Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  *  linux/drivers/mmc/pxa.c - PXA MMCI driver
  3  *
  4  *  Copyright (C) 2003 Russell King, All Rights Reserved.
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  *
 10  *  This hardware is really sick:
 11  *   - No way to clear interrupts.
 12  *   - Have to turn off the clock whenever we touch the device.
 13  *   - Doesn't tell you how many data blocks were transferred.
 14  *  Yuck!
 15  *
 16  *      1 and 3 byte data transfers not supported
 17  *      max block length up to 1023
 18  */
 19 #include <linux/config.h>
 20 #include <linux/module.h>
 21 #include <linux/init.h>
 22 #include <linux/ioport.h>
 23 #include <linux/device.h>
 24 #include <linux/delay.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/dma-mapping.h>
 27 #include <linux/mmc/host.h>
 28 #include <linux/mmc/protocol.h>
 29 
 30 #include <asm/dma.h>
 31 #include <asm/io.h>
 32 #include <asm/irq.h>
 33 #include <asm/scatterlist.h>
 34 #include <asm/sizes.h>
 35 
 36 #include <asm/arch/pxa-regs.h>
 37 #include <asm/arch/mmc.h>
 38 
 39 #include "pxamci.h"
 40 
 41 #ifdef CONFIG_MMC_DEBUG
 42 #define DBG(x...)       printk(KERN_DEBUG x)
 43 #else
 44 #define DBG(x...)       do { } while (0)
 45 #endif
 46 
 47 #define DRIVER_NAME     "pxa2xx-mci"
 48 
 49 #define NR_SG   1
 50 
 51 struct pxamci_host {
 52         struct mmc_host         *mmc;
 53         spinlock_t              lock;
 54         struct resource         *res;
 55         void __iomem            *base;
 56         int                     irq;
 57         int                     dma;
 58         unsigned int            clkrt;
 59         unsigned int            cmdat;
 60         unsigned int            imask;
 61         unsigned int            power_mode;
 62         struct pxamci_platform_data *pdata;
 63 
 64         struct mmc_request      *mrq;
 65         struct mmc_command      *cmd;
 66         struct mmc_data         *data;
 67 
 68         dma_addr_t              sg_dma;
 69         struct pxa_dma_desc     *sg_cpu;
 70         unsigned int            dma_len;
 71 
 72         unsigned int            dma_dir;
 73 };
 74 
 75 static inline unsigned int ns_to_clocks(unsigned int ns)
 76 {
 77         return (ns * (CLOCKRATE / 1000000) + 999) / 1000;
 78 }
 79 
 80 static void pxamci_stop_clock(struct pxamci_host *host)
 81 {
 82         if (readl(host->base + MMC_STAT) & STAT_CLK_EN) {
 83                 unsigned long timeout = 10000;
 84                 unsigned int v;
 85 
 86                 writel(STOP_CLOCK, host->base + MMC_STRPCL);
 87 
 88                 do {
 89                         v = readl(host->base + MMC_STAT);
 90                         if (!(v & STAT_CLK_EN))
 91                                 break;
 92                         udelay(1);
 93                 } while (timeout--);
 94 
 95                 if (v & STAT_CLK_EN)
 96                         dev_err(mmc_dev(host->mmc), "unable to stop clock\n");
 97         }
 98 }
 99 
100 static void pxamci_enable_irq(struct pxamci_host *host, unsigned int mask)
101 {
102         unsigned long flags;
103 
104         spin_lock_irqsave(&host->lock, flags);
105         host->imask &= ~mask;
106         writel(host->imask, host->base + MMC_I_MASK);
107         spin_unlock_irqrestore(&host->lock, flags);
108 }
109 
110 static void pxamci_disable_irq(struct pxamci_host *host, unsigned int mask)
111 {
112         unsigned long flags;
113 
114         spin_lock_irqsave(&host->lock, flags);
115         host->imask |= mask;
116         writel(host->imask, host->base + MMC_I_MASK);
117         spin_unlock_irqrestore(&host->lock, flags);
118 }
119 
120 static void pxamci_setup_data(struct pxamci_host *host, struct mmc_data *data)
121 {
122         unsigned int nob = data->blocks;
123         unsigned int timeout;
124         u32 dcmd;
