linux/drivers/dma/pch_dma.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Topcliff PCH DMA controller driver
   4 * Copyright (c) 2010 Intel Corporation
   5 * Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
   6 */
   7
   8#include <linux/dmaengine.h>
   9#include <linux/dma-mapping.h>
  10#include <linux/init.h>
  11#include <linux/pci.h>
  12#include <linux/slab.h>
  13#include <linux/interrupt.h>
  14#include <linux/module.h>
  15#include <linux/pch_dma.h>
  16
  17#include "dmaengine.h"
  18
  19#define DRV_NAME "pch-dma"
  20
  21#define DMA_CTL0_DISABLE                0x0
  22#define DMA_CTL0_SG                     0x1
  23#define DMA_CTL0_ONESHOT                0x2
  24#define DMA_CTL0_MODE_MASK_BITS         0x3
  25#define DMA_CTL0_DIR_SHIFT_BITS         2
  26#define DMA_CTL0_BITS_PER_CH            4
  27
  28#define DMA_CTL2_START_SHIFT_BITS       8
  29#define DMA_CTL2_IRQ_ENABLE_MASK        ((1UL << DMA_CTL2_START_SHIFT_BITS) - 1)
  30
  31#define DMA_STATUS_IDLE                 0x0
  32#define DMA_STATUS_DESC_READ            0x1
  33#define DMA_STATUS_WAIT                 0x2
  34#define DMA_STATUS_ACCESS               0x3
  35#define DMA_STATUS_BITS_PER_CH          2
  36#define DMA_STATUS_MASK_BITS            0x3
  37#define DMA_STATUS_SHIFT_BITS           16
  38#define DMA_STATUS_IRQ(x)               (0x1 << (x))
  39#define DMA_STATUS0_ERR(x)              (0x1 << ((x) + 8))
  40#define DMA_STATUS2_ERR(x)              (0x1 << (x))
  41
  42#define DMA_DESC_WIDTH_SHIFT_BITS       12
  43#define DMA_DESC_WIDTH_1_BYTE           (0x3 << DMA_DESC_WIDTH_SHIFT_BITS)
  44#define DMA_DESC_WIDTH_2_BYTES          (0x2 << DMA_DESC_WIDTH_SHIFT_BITS)
  45#define DMA_DESC_WIDTH_4_BYTES          (0x0 << DMA_DESC_WIDTH_SHIFT_BITS)
  46#define DMA_DESC_MAX_COUNT_1_BYTE       0x3FF
  47#define DMA_DESC_MAX_COUNT_2_BYTES      0x3FF
  48#define DMA_DESC_MAX_COUNT_4_BYTES      0x7FF
  49#define DMA_DESC_END_WITHOUT_IRQ        0x0
  50#define DMA_DESC_END_WITH_IRQ           0x1
  51#define DMA_DESC_FOLLOW_WITHOUT_IRQ     0x2
  52#define DMA_DESC_FOLLOW_WITH_IRQ        0x3
  53
  54#define MAX_CHAN_NR                     12
  55
  56#define DMA_MASK_CTL0_MODE      0x33333333
  57#define DMA_MASK_CTL2_MODE      0x00003333
  58
  59static unsigned int init_nr_desc_per_channel = 64;
  60module_param(init_nr_desc_per_channel, uint, 0644);
  61MODULE_PARM_DESC(init_nr_desc_per_channel,
  62                 "initial descriptors per channel (default: 64)");
  63
  64struct pch_dma_desc_regs {
  65        u32     dev_addr;
  66        u32     mem_addr;
  67        u32     size;
  68        u32     next;
  69};
  70
  71struct pch_dma_regs {
  72        u32     dma_ctl0;
  73        u32     dma_ctl1;
  74        u32     dma_ctl2;
  75        u32     dma_ctl3;
  76        u32     dma_sts0;
  77        u32     dma_sts1;
  78        u32     dma_sts2;
  79        u32     reserved3;
  80        struct pch_dma_desc_regs desc[MAX_CHAN_NR];
  81};
  82
  83struct pch_dma_desc {
  84        struct pch_dma_desc_regs regs;
  85        struct dma_async_tx_descriptor txd;
  86        struct list_head        desc_node;
  87        struct list_head        tx_list;
  88};
  89
  90struct pch_dma_chan {
  91        struct dma_chan         chan;
  92        void __iomem *membase;
  93        enum dma_transfer_direction dir;
  94        struct tasklet_struct   tasklet;
  95        unsigned long           err_status;
  96
  97        spinlock_t              lock;
  98
  99        struct list_head        active_list;
 100        struct list_head        queue;
 101        struct list_head        free_list;
 102        unsigned int            descs_allocated;
 103};
 104
 105#define PDC_DEV_ADDR    0x00
 106#define PDC_MEM_ADDR    0x04
 107#define PDC_SIZE        0x08
 108#define PDC_NEXT        0x0C
 109
 110#define channel_readl(pdc, name) \
 111        readl((pdc)->membase + PDC_##name)
 112#define channel_writel(pdc, name, val) \
 113        writel((val), (pdc)->membase + PDC_##name)
 114
 115struct pch_dma {
 116        struct dma_device       dma;
 117        void __iomem *membase;
 118        struct dma_pool         *pool;
 119        struct pch_dma_regs     regs;
 120        struct pch_dma_desc_regs ch_regs[MAX_CHAN_NR];
 121        struct pch_dma_chan     channels[MAX_CHAN_NR];
 122};
 123
 124#define PCH_DMA_CTL0    0x00
 125#define PCH_DMA_CTL1    0x04
 126#define PCH_DMA_CTL2    0x08
 127#define PCH_DMA_CTL3    0x0C
 128#define PCH_DMA_STS0    0x10
 129#define PCH_DMA_STS1    0x14
 130#define PCH_DMA_STS2    0x18
 131
 132#define dma_readl(pd, name) \
