text: /*
   *  linux/arch/arm/mach-pxa/ssp.c
   *
   *  based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
   *
   *  Copyright (C) 2003 Russell King.
   *  Copyright (C) 2003 Wolfson Microelectronics PLC
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   *  PXA2xx SSP driver.  This provides the generic core for simple
   *  IO-based SSP applications and allows easy port setup for DMA access.
   *
   *  Author: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/ioport.h>
  #include <linux/init.h>
  #include <linux/mutex.h>
  #include <linux/clk.h>
  #include <linux/err.h>
  #include <linux/platform_device.h>
  #include <linux/io.h>
  
  #include <asm/irq.h>
  #include <mach/hardware.h>
  #include <mach/ssp.h>
  #include <mach/regs-ssp.h>
  
  #ifdef CONFIG_PXA_SSP_LEGACY
  
  #define TIMEOUT 100000
  
  static irqreturn_t ssp_interrupt(int irq, void *dev_id)
  {
  	struct ssp_dev *dev = dev_id;
  	struct ssp_device *ssp = dev->ssp;
  	unsigned int status;
  
  	status = __raw_readl(ssp->mmio_base + SSSR);
  	__raw_writel(status, ssp->mmio_base + SSSR);
  
  	if (status & SSSR_ROR)
  		printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);
  
  	if (status & SSSR_TUR)
  		printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);
  
  	if (status & SSSR_BCE)
  		printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);
  
  	return IRQ_HANDLED;
  }
  
  /**
   * ssp_write_word - write a word to the SSP port
   * @data: 32-bit, MSB justified data to write.
   *
   * Wait for a free entry in the SSP transmit FIFO, and write a data
   * word to the SSP port.
   *
   * The caller is expected to perform the necessary locking.
   *
   * Returns:
   *   %-ETIMEDOUT	timeout occurred
   *   0			success
   */
  int ssp_write_word(struct ssp_dev *dev, u32 data)
  {
  	struct ssp_device *ssp = dev->ssp;
  	int timeout = TIMEOUT;
  
  	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_TNF)) {
  	        if (!--timeout)
  	        	return -ETIMEDOUT;
  		cpu_relax();
  	}
  
  	__raw_writel(data, ssp->mmio_base + SSDR);
  
  	return 0;
  }
  
  /**
   * ssp_read_word - read a word from the SSP port
   *
   * Wait for a data word in the SSP receive FIFO, and return the
   * received data.  Data is LSB justified.
   *
   * Note: Currently, if data is not expected to be received, this
   * function will wait for ever.
   *
   * The caller is expected to perform the necessary locking.
   *
   * Returns:
   *   %-ETIMEDOUT	timeout occurred
   *   32-bit data	success
   */
  int ssp_read_word(struct ssp_dev *dev, u32 *data)
  {
  	struct ssp_device *ssp = dev->ssp;
  	int timeout = TIMEOUT;
  
  	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE)) {
  	        if (!--timeout)
  	        	return -ETIMEDOUT;
  		cpu_relax();
  	}
  
  	*data = __raw_readl(ssp->mmio_base + SSDR);
  	return 0;
  }
  
  /**
   * ssp_flush - flush the transmit and receive FIFOs
   *
   * Wait for the SSP to idle, and ensure that the receive FIFO
   * is empty.
   *
   * The caller is expected to perform the necessary locking.
   */
  int ssp_flush(struct ssp_dev *dev)
  {
  	struct ssp_device *ssp = dev->ssp;
  	int timeout = TIMEOUT * 2;
  
