1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * BCM2835 DMA engine support 4 * 5 * Author: Florian Meier <florian.meier@koalo.de> 6 * Copyright 2013 7 * 8 * Based on 9 * OMAP DMAengine support by Russell King 10 * 11 * BCM2708 DMA Driver 12 * Copyright (C) 2010 Broadcom 13 * 14 * Raspberry Pi PCM I2S ALSA Driver 15 * Copyright (c) by Phil Poole 2013 16 * 17 * MARVELL MMP Peripheral DMA Driver 18 * Copyright 2012 Marvell International Ltd. 19 */ 20 #include <linux/dmaengine.h> 21 #include <linux/dma-mapping.h> 22 #include <linux/dmapool.h> 23 #include <linux/err.h> 24 #include <linux/init.h> 25 #include <linux/interrupt.h> 26 #include <linux/list.h> 27 #include <linux/module.h> 28 #include <linux/platform_device.h> 29 #include <linux/slab.h> 30 #include <linux/io.h> 31 #include <linux/spinlock.h> 32 #include <linux/of.h> 33 #include <linux/of_dma.h> 34 35 #include "virt-dma.h" 36 37 #define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14 38 #define BCM2835_DMA_CHAN_NAME_SIZE 8 39 40 /** 41 * struct bcm2835_dmadev - BCM2835 DMA controller 42 * @ddev: DMA device 43 * @base: base address of register map 44 * @dma_parms: DMA parameters (to convey 1 GByte max segment size to clients) 45 * @zero_page: bus address of zero page (to detect transactions copying from 46 * zero page and avoid accessing memory if so) 47 */ 48 struct bcm2835_dmadev { 49 struct dma_device ddev; 50 void __iomem *base; 51 struct device_dma_parameters dma_parms; 52 dma_addr_t zero_page; 53 }; 54 55 struct bcm2835_dma_cb { 56 uint32_t info; 57 uint32_t src; 58 uint32_t dst; 59 uint32_t length; 60 uint32_t stride; 61 uint32_t next; 62 uint32_t pad[2]; 63 }; 64 65 struct bcm2835_cb_entry { 66 struct bcm2835_dma_cb *cb; 67 dma_addr_t paddr; 68 }; 69 70 struct bcm2835_chan { 71 struct virt_dma_chan vc; 72 73 struct dma_slave_config cfg; 74 unsigned int dreq; 75 76 int ch; 77 struct bcm2835_desc *desc; 78 struct dma_pool *cb_pool; 79 80 void __iomem *chan_base; 81 int irq_number; 82 unsigned int irq_flags; 83 84 bool is_lite_channel; 85 }; 86 87 struct bcm2835_desc { 88 struct bcm2835_chan *c; 89 struct virt_dma_desc vd; 90 enum dma_transfer_direction dir; 91 92 unsigned int frames; 93 size_t size; 94 95 bool cyclic; 96 97 struct bcm2835_cb_entry cb_list[]; 98 }; 99 100 #define BCM2835_DMA_CS 0x00 101 #define BCM2835_DMA_ADDR 0x04 102 #define BCM2835_DMA_TI 0x08 103 #define BCM2835_DMA_SOURCE_AD 0x0c 104 #define BCM2835_DMA_DEST_AD 0x10 105 #define BCM2835_DMA_LEN 0x14 106 #define BCM2835_DMA_STRIDE 0x18 107 #define BCM2835_DMA_NEXTCB 0x1c 108 #define BCM2835_DMA_DEBUG 0x20 109 110 /* DMA CS Control and Status bits */ 111 #define BCM2835_DMA_ACTIVE BIT(0) /* activate the DMA */ 112 #define BCM2835_DMA_END BIT(1) /* current CB has ended */ 113 #define BCM2835_DMA_INT BIT(2) /* interrupt status */ 114 #define BCM2835_DMA_DREQ BIT(3) /* DREQ state */ 115 #define BCM2835_DMA_ISPAUSED BIT(4) /* Pause requested or not active */ 116 #define BCM2835_DMA_ISHELD BIT(5) /* Is held by DREQ flow control */ 117 #define BCM2835_DMA_WAITING_FOR_WRITES BIT(6) /* waiting for last 118 * AXI-write to ack 119 */ 120 #define BCM2835_DMA_ERR BIT(8) 121 #define BCM2835_DMA_PRIORITY(x) ((x & 15) << 16) /* AXI priority */ 122 #define BCM2835_DMA_PANIC_PRIORITY(x) ((x & 15) << 20) /* panic priority */ 123 /* current value of TI.BCM2835_DMA_WAIT_RESP */ 124 #define BCM2835_DMA_WAIT_FOR_WRITES BIT(28) 125 #define BCM2835_DMA_DIS_DEBUG BIT(29) /* disable debug pause signal */ 126 #define BCM2835_DMA_ABORT BIT(30) /* Stop current CB, go to next, WO */ 127 #define BCM2835_DMA_RESET BIT(31) /* WO, self clearing */ 128 129 /* Transfer information bits - also bcm2835_cb.info field */ 130 #define BCM2835_DMA_INT_EN BIT(0) 131 #define BCM2835_DMA_TDMODE BIT(1) /* 2D-Mode */ 132 #define BCM2835_DMA_WAIT_RESP BIT(3) /* wait for AXI-write to be acked */ 133 #define BCM2835_DMA_D_INC BIT(4) 134 #define BCM2835_DMA_D_WIDTH BIT(5) /* 128bit writes if set */ 135 #define BCM2835_DMA_D_DREQ BIT(6) /* enable DREQ for destination */ 136 #define BCM2835_DMA_D_IGNORE BIT(7) /* ignore destination writes */ 137 #define BCM2835_DMA_S_INC BIT(8) 138 #define BCM2835_DMA_S_WIDTH BIT(9) /* 128bit writes if set */ 139 #define BCM2835_DMA_S_DREQ BIT(10) /* enable SREQ for source */ 140 #define BCM2835_DMA_S_IGNORE BIT(11) /* ignore source reads - read 0 */ 141 #define BCM2835_DMA_BURST_LENGTH(x) ((x & 15) << 12) 142 #define BCM2835_DMA_PER_MAP(x) ((x & 31) << 16) /* REQ source */ 143 #define BCM2835_DMA_WAIT(x) ((x & 31) << 21) /* add DMA-wait cycles */ 144 #define BCM2835_DMA_NO_WIDE_BURSTS BIT(26) /* no 2 beat write bursts */ 145 146 /* debug register bits */ 147 #define BCM2835_DMA_DEBUG_LAST_NOT_SET_ERR BIT(0) 148 #define BCM2835_DMA_DEBUG_FIFO_ERR BIT(1) 149 #define BCM2835_DMA_DEBUG_READ_ERR BIT(2) 150 #define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_SHIFT 4 151 #define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_BITS 4 152 #define BCM2835_DMA_DEBUG_ID_SHIFT 16 153 #define BCM2835_DMA_DEBUG_ID_BITS 9 154 #define BCM2835_DMA_DEBUG_STATE_SHIFT 16 155 #define BCM2835_DMA_DEBUG_STATE_BITS 9 156 #define BCM2835_DMA_DEBUG_VERSION_SHIFT 25 157 #define BCM2835_DMA_DEBUG_VERSION_BITS 3 158 #define BCM2835_DMA_DEBUG_LITE BIT(28) 159 160 /* shared registers for all dma channels */ 161 #define BCM2835_DMA_INT_STATUS 0xfe0 162 #define BCM2835_DMA_ENABLE 0xff0 163 164 #define BCM2835_DMA_DATA_TYPE_S8 1 165 #define BCM2835_DMA_DATA_TYPE_S16 2 166 #define BCM2835_DMA_DATA_TYPE_S32 4 167 #define BCM2835_DMA_DATA_TYPE_S128 16 168 169 /* Valid only for channels 0 - 14, 15 has its own base address */ 170 #define BCM2835_DMA_CHAN(n) ((n) << 8) /* Base address */ 171 #define BCM2835_DMA_CHANIO(base, n) ((base) + BCM2835_DMA_CHAN(n)) 172 173 /* the max dma length for different channels */ 174 #define MAX_DMA_LEN SZ_1G 175 #define MAX_LITE_DMA_LEN (SZ_64K - 4) 176 177 static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c) 178 { 179 /* lite and normal channels have different max frame length */ 180 return c->is_lite_channel ? MAX_LITE_DMA_LEN : MAX_DMA_LEN; 181 } 182 183 /* how many frames of max_len size do we need to transfer len bytes */ 184 static inline size_t bcm2835_dma_frames_for_length(size_t len, 185 size_t max_len) 186 { 187 return DIV_ROUND_UP(len, max_len); 188 } 189 190 static inline struct bcm2835_dmadev *to_bcm2835_dma_dev(struct dma_device *d) 191 { 192 return container_of(d, struct bcm2835_dmadev, ddev); 193 } 194 195 static inline struct bcm2835_chan *to_bcm2835_dma_chan(struct dma_chan *c) 196 { 197 return container_of(c, struct bcm2835_chan, vc.chan); 198 } 199 200 static inline struct bcm2835_desc *to_bcm2835_dma_desc( 201 struct dma_async_tx_descriptor *t) 202 { 203 return container_of(t, struct bcm2835_desc, vd.tx); 204 } 205 206 static void bcm2835_dma_free_cb_chain(struct bcm2835_desc *desc) 207 { 208 size_t i; 209 210 for (i = 0; i < desc->frames; i++) 211 dma_pool_free(desc->c->cb_pool, desc->cb_list[i].cb, 212 desc->cb_list[i].paddr); 213 214 kfree(desc); 215 } 216 217 static void bcm2835_dma_desc_free(struct virt_dma_desc *vd) 218 { 219 bcm2835_dma_free_cb_chain( 220 container_of(vd, struct bcm2835_desc, vd)); 221 } 222 223 static void bcm2835_dma_create_cb_set_length( 224 struct bcm2835_chan *chan, 225 struct bcm2835_dma_cb *control_block, 226 size_t len, 227 size_t period_len, 228 size_t *total_len, 229 u32 finalextrainfo) 230 { 231 size_t max_len = bcm2835_dma_max_frame_length(chan); 232 233 /* set the length taking lite-channel limitations into account */ 234 control_block->length = min_t(u32, len, max_len); 235 236 /* finished if we have no period_length */ 237 if (!period_len) 238 return; 239 240 /* 241 * period_len means: that we need to generate 242 * transfers that are terminating at every 243 * multiple of period_len - this is typically 244 * used to set the interrupt flag in info 245 * which is required during cyclic transfers 246 */ 247 248 /* have we