 133        readl((pd)->membase + PCH_DMA_##name)
 134#define dma_writel(pd, name, val) \
 135        writel((val), (pd)->membase + PCH_DMA_##name)
 136
 137static inline
 138struct pch_dma_desc *to_pd_desc(struct dma_async_tx_descriptor *txd)
 139{
 140        return container_of(txd, struct pch_dma_desc, txd);
 141}
 142
 143static inline struct pch_dma_chan *to_pd_chan(struct dma_chan *chan)
 144{
 145        return container_of(chan, struct pch_dma_chan, chan);
 146}
 147
 148static inline struct pch_dma *to_pd(struct dma_device *ddev)
 149{
 150        return container_of(ddev, struct pch_dma, dma);
 151}
 152
 153static inline struct device *chan2dev(struct dma_chan *chan)
 154{
 155        return &chan->dev->device;
 156}
 157
 158static inline struct device *chan2parent(struct dma_chan *chan)
 159{
 160        return chan->dev->device.parent;
 161}
 162
 163static inline
 164struct pch_dma_desc *pdc_first_active(struct pch_dma_chan *pd_chan)
 165{
 166        return list_first_entry(&pd_chan->active_list,
 167                                struct pch_dma_desc, desc_node);
 168}
 169
 170static inline
 171struct pch_dma_desc *pdc_first_queued(struct pch_dma_chan *pd_chan)
 172{
 173        return list_first_entry(&pd_chan->queue,
 174                                struct pch_dma_desc, desc_node);
 175}
 176
 177static void pdc_enable_irq(struct dma_chan *chan, int enable)
 178{
 179        struct pch_dma *pd = to_pd(chan->device);
 180        u32 val;
 181        int pos;
 182
 183        if (chan->chan_id < 8)
 184                pos = chan->chan_id;
 185        else
 186                pos = chan->chan_id + 8;
 187
 188        val = dma_readl(pd, CTL2);
 189
 190        if (enable)
 191                val |= 0x1 << pos;
 192        else
 193                val &= ~(0x1 << pos);
 194
 195        dma_writel(pd, CTL2, val);
 196
 197        dev_dbg(chan2dev(chan), "pdc_enable_irq: chan %d -> %x\n",
 198                chan->chan_id, val);
 199}
 200
 201static void pdc_set_dir(struct dma_chan *chan)
 202{
 203        struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 204        struct pch_dma *pd = to_pd(chan->device);
 205        u32 val;
 206        u32 mask_mode;
 207        u32 mask_ctl;
 208
 209        if (chan->chan_id < 8) {
 210                val = dma_readl(pd, CTL0);
 211
 212                mask_mode = DMA_CTL0_MODE_MASK_BITS <<
 213                                        (DMA_CTL0_BITS_PER_CH * chan->chan_id);
 214                mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
 215                                       (DMA_CTL0_BITS_PER_CH * chan->chan_id));
 216                val &= mask_mode;
 217                if (pd_chan->dir == DMA_MEM_TO_DEV)
 218                        val |= 0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
 219                                       DMA_CTL0_DIR_SHIFT_BITS);
 220                else
 221                        val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
 222                                         DMA_CTL0_DIR_SHIFT_BITS));
 223
 224                val |= mask_ctl;
 225                dma_writel(pd, CTL0, val);
 226        } else {
 227                int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
 228                val = dma_readl(pd, CTL3);
 229
 230                mask_mode = DMA_CTL0_MODE_MASK_BITS <<
 231                                                (DMA_CTL0_BITS_PER_CH * ch);
 232                mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
 233                                                 (DMA_CTL0_BITS_PER_CH * ch));
 234                val &= mask_mode;
 235                if (pd_chan->dir == DMA_MEM_TO_DEV)
 236                        val |= 0x1 << (DMA_CTL0_BITS_PER_CH * ch +
 237                                       DMA_CTL0_DIR_SHIFT_BITS);
 238                else
 239                        val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * ch +
 240                                         DMA_CTL0_DIR_SHIFT_BITS));
 241                val |= mask_ctl;
 242                dma_writel(pd, CTL3, val);
 243        }
 244
 245        dev_dbg(chan2dev(chan), "pdc_set_dir: chan %d -> %x\n",
 246                chan->chan_id, val);
 247}
 248
 249static void pdc_set_mode(struct dma_chan *chan, u32 mode)
 250{
 251        struct pch_dma *pd = to_pd(chan->device);
 252        u32 val;
 253        u32 mask_ctl;
 254        u32 mask_dir;
 255
 256        if (chan->chan_id < 8) {
 257                mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
 258                           (DMA_CTL0_BITS_PER_CH * chan->chan_id));