  	/* ensure TX FIFO is empty instead of not full */
  	if (cpu_is_pxa3xx()) {
  		while (__raw_readl(ssp->mmio_base + SSSR) & 0xf00) {
  			if (!--timeout)
  				return -ETIMEDOUT;
  			cpu_relax();
  		}
  		timeout = TIMEOUT * 2;
  	}
  
  	do {
  		while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE) {
  		        if (!--timeout)
  		        	return -ETIMEDOUT;
  			(void)__raw_readl(ssp->mmio_base + SSDR);
  		}
  	        if (!--timeout)
  	        	return -ETIMEDOUT;
  	} while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_BSY);
  
  	return 0;
  }
  
  /**
   * ssp_enable - enable the SSP port
   *
   * Turn on the SSP port.
   */
  void ssp_enable(struct ssp_dev *dev)
  {
  	struct ssp_device *ssp = dev->ssp;
  	uint32_t sscr0;
  
  	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
  	sscr0 |= SSCR0_SSE;
  	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
  }
  
  /**
   * ssp_disable - shut down the SSP port
   *
   * Turn off the SSP port, optionally powering it down.
   */
  void ssp_disable(struct ssp_dev *dev)
  {
  	struct ssp_device *ssp = dev->ssp;
  	uint32_t sscr0;
  
  	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
  	sscr0 &= ~SSCR0_SSE;
  	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
  }
  
  /**
   * ssp_save_state - save the SSP configuration
   * @ssp: pointer to structure to save SSP configuration
   *
   * Save the configured SSP state for suspend.
   */
  void ssp_save_state(struct ssp_dev *dev, struct ssp_state *state)
  {
  	struct ssp_device *ssp = dev->ssp;
  
  	state->cr0 = __raw_readl(ssp->mmio_base + SSCR0);
  	state->cr1 = __raw_readl(ssp->mmio_base + SSCR1);
  	state->to  = __raw_readl(ssp->mmio_base + SSTO);
  	state->psp = __raw_readl(ssp->mmio_base + SSPSP);
  
  	ssp_disable(dev);
  }
  
  /**
   * ssp_restore_state - restore a previously saved SSP configuration
   * @ssp: pointer to configuration saved by ssp_save_state
   *
   * Restore the SSP configuration saved previously by ssp_save_state.
   */
  void ssp_restore_state(struct ssp_dev *dev, struct ssp_state *state)
  {
  	struct ssp_device *ssp = dev->ssp;
  	uint32_t sssr = SSSR_ROR | SSSR_TUR | SSSR_BCE;
  
  	__raw_writel(sssr, ssp->mmio_base + SSSR);
  
  	__raw_writel(state->cr0 & ~SSCR0_SSE, ssp->mmio_base + SSCR0);
  	__raw_writel(state->cr1, ssp->mmio_base + SSCR1);
  	__raw_writel(state->to,  ssp->mmio_base + SSTO);
  	__raw_writel(state->psp, ssp->mmio_base + SSPSP);
  	__raw_writel(state->cr0, ssp->mmio_base + SSCR0);
  }
  
  /**
   * ssp_config - configure SSP port settings
   * @mode: port operating mode
   * @flags: port config flags
   * @psp_flags: port PSP config flags
   * @speed: port speed
   *
   * Port MUST be disabled by ssp_disable before making any config changes.
   */
  int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
  {
  	struct ssp_device *ssp = dev->ssp;
  
  	dev->mode = mode;
  	dev->flags = flags;
  	dev->psp_flags = psp_flags;
  	dev->speed = speed;
  
  	/* set up port type, speed, port settings */
  	__raw_writel((dev->speed | dev->mode), ssp->mmio_base + SSCR0);
  	__raw_writel(dev->flags, ssp->mmio_base + SSCR1);
  	__raw_writel(dev->psp_flags, ssp->mmio_base + SSPSP);
  
  	return 0;
  }
  
  /**
   * ssp_init - setup the SSP port
   *
   * initialise and claim resources for the SSP port.
   *
   * Returns:
   *   %-ENODEV	if the SSP port is unavailable
   *   %-EBUSY	if the resources are already in use
   *   %0		on success
   */
  int ssp_init(struct ssp_dev *dev, u32 port, u32 init_flags)
  {
  	struct ssp_device *ssp;
  	int ret;
  
  	ssp = ssp_request(port, "SSP");
  	if (ssp == NULL)
  		return -ENODEV;
  
  	dev->ssp = ssp;
  	dev->port = port;
  
