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 #include <linux/io.h>
  32
  33 #include <asm/irq.h>
  34 #include <mach/hardware.h>
  35 #include <mach/ssp.h>
  36 #include <mach/regs-ssp.h>
  37
  38 #define TIMEOUT 100000
  39
  40 static irqreturn_t ssp_interrupt(int irq, void *dev_id)
  41 {
  42         struct ssp_dev *dev = dev_id;
  43         struct ssp_device *ssp = dev->ssp;
  44         unsigned int status;
  45
  46         status = __raw_readl(ssp->mmio_base + SSSR);
  47         __raw_writel(status, ssp->mmio_base + SSSR);
  48
  49         if (status & SSSR_ROR)
  50                 printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);
  51
  52         if (status & SSSR_TUR)
  53                 printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);
  54
  55         if (status & SSSR_BCE)
  56                 printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);
  57
  58         return IRQ_HANDLED;
  59 }
  60
  61 /**
  62  * ssp_write_word - write a word to the SSP port
  63  * @data: 32-bit, MSB justified data to write.
  64  *
  65  * Wait for a free entry in the SSP transmit FIFO, and write a data
  66  * word to the SSP port.
  67  *
  68  * The caller is expected to perform the necessary locking.
  69  *
  70  * Returns:
  71  *   %-ETIMEDOUT        timeout occurred
  72  *   0                  success
  73  */
  74 int ssp_write_word(struct ssp_dev *dev, u32 data)
  75 {
  76         struct ssp_device *ssp = dev->ssp;
  77         int timeout = TIMEOUT;
  78
  79         while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_TNF)) {
  80                 if (!--timeout)
  81                         return -ETIMEDOUT;
  82                 cpu_relax();
  83         }
  84
  85         __raw_writel(data, ssp->mmio_base + SSDR);
  86
  87         return 0;
  88 }
  89
  90 /**
  91  * ssp_read_word - read a word from the SSP port
  92  *
  93  * Wait for a data word in the SSP receive FIFO, and return the
  94  * received data.  Data is LSB justified.
  95  *
  96  * Note: Currently, if data is not expected to be received, this
  97  * function will wait for ever.
  98  *
  99  * The caller is expected to perform the necessary locking.
 100  *
 101  * Returns:
 102  *   %-ETIMEDOUT        timeout occurred
 103  *   32-bit data        success
 104  */
 105 int ssp_read_word(struct ssp_dev *dev, u32 *data)
 106 {
 107         struct ssp_device *ssp = dev->ssp;
 108         int timeout = TIMEOUT;
 109
 110         while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE)) {
 111                 if (!--timeout)
 112                         return -ETIMEDOUT;
 113                 cpu_relax();
 114         }
 115
 116         *data = __raw_readl(ssp->mmio_base + SSDR);
 117         return 0;
 118 }
 119
 120 /**
 121  * ssp_flush - flush the transmit and receive FIFOs
 122  *
 123  * Wait for the SSP to idle, and ensure that the receive FIFO
 124  * is empty.
 125  *
 126  * The caller is expected to perform the necessary locking.
 127  */
 128 int ssp_flush(struct ssp_dev *dev)
 129 {
 130         struct ssp_device *ssp = dev->ssp;
 131         int timeout = TIMEOUT * 2;
 132
 133         /* ensure TX FIFO is empty instead of not full */
 134         if (cpu_is_pxa3xx()) {
 135                 while (__raw_readl(ssp->mmio_base + SSSR) & 0xf00) {
 136                         if (!--timeout)
 137                                 return -ETIMEDOUT;
 138                         cpu_relax();
 139                 }
 140                 timeout = TIMEOUT * 2;
 141         }
 142
 143         do {
 144                 while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE) {
 145                         if (!--timeout)
 146                                 return -ETIMEDOUT;
 147                         (void)__raw_readl(ssp->mmio_base + SSDR);
 148                 }
 149                 if (!--timeout)
 150                         return -ETIMEDOUT;
 151         } while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_BSY);
 152
 153         return 0;
 154 }
 155
 156 /**
 157  * ssp_enable - enable the SSP port
 158  *
 159  * Turn on the SSP port.