 259                mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +\
 260                                 DMA_CTL0_DIR_SHIFT_BITS);
 261                val = dma_readl(pd, CTL0);
 262                val &= mask_dir;
 263                val |= mode << (DMA_CTL0_BITS_PER_CH * chan->chan_id);
 264                val |= mask_ctl;
 265                dma_writel(pd, CTL0, val);
 266        } else {
 267                int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
 268                mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
 269                                                 (DMA_CTL0_BITS_PER_CH * ch));
 270                mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * ch +\
 271                                 DMA_CTL0_DIR_SHIFT_BITS);
 272                val = dma_readl(pd, CTL3);
 273                val &= mask_dir;
 274                val |= mode << (DMA_CTL0_BITS_PER_CH * ch);
 275                val |= mask_ctl;
 276                dma_writel(pd, CTL3, val);
 277        }
 278
 279        dev_dbg(chan2dev(chan), "pdc_set_mode: chan %d -> %x\n",
 280                chan->chan_id, val);
 281}
 282
 283static u32 pdc_get_status0(struct pch_dma_chan *pd_chan)
 284{
 285        struct pch_dma *pd = to_pd(pd_chan->chan.device);
 286        u32 val;
 287
 288        val = dma_readl(pd, STS0);
 289        return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
 290                        DMA_STATUS_BITS_PER_CH * pd_chan->chan.chan_id));
 291}
 292
 293static u32 pdc_get_status2(struct pch_dma_chan *pd_chan)
 294{
 295        struct pch_dma *pd = to_pd(pd_chan->chan.device);
 296        u32 val;
 297
 298        val = dma_readl(pd, STS2);
 299        return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
 300                        DMA_STATUS_BITS_PER_CH * (pd_chan->chan.chan_id - 8)));
 301}
 302
 303static bool pdc_is_idle(struct pch_dma_chan *pd_chan)
 304{
 305        u32 sts;
 306
 307        if (pd_chan->chan.chan_id < 8)
 308                sts = pdc_get_status0(pd_chan);
 309        else
 310                sts = pdc_get_status2(pd_chan);
 311
 312
 313        if (sts == DMA_STATUS_IDLE)
 314                return true;
 315        else
 316                return false;
 317}
 318
 319static void pdc_dostart(struct pch_dma_chan *pd_chan, struct pch_dma_desc* desc)
 320{
 321        if (!pdc_is_idle(pd_chan)) {
 322                dev_err(chan2dev(&pd_chan->chan),
 323                        "BUG: Attempt to start non-idle channel\n");
 324                return;
 325        }
 326
 327        dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> dev_addr: %x\n",
 328                pd_chan->chan.chan_id, desc->regs.dev_addr);
 329        dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> mem_addr: %x\n",
 330                pd_chan->chan.chan_id, desc->regs.mem_addr);
 331        dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> size: %x\n",
 332                pd_chan->chan.chan_id, desc->regs.size);
 333        dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> next: %x\n",
 334                pd_chan->chan.chan_id, desc->regs.next);
 335
 336        if (list_empty(&desc->tx_list)) {
 337                channel_writel(pd_chan, DEV_ADDR, desc->regs.dev_addr);
 338                channel_writel(pd_chan, MEM_ADDR, desc->regs.mem_addr);
 339                channel_writel(pd_chan, SIZE, desc->regs.size);
 340                channel_writel(pd_chan, NEXT, desc->regs.next);
 341                pdc_set_mode(&pd_chan->chan, DMA_CTL0_ONESHOT);
 342        } else {
 343                channel_writel(pd_chan, NEXT, desc->txd.phys);
 344                pdc_set_mode(&pd_chan->chan, DMA_CTL0_SG);
 345        }
 346}
 347
 348static void pdc_chain_complete(struct pch_dma_chan *pd_chan,
 349                               struct pch_dma_desc *desc)
 350{
 351        struct dma_async_tx_descriptor *txd = &desc->txd;
 352        struct dmaengine_desc_callback cb;
 353
 354        dmaengine_desc_get_callback(txd, &cb);
 355        list_splice_init(&desc->tx_list, &pd_chan->free_list);
 356        list_move(&desc->desc_node, &pd_chan->free_list);
 357
 358        dmaengine_desc_callback_invoke(&cb, NULL);
 359}
 360
 361static void pdc_complete_all(struct pch_dma_chan *pd_chan)
 362{
 363        struct pch_dma_desc *desc, *_d;
 364        LIST_HEAD(list);
 365
 366        BUG_ON(!pdc_is_idle(pd_chan));
 367
 368        if (!list_empty(&pd_chan->queue))
 369                pdc_dostart(pd_chan, pdc_first_queued(pd_chan));
 370
 371        list_splice_init(&pd_chan->active_list, &list);