  	/* do we need to get irq */
  	if (!(init_flags & SSP_NO_IRQ)) {
  		ret = request_irq(ssp->irq, ssp_interrupt,
  				0, "SSP", dev);
  	    	if (ret)
  			goto out_region;
  		dev->irq = ssp->irq;
  	} else
  		dev->irq = NO_IRQ;
  
  	/* turn on SSP port clock */
  	clk_enable(ssp->clk);
  	return 0;
  
  out_region:
  	ssp_free(ssp);
  	return ret;
  }
  
  /**
   * ssp_exit - undo the effects of ssp_init
   *
   * release and free resources for the SSP port.
   */
  void ssp_exit(struct ssp_dev *dev)
  {
  	struct ssp_device *ssp = dev->ssp;
  
  	ssp_disable(dev);
  	if (dev->irq != NO_IRQ)
  		free_irq(dev->irq, dev);
  	clk_disable(ssp->clk);
  	ssp_free(ssp);
  }
  #endif /* CONFIG_PXA_SSP_LEGACY */
  
  static DEFINE_MUTEX(ssp_lock);
  static LIST_HEAD(ssp_list);
  
  struct ssp_device *ssp_request(int port, const char *label)
  {
  	struct ssp_device *ssp = NULL;
  
  	mutex_lock(&ssp_lock);
  
  	list_for_each_entry(ssp, &ssp_list, node) {
  		if (ssp->port_id == port && ssp->use_count == 0) {
  			ssp->use_count++;
  			ssp->label = label;
  			break;
  		}
  	}
  
  	mutex_unlock(&ssp_lock);
  
  	if (&ssp->node == &ssp_list)
  		return NULL;
  
  	return ssp;
  }
  EXPORT_SYMBOL(ssp_request);
  
  void ssp_free(struct ssp_device *ssp)
  {
  	mutex_lock(&ssp_lock);
  	if (ssp->use_count) {
  		ssp->use_count--;
  		ssp->label = NULL;
  	} else
  		dev_err(&ssp->pdev->dev, "device already free\n");
  	mutex_unlock(&ssp_lock);
  }
  EXPORT_SYMBOL(ssp_free);
  
  static int __devinit ssp_probe(struct platform_device *pdev)
  {
  	const struct platform_device_id *id = platform_get_device_id(pdev);
  	struct resource *res;
  	struct ssp_device *ssp;
  	int ret = 0;
  
  	ssp = kzalloc(sizeof(struct ssp_device), GFP_KERNEL);
  	if (ssp == NULL) {
  		dev_err(&pdev->dev, "failed to allocate memory");
  		return -ENOMEM;
  	}
  	ssp->pdev = pdev;
  
  	ssp->clk = clk_get(&pdev->dev, NULL);
  	if (IS_ERR(ssp->clk)) {
  		ret = PTR_ERR(ssp->clk);
  		goto err_free;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (res == NULL) {
  		dev_err(&pdev->dev, "no memory resource defined\n");
  		ret = -ENODEV;
  		goto err_free_clk;
  	}
  
  	res = request_mem_region(res->start, res->end - res->start + 1,
  			pdev->name);
  	if (res == NULL) {
  		dev_err(&pdev->dev, "failed to request memory resource\n");
  		ret = -EBUSY;
  		goto err_free_clk;
  	}
  
  	ssp->phys_base = res->start;
  
  	ssp->mmio_base = ioremap(res->start, res->end - res->start + 1);
  	if (ssp->mmio_base == NULL) {
  		dev_err(&pdev->dev, "failed to ioremap() registers\n");
  		ret = -ENODEV;
  		goto err_free_mem;
  	}
  
