drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 /* Copyright (c) 2010-2012 Broadcom. All rights reserved. */
   3
   4 #include <linux/kernel.h>
   5 #include <linux/types.h>
   6 #include <linux/errno.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/dma-mapping.h>
  10 #include <linux/io.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/mm.h>
  14 #include <linux/of.h>
  15 #include <soc/bcm2835/raspberrypi-firmware.h>
  16
  17 #define TOTAL_SLOTS (VCHIQ_SLOT_ZERO_SLOTS + 2 * 32)
  18
  19 #include "vchiq_arm.h"
  20 #include "vchiq_connected.h"
  21 #include "vchiq_pagelist.h"
  22
  23 #define MAX_FRAGMENTS (VCHIQ_NUM_CURRENT_BULKS * 2)
  24
  25 #define VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX 0
  26 #define VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX  1
  27
  28 #define BELL0   0x00
  29 #define BELL2   0x08
  30
  31 struct vchiq_2835_state {
  32         int inited;
  33         struct vchiq_arm_state arm_state;
  34 };
  35
  36 struct vchiq_pagelist_info {
  37         struct pagelist *pagelist;
  38         size_t pagelist_buffer_size;
  39         dma_addr_t dma_addr;
  40         enum dma_data_direction dma_dir;
  41         unsigned int num_pages;
  42         unsigned int pages_need_release;
  43         struct page **pages;
  44         struct scatterlist *scatterlist;
  45         unsigned int scatterlist_mapped;
  46 };
  47
  48 static void __iomem *g_regs;
  49 /* This value is the size of the L2 cache lines as understood by the
  50  * VPU firmware, which determines the required alignment of the
  51  * offsets/sizes in pagelists.
  52  *
  53  * Modern VPU firmware looks for a DT "cache-line-size" property in
  54  * the VCHIQ node and will overwrite it with the actual L2 cache size,
  55  * which the kernel must then respect.  That property was rejected
  56  * upstream, so we have to use the VPU firmware's compatibility value
  57  * of 32.
  58  */
  59 static unsigned int g_cache_line_size = 32;
  60 static unsigned int g_fragments_size;
  61 static char *g_fragments_base;
  62 static char *g_free_fragments;
  63 static struct semaphore g_free_fragments_sema;
  64 static struct device *g_dev;
  65
  66 static DEFINE_SEMAPHORE(g_free_fragments_mutex);
  67
  68 static irqreturn_t
  69 vchiq_doorbell_irq(int irq, void *dev_id);
  70
  71 static struct vchiq_pagelist_info *
  72 create_pagelist(char __user *buf, size_t count, unsigned short type);
  73
  74 static void
  75 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
  76               int actual);
  77
  78 int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state *state)
  79 {
  80         struct device *dev = &pdev->dev;
  81         struct vchiq_drvdata *drvdata = platform_get_drvdata(pdev);
  82         struct rpi_firmware *fw = drvdata->fw;
  83         struct vchiq_slot_zero *vchiq_slot_zero;
  84         void *slot_mem;
  85         dma_addr_t slot_phys;
  86         u32 channelbase;
  87         int slot_mem_size, frag_mem_size;
  88         int err, irq, i;
  89
  90         /*
  91          * VCHI messages between the CPU and firmware use
  92          * 32-bit bus addresses.