 372        list_splice_init(&pd_chan->queue, &pd_chan->active_list);
 373
 374        list_for_each_entry_safe(desc, _d, &list, desc_node)
 375                pdc_chain_complete(pd_chan, desc);
 376}
 377
 378static void pdc_handle_error(struct pch_dma_chan *pd_chan)
 379{
 380        struct pch_dma_desc *bad_desc;
 381
 382        bad_desc = pdc_first_active(pd_chan);
 383        list_del(&bad_desc->desc_node);
 384
 385        list_splice_init(&pd_chan->queue, pd_chan->active_list.prev);
 386
 387        if (!list_empty(&pd_chan->active_list))
 388                pdc_dostart(pd_chan, pdc_first_active(pd_chan));
 389
 390        dev_crit(chan2dev(&pd_chan->chan), "Bad descriptor submitted\n");
 391        dev_crit(chan2dev(&pd_chan->chan), "descriptor cookie: %d\n",
 392                 bad_desc->txd.cookie);
 393
 394        pdc_chain_complete(pd_chan, bad_desc);
 395}
 396
 397static void pdc_advance_work(struct pch_dma_chan *pd_chan)
 398{
 399        if (list_empty(&pd_chan->active_list) ||
 400                list_is_singular(&pd_chan->active_list)) {
 401                pdc_complete_all(pd_chan);
 402        } else {
 403                pdc_chain_complete(pd_chan, pdc_first_active(pd_chan));
 404                pdc_dostart(pd_chan, pdc_first_active(pd_chan));
 405        }
 406}
 407
 408static dma_cookie_t pd_tx_submit(struct dma_async_tx_descriptor *txd)
 409{
 410        struct pch_dma_desc *desc = to_pd_desc(txd);
 411        struct pch_dma_chan *pd_chan = to_pd_chan(txd->chan);
 412
 413        spin_lock(&pd_chan->lock);
 414
 415        if (list_empty(&pd_chan->active_list)) {
 416                list_add_tail(&desc->desc_node, &pd_chan->active_list);
 417                pdc_dostart(pd_chan, desc);
 418        } else {
 419                list_add_tail(&desc->desc_node, &pd_chan->queue);
 420        }
 421
 422        spin_unlock(&pd_chan->lock);
 423        return 0;
 424}
 425
 426static struct pch_dma_desc *pdc_alloc_desc(struct dma_chan *chan, gfp_t flags)
 427{
 428        struct pch_dma_desc *desc = NULL;
 429        struct pch_dma *pd = to_pd(chan->device);
 430        dma_addr_t addr;
 431
 432        desc = dma_pool_zalloc(pd->pool, flags, &addr);
 433        if (desc) {
 434                INIT_LIST_HEAD(&desc->tx_list);
 435                dma_async_tx_descriptor_init(&desc->txd, chan);
 436                desc->txd.tx_submit = pd_tx_submit;
 437                desc->txd.flags = DMA_CTRL_ACK;
 438                desc->txd.phys = addr;
 439        }
 440
 441        return desc;
 442}
 443
 444static struct pch_dma_desc *pdc_desc_get(struct pch_dma_chan *pd_chan)
 445{
 446        struct pch_dma_desc *desc, *_d;
 447        struct pch_dma_desc *ret = NULL;
 448        int i = 0;
 449
 450        spin_lock(&pd_chan->lock);
 451        list_for_each_entry_safe(desc, _d, &pd_chan->free_list, desc_node) {
 452                i++;
 453                if (async_tx_test_ack(&desc->txd)) {
 454                        list_del(&desc->desc_node);
 455                        ret = desc;
 456                        break;
 457                }
 458                dev_dbg(chan2dev(&pd_chan->chan), "desc %p not ACKed\n", desc);
 459        }
 460        spin_unlock(&pd_chan->lock);
 461        dev_dbg(chan2dev(&pd_chan->chan), "scanned %d descriptors\n", i);
 462
 463        if (!ret) {
 464                ret = pdc_alloc_desc(&pd_chan->chan, GFP_ATOMIC);
 465                if (ret) {
 466                        spin_lock(&pd_chan->lock);
 467                        pd_chan->descs_allocated++;
 468                        spin_unlock(&pd_chan->lock);
 469                } else {
 470                        dev_err(chan2dev(&pd_chan->chan),
 471                                "failed to alloc desc\n");
 472                }
 473        }
 474
 475        return ret;
 476}
 477
 478static void pdc_desc_put(struct pch_dma_chan *pd_chan,
 479                         struct pch_dma_desc *desc)
 480{
 481        if (desc) {
 482                spin_lock(&pd_chan->lock);
 483                list_splice_init(&desc->tx_list, &pd_chan->free_list);
 484                list_add(&desc->desc_node, &pd_chan->free_list);
 485                spin_unlock(&pd_chan->lock);
 486        }
 487}
 488
 489static int pd_alloc_chan_resources(struct dma_chan *chan)
 490{
 491        struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 492        struct pch_dma_desc *desc;
 493        LIST_HEAD(tmp_list);
 494        int i;
 495
 496        if (!pdc_is_idle(pd_chan)) {
 497                dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