 160  */
 161 void ssp_enable(struct ssp_dev *dev)
 162 {
 163         struct ssp_device *ssp = dev->ssp;
 164         uint32_t sscr0;
 165
 166         sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
 167         sscr0 |= SSCR0_SSE;
 168         __raw_writel(sscr0, ssp->mmio_base + SSCR0);
 169 }
 170
 171 /**
 172  * ssp_disable - shut down the SSP port
 173  *
 174  * Turn off the SSP port, optionally powering it down.
 175  */
 176 void ssp_disable(struct ssp_dev *dev)
 177 {
 178         struct ssp_device *ssp = dev->ssp;
 179         uint32_t sscr0;
 180
 181         sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
 182         sscr0 &= ~SSCR0_SSE;
 183         __raw_writel(sscr0, ssp->mmio_base + SSCR0);
 184 }
 185
 186 /**
 187  * ssp_save_state - save the SSP configuration
 188  * @ssp: pointer to structure to save SSP configuration
 189  *
 190  * Save the configured SSP state for suspend.
 191  */
 192 void ssp_save_state(struct ssp_dev *dev, struct ssp_state *state)
 193 {
 194         struct ssp_device *ssp = dev->ssp;
 195
 196         state->cr0 = __raw_readl(ssp->mmio_base + SSCR0);
 197         state->cr1 = __raw_readl(ssp->mmio_base + SSCR1);
 198         state->to  = __raw_readl(ssp->mmio_base + SSTO);
 199         state->psp = __raw_readl(ssp->mmio_base + SSPSP);
 200
 201         ssp_disable(dev);
 202 }
 203
 204 /**
 205  * ssp_restore_state - restore a previously saved SSP configuration
 206  * @ssp: pointer to configuration saved by ssp_save_state
 207  *
 208  * Restore the SSP configuration saved previously by ssp_save_state.
 209  */
 210 void ssp_restore_state(struct ssp_dev *dev, struct ssp_state *state)
 211 {
 212         struct ssp_device *ssp = dev->ssp;
 213         uint32_t sssr = SSSR_ROR | SSSR_TUR | SSSR_BCE;
 214
 215         __raw_writel(sssr, ssp->mmio_base + SSSR);
 216
 217         __raw_writel(state->cr0 & ~SSCR0_SSE, ssp->mmio_base + SSCR0);
 218         __raw_writel(state->cr1, ssp->mmio_base + SSCR1);
 219         __raw_writel(state->to,  ssp->mmio_base + SSTO);
 220         __raw_writel(state->psp, ssp->mmio_base + SSPSP);
 221         __raw_writel(state->cr0, ssp->mmio_base + SSCR0);
 222 }
 223
 224 /**
 225  * ssp_config - configure SSP port settings
 226  * @mode: port operating mode
 227  * @flags: port config flags
 228  * @psp_flags: port PSP config flags
 229  * @speed: port speed
 230  *
 231  * Port MUST be disabled by ssp_disable before making any config changes.
 232  */
 233 int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
 234 {
 235         struct ssp_device *ssp = dev->ssp;
 236
 237         dev->mode = mode;
 238         dev->flags = flags;
 239         dev->psp_flags = psp_flags;
 240         dev->speed = speed;
 241
 242         /* set up port type, speed, port settings */
 243         __raw_writel((dev->speed | dev->mode), ssp->mmio_base + SSCR0);
 244         __raw_writel(dev->flags, ssp->mmio_base + SSCR1);
 245         __raw_writel(dev->psp_flags, ssp->mmio_base + SSPSP);
 246
 247         return 0;
 248 }
 249
 250 /**
 251  * ssp_init - setup the SSP port
 252  *
 253  * initialise and claim resources for the SSP port.
 254  *
 255  * Returns:
 256  *   %-ENODEV   if the SSP port is unavailable
 257  *   %-EBUSY    if the resources are already in use
 258  *   %0         on success
 259  */
 260 int ssp_init(struct ssp_dev *dev, u32 port, u32 init_flags)
 261 {
 262         struct ssp_device *ssp;
 263         int ret;
 264
 265         ssp = ssp_request(port, "SSP");
 266         if (ssp == NULL)
 267                 return -ENODEV;
 268
 269         dev->ssp = ssp;
 270         dev->port = port;
 271
 272         /* do we need to get irq */
 273         if (!(init_flags & SSP_NO_IRQ)) {
 274                 ret = request_irq(ssp->irq, ssp_interrupt,
 275                                 0, "SSP", dev);
 276                 if (ret)
 277                         goto out_region;
 278                 dev->irq = ssp->irq;
 279         } else
 280                 dev->irq = NO_IRQ;
 281
 282         /* turn on SSP port clock */
 283         clk_enable(ssp->clk);
 284         return 0;
 285
 286 out_region:
 287         ssp_free(ssp);
 288         return ret;
 289 }
 290
 291 /**
 292  * ssp_exit - undo the effects of ssp_init
 293  *
 294  * release and free resources for the SSP port.
