arch/arm/plat-pxa/dma.c

   1 /*
   2  *  linux/arch/arm/plat-pxa/dma.c
   3  *
   4  *  PXA DMA registration and IRQ dispatching
   5  *
   6  *  Author:     Nicolas Pitre
   7  *  Created:    Nov 15, 2001
   8  *  Copyright:  MontaVista Software Inc.
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2 as
  12  *  published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/kernel.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/errno.h>
  21 #include <linux/dma-mapping.h>
  22
  23 #include <asm/system.h>
  24 #include <asm/irq.h>
  25 #include <asm/memory.h>
  26 #include <mach/hardware.h>
  27 #include <mach/dma.h>
  28
  29 #define DMA_DEBUG_NAME          "pxa_dma"
  30 #define DMA_MAX_REQUESTERS      64
  31
  32 struct dma_channel {
  33         char *name;
  34         pxa_dma_prio prio;
  35         void (*irq_handler)(int, void *);
  36         void *data;
  37         spinlock_t lock;
  38 };
  39
  40 static struct dma_channel *dma_channels;
  41 static int num_dma_channels;
  42
  43 /*
  44  * Debug fs
  45  */
  46 #ifdef CONFIG_DEBUG_FS
  47 #include <linux/debugfs.h>
  48 #include <linux/uaccess.h>
  49 #include <linux/seq_file.h>
  50
  51 static struct dentry *dbgfs_root, *dbgfs_state, **dbgfs_chan;
  52
  53 static int dbg_show_requester_chan(struct seq_file *s, void *p)
  54 {
  55         int pos = 0;
  56         int chan = (int)s->private;
  57         int i;
  58         u32 drcmr;
  59
  60         pos += seq_printf(s, "DMA channel %d requesters list :\n", chan);
  61         for (i = 0; i < DMA_MAX_REQUESTERS; i++) {
  62                 drcmr = DRCMR(i);
  63                 if ((drcmr & DRCMR_CHLNUM) == chan)
  64                         pos += seq_printf(s, "\tRequester %d (MAPVLD=%d)\n", i,
  65                                           !!(drcmr & DRCMR_MAPVLD));
  66         }
  67         return pos;
  68 }
  69
  70 static inline int dbg_burst_from_dcmd(u32 dcmd)
  71 {
  72         int burst = (dcmd >> 16) & 0x3;
  73
  74         return burst ? 4 << burst : 0;
  75 }
  76
  77 static int is_phys_valid(unsigned long addr)
  78 {
  79         return pfn_valid(__phys_to_pfn(addr));
  80 }
  81
  82 #define DCSR_STR(flag) (dcsr & DCSR_##flag ? #flag" " : "")
  83 #define DCMD_STR(flag) (dcmd & DCMD_##flag ? #flag" " : "")
  84
  85 static int dbg_show_descriptors(struct seq_file *s, void *p)
  86 {
  87         int pos = 0;
  88         int chan = (int)s->private;
  89         int i, max_show = 20, burst, width;
  90         u32 dcmd;
  91         unsigned long phys_desc;
  92         struct pxa_dma_desc *desc;
  93         unsigned long flags;
  94
  95         spin_lock_irqsave(&dma_channels[chan].lock, flags);
  96         phys_desc = DDADR(chan);
  97
  98         pos += seq_printf(s, "DMA channel %d descriptors :\n", chan);
  99         pos += seq_printf(s, "[%03d] First descriptor unknown\n", 0);
 100         for (i = 1; i < max_show && is_phys_valid(phys_desc); i++) {
 101                 desc = phys_to_virt(phys_desc);
 102                 dcmd = desc->dcmd;
 103                 burst = dbg_burst_from_dcmd(dcmd);
 104                 width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
 105
 106                 pos += seq_printf(s, "[%03d] Desc at %08lx(virt %p)\n",
 107                                   i, phys_desc, desc);
 108                 pos += seq_printf(s, "\tDDADR = %08x\n", desc->ddadr);
 109                 pos += seq_printf(s, "\tDSADR = %08x\n", desc->dsadr);
 110                 pos += seq_printf(s, "\tDTADR = %08x\n", desc->dtadr);
 111                 pos += seq_printf(s, "\tDCMD  = %08x (%s%s%s%s%s%s%sburst=%d"
 112                                   " width=%d len=%d)\n",
 113                                   dcmd,
 114                                   DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
 115                                   DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
 116                                   DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
 117                                   DCMD_STR(ENDIAN), burst, width,
 118                                   dcmd & DCMD_LENGTH);
 119                 phys_desc = desc->ddadr;
 120         }
 121         if (i == max_show)
 122                 pos += seq_printf(s, "[%03d] Desc at %08lx ... max display reached\n",
 123                                   i, phys_desc);
 124         else
 125                 pos += seq_printf(s, "[%03d] Desc at %08lx is %s\n",
 126                                   i, phys_desc, phys_desc == DDADR_STOP ?