  93          */
  94         err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
  95
  96         if (err < 0)
  97                 return err;
  98
  99         g_cache_line_size = drvdata->cache_line_size;
 100         g_fragments_size = 2 * g_cache_line_size;
 101
 102         /* Allocate space for the channels in coherent memory */
 103         slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE);
 104         frag_mem_size = PAGE_ALIGN(g_fragments_size * MAX_FRAGMENTS);
 105
 106         slot_mem = dmam_alloc_coherent(dev, slot_mem_size + frag_mem_size,
 107                                        &slot_phys, GFP_KERNEL);
 108         if (!slot_mem) {
 109                 dev_err(dev, "could not allocate DMA memory\n");
 110                 return -ENOMEM;
 111         }
 112
 113         WARN_ON(((unsigned long)slot_mem & (PAGE_SIZE - 1)) != 0);
 114
 115         vchiq_slot_zero = vchiq_init_slots(slot_mem, slot_mem_size);
 116         if (!vchiq_slot_zero)
 117                 return -EINVAL;
 118
 119         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_OFFSET_IDX] =
 120                 (int)slot_phys + slot_mem_size;
 121         vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX] =
 122                 MAX_FRAGMENTS;
 123
 124         g_fragments_base = (char *)slot_mem + slot_mem_size;
 125
 126         g_free_fragments = g_fragments_base;
 127         for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
 128                 *(char **)&g_fragments_base[i*g_fragments_size] =
 129                         &g_fragments_base[(i + 1)*g_fragments_size];
 130         }
 131         *(char **)&g_fragments_base[i * g_fragments_size] = NULL;
 132         sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
 133
 134         if (vchiq_init_state(state, vchiq_slot_zero) != VCHIQ_SUCCESS)
 135                 return -EINVAL;
 136
 137         g_regs = devm_platform_ioremap_resource(pdev, 0);
 138         if (IS_ERR(g_regs))
 139                 return PTR_ERR(g_regs);
 140
 141         irq = platform_get_irq(pdev, 0);
 142         if (irq <= 0)
 143                 return irq;
 144
 145         err = devm_request_irq(dev, irq, vchiq_doorbell_irq, IRQF_IRQPOLL,
 146                                "VCHIQ doorbell", state);
 147         if (err) {
 148                 dev_err(dev, "failed to register irq=%d\n", irq);
 149                 return err;
 150         }
 151
 152         /* Send the base address of the slots to VideoCore */
 153         channelbase = slot_phys;
 154         err = rpi_firmware_property(fw, RPI_FIRMWARE_VCHIQ_INIT,
 155                                     &channelbase, sizeof(channelbase));
 156         if (err || channelbase) {
 157                 dev_err(dev, "failed to set channelbase\n");
 158                 return err ? : -ENXIO;
 159         }
 160
 161         g_dev = dev;
 162         vchiq_log_info(vchiq_arm_log_level,
 163                 "vchiq_init - done (slots %pK, phys %pad)",
 164                 vchiq_slot_zero, &slot_phys);
 165
 166         vchiq_call_connected_callbacks();
 167
 168         return 0;
 169 }
 170
 171 enum vchiq_status
 172 vchiq_platform_init_state(struct vchiq_state *state)
 173 {
 174         enum vchiq_status status = VCHIQ_SUCCESS;
 175         struct vchiq_2835_state *platform_state;
 176
 177         state->platform_state = kzalloc(sizeof(*platform_state), GFP_KERNEL);
 178         if (!state->platform_state)
 179                 return VCHIQ_ERROR;
 180
 181         platform_state = (struct vchiq_2835_state *)state->platform_state;
 182
 183         platform_state->inited = 1;
 184         status = vchiq_arm_init_state(state, &platform_state->arm_state);
 185
 186         if (status != VCHIQ_SUCCESS)
 187                 platform_state->inited = 0;
 188
 189         return status;
 190 }
 191
 192 struct vchiq_arm_state*
 193 vchiq_platform_get_arm_state(struct vchiq_state *state)
 194 {
 195         struct vchiq_2835_state *platform_state;
 196
 197         platform_state   = (struct vchiq_2835_state *)state->platform_state;
 198
 199         WARN_ON_ONCE(!platform_state->inited);
 200
 201         return &platform_state->arm_state;
 202 }
 203
 204 void
 205 remote_event_signal(struct remote_event *event)
 206 {
 207         wmb();
 208
 209         event->fired = 1;
 210
 211         dsb(sy);         /* data barrier operation */
 212
 213         if (event->armed)
 214                 writel(0, g_regs + BELL2); /* trigger vc interrupt */
 215 }
 216
 217 enum vchiq_status
 218 vchiq_prepare_bulk_data(struct vchiq_bulk *bulk, void *offset, int size,
 219                         int dir)
 220 {
 221         struct vchiq_pagelist_info *pagelistinfo;
 222
 223         pagelistinfo = create_pagelist((char __user *)offset, size,
 224                                        (dir == VCHIQ_BULK_RECEIVE)
 225                                        ? PAGELIST_READ
 226                                        : PAGELIST_WRITE);
 227
 228         if (!pagelistinfo)
 229                 return VCHIQ_ERROR;
 230
 231         bulk->data = (void *)(unsigned long)pagelistinfo->dma_addr;
 232
 233         /*
 234          * Store the pagelistinfo address in remote_data,
 235          * which isn't used by the slave.