filled in period_length yet? */ 249 if (*total_len + control_block->length < period_len) { 250 /* update number of bytes in this period so far */ 251 *total_len += control_block->length; 252 return; 253 } 254 255 /* calculate the length that remains to reach period_length */ 256 control_block->length = period_len - *total_len; 257 258 /* reset total_length for next period */ 259 *total_len = 0; 260 261 /* add extrainfo bits in info */ 262 control_block->info |= finalextrainfo; 263 } 264 265 static inline size_t bcm2835_dma_count_frames_for_sg( 266 struct bcm2835_chan *c, 267 struct scatterlist *sgl, 268 unsigned int sg_len) 269 { 270 size_t frames = 0; 271 struct scatterlist *sgent; 272 unsigned int i; 273 size_t plength = bcm2835_dma_max_frame_length(c); 274 275 for_each_sg(sgl, sgent, sg_len, i) 276 frames += bcm2835_dma_frames_for_length( 277 sg_dma_len(sgent), plength); 278 279 return frames; 280 } 281 282 /** 283 * bcm2835_dma_create_cb_chain - create a control block and fills data in 284 * 285 * @chan: the @dma_chan for which we run this 286 * @direction: the direction in which we transfer 287 * @cyclic: it is a cyclic transfer 288 * @info: the default info bits to apply per controlblock 289 * @frames: number of controlblocks to allocate 290 * @src: the src address to assign (if the S_INC bit is set 291 * in @info, then it gets incremented) 292 * @dst: the dst address to assign (if the D_INC bit is set 293 * in @info, then it gets incremented) 294 * @buf_len: the full buffer length (may also be 0) 295 * @period_len: the period length when to apply @finalextrainfo 296 * in addition to the last transfer 297 * this will also break some control-blocks early 298 * @finalextrainfo: additional bits in last controlblock 299 * (or when period_len is reached in case of cyclic) 300 * @gfp: the GFP flag to use for allocation 301 */ 302 static struct bcm2835_desc *bcm2835_dma_create_cb_chain( 303 struct dma_chan *chan, enum dma_transfer_direction direction, 304 bool cyclic, u32 info, u32 finalextrainfo, size_t frames, 305 dma_addr_t src, dma_addr_t dst, size_t buf_len, 306 size_t period_len, gfp_t gfp) 307 { 308 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 309 size_t len = buf_len, total_len; 310 size_t frame; 311 struct bcm2835_desc *d; 312 struct bcm2835_cb_entry *cb_entry; 313 struct bcm2835_dma_cb *control_block; 314 315 if (!frames) 316 return NULL; 317 318 /* allocate and setup the descriptor. */ 319 d = kzalloc(struct_size(d, cb_list, frames), gfp); 320 if (!d) 321 return NULL; 322 323 d->c = c; 324 d->dir = direction; 325 d->cyclic = cyclic; 326 327 /* 328 * Iterate over all frames, create a control block 329 * for each frame and link them together. 330 */ 331 for (frame = 0, total_len = 0; frame < frames; d->frames++, frame++) { 332 cb_entry = &d->cb_list[frame]; 333 cb_entry->cb = dma_pool_alloc(c->cb_pool, gfp, 334 &cb_entry->paddr); 335 if (!cb_entry->cb) 336 goto error_cb; 337 338 /* fill in the control block */ 339 control_block = cb_entry->cb; 340 control_block->info = info; 341 control_block->src = src; 342 control_block->dst = dst; 343 control_block->stride = 0; 344 control_block->next = 0; 345 /* set up length in control_block if requested */ 346 if (buf_len) { 347 /* calculate length honoring period_length */ 348 bcm2835_dma_create_cb_set_length( 349 c, control_block, 350 len, period_len, &total_len, 351 cyclic ? finalextrainfo : 0); 352 353 /* calculate new remaining length */ 354 len -= control_block->length; 355 } 356 357 /* link this the last controlblock */ 358 if (frame) 359 d->cb_list[frame - 1].cb->next = cb_entry->paddr; 360 361 /* update src and dst and length */ 362 if (src && (info & BCM2835_DMA_S_INC)) 363 src += control_block->length; 364 if (dst && (info & BCM2835_DMA_D_INC)) 365 dst += control_block->length; 366 367 /* Length of total transfer */ 368 d->size += control_block->length; 369 } 370 371 /* the last frame requires extra flags */ 372 d->cb_list[d->frames - 1].cb->info |= finalextrainfo; 373 374 /* detect a size missmatch */ 375 if (buf_len && (d->size != buf_len)) 376 goto error_cb; 377 378 return d; 379 error_cb: 380 bcm2835_dma_free_cb_chain(d); 381 382 return NULL; 383 } 384 385 static void bcm2835_dma_fill_cb_chain_with_sg( 386 struct dma_chan *chan, 387 enum dma_transfer_direction direction, 388 struct bcm2835_cb_entry *cb, 389 struct scatterlist *sgl, 390 unsigned int sg_len) 391 { 392 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 393 size_t len, max_len; 394 unsigned int i; 395 dma_addr_t addr; 396 struct scatterlist *sgent; 397 398 max_len = bcm2835_dma_max_frame_length(c); 399 for_each_sg(sgl, sgent, sg_len, i) { 400 for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent); 401 len > 0; 402 addr += cb->cb->length, len -= cb->cb->length, cb++) { 403 if (direction == DMA_DEV_TO_MEM) 404 cb->cb->dst = addr; 405 else 406 cb->cb->src = addr; 407 cb->cb->length = min(len, max_len); 408 } 409 } 410 } 411 412 static void bcm2835_dma_abort(struct bcm2835_chan *c) 413 { 414 void __iomem *chan_base = c->chan_base; 415 long int timeout = 10000; 416 417 /* 418 * A zero control block address means the channel is idle. 419 * (The ACTIVE flag in the CS register is not a reliable indicator.) 420 */ 421 if (!readl(chan_base + BCM2835_DMA_ADDR)) 422 return; 423 424 /* Write 0 to the active bit - Pause the DMA */ 425 writel(0, chan_base + BCM2835_DMA_CS); 426 427 /* Wait for any current AXI transfer to complete */ 428 while ((readl(chan_base + BCM2835_DMA_CS) & 429 BCM2835_DMA_WAITING_FOR_WRITES) && --timeout) 430 cpu_relax(); 431 432 /* Peripheral might be stuck and fail to signal AXI write responses */ 433 if (!timeout) 434 dev_err(c->vc.chan.device->dev, 435 "failed to complete outstanding writes\n"); 436 437 writel(BCM2835_DMA_RESET, chan_base + BCM2835_DMA_CS); 438 } 439 440 static void bcm2835_dma_start_desc(struct bcm2835_chan *c) 441 { 442 struct virt_dma_desc *vd = vchan_next_desc(&c->vc); 443 struct bcm2835_desc *d; 444 445 if (!vd) { 446 c->desc = NULL; 447 return; 448 } 449 450 list_del(&vd->node); 451 452 c->desc = d = to_bcm2835_dma_desc(&vd->tx); 453 454 writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR); 455 writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS); 456 } 457 458 static irqreturn_t bcm2835_dma_callback(int irq, void *data) 459 { 460 struct bcm2835_chan *c = data; 461 struct bcm2835_desc *d; 462 unsigned long flags; 463 464 /* check the shared interrupt */ 465 if (c->irq_flags & IRQF_SHARED) { 466 /* check if the interrupt is enabled */ 467 flags = readl(c->chan_base + BCM2835_DMA_CS); 468 /* if not set then we are not the reason for the irq */ 469 if (!(flags & BCM2835_DMA_INT)) 470 return IRQ_NONE; 471 } 472 473 spin_lock_irqsave(&c->vc.lock, flags); 474 475 /* 476 * Clear the INT flag to receive further interrupts. Keep the channel 477 * active in case the descriptor is cyclic or in case the client has 478 * already terminated the descriptor and issued a new one. (May happen 479 * if this IRQ handler is threaded.) If the channel is finished, it 480 * will remain idle despite the ACTIVE flag being set. 481 */ 482 writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE, 483 c->chan_base + BCM2835_DMA_CS); 484 485 d = c->desc; 486 487 if (d) { 488 if (d->cyclic) { 489 /* call the cyclic callback */ 490 vchan_cyclic_callback(&d->vd); 491 } else if (!readl(c->chan_base + BCM2835_DMA_ADDR)) { 492 vchan_cookie_complete(&c->desc->vd); 493 bcm2835_dma_start_desc(c); 494 } 495 } 496 497 spin_unlock_irqrestore(&c->vc.lock, flags); 498 499 return IRQ_HANDLED; 500 } 501 502 static int bcm2835_dma_alloc_chan_resources(struct dma_chan *chan) 503 { 504 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 505 struct device *dev = c->vc.chan.device->dev; 506 507 dev_dbg(dev, "Allocating DMA channel %d\n", c->ch); 508 509 /* 510 * Control blocks are 256 bit in length and must start at a 256 bit 511 * (32 byte) aligned address (BCM2835 ARM Peripherals, sec. 4.2.1.1). 