 127                                   "DDADR_STOP" : "invalid");
 128
 129         spin_unlock_irqrestore(&dma_channels[chan].lock, flags);
 130         return pos;
 131 }
 132
 133 static int dbg_show_chan_state(struct seq_file *s, void *p)
 134 {
 135         int pos = 0;
 136         int chan = (int)s->private;
 137         u32 dcsr, dcmd;
 138         int burst, width;
 139         static char *str_prio[] = { "high", "normal", "low" };
 140
 141         dcsr = DCSR(chan);
 142         dcmd = DCMD(chan);
 143         burst = dbg_burst_from_dcmd(dcmd);
 144         width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
 145
 146         pos += seq_printf(s, "DMA channel %d\n", chan);
 147         pos += seq_printf(s, "\tPriority : %s\n",
 148                           str_prio[dma_channels[chan].prio]);
 149         pos += seq_printf(s, "\tUnaligned transfer bit: %s\n",
 150                           DALGN & (1 << chan) ? "yes" : "no");
 151         pos += seq_printf(s, "\tDCSR  = %08x (%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s)\n",
 152                           dcsr, DCSR_STR(RUN), DCSR_STR(NODESC),
 153                           DCSR_STR(STOPIRQEN), DCSR_STR(EORIRQEN),
 154                           DCSR_STR(EORJMPEN), DCSR_STR(EORSTOPEN),
 155                           DCSR_STR(SETCMPST), DCSR_STR(CLRCMPST),
 156                           DCSR_STR(CMPST), DCSR_STR(EORINTR), DCSR_STR(REQPEND),
 157                           DCSR_STR(STOPSTATE), DCSR_STR(ENDINTR),
 158                           DCSR_STR(STARTINTR), DCSR_STR(BUSERR));
 159
 160         pos += seq_printf(s, "\tDCMD  = %08x (%s%s%s%s%s%s%sburst=%d width=%d"
 161                           " len=%d)\n",
 162                           dcmd,
 163                           DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
 164                           DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
 165                           DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
 166                           DCMD_STR(ENDIAN), burst, width, dcmd & DCMD_LENGTH);
 167         pos += seq_printf(s, "\tDSADR = %08x\n", DSADR(chan));
 168         pos += seq_printf(s, "\tDTADR = %08x\n", DTADR(chan));
 169         pos += seq_printf(s, "\tDDADR = %08x\n", DDADR(chan));
 170         return pos;
 171 }
 172
 173 static int dbg_show_state(struct seq_file *s, void *p)
 174 {
 175         int pos = 0;
 176
 177         /* basic device status */
 178         pos += seq_printf(s, "DMA engine status\n");
 179         pos += seq_printf(s, "\tChannel number: %d\n", num_dma_channels);
 180
 181         return pos;
 182 }
 183
 184 #define DBGFS_FUNC_DECL(name) \
 185 static int dbg_open_##name(struct inode *inode, struct file *file) \
 186 { \
 187         return single_open(file, dbg_show_##name, inode->i_private); \
 188 } \
 189 static const struct file_operations dbg_fops_##name = { \
 190         .owner          = THIS_MODULE, \
 191         .open           = dbg_open_##name, \
 192         .llseek         = seq_lseek, \
 193         .read           = seq_read, \
 194         .release        = single_release, \
 195 }
 196
 197 DBGFS_FUNC_DECL(state);
 198 DBGFS_FUNC_DECL(chan_state);
 199 DBGFS_FUNC_DECL(descriptors);
 200 DBGFS_FUNC_DECL(requester_chan);
 201
 202 static struct dentry *pxa_dma_dbg_alloc_chan(int ch, struct dentry *chandir)
 203 {
 204         char chan_name[11];