 236          */
 237         bulk->remote_data = pagelistinfo;
 238
 239         return VCHIQ_SUCCESS;
 240 }
 241
 242 void
 243 vchiq_complete_bulk(struct vchiq_bulk *bulk)
 244 {
 245         if (bulk && bulk->remote_data && bulk->actual)
 246                 free_pagelist((struct vchiq_pagelist_info *)bulk->remote_data,
 247                               bulk->actual);
 248 }
 249
 250 int vchiq_dump_platform_state(void *dump_context)
 251 {
 252         char buf[80];
 253         int len;
 254
 255         len = snprintf(buf, sizeof(buf),
 256                 "  Platform: 2835 (VC master)");
 257         return vchiq_dump(dump_context, buf, len + 1);
 258 }
 259
 260 /*
 261  * Local functions
 262  */
 263
 264 static irqreturn_t
 265 vchiq_doorbell_irq(int irq, void *dev_id)
 266 {
 267         struct vchiq_state *state = dev_id;
 268         irqreturn_t ret = IRQ_NONE;
 269         unsigned int status;
 270
 271         /* Read (and clear) the doorbell */
 272         status = readl(g_regs + BELL0);
 273
 274         if (status & 0x4) {  /* Was the doorbell rung? */
 275                 remote_event_pollall(state);
 276                 ret = IRQ_HANDLED;
 277         }
 278
 279         return ret;
 280 }
 281
 282 static void
 283 cleanup_pagelistinfo(struct vchiq_pagelist_info *pagelistinfo)
 284 {
 285         if (pagelistinfo->scatterlist_mapped) {
 286                 dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 287                              pagelistinfo->num_pages, pagelistinfo->dma_dir);
 288         }
 289
 290         if (pagelistinfo->pages_need_release)
 291                 unpin_user_pages(pagelistinfo->pages, pagelistinfo->num_pages);
 292
 293         dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size,
 294                           pagelistinfo->pagelist, pagelistinfo->dma_addr);
 295 }
 296
 297 /* There is a potential problem with partial cache lines (pages?)
 298  * at the ends of the block when reading. If the CPU accessed anything in
 299  * the same line (page?) then it may have pulled old data into the cache,
 300  * obscuring the new data underneath. We can solve this by transferring the
 301  * partial cache lines separately, and allowing the ARM to copy into the
 302  * cached area.
 303  */
 304
 305 static struct vchiq_pagelist_info *
 306 create_pagelist(char __user *buf, size_t count, unsigned short type)
 307 {
 308         struct pagelist *pagelist;
 309         struct vchiq_pagelist_info *pagelistinfo;
 310         struct page **pages;
 311         u32 *addrs;
 312         unsigned int num_pages, offset, i, k;
 313         int actual_pages;
 314         size_t pagelist_size;
 315         struct scatterlist *scatterlist, *sg;
 316         int dma_buffers;
 317         dma_addr_t dma_addr;
 318
 319         if (count >= INT_MAX - PAGE_SIZE)
 320                 return NULL;
 321
 322         offset = ((unsigned int)(unsigned long)buf & (PAGE_SIZE - 1));
 323         num_pages = DIV_ROUND_UP(count + offset, PAGE_SIZE);
 324
 325         if (num_pages > (SIZE_MAX - sizeof(struct pagelist) -
 326                          sizeof(struct vchiq_pagelist_info)) /
 327                         (sizeof(u32) + sizeof(pages[0]) +
 328                          sizeof(struct scatterlist)))
 329                 return NULL;
 330
 331         pagelist_size = sizeof(struct pagelist) +
 332                         (num_pages * sizeof(u32)) +
 333                         (num_pages * sizeof(pages[0]) +
 334                         (num_pages * sizeof(struct scatterlist))) +
 335                         sizeof(struct vchiq_pagelist_info);
 336
 337         /* Allocate enough storage to hold the page pointers and the page
 338          * list
 339          */
 340         pagelist = dma_alloc_coherent(g_dev, pagelist_size, &dma_addr,
 341                                       GFP_KERNEL);
 342
 343         vchiq_log_trace(vchiq_arm_log_level, "%s - %pK", __func__, pagelist);
 344
 345         if (!pagelist)
 346                 return NULL;
 347
 348         addrs           = pagelist->addrs;
 349         pages           = (struct page **)(addrs + num_pages);
 350         scatterlist     = (struct scatterlist *)(pages + num_pages);
 351         pagelistinfo    = (struct vchiq_pagelist_info *)
 352                           (scatterlist + num_pages);
 353
 354         pagelist->length = count;
 355         pagelist->type = type;
 356         pagelist->offset = offset;
 357
 358         /* Populate the fields of the pagelistinfo structure */
 359         pagelistinfo->pagelist = pagelist;
 360         pagelistinfo->pagelist_buffer_size = pagelist_size;
 361         pagelistinfo->dma_addr = dma_addr;
 362         pagelistinfo->dma_dir =  (type == PAGELIST_WRITE) ?
