arch/arm/mach-pxa/ssp.c

   1 /*
   2  *  linux/arch/arm/mach-pxa/ssp.c
   3  *
   4  *  based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
   5  *
   6  *  Copyright (C) 2003 Russell King.
   7  *  Copyright (C) 2003 Wolfson Microelectronics PLC
   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  *  PXA2xx SSP driver.  This provides the generic core for simple
  14  *  IO-based SSP applications and allows easy port setup for DMA access.
  15  *
  16  *  Author: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/errno.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/ioport.h>
  26 #include <linux/init.h>
  27 #include <linux/mutex.h>
  28 #include <linux/clk.h>
  29 #include <linux/err.h>
  30 #include <linux/platform_device.h>
  31
  32 #include <asm/io.h>
  33 #include <asm/irq.h>
  34 #include <asm/hardware.h>
  35 #include <asm/arch/ssp.h>
  36 #include <asm/arch/pxa-regs.h>
  37 #include <asm/arch/regs-ssp.h>
  38
  39 #define TIMEOUT 100000
  40
  41 static irqreturn_t ssp_interrupt(int irq, void *dev_id)
  42 {
  43         struct ssp_dev *dev = dev_id;
  44         struct ssp_device *ssp = dev->ssp;
  45         unsigned int status;
  46
  47         status = __raw_readl(ssp->mmio_base + SSSR);
  48         __raw_writel(status, ssp->mmio_base + SSSR);
  49
  50         if (status & SSSR_ROR)
  51                 printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);
  52
  53         if (status & SSSR_TUR)
  54                 printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);
  55
  56         if (status & SSSR_BCE)
  57                 printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);
  58
  59         return IRQ_HANDLED;
  60 }
  61
  62 /**
  63  * ssp_write_word - write a word to the SSP port
  64  * @data: 32-bit, MSB justified data to write.
  65  *
  66  * Wait for a free entry in the SSP transmit FIFO, and write a data
  67  * word to the SSP port.
  68  *
  69  * The caller is expected to perform the necessary locking.
  70  *
  71  * Returns:
  72  *   %-ETIMEDOUT        timeout occurred
  73  *   0                  success
  74  */
  75 int ssp_write_word(struct ssp_dev *dev, u32 data)
  76 {
  77         struct ssp_device *ssp = dev->ssp;
  78         int timeout = TIMEOUT;
  79
  80         while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_TNF)) {
  81                 if (!--timeout)
  82                         return -ETIMEDOUT;
  83                 cpu_relax();
  84         }
  85
  86         __raw_writel(data, ssp->mmio_base + SSDR);
  87
  88         return 0;
  89 }
  90
  91 /**
  92  * ssp_read_word - read a word from the SSP port
  93  *
  94  * Wait for a data word in the SSP receive FIFO, and return the
  95  * received data.  Data is LSB justified.
  96  *
  97  * Note: Currently, if data is not expected to be received, this
  98  * function will wait for ever.
  99  *
 100  * The caller is expected to perform the necessary locking.
 101  *
 102  * Returns:
 103  *   %-ETIMEDOUT        timeout occurred
 104  *   32-bit data        success
 105  */
 106 int ssp_read_word(struct ssp_dev *dev, u32 *data)
 107 {
 108         struct ssp_device *ssp = dev->ssp;
 109         int timeout = TIMEOUT;
 110
 111         while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE)) {
 112                 if (!--timeout)
 113                         return -ETIMEDOUT;
 114                 cpu_relax();
 115         }
 116
 117         *data = __raw_readl(ssp->mmio_base + SSDR);
 118         return 0;
 119 }
 120
 121 /**
 122  * ssp_flush - flush the transmit and receive FIFOs
 123  *
 124  * Wait for the SSP to idle, and ensure that the receive FIFO
 125  * is empty.
 126  *
 127  * The caller is expected to perform the necessary locking.
 128  */
 129 int ssp_flush(struct ssp_dev *dev)
 130 {
 131         struct ssp_device *ssp = dev->ssp;
 132         int timeout = TIMEOUT * 2;
 133
 134         /* ensure TX FIFO is empty instead of not full */
 135         if (cpu_is_pxa3xx()) {
 136                 while (__raw_readl(ssp->mmio_base + SSSR) & 0xf00) {
 137                         if (!--timeout)
 138                                 return -ETIMEDOUT;
 139                         cpu_relax();
 140                 }
 141                 timeout = TIMEOUT * 2;
 142         }
 143
 144         do {
 145                 while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE) {
 146                         if (!--timeout)
 147                                 return -ETIMEDOUT;
 148                         (void)__raw_readl(ssp->mmio_base + SSDR);
 149                 }
 150                 if (!--timeout)
 151                         return -ETIMEDOUT;
 152         } while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_BSY);
 153
 154         return 0;
 155 }
 156
 157 /**
 158  * ssp_enable - enable the SSP port
 159  *
 160  * Turn on the SSP port.
