanup).
1493 * We can't use bit zero of stateram->rx_sop, since that
1494 * refers to an entire "DMA packet" not just emptying the
1495 * current fifo. Most segments need multiple usb packets.
1496 */
1497 if (channel->status == MUSB_DMA_STATUS_BUSY)
1498 udelay(50);
1499
1500 /* scan the current list, reporting any data that was
1501 * transferred and acking any IRQ
1502 */
1503 cppi_rx_scan(controller, cppi_ch->index);
1504
1505 /* clobber the existing state once it's idle
1506 *
1507 * NOTE: arguably, we should also wait for all the other
1508 * RX channels to quiesce (how??) and then temporarily
1509 * disable RXCPPI_CTRL_REG ... but it seems that we can
1510 * rely on the controller restarting from state ram, with
1511 * only RXCPPI_BUFCNT state being bogus. BUFCNT will
1512 * correct itself after the next DMA transfer though.
1513 *
1514 * REVISIT does using rndis mode change that?
1515 */
1516 cppi_reset_rx(cppi_ch->state_ram);
1517
1518 /* next DMA request _should_ load cppi head ptr */
1519
1520 /* ... we don't "free" that list, only mutate it in place. */
1521 cppi_dump_rx(5, cppi_ch, " (done abort)");
1522
1523 /* clean up previously pending bds */
1524 cppi_bd_free(cppi_ch, cppi_ch->last_processed);
1525 cppi_ch->last_processed = NULL;
1526
1527 while (queue) {
1528 struct cppi_descriptor *tmp = queue->next;
1529
1530 cppi_bd_free(cppi_ch, queue);
1531 queue = tmp;
1532 }
1533 }
1534
1535 channel->status = MUSB_DMA_STATUS_FREE;
1536 cppi_ch->buf_dma = 0;
1537 cppi_ch->offset = 0;
1538 cppi_ch->buf_len = 0;
1539 cppi_ch->maxpacket = 0;
1540 return 0;
1541}
1542
1543/* TBD Queries:
1544 *
1545 * Power Management ... probably turn off cppi during suspend, restart;
1546 * check state ram? Clocking is presumably shared with usb core.
1547 */