 363                                   DMA_TO_DEVICE : DMA_FROM_DEVICE;
 364         pagelistinfo->num_pages = num_pages;
 365         pagelistinfo->pages_need_release = 0;
 366         pagelistinfo->pages = pages;
 367         pagelistinfo->scatterlist = scatterlist;
 368         pagelistinfo->scatterlist_mapped = 0;
 369
 370         if (is_vmalloc_addr((void __force *)buf)) {
 371                 unsigned long length = count;
 372                 unsigned int off = offset;
 373
 374                 for (actual_pages = 0; actual_pages < num_pages;
 375                      actual_pages++) {
 376                         struct page *pg =
 377                                 vmalloc_to_page((void __force *)(buf +
 378                                                  (actual_pages * PAGE_SIZE)));
 379                         size_t bytes = PAGE_SIZE - off;
 380
 381                         if (!pg) {
 382                                 cleanup_pagelistinfo(pagelistinfo);
 383                                 return NULL;
 384                         }
 385
 386                         if (bytes > length)
 387                                 bytes = length;
 388                         pages[actual_pages] = pg;
 389                         length -= bytes;
 390                         off = 0;
 391                 }
 392                 /* do not try and release vmalloc pages */
 393         } else {
 394                 actual_pages = pin_user_pages_fast(
 395                                           (unsigned long)buf & PAGE_MASK,
 396                                           num_pages,
 397                                           type == PAGELIST_READ,
 398                                           pages);
 399
 400                 if (actual_pages != num_pages) {
 401                         vchiq_log_info(vchiq_arm_log_level,
 402                                        "%s - only %d/%d pages locked",
 403                                        __func__, actual_pages, num_pages);
 404
 405                         /* This is probably due to the process being killed */
 406                         if (actual_pages > 0)
 407                                 unpin_user_pages(pages, actual_pages);
 408                         cleanup_pagelistinfo(pagelistinfo);
 409                         return NULL;
 410                 }
 411                  /* release user pages */
 412                 pagelistinfo->pages_need_release = 1;
 413         }
 414
 415         /*
 416          * Initialize the scatterlist so that the magic cookie
 417          *  is filled if debugging is enabled
 418          */
 419         sg_init_table(scatterlist, num_pages);
 420         /* Now set the pages for each scatterlist */
 421         for (i = 0; i < num_pages; i++) {
 422                 unsigned int len = PAGE_SIZE - offset;
 423
 424                 if (len > count)
 425                         len = count;
 426                 sg_set_page(scatterlist + i, pages[i], len, offset);
 427                 offset = 0;
 428                 count -= len;
 429         }
 430
 431         dma_buffers = dma_map_sg(g_dev,
 432                                  scatterlist,
 433                                  num_pages,
 434                                  pagelistinfo->dma_dir);
 435
 436         if (dma_buffers == 0) {
 437                 cleanup_pagelistinfo(pagelistinfo);
 438                 return NULL;
 439         }
 440
 441         pagelistinfo->scatterlist_mapped = 1;
 442
 443         /* Combine adjacent blocks for performance */
 444         k = 0;
 445         for_each_sg(scatterlist, sg, dma_buffers, i) {
 446                 u32 len = sg_dma_len(sg);
 447                 u32 addr = sg_dma_address(sg);
 448
 449                 /* Note: addrs is the address + page_count - 1
 450                  * The firmware expects blocks after the first to be page-
 451                  * aligned and a multiple of the page size
 452                  */
 453                 WARN_ON(len == 0);
 454                 WARN_ON(i && (i != (dma_buffers - 1)) && (len & ~PAGE_MASK));
 455                 WARN_ON(i && (addr & ~PAGE_MASK));
 456                 if (k > 0 &&
 457                     ((addrs[k - 1] & PAGE_MASK) +
 458                      (((addrs[k - 1] & ~PAGE_MASK) + 1) << PAGE_SHIFT))
 459                     == (addr & PAGE_MASK))