125         int i;
126 
127         host->data = data;
128 
129         if (data->flags & MMC_DATA_STREAM)
130                 nob = 0xffff;
131 
132         writel(nob, host->base + MMC_NOB);
133         writel(1 << data->blksz_bits, host->base + MMC_BLKLEN);
134 
135         timeout = ns_to_clocks(data->timeout_ns) + data->timeout_clks;
136         writel((timeout + 255) / 256, host->base + MMC_RDTO);
137 
138         if (data->flags & MMC_DATA_READ) {
139                 host->dma_dir = DMA_FROM_DEVICE;
140                 dcmd = DCMD_INCTRGADDR | DCMD_FLOWTRG;
141                 DRCMRTXMMC = 0;
142                 DRCMRRXMMC = host->dma | DRCMR_MAPVLD;
143         } else {
144                 host->dma_dir = DMA_TO_DEVICE;
145                 dcmd = DCMD_INCSRCADDR | DCMD_FLOWSRC;
146                 DRCMRRXMMC = 0;
147                 DRCMRTXMMC = host->dma | DRCMR_MAPVLD;
148         }
149 
150         dcmd |= DCMD_BURST32 | DCMD_WIDTH1;
151 
152         host->dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
153                                    host->dma_dir);
154 
155         for (i = 0; i < host->dma_len; i++) {
156                 if (data->flags & MMC_DATA_READ) {
157                         host->sg_cpu[i].dsadr = host->res->start + MMC_RXFIFO;
158                         host->sg_cpu[i].dtadr = sg_dma_address(&data->sg[i]);
159                 } else {
160                         host->sg_cpu[i].dsadr = sg_dma_address(&data->sg[i]);
161                         host->sg_cpu[i].dtadr = host->res->start + MMC_TXFIFO;
162                 }
163                 host->sg_cpu[i].dcmd = dcmd | sg_dma_len(&data->sg[i]);
164                 host->sg_cpu[i].ddadr = host->sg_dma + (i + 1) *
165                                         sizeof(struct pxa_dma_desc);
166         }
167         host->sg_cpu[host->dma_len - 1].ddadr = DDADR_STOP;
168         wmb();
169 
170         DDADR(host->dma) = host->sg_dma;
171         DCSR(host->dma) = DCSR_RUN;
172 }
173 
174 static void pxamci_start_cmd(struct pxamci_host *host, struct mmc_command *cmd, unsigned int cmdat)
175 {
176         WARN_ON(host->cmd != NULL);
177         host->cmd = cmd;
178 
179         if (cmd->flags & MMC_RSP_BUSY)
180                 cmdat |= CMDAT_BUSY;
181 
182         switch (cmd->flags & (MMC_RSP_MASK | MMC_RSP_CRC)) {
183         case MMC_RSP_SHORT | MMC_RSP_CRC:
184                 cmdat |= CMDAT_RESP_SHORT;
185                 break;
186         case MMC_RSP_SHORT:
187                 cmdat |= CMDAT_RESP_R3;
188                 break;
189         case MMC_RSP_LONG | MMC_RSP_CRC:
190                 cmdat |= CMDAT_RESP_R2;
191                 break;
192         default:
193                 break;
194         }
195 
196         writel(cmd->opcode, host->base + MMC_CMD);
197         writel(cmd->arg >> 16, host->base + MMC_ARGH);
198         writel(cmd->arg & 0xffff, host->base + MMC_ARGL);
199         writel(cmdat, host->base + MMC_CMDAT);
200         writel(host->clkrt, host->base + MMC_CLKRT);
201 
202         writel(START_CLOCK, host->base + MMC_STRPCL);
203 
204         pxamci_enable_irq(host, END_CMD_RES);
205 }
206 
207 static void pxamci_finish_request(struct pxamci_host *host, struct mmc_request *mrq)
208 {
209         DBG("PXAMCI: request done\n");
210         host->mrq = NULL;
211         host->cmd = NULL;
212         host->data = NULL;
213         mmc_request_done(host->mmc, mrq);
214 }
215 
216 static int pxamci_cmd_done(struct pxamci_host *host, unsigned int stat)
217 {
218         struct mmc_command *cmd = host->cmd;
219         int i;
220         u32 v;
221 
222         if (!cmd)
223                 return 0;
224 
225         host->cmd = NULL;
226 
227         /*
228          * Did I mention this is Sick.  We always need to
229          * discard the upper 8 bits of the first 16-bit word.
