drivers/dma/hsu/hsu.c

   1 /*
   2  * Core driver for the High Speed UART DMA
   3  *
   4  * Copyright (C) 2015 Intel Corporation
   5  * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
   6  *
   7  * Partially based on the bits found in drivers/tty/serial/mfd.c.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 /*
  15  * DMA channel allocation:
  16  * 1. Even number chans are used for DMA Read (UART TX), odd chans for DMA
  17  *    Write (UART RX).
  18  * 2. 0/1 channel are assigned to port 0, 2/3 chan to port 1, 4/5 chan to
  19  *    port 3, and so on.
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/dma-mapping.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28
  29 #include "hsu.h"
  30
  31 #define HSU_DMA_BUSWIDTHS                               \
  32         BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED)       |       \
  33         BIT(DMA_SLAVE_BUSWIDTH_1_BYTE)          |       \
  34         BIT(DMA_SLAVE_BUSWIDTH_2_BYTES)         |       \
  35         BIT(DMA_SLAVE_BUSWIDTH_3_BYTES)         |       \
  36         BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)         |       \
  37         BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)         |       \
  38         BIT(DMA_SLAVE_BUSWIDTH_16_BYTES)
  39
  40 static inline void hsu_chan_disable(struct hsu_dma_chan *hsuc)
  41 {
  42         hsu_chan_writel(hsuc, HSU_CH_CR, 0);
  43 }
  44
  45 static inline void hsu_chan_enable(struct hsu_dma_chan *hsuc)
  46 {
  47         u32 cr = HSU_CH_CR_CHA;
  48
  49         if (hsuc->direction == DMA_MEM_TO_DEV)
  50                 cr &= ~HSU_CH_CR_CHD;
  51         else if (hsuc->direction == DMA_DEV_TO_MEM)
  52                 cr |= HSU_CH_CR_CHD;
  53
  54         hsu_chan_writel(hsuc, HSU_CH_CR, cr);
  55 }
  56
  57 static void hsu_dma_chan_start(struct hsu_dma_chan *hsuc)
  58 {
  59         struct dma_slave_config *config = &hsuc->config;
  60         struct hsu_dma_desc *desc = hsuc->desc;
  61         u32 bsr = 0, mtsr = 0;  /* to shut the compiler up */
  62         u32 dcr = HSU_CH_DCR_CHSOE | HSU_CH_DCR_CHEI;
  63         unsigned int i, count;
  64
  65         if (hsuc->direction == DMA_MEM_TO_DEV) {
  66                 bsr = config->dst_maxburst;
  67                 mtsr = config->src_addr_width;
  68         } else if (hsuc->direction == DMA_DEV_TO_MEM) {
  69                 bsr = config->src_maxburst;
  70                 mtsr = config->dst_addr_width;
  71         }
  72
  73         hsu_chan_disable(hsuc);
  74
  75         hsu_chan_writel(hsuc, HSU_CH_DCR, 0);
  76         hsu_chan_writel(hsuc, HSU_CH_BSR, bsr);
  77         hsu_chan_writel(hsuc, HSU_CH_MTSR, mtsr);
  78
  79         /* Set descriptors */
  80         count = (desc->nents - desc->active) % HSU_DMA_CHAN_NR_DESC;
  81         for (i = 0; i < count; i++) {
  82                 hsu_chan_writel(hsuc, HSU_CH_DxSAR(i), desc->sg[i].addr);
  83                 hsu_chan_writel(hsuc, HSU_CH_DxTSR(i), desc->sg[i].len);
  84
  85                 /* Prepare value for DCR */
  86                 dcr |= HSU_CH_DCR_DESCA(i);
  87                 dcr |= HSU_CH_DCR_CHTOI(i);     /* timeout bit, see HSU Errata 1 */
  88
  89                 desc->active++;
  90         }
  91         /* Only for the last descriptor in the chain */
  92         dcr |= HSU_CH_DCR_CHSOD(count - 1);
  93         dcr |= HSU_CH_DCR_CHDI(count - 1);
  94
  95         hsu_chan_writel(hsuc, HSU_CH_DCR, dcr);
  96
  97         hsu_chan_enable(hsuc);
  98 }
  99
 100 static void hsu_dma_stop_channel(struct hsu_dma_chan *hsuc)
 101 {
 102         hsu_chan_disable(hsuc);
 103         hsu_chan_writel(hsuc, HSU_CH_DCR, 0);
 104 }
 105
 106 static void hsu_dma_start_channel(struct hsu_dma_chan *hsuc)
 107 {
 108         hsu_dma_chan_start(hsuc);
 109 }
 110
 111 static void hsu_dma_start_transfer(struct hsu_dma_chan *hsuc)
 112 {
 113         struct virt_dma_desc *vdesc;