 498                return -EIO;
 499        }
 500
 501        if (!list_empty(&pd_chan->free_list))
 502                return pd_chan->descs_allocated;
 503
 504        for (i = 0; i < init_nr_desc_per_channel; i++) {
 505                desc = pdc_alloc_desc(chan, GFP_KERNEL);
 506
 507                if (!desc) {
 508                        dev_warn(chan2dev(chan),
 509                                "Only allocated %d initial descriptors\n", i);
 510                        break;
 511                }
 512
 513                list_add_tail(&desc->desc_node, &tmp_list);
 514        }
 515
 516        spin_lock_irq(&pd_chan->lock);
 517        list_splice(&tmp_list, &pd_chan->free_list);
 518        pd_chan->descs_allocated = i;
 519        dma_cookie_init(chan);
 520        spin_unlock_irq(&pd_chan->lock);
 521
 522        pdc_enable_irq(chan, 1);
 523
 524        return pd_chan->descs_allocated;
 525}
 526
 527static void pd_free_chan_resources(struct dma_chan *chan)
 528{
 529        struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 530        struct pch_dma *pd = to_pd(chan->device);
 531        struct pch_dma_desc *desc, *_d;
 532        LIST_HEAD(tmp_list);
 533
 534        BUG_ON(!pdc_is_idle(pd_chan));
 535        BUG_ON(!list_empty(&pd_chan->active_list));
 536        BUG_ON(!list_empty(&pd_chan->queue));
 537
 538        spin_lock_irq(&pd_chan->lock);
 539        list_splice_init(&pd_chan->free_list, &tmp_list);
 540        pd_chan->descs_allocated = 0;
 541        spin_unlock_irq(&pd_chan->lock);
 542
 543        list_for_each_entry_safe(desc, _d, &tmp_list, desc_node)
 544                dma_pool_free(pd->pool, desc, desc->txd.phys);
 545
 546        pdc_enable_irq(chan, 0);
 547}
 548
 549static enum dma_status pd_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 550                                    struct dma_tx_state *txstate)
 551{
 552        return dma_cookie_status(chan, cookie, txstate);
 553}
 554
 555static void pd_issue_pending(struct dma_chan *chan)
 556{
 557        struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 558
 559        if (pdc_is_idle(pd_chan)) {
 560                spin_lock(&pd_chan->lock);
 561                pdc_advance_work(pd_chan);
 562                spin_unlock(&pd_chan->lock);
 563        }
 564}
 565
 566static struct dma_async_tx_descriptor *pd_prep_slave_sg(struct dma_chan *chan,
 567                        struct scatterlist *sgl, unsigned int sg_len,
 568                        enum dma_transfer_direction direction, unsigned long flags,
 569                        void *context)
 570{
 571        struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 572        struct pch_dma_slave *pd_slave = chan->private;
 573        struct pch_dma_desc *first = NULL;
 574        struct pch_dma_desc *prev = NULL;
 575        struct pch_dma_desc *desc = NULL;
 576        struct scatterlist *sg;
 577        dma_addr_t reg;
 578        int i;
 579
 580        if (unlikely(!sg_len)) {
 581                dev_info(chan2dev(chan), "prep_slave_sg: length is zero!\n");
 582                return NULL;
 583        }
 584
 585        if (direction == DMA_DEV_TO_MEM)
 586                reg = pd_slave->rx_reg;
 587        else if (direction == DMA_MEM_TO_DEV)
 588                reg = pd_slave->tx_reg;
 589        else
 590                return NULL;
 591
 592        pd_chan->dir = direction;
 593        pdc_set_dir(chan);
 594
 595        for_each_sg(sgl, sg, sg_len, i) {
 596                desc = pdc_desc_get(pd_chan);
 597
 598                if (!desc)
 599                        goto err_desc_get;
 600
 601                desc->regs.dev_addr = reg;
 602                desc->regs.mem_addr = sg_dma_address(sg);
 603                desc->regs.size = sg_dma_len(sg);
 604                desc->regs.next = DMA_DESC_FOLLOW_WITHOUT_IRQ;
 605
 606                switch (pd_slave->width) {
 607                case PCH_DMA_WIDTH_1_BYTE:
 608                        if (desc->regs.size > DMA_DESC_MAX_COUNT_1_BYTE)
 609                                goto err_desc_get;
 610                        desc->regs.size |= DMA_DESC_WIDTH_1_BYTE;
 611                        break;
 612                case PCH_DMA_WIDTH_2_BYTES:
 613                        if (desc->regs.size > DMA_DESC_MAX_COUNT_2_BYTES)
 614                                goto err_desc_get;
 615                        desc->regs.size |= DMA_DESC_WIDTH_2_BYTES;
 616                        break;
 617                case PCH_DMA_WIDTH_4_BYTES:
 618                        if (desc->regs.size > DMA_DESC_MAX_COUNT_4_BYTES)