230          */
231         v = readl(host->base + MMC_RES) & 0xffff;
232         for (i = 0; i < 4; i++) {
233                 u32 w1 = readl(host->base + MMC_RES) & 0xffff;
234                 u32 w2 = readl(host->base + MMC_RES) & 0xffff;
235                 cmd->resp[i] = v << 24 | w1 << 8 | w2 >> 8;
236                 v = w2;
237         }
238 
239         if (stat & STAT_TIME_OUT_RESPONSE) {
240                 cmd->error = MMC_ERR_TIMEOUT;
241         } else if (stat & STAT_RES_CRC_ERR && cmd->flags & MMC_RSP_CRC) {
242 #ifdef CONFIG_PXA27x
243                 /*
244                  * workaround for erratum #42:
245                  * Intel PXA27x Family Processor Specification Update Rev 001
246                  */
247                 if (cmd->opcode == MMC_ALL_SEND_CID ||
248                     cmd->opcode == MMC_SEND_CSD ||
249                     cmd->opcode == MMC_SEND_CID) {
250                         /* a bogus CRC error can appear if the msb of
251                            the 15 byte response is a one */
252                         if ((cmd->resp[0] & 0x80000000) == 0)
253                                 cmd->error = MMC_ERR_BADCRC;
254                 } else {
255                         DBG("ignoring CRC from command %d - *risky*\n",cmd->opcode);
256                 }
257 #else
258                 cmd->error = MMC_ERR_BADCRC;
259 #endif
260         }
261 
262         pxamci_disable_irq(host, END_CMD_RES);
263         if (host->data && cmd->error == MMC_ERR_NONE) {
264                 pxamci_enable_irq(host, DATA_TRAN_DONE);
265         } else {
266                 pxamci_finish_request(host, host->mrq);
267         }
268 
269         return 1;
270 }
271 
272 static int pxamci_data_done(struct pxamci_host *host, unsigned int stat)
273 {
274         struct mmc_data *data = host->data;
275 
276         if (!data)
277                 return 0;
278 
279         DCSR(host->dma) = 0;
280         dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
281                      host->dma_dir);
282 
283         if (stat & STAT_READ_TIME_OUT)
284                 data->error = MMC_ERR_TIMEOUT;
285         else if (stat & (STAT_CRC_READ_ERROR|STAT_CRC_WRITE_ERROR))
286                 data->error = MMC_ERR_BADCRC;
287 
288         /*
289          * There appears to be a hardware design bug here.  There seems to
290          * be no way to find out how much data was transferred to the card.
291          * This means that if there was an error on any block, we mark all
292          * data blocks as being in error.
293          */
294         if (data->error == MMC_ERR_NONE)
295                 data->bytes_xfered = data->blocks << data->blksz_bits;
296         else
297                 data->bytes_xfered = 0;
298 
299         pxamci_disable_irq(host, DATA_TRAN_DONE);
300 
301         host->data = NULL;
302         if (host->mrq->stop && data->error == MMC_ERR_NONE) {
303                 pxamci_stop_clock(host);
304                 pxamci_start_cmd(host, host->mrq->stop, 0);
305         } else {
306                 pxamci_finish_request(host, host->mrq);
307         }
308 
309         return 1;
310 }
311 
312 static irqreturn_t pxamci_irq(int irq, void *devid, struct pt_regs *regs)
313 {
314         struct pxamci_host *host = devid;
315         unsigned int ireg;
316         int handled = 0;
317 
318         ireg = readl(host->base + MMC_I_REG);
319 
320         DBG("PXAMCI: irq %08x\n", ireg);
321 
322         if (ireg) {
323                 unsigned stat = readl(host->base + MMC_STAT);
324 
325                 DBG("PXAMCI: stat %08x\n", stat);
326 
327                 if (ireg & END_CMD_RES)
328                         handled |= pxamci_cmd_done(host, stat);
329                 if (ireg & DATA_TRAN_DONE)
330                         handled |= pxamci_data_done(host, stat);
331         }
332 
333         return IRQ_RETVAL(handled);
334 }
335 
336 static void pxamci_request(struct mmc_host *mmc, struct mmc_request *mrq)
337 {
338         struct pxamci_host *host = mmc_priv(mmc);
339         unsigned int cmdat;
340 
341         WARN_ON(host->mrq != NULL);
342 
343         host->mrq = mrq;
344 
345         pxamci_stop_clock(host);
346 
347         cmdat = host->cmdat;
348         host->cmdat &= ~CMDAT_INIT;
349 
350         if (mrq->data) {
351                 pxamci_setup_data(host, mrq->data);
352 
353                 cmdat &= ~CMDAT_BUSY;