512 */ 513 c->cb_pool = dma_pool_create(dev_name(dev), dev, 514 sizeof(struct bcm2835_dma_cb), 32, 0); 515 if (!c->cb_pool) { 516 dev_err(dev, "unable to allocate descriptor pool\n"); 517 return -ENOMEM; 518 } 519 520 return request_irq(c->irq_number, bcm2835_dma_callback, 521 c->irq_flags, "DMA IRQ", c); 522 } 523 524 static void bcm2835_dma_free_chan_resources(struct dma_chan *chan) 525 { 526 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 527 528 vchan_free_chan_resources(&c->vc); 529 free_irq(c->irq_number, c); 530 dma_pool_destroy(c->cb_pool); 531 532 dev_dbg(c->vc.chan.device->dev, "Freeing DMA channel %u\n", c->ch); 533 } 534 535 static size_t bcm2835_dma_desc_size(struct bcm2835_desc *d) 536 { 537 return d->size; 538 } 539 540 static size_t bcm2835_dma_desc_size_pos(struct bcm2835_desc *d, dma_addr_t addr) 541 { 542 unsigned int i; 543 size_t size; 544 545 for (size = i = 0; i < d->frames; i++) { 546 struct bcm2835_dma_cb *control_block = d->cb_list[i].cb; 547 size_t this_size = control_block->length; 548 dma_addr_t dma; 549 550 if (d->dir == DMA_DEV_TO_MEM) 551 dma = control_block->dst; 552 else 553 dma = control_block->src; 554 555 if (size) 556 size += this_size; 557 else if (addr >= dma && addr < dma + this_size) 558 size += dma + this_size - addr; 559 } 560 561 return size; 562 } 563 564 static enum dma_status bcm2835_dma_tx_status(struct dma_chan *chan, 565 dma_cookie_t cookie, struct dma_tx_state *txstate) 566 { 567 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 568 struct virt_dma_desc *vd; 569 enum dma_status ret; 570 unsigned long flags; 571 572 ret = dma_cookie_status(chan, cookie, txstate); 573 if (ret == DMA_COMPLETE || !txstate) 574 return ret; 575 576 spin_lock_irqsave(&c->vc.lock, flags); 577 vd = vchan_find_desc(&c->vc, cookie); 578 if (vd) { 579 txstate->residue = 580 bcm2835_dma_desc_size(to_bcm2835_dma_desc(&vd->tx)); 581 } else if (c->desc && c->desc->vd.tx.cookie == cookie) { 582 struct bcm2835_desc *d = c->desc; 583 dma_addr_t pos; 584 585 if (d->dir == DMA_MEM_TO_DEV) 586 pos = readl(c->chan_base + BCM2835_DMA_SOURCE_AD); 587 else if (d->dir == DMA_DEV_TO_MEM) 588 pos = readl(c->chan_base + BCM2835_DMA_DEST_AD); 589 else 590 pos = 0; 591 592 txstate->residue = bcm2835_dma_desc_size_pos(d, pos); 593 } else { 594 txstate->residue = 0; 595 } 596 597 spin_unlock_irqrestore(&c->vc.lock, flags); 598 599 return ret; 600 } 601 602 static void bcm2835_dma_issue_pending(struct dma_chan *chan) 603 { 604 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 605 unsigned long flags; 606 607 spin_lock_irqsave(&c->vc.lock, flags); 608 if (vchan_issue_pending(&c->vc) && !c->desc) 609 bcm2835_dma_start_desc(c); 610 611 spin_unlock_irqrestore(&c->vc.lock, flags); 612 } 613 614 static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy( 615 struct dma_chan *chan, dma_addr_t dst, dma_addr_t src, 616 size_t len, unsigned long flags) 617 { 618 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 619 struct bcm2835_desc *d; 620 u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC; 621 u32 extra = BCM2835_DMA_INT_EN | BCM2835_DMA_WAIT_RESP; 622 size_t max_len = bcm2835_dma_max_frame_length(c); 623 size_t frames; 624 625 /* if src, dst or len is not given return with an error */ 626 if (!src || !dst || !len) 627 return NULL; 628 629 /* calculate number of frames */ 630 frames = bcm2835_dma_frames_for_length(len, max_len); 631 632 /* allocate the CB chain - this also fills in the pointers */ 633 d = bcm2835_dma_create_cb_chain(chan, DMA_MEM_TO_MEM, false, 634 info, extra, frames, 635 src, dst, len, 0, GFP_KERNEL); 636 if (!d) 637 return NULL; 638 639 return vchan_tx_prep(&c->vc, &d->vd, flags); 640 } 641 642 static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg( 643 struct dma_chan *chan, 644 struct scatterlist *sgl, unsigned int sg_len, 645 enum dma_transfer_direction direction, 646 unsigned long flags, void *context) 647 { 648 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 649 struct bcm2835_desc *d; 650 dma_addr_t src = 0, dst = 0; 651 u32 info = BCM2835_DMA_WAIT_RESP; 652 u32 extra = BCM2835_DMA_INT_EN; 653 size_t frames; 654 655 if (!is_slave_direction(direction)) { 656 dev_err(chan->device->dev, 657 "%s: bad direction?