 619                                goto err_desc_get;
 620                        desc->regs.size |= DMA_DESC_WIDTH_4_BYTES;
 621                        break;
 622                default:
 623                        goto err_desc_get;
 624                }
 625
 626                if (!first) {
 627                        first = desc;
 628                } else {
 629                        prev->regs.next |= desc->txd.phys;
 630                        list_add_tail(&desc->desc_node, &first->tx_list);
 631                }
 632
 633                prev = desc;
 634        }
 635
 636        if (flags & DMA_PREP_INTERRUPT)
 637                desc->regs.next = DMA_DESC_END_WITH_IRQ;
 638        else
 639                desc->regs.next = DMA_DESC_END_WITHOUT_IRQ;
 640
 641        first->txd.cookie = -EBUSY;
 642        desc->txd.flags = flags;
 643
 644        return &first->txd;
 645
 646err_desc_get:
 647        dev_err(chan2dev(chan), "failed to get desc or wrong parameters\n");
 648        pdc_desc_put(pd_chan, first);
 649        return NULL;
 650}
 651
 652static int pd_device_terminate_all(struct dma_chan *chan)
 653{
 654        struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 655        struct pch_dma_desc *desc, *_d;
 656        LIST_HEAD(list);
 657
 658        spin_lock_irq(&pd_chan->lock);
 659
 660        pdc_set_mode(&pd_chan->chan, DMA_CTL0_DISABLE);
 661
 662        list_splice_init(&pd_chan->active_list, &list);
 663        list_splice_init(&pd_chan->queue, &list);
 664
 665        list_for_each_entry_safe(desc, _d, &list, desc_node)
 666                pdc_chain_complete(pd_chan, desc);
 667
 668        spin_unlock_irq(&pd_chan->lock);
 669
 670        return 0;
 671}
 672
 673static void pdc_tasklet(struct tasklet_struct *t)
 674{
 675        struct pch_dma_chan *pd_chan = from_tasklet(pd_chan, t, tasklet);
 676        unsigned long flags;
 677
 678        if (!pdc_is_idle(pd_chan)) {
 679                dev_err(chan2dev(&pd_chan->chan),
 680                        "BUG: handle non-idle channel in tasklet\n");
 681                return;
 682        }
 683
 684        spin_lock_irqsave(&pd_chan->lock, flags);
 685        if (test_and_clear_bit(0, &pd_chan->err_status))
 686                pdc_handle_error(pd_chan);
 687        else
 688                pdc_advance_work(pd_chan);
 689        spin_unlock_irqrestore(&pd_chan->lock, flags);
 690}
 691
 692static irqreturn_t pd_irq(int irq, void *devid)
 693{
 694        struct pch_dma *pd = (struct pch_dma *)devid;
 695        struct pch_dma_chan *pd_chan;
 696        u32 sts0;
 697        u32 sts2;
 698        int i;
 699        int ret0 = IRQ_NONE;
 700        int ret2 = IRQ_NONE;
 701
 702        sts0 = dma_readl(pd, STS0);
 703        sts2 = dma_readl(pd, STS2);
 704
 705        dev_dbg(pd->dma.dev, "pd_irq sts0: %x\n", sts0);
 706
 707        for (i = 0; i < pd->dma.chancnt; i++) {
 708                pd_chan = &pd->channels[i];
 709
 710                if (i < 8) {
 711                        if (sts0 & DMA_STATUS_IRQ(i)) {
 712                                if (sts0 & DMA_STATUS0_ERR(i))
 713                                        set_bit(0, &pd_chan->err_status);
 714
 715                                tasklet_schedule(&pd_chan->tasklet);
 716                                ret0 = IRQ_HANDLED;
 717                        }
 718                } else {
 719                        if (sts2 & DMA_STATUS_IRQ(i - 8)) {
 720                                if (sts2 & DMA_STATUS2_ERR(i))
 721                                        set_bit(0, &pd_chan->err_status);
 722
 723                                tasklet_schedule(&pd_chan->tasklet);
 724                                ret2 = IRQ_HANDLED;
 725                        }
 726                }
 727        }
 728
 729        /* clear interrupt bits in status register */
 730        if (ret0)
 731                dma_writel(pd, STS0, sts0);
 732        if (ret2)
 733                dma_writel(pd, STS2, sts2);
 734
 735        return ret0 | ret2;
 736}
 737
 738static void __maybe_unused pch_dma_save_regs(struct pch_dma *pd)
 739{
 740        struct pch_dma_chan *pd_chan;
 741        struct dma_chan *chan, *_c;
 742        int i = 0;
 743
 744        pd->regs.dma_ctl0 = dma_readl(pd, CTL0);
 745        pd->regs.dma_ctl1 = dma_readl(pd, CTL1);
 746        pd->regs.dma_ctl2 = dma_readl(pd, CTL2);
 747        pd->regs.dma_ctl3 = dma_readl(pd, CTL3);
 748
 749        list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
 750                pd_chan = to_pd_chan(chan);
 751
 752                pd->ch_regs[i].dev_addr = channel_readl(pd_chan, DEV_ADDR);