354                 cmdat |= CMDAT_DATAEN | CMDAT_DMAEN;
355                 if (mrq->data->flags & MMC_DATA_WRITE)
356                         cmdat |= CMDAT_WRITE;
357 
358                 if (mrq->data->flags & MMC_DATA_STREAM)
359                         cmdat |= CMDAT_STREAM;
360         }
361 
362         pxamci_start_cmd(host, mrq->cmd, cmdat);
363 }
364 
365 static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
366 {
367         struct pxamci_host *host = mmc_priv(mmc);
368 
369         DBG("pxamci_set_ios: clock %u power %u vdd %u.%02u\n",
370             ios->clock, ios->power_mode, ios->vdd / 100,
371             ios->vdd % 100);
372 
373         if (ios->clock) {
374                 unsigned int clk = CLOCKRATE / ios->clock;
375                 if (CLOCKRATE / clk > ios->clock)
376                         clk <<= 1;
377                 host->clkrt = fls(clk) - 1;
378                 pxa_set_cken(CKEN12_MMC, 1);
379 
380                 /*
381                  * we write clkrt on the next command
382                  */
383         } else {
384                 pxamci_stop_clock(host);
385                 pxa_set_cken(CKEN12_MMC, 0);
386         }
387 
388         if (host->power_mode != ios->power_mode) {
389                 host->power_mode = ios->power_mode;
390 
391                 if (host->pdata && host->pdata->setpower)
392                         host->pdata->setpower(mmc->dev, ios->vdd);
393 
394                 if (ios->power_mode == MMC_POWER_ON)
395                         host->cmdat |= CMDAT_INIT;
396         }
397 
398         DBG("pxamci_set_ios: clkrt = %x cmdat = %x\n",
399             host->clkrt, host->cmdat);
400 }
401 
402 static struct mmc_host_ops pxamci_ops = {
403         .request        = pxamci_request,
404         .set_ios        = pxamci_set_ios,
405 };
406 
407 static void pxamci_dma_irq(int dma, void *devid, struct pt_regs *regs)
408 {
409         printk(KERN_ERR "DMA%d: IRQ???\n", dma);
410         DCSR(dma) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
411 }
412 
413 static irqreturn_t pxamci_detect_irq(int irq, void *devid, struct pt_regs *regs)
414 {
415         mmc_detect_change(devid);
416         return IRQ_HANDLED;
417 }
418 
419 static int pxamci_probe(struct device *dev)
420 {
421         struct platform_device *pdev = to_platform_device(dev);
422         struct mmc_host *mmc;
423         struct pxamci_host *host = NULL;
424         struct resource *r;
425         int ret, irq;
426 
427         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
428         irq = platform_get_irq(pdev, 0);
429         if (!r || irq == NO_IRQ)
430                 return -ENXIO;
431 
432         r = request_mem_region(r->start, SZ_4K, DRIVER_NAME);
433         if (!r)
434                 return -EBUSY;
435 
436         mmc = mmc_alloc_host(sizeof(struct pxamci_host), dev);
437         if (!mmc) {
438                 ret = -ENOMEM;
439                 goto out;
440         }
441 
442         mmc->ops = &pxamci_ops;
443         mmc->f_min = CLOCKRATE_MIN;
444         mmc->f_max = CLOCKRATE_MAX;
445 
446         /*
447          * We can do SG-DMA, but we don't because we never know how much
448          * data we successfully wrote to the card.
449          */
450         mmc->max_phys_segs = NR_SG;
451 
452         /*
453          * Our hardware DMA can handle a maximum of one page per SG entry.
454          */
455         mmc->max_seg_size = PAGE_SIZE;
456 
457         host = mmc_priv(mmc);
458         host->mmc = mmc;
459         host->dma = -1;
460         host->pdata = pdev->dev.platform_data;
461         mmc->ocr_avail = host->pdata ?
462                          host->pdata->ocr_mask :
463                          MMC_VDD_32_33|MMC_VDD_33_34;
464 
465         host->sg_cpu = dma_alloc_coherent(dev, PAGE_SIZE, &host->sg_dma, GFP_KERNEL);
466         if (!host->sg_cpu) {
467                 ret = -ENOMEM;
468                 goto out;
469         }
470 
471         spin_lock_init(&host->lock);
472         host->res = r;
473         host->irq = irq;
474         host->imask = MMC_I_MASK_ALL;
475 
476         host->base = ioremap(r->start, SZ_4K);
477         if (!host->base) {
478                 ret = -ENOMEM;
479                 goto out;
480         }
481 
482         /*
483          * Ensure that the host controller is shut down, and setup
484          * with our defaults.