\n", __func__); 658 return NULL; 659 } 660 661 if (c->dreq != 0) 662 info |= BCM2835_DMA_PER_MAP(c->dreq); 663 664 if (direction == DMA_DEV_TO_MEM) { 665 if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) 666 return NULL; 667 src = c->cfg.src_addr; 668 info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC; 669 } else { 670 if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) 671 return NULL; 672 dst = c->cfg.dst_addr; 673 info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC; 674 } 675 676 /* count frames in sg list */ 677 frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len); 678 679 /* allocate the CB chain */ 680 d = bcm2835_dma_create_cb_chain(chan, direction, false, 681 info, extra, 682 frames, src, dst, 0, 0, 683 GFP_NOWAIT); 684 if (!d) 685 return NULL; 686 687 /* fill in frames with scatterlist pointers */ 688 bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list, 689 sgl, sg_len); 690 691 return vchan_tx_prep(&c->vc, &d->vd, flags); 692 } 693 694 static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic( 695 struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, 696 size_t period_len, enum dma_transfer_direction direction, 697 unsigned long flags) 698 { 699 struct bcm2835_dmadev *od = to_bcm2835_dma_dev(chan->device); 700 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 701 struct bcm2835_desc *d; 702 dma_addr_t src, dst; 703 u32 info = BCM2835_DMA_WAIT_RESP; 704 u32 extra = 0; 705 size_t max_len = bcm2835_dma_max_frame_length(c); 706 size_t frames; 707 708 /* Grab configuration */ 709 if (!is_slave_direction(direction)) { 710 dev_err(chan->device->dev, "%s: bad direction?\n", __func__); 711 return NULL; 712 } 713 714 if (!buf_len) { 715 dev_err(chan->device->dev, 716 "%s: bad buffer length (= 0)\n", __func__); 717 return NULL; 718 } 719 720 if (flags & DMA_PREP_INTERRUPT) 721 extra |= BCM2835_DMA_INT_EN; 722 else 723 period_len = buf_len; 724 725 /* 726 * warn if buf_len is not a multiple of period_len - this may leed 727 * to unexpected latencies for interrupts and thus audiable clicks 728 */ 729 if (buf_len % period_len) 730 dev_warn_once(chan->device->dev, 731 "%s: buffer_length (%zd) is not a multiple of period_len (%zd)\n", 732 __func__, buf_len, period_len); 733 734 /* Setup DREQ channel */ 735 if (c->dreq != 0) 736 info |= BCM2835_DMA_PER_MAP(c->dreq); 737 738 if (direction == DMA_DEV_TO_MEM) { 739 if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) 740 return NULL; 741 src = c->cfg.src_addr; 742 dst = buf_addr; 743 info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC; 744 } else { 745 if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) 746 return NULL; 747 dst = c->cfg.dst_addr; 748 src = buf_addr; 749 info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC; 750 751 /* non-lite channels can write zeroes w/o accessing memory */ 752 if (buf_addr == od->zero_page && !c->is_lite_channel) 753 info |= BCM2835_DMA_S_IGNORE; 754 } 755 756 /* calculate number of frames */ 757 frames = /* number of periods */ 758 DIV_ROUND_UP(buf_len, period_len) * 759 /* number of frames per period */ 760 bcm2835_dma_frames_for_length(period_len, max_len); 761 762 /* 763 * allocate the CB chain 764 * note that we need to use GFP_NOWAIT, as the ALSA i2s dmaengine 765 * implementation calls prep_dma_cyclic with interrupts disabled. 