 114
 115         /* Get the next descriptor */
 116         vdesc = vchan_next_desc(&hsuc->vchan);
 117         if (!vdesc) {
 118                 hsuc->desc = NULL;
 119                 return;
 120         }
 121
 122         list_del(&vdesc->node);
 123         hsuc->desc = to_hsu_dma_desc(vdesc);
 124
 125         /* Start the channel with a new descriptor */
 126         hsu_dma_start_channel(hsuc);
 127 }
 128
 129 static u32 hsu_dma_chan_get_sr(struct hsu_dma_chan *hsuc)
 130 {
 131         unsigned long flags;
 132         u32 sr;
 133
 134         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 135         sr = hsu_chan_readl(hsuc, HSU_CH_SR);
 136         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 137
 138         return sr & ~(HSU_CH_SR_DESCE_ANY | HSU_CH_SR_CDESC_ANY);
 139 }
 140
 141 irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr)
 142 {
 143         struct hsu_dma_chan *hsuc;
 144         struct hsu_dma_desc *desc;
 145         unsigned long flags;
 146         u32 sr;
 147
 148         /* Sanity check */
 149         if (nr >= chip->hsu->nr_channels)
 150                 return IRQ_NONE;
 151
 152         hsuc = &chip->hsu->chan[nr];
 153
 154         /*
 155          * No matter what situation, need read clear the IRQ status
 156          * There is a bug, see Errata 5, HSD 2900918
 157          */
 158         sr = hsu_dma_chan_get_sr(hsuc);
 159         if (!sr)
 160                 return IRQ_NONE;
 161
 162         /* Timeout IRQ, need wait some time, see Errata 2 */
 163         if (hsuc->direction == DMA_DEV_TO_MEM && (sr & HSU_CH_SR_DESCTO_ANY))
 164                 udelay(2);
 165
 166         sr &= ~HSU_CH_SR_DESCTO_ANY;
 167         if (!sr)
 168                 return IRQ_HANDLED;
 169
 170         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 171         desc = hsuc->desc;
 172         if (desc) {
 173                 if (sr & HSU_CH_SR_CHE) {
 174                         desc->status = DMA_ERROR;
 175                 } else if (desc->active < desc->nents) {
 176                         hsu_dma_start_channel(hsuc);
 177                 } else {
 178                         vchan_cookie_complete(&desc->vdesc);
 179                         desc->status = DMA_COMPLETE;
 180                         hsu_dma_start_transfer(hsuc);
 181                 }
 182         }
 183         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 184
 185         return IRQ_HANDLED;
 186 }
 187 EXPORT_SYMBOL_GPL(hsu_dma_irq);
 188
 189 static struct hsu_dma_desc *hsu_dma_alloc_desc(unsigned int nents)
 190 {
 191         struct hsu_dma_desc *desc;
 192
 193         desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
 194         if (!desc)
 195                 return NULL;
 196
 197         desc->sg = kcalloc(nents, sizeof(*desc->sg), GFP_NOWAIT);
 198         if (!desc->sg) {
 199                 kfree(desc);
 200                 return NULL;
 201         }
 202
 203         return desc;
 204 }
 205
 206 static void hsu_dma_desc_free(struct virt_dma_desc *vdesc)
 207 {
 208         struct hsu_dma_desc *desc = to_hsu_dma_desc(vdesc);
 209
 210         kfree(desc->sg);
 211         kfree(desc);
 212 }
 213
 214 static struct dma_async_tx_descriptor *hsu_dma_prep_slave_sg(
 215                 struct dma_chan *chan, struct scatterlist *sgl,
 216                 unsigned int sg_len, enum dma_transfer_direction direction,
 217                 unsigned long flags, void *context)
 218 {
 219         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 220         struct hsu_dma_desc *desc;
 221         struct scatterlist *sg;
 222         unsigned int i;
 223
 224         desc = hsu_dma_alloc_desc(sg_len);
 225         if (!desc)
 226                 return NULL;
 227
 228         for_each_sg(sgl, sg, sg_len, i) {
 229                 desc->sg[i].addr = sg_dma_address(sg);
 230                 desc->sg[i].len = sg_dma_len(sg);