 753                pd->ch_regs[i].mem_addr = channel_readl(pd_chan, MEM_ADDR);
 754                pd->ch_regs[i].size = channel_readl(pd_chan, SIZE);
 755                pd->ch_regs[i].next = channel_readl(pd_chan, NEXT);
 756
 757                i++;
 758        }
 759}
 760
 761static void __maybe_unused pch_dma_restore_regs(struct pch_dma *pd)
 762{
 763        struct pch_dma_chan *pd_chan;
 764        struct dma_chan *chan, *_c;
 765        int i = 0;
 766
 767        dma_writel(pd, CTL0, pd->regs.dma_ctl0);
 768        dma_writel(pd, CTL1, pd->regs.dma_ctl1);
 769        dma_writel(pd, CTL2, pd->regs.dma_ctl2);
 770        dma_writel(pd, CTL3, pd->regs.dma_ctl3);
 771
 772        list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
 773                pd_chan = to_pd_chan(chan);
 774
 775                channel_writel(pd_chan, DEV_ADDR, pd->ch_regs[i].dev_addr);
 776                channel_writel(pd_chan, MEM_ADDR, pd->ch_regs[i].mem_addr);
 777                channel_writel(pd_chan, SIZE, pd->ch_regs[i].size);
 778                channel_writel(pd_chan, NEXT, pd->ch_regs[i].next);
 779
 780                i++;
 781        }
 782}
 783
 784static int __maybe_unused pch_dma_suspend(struct device *dev)
 785{
 786        struct pch_dma *pd = dev_get_drvdata(dev);
 787
 788        if (pd)
 789                pch_dma_save_regs(pd);
 790
 791        return 0;
 792}
 793
 794static int __maybe_unused pch_dma_resume(struct device *dev)
 795{
 796        struct pch_dma *pd = dev_get_drvdata(dev);
 797
 798        if (pd)
 799                pch_dma_restore_regs(pd);
 800
 801        return 0;
 802}
 803
 804static int pch_dma_probe(struct pci_dev *pdev,
 805                                   const struct pci_device_id *id)
 806{
 807        struct pch_dma *pd;
 808        struct pch_dma_regs *regs;
 809        unsigned int nr_channels;
 810        int err;
 811        int i;
 812
 813        nr_channels = id->driver_data;
 814        pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 815        if (!pd)
 816                return -ENOMEM;
 817
 818        pci_set_drvdata(pdev, pd);
 819
 820        err = pci_enable_device(pdev);
 821        if (err) {
 822                dev_err(&pdev->dev, "Cannot enable PCI device\n");
 823                goto err_free_mem;
 824        }
 825
 826        if (!(pci_resource_flags(pdev, 1) & IORESOURCE_MEM)) {
 827                dev_err(&pdev->dev, "Cannot find proper base address\n");
 828                err = -ENODEV;
 829                goto err_disable_pdev;
 830        }
 831
 832        err = pci_request_regions(pdev, DRV_NAME);
 833        if (err) {
 834                dev_err(&pdev->dev, "Cannot obtain PCI resources\n");
 835                goto err_disable_pdev;
 836        }
 837
 838        err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
 839        if (err) {
 840                dev_err(&pdev->dev, "Cannot set proper DMA config\n");
 841                goto err_free_res;
 842        }
 843
 844        regs = pd->membase = pci_iomap(pdev, 1, 0);
 845        if (!pd->membase) {
 846                dev_err(&pdev->dev, "Cannot map MMIO registers\n");
 847                err = -ENOMEM;
 848                goto err_free_res;
 849        }
 850
 851        pci_set_master(pdev);
 852        pd->dma.dev = &pdev->dev;
 853
 854        err = request_irq(pdev->irq, pd_irq, IRQF_SHARED, DRV_NAME, pd);
 855        if (err) {
 856                dev_err(&pdev->dev, "Failed to request IRQ\n");
 857                goto err_iounmap;
 858        }
 859
 860        pd->pool = dma_pool_create("pch_dma_desc_pool", &pdev->dev,
 861                                   sizeof(struct pch_dma_desc), 4, 0);
 862        if (!pd->pool) {
 863                dev_err(&pdev->dev, "Failed to alloc DMA descriptors\n");
 864                err = -ENOMEM;
 865                goto err_free_irq;
 866        }
 867
 868
 869        INIT_LIST_HEAD(&pd->dma.channels);
 870
 871        for (i = 0; i < nr_channels; i++) {
 872                struct pch_dma_chan *pd_chan = &pd->channels[i];
 873
 874                pd_chan->chan.device = &pd->dma;
 875                dma_cookie_init(&pd_chan->chan);
 876
 877                pd_chan->membase = &regs->desc[i];
 878
 879                spin_lock_init(&pd_chan->lock);
 880
 881                INIT_LIST_HEAD(&pd_chan->active_list);
 882                INIT_LIST_HEAD(&pd_chan->queue);
 883                INIT_LIST_HEAD(&pd_chan->free_list);
 884
 885                tasklet_setup(&pd_chan->tasklet, pdc_tasklet);
 886                list_add_tail(&pd_chan->chan.device_node, &pd->dma.channels);