766 */ 767 d = bcm2835_dma_create_cb_chain(chan, direction, true, 768 info, extra, 769 frames, src, dst, buf_len, 770 period_len, GFP_NOWAIT); 771 if (!d) 772 return NULL; 773 774 /* wrap around into a loop */ 775 d->cb_list[d->frames - 1].cb->next = d->cb_list[0].paddr; 776 777 return vchan_tx_prep(&c->vc, &d->vd, flags); 778 } 779 780 static int bcm2835_dma_slave_config(struct dma_chan *chan, 781 struct dma_slave_config *cfg) 782 { 783 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 784 785 c->cfg = *cfg; 786 787 return 0; 788 } 789 790 static int bcm2835_dma_terminate_all(struct dma_chan *chan) 791 { 792 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 793 unsigned long flags; 794 LIST_HEAD(head); 795 796 spin_lock_irqsave(&c->vc.lock, flags); 797 798 /* stop DMA activity */ 799 if (c->desc) { 800 vchan_terminate_vdesc(&c->desc->vd); 801 c->desc = NULL; 802 bcm2835_dma_abort(c); 803 } 804 805 vchan_get_all_descriptors(&c->vc, &head); 806 spin_unlock_irqrestore(&c->vc.lock, flags); 807 vchan_dma_desc_free_list(&c->vc, &head); 808 809 return 0; 810 } 811 812 static void bcm2835_dma_synchronize(struct dma_chan *chan) 813 { 814 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan); 815 816 vchan_synchronize(&c->vc); 817 } 818 819 static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, 820 int irq, unsigned int irq_flags) 821 { 822 struct bcm2835_chan *c; 823 824 c = devm_kzalloc(d->ddev.dev, sizeof(*c), GFP_KERNEL); 825 if (!c) 826 return -ENOMEM; 827 828 c->vc.desc_free = bcm2835_dma_desc_free; 829 vchan_init(&c->vc, &d->ddev); 830 831 c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id); 832 c->ch = chan_id; 833 c->irq_number = irq; 834 c->irq_flags = irq_flags; 835 836 /* check in DEBUG register if this is a LITE channel */ 837 if (readl(c->chan_base + BCM2835_DMA_DEBUG) & 838 BCM2835_DMA_DEBUG_LITE) 839 c->is_lite_channel = true; 840 841 return 0; 842 } 843 844 static void bcm2835_dma_free(struct bcm2835_dmadev *od) 845 { 846 struct bcm2835_chan *c, *next; 847 848 list_for_each_entry_safe(c, next, &od->ddev.channels, 849 vc.chan.device_node) { 850 list_del(&c->vc.chan.device_node); 851 tasklet_kill(&c->vc.task); 852 } 853 854 dma_unmap_page_attrs(od->ddev.dev, od->zero_page, PAGE_SIZE, 855 DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); 856 } 857 858 static const struct of_device_id bcm2835_dma_of_match[] = { 859 { .compatible = "brcm,bcm2835-dma", }, 860 {}, 861 }; 862 MODULE_DEVICE_TABLE(of, bcm2835_dma_of_match); 863 864 static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec, 865 struct of_dma *ofdma) 866 { 867 struct bcm2835_dmadev *d = ofdma->of_dma_data; 868 struct dma_chan *chan; 869 870 chan = dma_get_any_slave_channel(&d->ddev); 871 if (!chan) 872 return NULL; 873 874 /* Set DREQ from param */ 875 to_bcm2835_dma_chan(chan)->dreq = spec->args[0]; 876 877 return chan; 878 } 879 880 static int bcm2835_dma_probe(struct platform_device *pdev) 881 { 882 struct bcm2835_dmadev *od; 883 struct resource *res; 884 void __iomem *base; 885 int rc; 886 int i, j; 887 int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1]; 888 int irq_flags; 889 uint32_t chans_available; 890 char chan_name[BCM2835_DMA_CHAN_NAME_SIZE]; 891 892 if (!pdev->dev.dma_mask) 893 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; 894 895 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); 896 if (rc) { 897 dev_err(&pdev->dev, "Unable to set DMA mask\n"); 898 return rc; 899 } 900 901 od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL); 902 if (!od) 903 return -ENOMEM; 904 905 pdev->dev.dma_parms = &od->dma_parms; 906 dma_set_max_seg_size(&pdev->dev, 0x3FFFFFFF); 907 908 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 909 base = devm_ioremap_resource(&pdev->dev, res); 910 if (IS_ERR(base)) 911 return PTR_ERR(base); 912 913 od->base = base; 914 915 dma_cap_set(DMA_SLAVE, od->ddev.cap_mask); 916 dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask); 917 dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask); 918 dma_cap_set(DMA_MEMCPY, od->ddev.cap_mask); 919 od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources; 920 od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources; 921 od->ddev.device_tx_status = bcm2835_dma_tx_status; 922 od->ddev.device_issue_pending = bcm2835_dma_issue_pending; 923 