 231
 232                 desc->length += sg_dma_len(sg);
 233         }
 234
 235         desc->nents = sg_len;
 236         desc->direction = direction;
 237         /* desc->active = 0 by kzalloc */
 238         desc->status = DMA_IN_PROGRESS;
 239
 240         return vchan_tx_prep(&hsuc->vchan, &desc->vdesc, flags);
 241 }
 242
 243 static void hsu_dma_issue_pending(struct dma_chan *chan)
 244 {
 245         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 246         unsigned long flags;
 247
 248         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 249         if (vchan_issue_pending(&hsuc->vchan) && !hsuc->desc)
 250                 hsu_dma_start_transfer(hsuc);
 251         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 252 }
 253
 254 static size_t hsu_dma_active_desc_size(struct hsu_dma_chan *hsuc)
 255 {
 256         struct hsu_dma_desc *desc = hsuc->desc;
 257         size_t bytes = 0;
 258         int i;
 259
 260         for (i = desc->active; i < desc->nents; i++)
 261                 bytes += desc->sg[i].len;
 262
 263         i = HSU_DMA_CHAN_NR_DESC - 1;
 264         do {
 265                 bytes += hsu_chan_readl(hsuc, HSU_CH_DxTSR(i));
 266         } while (--i >= 0);
 267
 268         return bytes;
 269 }
 270
 271 static enum dma_status hsu_dma_tx_status(struct dma_chan *chan,
 272         dma_cookie_t cookie, struct dma_tx_state *state)
 273 {
 274         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 275         struct virt_dma_desc *vdesc;
 276         enum dma_status status;
 277         size_t bytes;
 278         unsigned long flags;
 279
 280         status = dma_cookie_status(chan, cookie, state);
 281         if (status == DMA_COMPLETE)
 282                 return status;
 283
 284         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 285         vdesc = vchan_find_desc(&hsuc->vchan, cookie);
 286         if (hsuc->desc && cookie == hsuc->desc->vdesc.tx.cookie) {
 287                 bytes = hsu_dma_active_desc_size(hsuc);
 288                 dma_set_residue(state, bytes);
 289                 status = hsuc->desc->status;
 290         } else if (vdesc) {
 291                 bytes = to_hsu_dma_desc(vdesc)->length;
 292                 dma_set_residue(state, bytes);
 293         }
 294         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 295
 296         return status;
 297 }
 298
 299 static int hsu_dma_slave_config(struct dma_chan *chan,
 300                                 struct dma_slave_config *config)
 301 {
 302         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 303
 304         /* Check if chan will be configured for slave transfers */
 305         if (!is_slave_direction(config->direction))
 306                 return -EINVAL;
 307
 308         memcpy(&hsuc->config, config, sizeof(hsuc->config));
 309
 310         return 0;
 311 }
 312
 313 static int hsu_dma_pause(struct dma_chan *chan)
 314 {
 315         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 316         unsigned long flags;
 317
 318         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 319         if (hsuc->desc && hsuc->desc->status == DMA_IN_PROGRESS) {
 320                 hsu_chan_disable(hsuc);
 321                 hsuc->desc->status = DMA_PAUSED;
 322         }
 323         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 324
 325         return 0;
 326 }
 327
 328 static int hsu_dma_resume(struct dma_chan *chan)
 329 {
 330         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 331         unsigned long flags;
 332
 333         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 334         if (hsuc->desc && hsuc->desc->status == DMA_PAUSED) {
 335                 hsuc->desc->status = DMA_IN_PROGRESS;
 336                 hsu_chan_enable(hsuc);
 337         }
 338         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 339
 340         return 0;
 341 }