 161  */
 162 void ssp_enable(struct ssp_dev *dev)
 163 {
 164         struct ssp_device *ssp = dev->ssp;
 165         uint32_t sscr0;
 166
 167         sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
 168         sscr0 |= SSCR0_SSE;
 169         __raw_writel(sscr0, ssp->mmio_base + SSCR0);
 170 }
 171
 172 /**
 173  * ssp_disable - shut down the SSP port
 174  *
 175  * Turn off the SSP port, optionally powering it down.
 176  */
 177 void ssp_disable(struct ssp_dev *dev)
 178 {
 179         struct ssp_device *ssp = dev->ssp;
 180         uint32_t sscr0;
 181
 182         sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
 183         sscr0 &= ~SSCR0_SSE;
 184         __raw_writel(sscr0, ssp->mmio_base + SSCR0);
 185 }
 186
 187 /**
 188  * ssp_save_state - save the SSP configuration
 189  * @ssp: pointer to structure to save SSP configuration
 190  *
 191  * Save the configured SSP state for suspend.
 192  */
 193 void ssp_save_state(struct ssp_dev *dev, struct ssp_state *state)
 194 {
 195         struct ssp_device *ssp = dev->ssp;
 196
 197         state->cr0 = __raw_readl(ssp->mmio_base + SSCR0);
 198         state->cr1 = __raw_readl(ssp->mmio_base + SSCR1);
 199         state->to  = __raw_readl(ssp->mmio_base + SSTO);
 200         state->psp = __raw_readl(ssp->mmio_base + SSPSP);
 201
 202         ssp_disable(dev);
 203 }
 204
 205 /**
 206  * ssp_restore_state - restore a previously saved SSP configuration
 207  * @ssp: pointer to configuration saved by ssp_save_state
 208  *
 209  * Restore the SSP configuration saved previously by ssp_save_state.
 210  */
 211 void ssp_restore_state(struct ssp_dev *dev, struct ssp_state *state)
 212 {
 213         struct ssp_device *ssp = dev->ssp;
 214         uint32_t sssr = SSSR_ROR | SSSR_TUR | SSSR_BCE;
 215
 216         __raw_writel(sssr, ssp->mmio_base + SSSR);
 217
 218         __raw_writel(state->cr0 & ~SSCR0_SSE, ssp->mmio_base + SSCR0);
 219         __raw_writel(state->cr1, ssp->mmio_base + SSCR1);
 220         __raw_writel(state->to,  ssp->mmio_base + SSTO);
 221         __raw_writel(state->psp, ssp->mmio_base + SSPSP);
 222         __raw_writel(state->cr0, ssp->mmio_base + SSCR0);
 223 }
 224
 225 /**
 226  * ssp_config - configure SSP port settings
 227  * @mode: port operating mode
 228  * @flags: port config flags
 229  * @psp_flags: port PSP config flags
 230  * @speed: port speed
 231  *
 232  * Port MUST be disabled by ssp_disable before making any config changes.
 233  */
 234 int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
 235 {
 236         struct ssp_device *ssp = dev->ssp;
 237
 238         dev->mode = mode;
 239         dev->flags = flags;
 240         dev->psp_flags = psp_flags;
 241         dev->speed = speed;
 242
 243         /* set up port type, speed, port settings */
 244         __raw_writel((dev->speed | dev->mode), ssp->mmio_base + SSCR0);
 245         __raw_writel(dev->flags, ssp->mmio_base + SSCR1);
 246         __raw_writel(dev->psp_flags, ssp->mmio_base + SSPSP);
 247
 248         return 0;
 249 }
 250
 251 /**
 252  * ssp_init - setup the SSP port
 253  *
 254  * initialise and claim resources for the SSP port.
 255  *
 256  * Returns:
 257  *   %-ENODEV   if the SSP port is unavailable
 258  *   %-EBUSY    if the resources are already in use
 259  *   %0         on success
 260  */
 261 int ssp_init(struct ssp_dev *dev, u32 port, u32 init_flags)
 262 {
 263         struct ssp_device *ssp;
 264         int ret;
 265
 266         ssp = ssp_request(port, "SSP");
 267         if (ssp == NULL)
 268                 return -ENODEV;
 269
 270         dev->ssp = ssp;
 271         dev->port = port;
 272
 273         /* do we need to get irq */
 274         if (!(init_flags & SSP_NO_IRQ)) {
 275                 ret = request_irq(ssp->irq, ssp_interrupt,
 276                                 0, "SSP", dev);
 277                 if (ret)
 278                         goto out_region;
 279                 dev->irq = ssp->irq;
 280         } else
 281                 dev->irq = NO_IRQ;
 282
 283         /* turn on SSP port clock */
 284         clk_enable(ssp->clk);
 285         return 0;
 286
 287 out_region:
 288         ssp_free(ssp);
 289         return ret;
 290 }
 291
 292 /**
 293  * ssp_exit - undo the effects of ssp_init
 294  *
 295  * release and free resources for the SSP port.