 460                         addrs[k - 1] += ((len + PAGE_SIZE - 1) >> PAGE_SHIFT);
 461                 else
 462                         addrs[k++] = (addr & PAGE_MASK) |
 463                                 (((len + PAGE_SIZE - 1) >> PAGE_SHIFT) - 1);
 464         }
 465
 466         /* Partial cache lines (fragments) require special measures */
 467         if ((type == PAGELIST_READ) &&
 468                 ((pagelist->offset & (g_cache_line_size - 1)) ||
 469                 ((pagelist->offset + pagelist->length) &
 470                 (g_cache_line_size - 1)))) {
 471                 char *fragments;
 472
 473                 if (down_interruptible(&g_free_fragments_sema)) {
 474                         cleanup_pagelistinfo(pagelistinfo);
 475                         return NULL;
 476                 }
 477
 478                 WARN_ON(!g_free_fragments);
 479
 480                 down(&g_free_fragments_mutex);
 481                 fragments = g_free_fragments;
 482                 WARN_ON(!fragments);
 483                 g_free_fragments = *(char **) g_free_fragments;
 484                 up(&g_free_fragments_mutex);
 485                 pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
 486                         (fragments - g_fragments_base) / g_fragments_size;
 487         }
 488
 489         return pagelistinfo;
 490 }
 491
 492 static void
 493 free_pagelist(struct vchiq_pagelist_info *pagelistinfo,
 494               int actual)
 495 {
 496         struct pagelist *pagelist = pagelistinfo->pagelist;
 497         struct page **pages = pagelistinfo->pages;
 498         unsigned int num_pages = pagelistinfo->num_pages;
 499
 500         vchiq_log_trace(vchiq_arm_log_level, "%s - %pK, %d",
 501                         __func__, pagelistinfo->pagelist, actual);
 502
 503         /*
 504          * NOTE: dma_unmap_sg must be called before the
 505          * cpu can touch any of the data/pages.
 506          */
 507         dma_unmap_sg(g_dev, pagelistinfo->scatterlist,
 508                      pagelistinfo->num_pages, pagelistinfo->dma_dir);
 509         pagelistinfo->scatterlist_mapped = 0;
 510
 511         /* Deal with any partial cache lines (fragments) */
 512         if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS) {
 513                 char *fragments = g_fragments_base +
 514                         (pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
 515                         g_fragments_size;
 516                 int head_bytes, tail_bytes;
 517
 518                 head_bytes = (g_cache_line_size - pagelist->offset) &
 519                         (g_cache_line_size - 1);
 520                 tail_bytes = (pagelist->offset + actual) &
 521                         (g_cache_line_size - 1);
 522
 523                 if ((actual >= 0) && (head_bytes != 0)) {
 524                         if (head_bytes > actual)
 525                                 head_bytes = actual;
 526
 527                         memcpy((char *)kmap(pages[0]) +
 528                                 pagelist->offset,
 529                                 fragments,
 530                                 head_bytes);
 531                         kunmap(pages[0]);
 532                 }
 533                 if ((actual >= 0) && (head_bytes < actual) &&
 534                         (tail_bytes != 0)) {
 535                         memcpy((char *)kmap(pages[num_pages - 1]) +
 536                                 ((pagelist->offset + actual) &
 537                                 (PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),
 538                                 fragments + g_cache_line_size,
 539                                 tail_bytes);
 540                         kunmap(pages[num_pages - 1]);
 541                 }
 542
 543                 down(&g_free_fragments_mutex);
 544                 *(char **)fragments = g_free_fragments;
 545                 g_free_fragments = fragments;
 546                 up(&g_free_fragments_mutex);
 547                 up(&g_free_fragments_sema);
 548         }
 549
 550         /* Need to mark all the pages dirty. */
 551         if (pagelist->type != PAGELIST_WRITE &&
 552             pagelistinfo->pages_need_release) {
 553                 unsigned int i;
 554
 555                 for (i = 0; i < num_pages; i++)
 556                         set_page_dirty(pages[i]);
 557         }
 558
 559         cleanup_pagelistinfo(pagelistinfo);
 560 }