 295  */
 296 void ssp_exit(struct ssp_dev *dev)
 297 {
 298         struct ssp_device *ssp = dev->ssp;
 299
 300         ssp_disable(dev);
 301         if (dev->irq != NO_IRQ)
 302                 free_irq(dev->irq, dev);
 303         clk_disable(ssp->clk);
 304         ssp_free(ssp);
 305 }
 306
 307 static DEFINE_MUTEX(ssp_lock);
 308 static LIST_HEAD(ssp_list);
 309
 310 struct ssp_device *ssp_request(int port, const char *label)
 311 {
 312         struct ssp_device *ssp = NULL;
 313
 314         mutex_lock(&ssp_lock);
 315
 316         list_for_each_entry(ssp, &ssp_list, node) {
 317                 if (ssp->port_id == port && ssp->use_count == 0) {
 318                         ssp->use_count++;
 319                         ssp->label = label;
 320                         break;
 321                 }
 322         }
 323
 324         mutex_unlock(&ssp_lock);
 325
 326         if (&ssp->node == &ssp_list)
 327                 return NULL;
 328
 329         return ssp;
 330 }
 331 EXPORT_SYMBOL(ssp_request);
 332
 333 void ssp_free(struct ssp_device *ssp)
 334 {
 335         mutex_lock(&ssp_lock);
 336         if (ssp->use_count) {
 337                 ssp->use_count--;
 338                 ssp->label = NULL;
 339         } else
 340                 dev_err(&ssp->pdev->dev, "device already free\n");
 341         mutex_unlock(&ssp_lock);
 342 }
 343 EXPORT_SYMBOL(ssp_free);
 344
 345 static int __devinit ssp_probe(struct platform_device *pdev)
 346 {
 347         const struct platform_device_id *id = platform_get_device_id(pdev);
 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, NULL);
 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 = (int)id->driver_data;
 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 const struct platform_device_id ssp_id_table[] = {
 462         { "pxa25x-ssp",         PXA25x_SSP },
 463         { "pxa25x-nssp",        PXA25x_NSSP },
 464         { "pxa27x-ssp",         PXA27x_SSP },
 465         { },
 466 };
 467
 468 static struct platform_driver ssp_driver = {
 469         .probe          = ssp_probe,
 470         .remove         = __devexit_p(ssp_remove),
 471         .driver         = {
 472                 .owner  = THIS_MODULE,
 473                 .name   = "pxa2xx-ssp",
 474         },
 475         .id_table       = ssp_id_table,
 476 };
 477
 478 static int __init pxa_ssp_init(void)
 479 {
 480         return platform_driver_register(&ssp_driver);
 481 }
 482
 483 static void __exit pxa_ssp_exit(void)
 484 {
 485         platform_driver_unregister(&ssp_driver);
 486 }
 487
 488 arch_initcall(pxa_ssp_init);
 489 module_exit(pxa_ssp_exit);
 490
 491 EXPORT_SYMBOL(ssp_write_word);
 492 EXPORT_SYMBOL(ssp_read_word);
 493 EXPORT_SYMBOL(ssp_flush);
 494 EXPORT_SYMBOL(ssp_enable);
 495 EXPORT_SYMBOL(ssp_disable);
 496 EXPORT_SYMBOL(ssp_save_state);
 497 EXPORT_SYMBOL(ssp_restore_state);
 498 EXPORT_SYMBOL(ssp_init);
 499 EXPORT_SYMBOL(ssp_exit);
 500 EXPORT_SYMBOL(ssp_config);
 501
 502 MODULE_DESCRIPTION("PXA SSP driver");
 503 MODULE_AUTHOR("Liam Girdwood");
 504 MODULE_LICENSE("GPL");
 505