485          */
486         pxamci_stop_clock(host);
487         writel(0, host->base + MMC_SPI);
488         writel(64, host->base + MMC_RESTO);
489         writel(host->imask, host->base + MMC_I_MASK);
490 
491         host->dma = pxa_request_dma(DRIVER_NAME, DMA_PRIO_LOW,
492                                     pxamci_dma_irq, host);
493         if (host->dma < 0) {
494                 ret = -EBUSY;
495                 goto out;
496         }
497 
498         ret = request_irq(host->irq, pxamci_irq, 0, DRIVER_NAME, host);
499         if (ret)
500                 goto out;
501 
502         dev_set_drvdata(dev, mmc);
503 
504         if (host->pdata && host->pdata->init)
505                 host->pdata->init(dev, pxamci_detect_irq, mmc);
506 
507         mmc_add_host(mmc);
508 
509         return 0;
510 
511  out:
512         if (host) {
513                 if (host->dma >= 0)
514                         pxa_free_dma(host->dma);
515                 if (host->base)
516                         iounmap(host->base);
517                 if (host->sg_cpu)
518                         dma_free_coherent(dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
519         }
520         if (mmc)
521                 mmc_free_host(mmc);
522         release_resource(r);
523         return ret;
524 }
525 
526 static int pxamci_remove(struct device *dev)
527 {
528         struct mmc_host *mmc = dev_get_drvdata(dev);
529 
530         dev_set_drvdata(dev, NULL);
531 
532         if (mmc) {
533                 struct pxamci_host *host = mmc_priv(mmc);
534 
535                 if (host->pdata && host->pdata->exit)
536                         host->pdata->exit(dev, mmc);
537 
538                 mmc_remove_host(mmc);
539 
540                 pxamci_stop_clock(host);
541                 writel(TXFIFO_WR_REQ|RXFIFO_RD_REQ|CLK_IS_OFF|STOP_CMD|
542                        END_CMD_RES|PRG_DONE|DATA_TRAN_DONE,
543                        host->base + MMC_I_MASK);
544 
545                 DRCMRRXMMC = 0;
546                 DRCMRTXMMC = 0;
547 
548                 free_irq(host->irq, host);
549                 pxa_free_dma(host->dma);
550                 iounmap(host->base);
551                 dma_free_coherent(dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
552 
553                 release_resource(host->res);
554 
555                 mmc_free_host(mmc);
556         }
557         return 0;
558 }
559 
560 #ifdef CONFIG_PM
561 static int pxamci_suspend(struct device *dev, u32 state, u32 level)
562 {
563         struct mmc_host *mmc = dev_get_drvdata(dev);
564         int ret = 0;
565 
566         if (mmc && level == SUSPEND_DISABLE)
567                 ret = mmc_suspend_host(mmc, state);
568 
569         return ret;
570 }
571 
572 static int pxamci_resume(struct device *dev, u32 level)
573 {
574         struct mmc_host *mmc = dev_get_drvdata(dev);
575         int ret = 0;
576 
577         if (mmc && level == RESUME_ENABLE)
578                 ret = mmc_resume_host(mmc);
579 
580         return ret;
581 }
582 #else
583 #define pxamci_suspend  NULL
584 #define pxamci_resume   NULL
585 #endif
586 
587 static struct device_driver pxamci_driver = {
588         .name           = DRIVER_NAME,
589         .bus            = &platform_bus_type,
590         .probe          = pxamci_probe,
591         .remove         = pxamci_remove,
592         .suspend        = pxamci_suspend,
593         .resume         = pxamci_resume,
594 };
595 
596 static int __init pxamci_init(void)
597 {
598         return driver_register(&pxamci_driver);
599 }
600 
601 static void __exit pxamci_exit(void)
602 {
603         driver_unregister(&pxamci_driver);
604 }
605 
606 module_init(pxamci_init);
607 module_exit(pxamci_exit);
608 
609 MODULE_DESCRIPTION("PXA Multimedia Card Interface Driver");
610 MODULE_LICENSE("GPL");
611 
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