 205         struct dentry *chan, *chan_state = NULL, *chan_descr = NULL;
 206         struct dentry *chan_reqs = NULL;
 207         void *dt;
 208
 209         scnprintf(chan_name, sizeof(chan_name), "%d", ch);
 210         chan = debugfs_create_dir(chan_name, chandir);
 211         dt = (void *)ch;
 212
 213         if (chan)
 214                 chan_state = debugfs_create_file("state", 0400, chan, dt,
 215                                                  &dbg_fops_chan_state);
 216         if (chan_state)
 217                 chan_descr = debugfs_create_file("descriptors", 0400, chan, dt,
 218                                                  &dbg_fops_descriptors);
 219         if (chan_descr)
 220                 chan_reqs = debugfs_create_file("requesters", 0400, chan, dt,
 221                                                 &dbg_fops_requester_chan);
 222         if (!chan_reqs)
 223                 goto err_state;
 224
 225         return chan;
 226
 227 err_state:
 228         debugfs_remove_recursive(chan);
 229         return NULL;
 230 }
 231
 232 static void pxa_dma_init_debugfs(void)
 233 {
 234         int i;
 235         struct dentry *chandir;
 236
 237         dbgfs_root = debugfs_create_dir(DMA_DEBUG_NAME, NULL);
 238         if (IS_ERR(dbgfs_root) || !dbgfs_root)
 239                 goto err_root;
 240
 241         dbgfs_state = debugfs_create_file("state", 0400, dbgfs_root, NULL,
 242                                           &dbg_fops_state);
 243         if (!dbgfs_state)
 244                 goto err_state;
 245
 246         dbgfs_chan = kmalloc(sizeof(*dbgfs_state) * num_dma_channels,
 247                              GFP_KERNEL);
 248         if (!dbgfs_state)
 249                 goto err_alloc;
 250
 251         chandir = debugfs_create_dir("channels", dbgfs_root);
 252         if (!chandir)
 253                 goto err_chandir;
 254
 255         for (i = 0; i < num_dma_channels; i++) {
 256                 dbgfs_chan[i] = pxa_dma_dbg_alloc_chan(i, chandir);
 257                 if (!dbgfs_chan[i])
 258                         goto err_chans;
 259         }
 260
 261         return;
 262 err_chans:
 263 err_chandir:
 264         kfree(dbgfs_chan);
 265 err_alloc:
 266 err_state:
 267         debugfs_remove_recursive(dbgfs_root);
 268 err_root:
 269         pr_err("pxa_dma: debugfs is not available\n");
 270 }
 271
 272 static void __exit pxa_dma_cleanup_debugfs(void)
 273 {
 274         debugfs_remove_recursive(dbgfs_root);
 275 }
 276 #else
 277 static inline void pxa_dma_init_debugfs(void) {}
 278 static inline void pxa_dma_cleanup_debugfs(void) {}
 279 #endif
 280
 281 int pxa_request_dma (char *name, pxa_dma_prio prio,
 282                         void (*irq_handler)(int, void *),
 283                         void *data)
 284 {
 285         unsigned long flags;
 286         int i, found = 0;
 287
 288         /* basic sanity checks */
 289         if (!name || !irq_handler)
 290                 return -EINVAL;
 291
 292         local_irq_save(flags);
 293
 294         do {
 295                 /* try grabbing a DMA channel with the requested priority */
 296                 for (i = 0; i < num_dma_channels; i++) {
 297                         if ((dma_channels[i].prio == prio) &&
 298                             !dma_channels[i].name) {
 299                                 found = 1;
