Staging
v0.7.0
v0.7.0
https://github.com/torvalds/linux
Tip revision: c59765042f53a79a7a65585042ff463b69cb248c authored by Linus Torvalds on 10 January 2009, 23:43:05 UTC
Linux 2.6.29-rc1
Linux 2.6.29-rc1
Tip revision: c597650
ssp.c
/*
* 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/pxa-regs.h>
#include <mach/regs-ssp.h>
#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);
}
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, int type)
{
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 = type;
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 int __devinit pxa25x_ssp_probe(struct platform_device *pdev)
{
return ssp_probe(pdev, PXA25x_SSP);
}
static int __devinit pxa25x_nssp_probe(struct platform_device *pdev)
{
return ssp_probe(pdev, PXA25x_NSSP);
}
static int __devinit pxa27x_ssp_probe(struct platform_device *pdev)
{
return ssp_probe(pdev, PXA27x_SSP);
}
static struct platform_driver pxa25x_ssp_driver = {
.driver = {
.name = "pxa25x-ssp",
},
.probe = pxa25x_ssp_probe,
.remove = __devexit_p(ssp_remove),
};
static struct platform_driver pxa25x_nssp_driver = {
.driver = {
.name = "pxa25x-nssp",
},
.probe = pxa25x_nssp_probe,
.remove = __devexit_p(ssp_remove),
};
static struct platform_driver pxa27x_ssp_driver = {
.driver = {
.name = "pxa27x-ssp",
},
.probe = pxa27x_ssp_probe,
.remove = __devexit_p(ssp_remove),
};
static int __init pxa_ssp_init(void)
{
int ret = 0;
ret = platform_driver_register(&pxa25x_ssp_driver);
if (ret) {
printk(KERN_ERR "failed to register pxa25x_ssp_driver");
return ret;
}
ret = platform_driver_register(&pxa25x_nssp_driver);
if (ret) {
printk(KERN_ERR "failed to register pxa25x_nssp_driver");
return ret;
}
ret = platform_driver_register(&pxa27x_ssp_driver);
if (ret) {
printk(KERN_ERR "failed to register pxa27x_ssp_driver");
return ret;
}
return ret;
}
static void __exit pxa_ssp_exit(void)
{
platform_driver_unregister(&pxa25x_ssp_driver);
platform_driver_unregister(&pxa25x_nssp_driver);
platform_driver_unregister(&pxa27x_ssp_driver);
}
arch_initcall(pxa_ssp_init);
module_exit(pxa_ssp_exit);
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);
MODULE_DESCRIPTION("PXA SSP driver");
MODULE_AUTHOR("Liam Girdwood");
MODULE_LICENSE("GPL");