 342
 343 static int hsu_dma_terminate_all(struct dma_chan *chan)
 344 {
 345         struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
 346         unsigned long flags;
 347         LIST_HEAD(head);
 348
 349         spin_lock_irqsave(&hsuc->vchan.lock, flags);
 350
 351         hsu_dma_stop_channel(hsuc);
 352         if (hsuc->desc) {
 353                 hsu_dma_desc_free(&hsuc->desc->vdesc);
 354                 hsuc->desc = NULL;
 355         }
 356
 357         vchan_get_all_descriptors(&hsuc->vchan, &head);
 358         spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 359         vchan_dma_desc_free_list(&hsuc->vchan, &head);
 360
 361         return 0;
 362 }
 363
 364 static void hsu_dma_free_chan_resources(struct dma_chan *chan)
 365 {
 366         vchan_free_chan_resources(to_virt_chan(chan));
 367 }
 368
 369 int hsu_dma_probe(struct hsu_dma_chip *chip)
 370 {
 371         struct hsu_dma *hsu;
 372         void __iomem *addr = chip->regs + chip->offset;
 373         unsigned short i;
 374         int ret;
 375
 376         hsu = devm_kzalloc(chip->dev, sizeof(*hsu), GFP_KERNEL);
 377         if (!hsu)
 378                 return -ENOMEM;
 379
 380         chip->hsu = hsu;
 381
 382         /* Calculate nr_channels from the IO space length */
 383         hsu->nr_channels = (chip->length - chip->offset) / HSU_DMA_CHAN_LENGTH;
 384
 385         hsu->chan = devm_kcalloc(chip->dev, hsu->nr_channels,
 386                                  sizeof(*hsu->chan), GFP_KERNEL);
 387         if (!hsu->chan)
 388                 return -ENOMEM;
 389
 390         INIT_LIST_HEAD(&hsu->dma.channels);
 391         for (i = 0; i < hsu->nr_channels; i++) {
 392                 struct hsu_dma_chan *hsuc = &hsu->chan[i];
 393
 394                 hsuc->vchan.desc_free = hsu_dma_desc_free;
 395                 vchan_init(&hsuc->vchan, &hsu->dma);
 396
 397                 hsuc->direction = (i & 0x1) ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
 398                 hsuc->reg = addr + i * HSU_DMA_CHAN_LENGTH;
 399         }
 400
 401         dma_cap_set(DMA_SLAVE, hsu->dma.cap_mask);
 402         dma_cap_set(DMA_PRIVATE, hsu->dma.cap_mask);
 403
 404         hsu->dma.device_free_chan_resources = hsu_dma_free_chan_resources;
 405
 406         hsu->dma.device_prep_slave_sg = hsu_dma_prep_slave_sg;
 407
 408         hsu->dma.device_issue_pending = hsu_dma_issue_pending;
 409         hsu->dma.device_tx_status = hsu_dma_tx_status;
 410
 411         hsu->dma.device_config = hsu_dma_slave_config;
 412         hsu->dma.device_pause = hsu_dma_pause;
 413         hsu->dma.device_resume = hsu_dma_resume;
 414         hsu->dma.device_terminate_all = hsu_dma_terminate_all;
 415
 416         hsu->dma.src_addr_widths = HSU_DMA_BUSWIDTHS;
 417         hsu->dma.dst_addr_widths = HSU_DMA_BUSWIDTHS;
 418         hsu->dma.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
 419         hsu->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
 420
 421         hsu->dma.dev = chip->dev;
 422
 423         ret = dma_async_device_register(&hsu->dma);
 424         if (ret)
 425                 return ret;
 426
 427         dev_info(chip->dev, "Found HSU DMA, %d channels\n", hsu->nr_channels);
 428         return 0;
 429 }
 430 EXPORT_SYMBOL_GPL(hsu_dma_probe);
 431
 432 int hsu_dma_remove(struct hsu_dma_chip *chip)
 433 {
 434         struct hsu_dma *hsu = chip->hsu;
 435         unsigned short i;
 436
 437         dma_async_device_unregister(&hsu->dma);
 438
 439         for (i = 0; i < hsu->nr_channels; i++) {
 440                 struct hsu_dma_chan *hsuc = &hsu->chan[i];
 441
 442                 tasklet_kill(&hsuc->vchan.task);
 443         }
 444
 445         return 0;
 446 }
 447 EXPORT_SYMBOL_GPL(hsu_dma_remove);
 448
 449 MODULE_LICENSE("GPL v2");
 450 MODULE_DESCRIPTION("High Speed UART DMA core driver");
 451 MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");