 300                                 break;
 301                         }
 302                 }
 303                 /* if requested prio group is full, try a hier priority */
 304         } while (!found && prio--);
 305
 306         if (found) {
 307                 DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
 308                 dma_channels[i].name = name;
 309                 dma_channels[i].irq_handler = irq_handler;
 310                 dma_channels[i].data = data;
 311         } else {
 312                 printk (KERN_WARNING "No more available DMA channels for %s\n", name);
 313                 i = -ENODEV;
 314         }
 315
 316         local_irq_restore(flags);
 317         return i;
 318 }
 319 EXPORT_SYMBOL(pxa_request_dma);
 320
 321 void pxa_free_dma (int dma_ch)
 322 {
 323         unsigned long flags;
 324
 325         if (!dma_channels[dma_ch].name) {
 326                 printk (KERN_CRIT
 327                         "%s: trying to free channel %d which is already freed\n",
 328                         __func__, dma_ch);
 329                 return;
 330         }
 331
 332         local_irq_save(flags);
 333         DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
 334         dma_channels[dma_ch].name = NULL;
 335         local_irq_restore(flags);
 336 }
 337 EXPORT_SYMBOL(pxa_free_dma);
 338
 339 static irqreturn_t dma_irq_handler(int irq, void *dev_id)
 340 {
 341         int i, dint = DINT;
 342         struct dma_channel *channel;
 343
 344         while (dint) {
 345                 i = __ffs(dint);
 346                 dint &= (dint - 1);
 347                 channel = &dma_channels[i];
 348                 if (channel->name && channel->irq_handler) {
 349                         channel->irq_handler(i, channel->data);
 350                 } else {
 351                         /*
 352                          * IRQ for an unregistered DMA channel:
 353                          * let's clear the interrupts and disable it.
 354                          */
 355                         printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
 356                         DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
 357                 }
 358         }
 359         return IRQ_HANDLED;
 360 }
 361
 362 int __init pxa_init_dma(int irq, int num_ch)
 363 {
 364         int i, ret;
 365
 366         dma_channels = kzalloc(sizeof(struct dma_channel) * num_ch, GFP_KERNEL);
 367         if (dma_channels == NULL)
 368                 return -ENOMEM;
 369
 370         /* dma channel priorities on pxa2xx processors:
 371          * ch 0 - 3,  16 - 19  <--> (0) DMA_PRIO_HIGH
 372          * ch 4 - 7,  20 - 23  <--> (1) DMA_PRIO_MEDIUM
 373          * ch 8 - 15, 24 - 31  <--> (2) DMA_PRIO_LOW
 374          */
 375         for (i = 0; i < num_ch; i++) {
 376                 DCSR(i) = 0;
 377                 dma_channels[i].prio = min((i & 0xf) >> 2, DMA_PRIO_LOW);
 378                 spin_lock_init(&dma_channels[i].lock);
 379         }
 380
 381         ret = request_irq(irq, dma_irq_handler, IRQF_DISABLED, "DMA", NULL);
 382         if (ret) {
 383                 printk (KERN_CRIT "Wow!  Can't register IRQ for DMA\n");
 384                 kfree(dma_channels);
 385                 return ret;
 386         }
 387         num_dma_channels = num_ch;
 388
 389         pxa_dma_init_debugfs();
 390
 391         return 0;
 392 }