 296  */
 297 void ssp_exit(struct ssp_dev *dev)
 298 {
 299         struct ssp_device *ssp = dev->ssp;
 300
 301         ssp_disable(dev);
 302         if (dev->irq != NO_IRQ)
 303                 free_irq(dev->irq, dev);
 304         clk_disable(ssp->clk);
 305         ssp_free(ssp);
 306 }
 307
 308 static DEFINE_MUTEX(ssp_lock);
 309 static LIST_HEAD(ssp_list);
 310
 311 struct ssp_device *ssp_request(int port, const char *label)
 312 {
 313         struct ssp_device *ssp = NULL;
 314
 315         mutex_lock(&ssp_lock);
 316
 317         list_for_each_entry(ssp, &ssp_list, node) {
 318                 if (ssp->port_id == port && ssp->use_count == 0) {
 319                         ssp->use_count++;
 320                         ssp->label = label;
 321                         break;
 322                 }
 323         }
 324
 325         mutex_unlock(&ssp_lock);
 326
 327         if (&ssp->node == &ssp_list)
 328                 return NULL;
 329
 330         return ssp;
 331 }
 332 EXPORT_SYMBOL(ssp_request);
 333
 334 void ssp_free(struct ssp_device *ssp)
 335 {
 336         mutex_lock(&ssp_lock);
 337         if (ssp->use_count) {
 338                 ssp->use_count--;
 339                 ssp->label = NULL;
 340         } else
 341                 dev_err(&ssp->pdev->dev, "device already free\n");
 342         mutex_unlock(&ssp_lock);
 343 }
 344 EXPORT_SYMBOL(ssp_free);
 345
 346 static int __devinit ssp_probe(struct platform_device *pdev, int type)
 347 {
 348         struct resource *res;
 349         struct ssp_device *ssp;
 350         int ret = 0;
 351
 352         ssp = kzalloc(sizeof(struct ssp_device), GFP_KERNEL);
 353         if (ssp == NULL) {
 354                 dev_err(&pdev->dev, "failed to allocate memory");
 355                 return -ENOMEM;
 356         }
 357         ssp->pdev = pdev;
 358
 359         ssp->clk = clk_get(&pdev->dev, "SSPCLK");
 360         if (IS_ERR(ssp->clk)) {
 361                 ret = PTR_ERR(ssp->clk);
 362                 goto err_free;
 363         }
 364
 365         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 366         if (res == NULL) {
 367                 dev_err(&pdev->dev, "no memory resource defined\n");
 368                 ret = -ENODEV;
 369                 goto err_free_clk;
 370         }
 371
 372         res = request_mem_region(res->start, res->end - res->start + 1,
 373                         pdev->name);
 374         if (res == NULL) {
 375                 dev_err(&pdev->dev, "failed to request memory resource\n");
 376                 ret = -EBUSY;
 377                 goto err_free_clk;
 378         }
 379
 380         ssp->phys_base = res->start;
 381
 382         ssp->mmio_base = ioremap(res->start, res->end - res->start + 1);
 383         if (ssp->mmio_base == NULL) {
 384                 dev_err(&pdev->dev, "failed to ioremap() registers\n");
 385                 ret = -ENODEV;
 386                 goto err_free_mem;
 387         }
 388
 389         ssp->irq = platform_get_irq(pdev, 0);
 390         if (ssp->irq < 0) {
 391                 dev_err(&pdev->dev, "no IRQ resource defined\n");
 392                 ret = -ENODEV;
 393                 goto err_free_io;
 394         }
 395
 396         res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 397         if (res == NULL) {
 398                 dev_err(&pdev->dev, "no SSP RX DRCMR defined\n");
 399                 ret = -ENODEV;
 400                 goto err_free_io;
 401         }
 402         ssp->drcmr_rx = res->start;
 403
 404         res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 405         if (res == NULL) {
 406                 dev_err(&pdev->dev, "no SSP TX DRCMR defined\n");
 407                 ret = -ENODEV;
 408                 goto err_free_io;
 409         }
 410         ssp->drcmr_tx = res->start;
 411
 412         /* PXA2xx/3xx SSP ports starts from 1 and the internal pdev->id
 413          * starts from 0, do a translation here
 414          */