 887        }
 888
 889        dma_cap_zero(pd->dma.cap_mask);
 890        dma_cap_set(DMA_PRIVATE, pd->dma.cap_mask);
 891        dma_cap_set(DMA_SLAVE, pd->dma.cap_mask);
 892
 893        pd->dma.device_alloc_chan_resources = pd_alloc_chan_resources;
 894        pd->dma.device_free_chan_resources = pd_free_chan_resources;
 895        pd->dma.device_tx_status = pd_tx_status;
 896        pd->dma.device_issue_pending = pd_issue_pending;
 897        pd->dma.device_prep_slave_sg = pd_prep_slave_sg;
 898        pd->dma.device_terminate_all = pd_device_terminate_all;
 899
 900        err = dma_async_device_register(&pd->dma);
 901        if (err) {
 902                dev_err(&pdev->dev, "Failed to register DMA device\n");
 903                goto err_free_pool;
 904        }
 905
 906        return 0;
 907
 908err_free_pool:
 909        dma_pool_destroy(pd->pool);
 910err_free_irq:
 911        free_irq(pdev->irq, pd);
 912err_iounmap:
 913        pci_iounmap(pdev, pd->membase);
 914err_free_res:
 915        pci_release_regions(pdev);
 916err_disable_pdev:
 917        pci_disable_device(pdev);
 918err_free_mem:
 919        kfree(pd);
 920        return err;
 921}
 922
 923static void pch_dma_remove(struct pci_dev *pdev)
 924{
 925        struct pch_dma *pd = pci_get_drvdata(pdev);
 926        struct pch_dma_chan *pd_chan;
 927        struct dma_chan *chan, *_c;
 928
 929        if (pd) {
 930                dma_async_device_unregister(&pd->dma);
 931
 932                free_irq(pdev->irq, pd);
 933
 934                list_for_each_entry_safe(chan, _c, &pd->dma.channels,
 935                                         device_node) {
 936                        pd_chan = to_pd_chan(chan);
 937
 938                        tasklet_kill(&pd_chan->tasklet);
 939                }
 940
 941                dma_pool_destroy(pd->pool);
 942                pci_iounmap(pdev, pd->membase);
 943                pci_release_regions(pdev);
 944                pci_disable_device(pdev);
 945                kfree(pd);
 946        }
 947}
 948
 949/* PCI Device ID of DMA device */
 950#define PCI_DEVICE_ID_EG20T_PCH_DMA_8CH        0x8810
 951#define PCI_DEVICE_ID_EG20T_PCH_DMA_4CH        0x8815
 952#define PCI_DEVICE_ID_ML7213_DMA1_8CH   0x8026
 953#define PCI_DEVICE_ID_ML7213_DMA2_8CH   0x802B
 954#define PCI_DEVICE_ID_ML7213_DMA3_4CH   0x8034
 955#define PCI_DEVICE_ID_ML7213_DMA4_12CH  0x8032
 956#define PCI_DEVICE_ID_ML7223_DMA1_4CH   0x800B
 957#define PCI_DEVICE_ID_ML7223_DMA2_4CH   0x800E
 958#define PCI_DEVICE_ID_ML7223_DMA3_4CH   0x8017
 959#define PCI_DEVICE_ID_ML7223_DMA4_4CH   0x803B
 960#define PCI_DEVICE_ID_ML7831_DMA1_8CH   0x8810
 961#define PCI_DEVICE_ID_ML7831_DMA2_4CH   0x8815
 962
 963static const struct pci_device_id pch_dma_id_table[] = {
 964        { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_EG20T_PCH_DMA_8CH), 8 },
 965        { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_EG20T_PCH_DMA_4CH), 4 },
 966        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA1_8CH), 8}, /* UART Video */
 967        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA2_8CH), 8}, /* PCMIF SPI */
 968        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA3_4CH), 4}, /* FPGA */
 969        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA4_12CH), 12}, /* I2S */
 970        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA1_4CH), 4}, /* UART */
 971        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA2_4CH), 4}, /* Video SPI */
 972        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA3_4CH), 4}, /* Security */
 973        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA4_4CH), 4}, /* FPGA */
 974        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_DMA1_8CH), 8}, /* UART */
 975        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_DMA2_4CH), 4}, /* SPI */
 976        { 0, },
 977};
 978
 979static SIMPLE_DEV_PM_OPS(pch_dma_pm_ops, pch_dma_suspend, pch_dma_resume);
 980
 981static struct pci_driver pch_dma_driver = {
 982        .name           = DRV_NAME,
 983        .id_table       = pch_dma_id_table,
 984        .probe          = pch_dma_probe,
 985        .remove         = pch_dma_remove,
 986        .driver.pm      = &pch_dma_pm_ops,
 987};
 988
 989module_pci_driver(pch_dma_driver);
 990
 991MODULE_DESCRIPTION("Intel EG20T PCH / LAPIS Semicon ML7213/ML7223/ML7831 IOH "
 992                   "DMA controller driver");
 993MODULE_AUTHOR("Yong Wang <yong.y.wang@intel.com>");
 994MODULE_LICENSE("GPL v2");
 995MODULE_DEVICE_TABLE(pci, pch_dma_id_table);
 996