od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic; 924 od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg; 925 od->ddev.device_prep_dma_memcpy = bcm2835_dma_prep_dma_memcpy; 926 od->ddev.device_config = bcm2835_dma_slave_config; 927 od->ddev.device_terminate_all = bcm2835_dma_terminate_all; 928 od->ddev.device_synchronize = bcm2835_dma_synchronize; 929 od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); 930 od->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); 931 od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) | 932 BIT(DMA_MEM_TO_MEM); 933 od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; 934 od->ddev.descriptor_reuse = true; 935 od->ddev.dev = &pdev->dev; 936 INIT_LIST_HEAD(&od->ddev.channels); 937 938 platform_set_drvdata(pdev, od); 939 940 od->zero_page = dma_map_page_attrs(od->ddev.dev, ZERO_PAGE(0), 0, 941 PAGE_SIZE, DMA_TO_DEVICE, 942 DMA_ATTR_SKIP_CPU_SYNC); 943 if (dma_mapping_error(od->ddev.dev, od->zero_page)) { 944 dev_err(&pdev->dev, "Failed to map zero page\n"); 945 return -ENOMEM; 946 } 947 948 /* Request DMA channel mask from device tree */ 949 if (of_property_read_u32(pdev->dev.of_node, 950 "brcm,dma-channel-mask", 951 &chans_available)) { 952 dev_err(&pdev->dev, "Failed to get channel mask\n"); 953 rc = -EINVAL; 954 goto err_no_dma; 955 } 956 957 /* get irqs for each channel that we support */ 958 for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) { 959 /* skip masked out channels */ 960 if (!(chans_available & (1 << i))) { 961 irq[i] = -1; 962 continue; 963 } 964 965 /* get the named irq */ 966 snprintf(chan_name, sizeof(chan_name), "dma%i", i); 967 irq[i] = platform_get_irq_byname(pdev, chan_name); 968 if (irq[i] >= 0) 969 continue; 970 971 /* legacy device tree case handling */ 972 dev_warn_once(&pdev->dev, 973 "missing interrupt-names property in device tree - legacy interpretation is used\n"); 974 /* 975 * in case of channel >= 11 976 * use the 11th interrupt and that is shared 977 */ 978 irq[i] = platform_get_irq(pdev, i < 11 ? i : 11); 979 } 980 981 /* get irqs for each channel */ 982 for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) { 983 /* skip channels without irq */ 984 if (irq[i] < 0) 985 continue; 986 987 /* check if there are other channels that also use this irq */ 988 irq_flags = 0; 989 for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++) 990 if ((i != j) && (irq[j] == irq[i])) { 991 irq_flags = IRQF_SHARED; 992 break; 993 } 994 995 /* initialize the channel */ 996 rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags); 997 if (rc) 998 goto err_no_dma; 999 } 1000 1001 dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i); 1002 1003 /* Device-tree DMA controller registration */ 1004 rc = of_dma_controller_register(pdev->dev.of_node, 1005 bcm2835_dma_xlate, od); 1006 if (rc) { 1007 dev_err(&pdev->dev, "Failed to register DMA controller\n"); 1008 goto err_no_dma; 1009 } 1010 1011 rc = dma_async_device_register(&od->ddev); 1012 if (rc) { 1013 dev_err(&pdev->dev, 1014 "Failed to register slave DMA engine device: %d\n", rc); 1015 goto err_no_dma; 1016 } 1017 1018 dev_dbg(&pdev->dev, "Load BCM2835 DMA engine driver\n"); 1019 1020 return 0; 1021 1022 err_no_dma: 1023 bcm2835_dma_free(od); 1024 return rc; 1025 } 1026 1027 static int bcm2835_dma_remove(struct platform_device *pdev) 1028 { 1029 struct bcm2835_dmadev *od = platform_get_drvdata(pdev); 1030 1031 dma_async_device_unregister(&od->ddev); 1032 bcm2835_dma_free(od); 1033 1034 return 0; 1035 } 1036 1037 static struct platform_driver bcm2835_dma_driver = { 1038 .probe = bcm2835_dma_probe, 1039 .remove = bcm2835_dma_remove, 1040 .driver = { 1041 .name = "bcm2835-dma", 1042 .of_match_table = of_match_ptr(bcm2835_dma_of_match), 1043 }, 1044 }; 1045 1046 module_platform_driver(bcm2835_dma_driver); 1047 1048 MODULE_ALIAS("platform:bcm2835-dma"); 1049 MODULE_DESCRIPTION("BCM2835 DMA engine driver"); 1050 MODULE_AUTHOR("Florian Meier <florian.meier@koalo.de>"); 1051 MODULE_LICENSE("GPL"); 1052