 415         ssp->port_id = pdev->id + 1;
 416         ssp->use_count = 0;
 417         ssp->type = type;
 418
 419         mutex_lock(&ssp_lock);
 420         list_add(&ssp->node, &ssp_list);
 421         mutex_unlock(&ssp_lock);
 422
 423         platform_set_drvdata(pdev, ssp);
 424         return 0;
 425
 426 err_free_io:
 427         iounmap(ssp->mmio_base);
 428 err_free_mem:
 429         release_mem_region(res->start, res->end - res->start + 1);
 430 err_free_clk:
 431         clk_put(ssp->clk);
 432 err_free:
 433         kfree(ssp);
 434         return ret;
 435 }
 436
 437 static int __devexit ssp_remove(struct platform_device *pdev)
 438 {
 439         struct resource *res;
 440         struct ssp_device *ssp;
 441
 442         ssp = platform_get_drvdata(pdev);
 443         if (ssp == NULL)
 444                 return -ENODEV;
 445
 446         iounmap(ssp->mmio_base);
 447
 448         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 449         release_mem_region(res->start, res->end - res->start + 1);
 450
 451         clk_put(ssp->clk);
 452
 453         mutex_lock(&ssp_lock);
 454         list_del(&ssp->node);
 455         mutex_unlock(&ssp_lock);
 456
 457         kfree(ssp);
 458         return 0;
 459 }
 460
 461 static int __devinit pxa25x_ssp_probe(struct platform_device *pdev)
 462 {
 463         return ssp_probe(pdev, PXA25x_SSP);
 464 }
 465
 466 static int __devinit pxa25x_nssp_probe(struct platform_device *pdev)
 467 {
 468         return ssp_probe(pdev, PXA25x_NSSP);
 469 }
 470
 471 static int __devinit pxa27x_ssp_probe(struct platform_device *pdev)
 472 {
 473         return ssp_probe(pdev, PXA27x_SSP);
 474 }
 475
 476 static struct platform_driver pxa25x_ssp_driver = {
 477         .driver         = {
 478                 .name   = "pxa25x-ssp",
 479         },
 480         .probe          = pxa25x_ssp_probe,
 481         .remove         = __devexit_p(ssp_remove),
 482 };
 483
 484 static struct platform_driver pxa25x_nssp_driver = {
 485         .driver         = {
 486                 .name   = "pxa25x-nssp",
 487         },
 488         .probe          = pxa25x_nssp_probe,
 489         .remove         = __devexit_p(ssp_remove),
 490 };
 491
 492 static struct platform_driver pxa27x_ssp_driver = {
 493         .driver         = {
 494                 .name   = "pxa27x-ssp",
 495         },
 496         .probe          = pxa27x_ssp_probe,
 497         .remove         = __devexit_p(ssp_remove),
 498 };
 499
 500 static int __init pxa_ssp_init(void)
 501 {
 502         int ret = 0;
 503
 504         ret = platform_driver_register(&pxa25x_ssp_driver);
 505         if (ret) {
 506                 printk(KERN_ERR "failed to register pxa25x_ssp_driver");
 507                 return ret;
 508         }
 509
 510         ret = platform_driver_register(&pxa25x_nssp_driver);
 511         if (ret) {
 512                 printk(KERN_ERR "failed to register pxa25x_nssp_driver");
 513                 return ret;
 514         }
 515
 516         ret = platform_driver_register(&pxa27x_ssp_driver);
 517         if (ret) {
 518                 printk(KERN_ERR "failed to register pxa27x_ssp_driver");
 519                 return ret;
 520         }
 521
 522         return ret;
 523 }
 524
 525 static void __exit pxa_ssp_exit(void)
 526 {
 527         platform_driver_unregister(&pxa25x_ssp_driver);
 528         platform_driver_unregister(&pxa25x_nssp_driver);
 529         platform_driver_unregister(&pxa27x_ssp_driver);
 530 }
 531
 532 arch_initcall(pxa_ssp_init);
 533 module_exit(pxa_ssp_exit);
 534
 535 EXPORT_SYMBOL(ssp_write_word);
 536 EXPORT_SYMBOL(ssp_read_word);
 537 EXPORT_SYMBOL(ssp_flush);
 538 EXPORT_SYMBOL(ssp_enable);
 539 EXPORT_SYMBOL(ssp_disable);
 540 EXPORT_SYMBOL(ssp_save_state);
 541 EXPORT_SYMBOL(ssp_restore_state);
 542 EXPORT_SYMBOL(ssp_init);
 543 EXPORT_SYMBOL(ssp_exit);
 544 EXPORT_SYMBOL(ssp_config);
 545
 546 MODULE_DESCRIPTION("PXA SSP driver");
 547 MODULE_AUTHOR("Liam Girdwood");
 548 MODULE_LICENSE("GPL");
 549