  	ssp->irq = platform_get_irq(pdev, 0);
  	if (ssp->irq < 0) {
  		dev_err(&pdev->dev, "no IRQ resource defined\n");
  		ret = -ENODEV;
  		goto err_free_io;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
  	if (res == NULL) {
  		dev_err(&pdev->dev, "no SSP RX DRCMR defined\n");
  		ret = -ENODEV;
  		goto err_free_io;
  	}
  	ssp->drcmr_rx = res->start;
  
  	res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
  	if (res == NULL) {
  		dev_err(&pdev->dev, "no SSP TX DRCMR defined\n");
  		ret = -ENODEV;
  		goto err_free_io;
  	}
  	ssp->drcmr_tx = res->start;
  
  	/* PXA2xx/3xx SSP ports starts from 1 and the internal pdev->id
  	 * starts from 0, do a translation here
  	 */
  	ssp->port_id = pdev->id + 1;
  	ssp->use_count = 0;
  	ssp->type = (int)id->driver_data;
  
  	mutex_lock(&ssp_lock);
  	list_add(&ssp->node, &ssp_list);
  	mutex_unlock(&ssp_lock);
  
  	platform_set_drvdata(pdev, ssp);
  	return 0;
  
  err_free_io:
  	iounmap(ssp->mmio_base);
  err_free_mem:
  	release_mem_region(res->start, res->end - res->start + 1);
  err_free_clk:
  	clk_put(ssp->clk);
  err_free:
  	kfree(ssp);
  	return ret;
  }
  
  static int __devexit ssp_remove(struct platform_device *pdev)
  {
  	struct resource *res;
  	struct ssp_device *ssp;
  
  	ssp = platform_get_drvdata(pdev);
  	if (ssp == NULL)
  		return -ENODEV;
  
  	iounmap(ssp->mmio_base);
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	release_mem_region(res->start, res->end - res->start + 1);
  
  	clk_put(ssp->clk);
  
  	mutex_lock(&ssp_lock);
  	list_del(&ssp->node);
  	mutex_unlock(&ssp_lock);
  
  	kfree(ssp);
  	return 0;
  }
  
  static const struct platform_device_id ssp_id_table[] = {
  	{ "pxa25x-ssp",		PXA25x_SSP },
  	{ "pxa25x-nssp",	PXA25x_NSSP },
  	{ "pxa27x-ssp",		PXA27x_SSP },
  	{ },
  };
  
  static struct platform_driver ssp_driver = {
  	.probe		= ssp_probe,
  	.remove		= __devexit_p(ssp_remove),
  	.driver		= {
  		.owner	= THIS_MODULE,
  		.name	= "pxa2xx-ssp",
  	},
  	.id_table	= ssp_id_table,
  };
  
  static int __init pxa_ssp_init(void)
  {
  	return platform_driver_register(&ssp_driver);
  }
  
  static void __exit pxa_ssp_exit(void)
  {
  	platform_driver_unregister(&ssp_driver);
  }
  
  arch_initcall(pxa_ssp_init);
  module_exit(pxa_ssp_exit);
  
  #ifdef CONFIG_PXA_SSP_LEGACY
  EXPORT_SYMBOL(ssp_write_word);
  EXPORT_SYMBOL(ssp_read_word);
  EXPORT_SYMBOL(ssp_flush);
  EXPORT_SYMBOL(ssp_enable);
  EXPORT_SYMBOL(ssp_disable);
  EXPORT_SYMBOL(ssp_save_state);
  EXPORT_SYMBOL(ssp_restore_state);
  EXPORT_SYMBOL(ssp_init);
  EXPORT_SYMBOL(ssp_exit);
  EXPORT_SYMBOL(ssp_config);
  #endif
  
  MODULE_DESCRIPTION("PXA SSP driver");
  MODULE_AUTHOR("Liam Girdwood");
  MODULE_LICENSE("GPL");
  
  