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acrn-kernel/arch/arm/mach-pxa/ssp.c

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/*
* 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>
*
* Revision history:
* 22nd Aug 2003 Initial version.
* 20th Dec 2004 Added ssp_config for changing port config without
* closing the port.
* 4th Aug 2005 Added option to disable irq handler registration and
* cleaned up irq and clock detection.
*/
#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 <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/arch/ssp.h>
#include <asm/arch/pxa-regs.h>
#define PXA_SSP_PORTS 3
struct ssp_info_ {
int irq;
u32 clock;
};
/*
* SSP port clock and IRQ settings
*/
static const struct ssp_info_ ssp_info[PXA_SSP_PORTS] = {
#if defined (CONFIG_PXA27x)
{IRQ_SSP, CKEN23_SSP1},
{IRQ_SSP2, CKEN3_SSP2},
{IRQ_SSP3, CKEN4_SSP3},
#else
{IRQ_SSP, CKEN3_SSP},
{IRQ_NSSP, CKEN9_NSSP},
{IRQ_ASSP, CKEN10_ASSP},
#endif
};
static DECLARE_MUTEX(sem);
static int use_count[PXA_SSP_PORTS] = {0, 0, 0};
static irqreturn_t ssp_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct ssp_dev *dev = (struct ssp_dev*) dev_id;
unsigned int status = SSSR_P(dev->port);
SSSR_P(dev->port) = status; /* clear status bits */
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 (for future)
* 0 success
*/
int ssp_write_word(struct ssp_dev *dev, u32 data)
{
while (!(SSSR_P(dev->port) & SSSR_TNF))
cpu_relax();
SSDR_P(dev->port) = data;
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 (for future)
* 32-bit data success
*/
int ssp_read_word(struct ssp_dev *dev)
{
while (!(SSSR_P(dev->port) & SSSR_RNE))
cpu_relax();
return SSDR_P(dev->port);
}
/**
* 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.
*/
void ssp_flush(struct ssp_dev *dev)
{
do {
while (SSSR_P(dev->port) & SSSR_RNE) {
(void) SSDR_P(dev->port);
}
} while (SSSR_P(dev->port) & SSSR_BSY);
}
/**
* ssp_enable - enable the SSP port
*
* Turn on the SSP port.
*/
void ssp_enable(struct ssp_dev *dev)
{
SSCR0_P(dev->port) |= SSCR0_SSE;
}
/**
* ssp_disable - shut down the SSP port
*
* Turn off the SSP port, optionally powering it down.
*/
void ssp_disable(struct ssp_dev *dev)
{
SSCR0_P(dev->port) &= ~SSCR0_SSE;
}
/**
* 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 *ssp)
{
ssp->cr0 = SSCR0_P(dev->port);
ssp->cr1 = SSCR1_P(dev->port);
ssp->to = SSTO_P(dev->port);
ssp->psp = SSPSP_P(dev->port);
SSCR0_P(dev->port) &= ~SSCR0_SSE;
}
/**
* 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 *ssp)
{
SSSR_P(dev->port) = SSSR_ROR | SSSR_TUR | SSSR_BCE;
SSCR0_P(dev->port) = ssp->cr0 & ~SSCR0_SSE;
SSCR1_P(dev->port) = ssp->cr1;
SSTO_P(dev->port) = ssp->to;
SSPSP_P(dev->port) = ssp->psp;
SSCR0_P(dev->port) = ssp->cr0;
}
/**
* 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)
{
dev->mode = mode;
dev->flags = flags;
dev->psp_flags = psp_flags;
dev->speed = speed;
/* set up port type, speed, port settings */
SSCR0_P(dev->port) = (dev->speed | dev->mode);
SSCR1_P(dev->port) = dev->flags;
SSPSP_P(dev->port) = dev->psp_flags;
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)
{
int ret;
if (port > PXA_SSP_PORTS || port == 0)
return -ENODEV;
down(&sem);
if (use_count[port - 1]) {
up(&sem);
return -EBUSY;
}
use_count[port - 1]++;
if (!request_mem_region(__PREG(SSCR0_P(port)), 0x2c, "SSP")) {
use_count[port - 1]--;
up(&sem);
return -EBUSY;
}
dev->port = port;
/* do we need to get irq */
if (!(init_flags & SSP_NO_IRQ)) {
ret = request_irq(ssp_info[port-1].irq, ssp_interrupt,
0, "SSP", dev);
if (ret)
goto out_region;
dev->irq = ssp_info[port-1].irq;
} else
dev->irq = 0;
/* turn on SSP port clock */
pxa_set_cken(ssp_info[port-1].clock, 1);
up(&sem);
return 0;
out_region:
release_mem_region(__PREG(SSCR0_P(port)), 0x2c);
use_count[port - 1]--;
up(&sem);
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)
{
down(&sem);
SSCR0_P(dev->port) &= ~SSCR0_SSE;
if (dev->port > PXA_SSP_PORTS || dev->port == 0) {
printk(KERN_WARNING "SSP: tried to close invalid port\n");
return;
}
pxa_set_cken(ssp_info[dev->port-1].clock, 0);
if (dev->irq)
free_irq(dev->irq, dev);
release_mem_region(__PREG(SSCR0_P(dev->port)), 0x2c);
use_count[dev->port - 1]--;
up(&sem);
}
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");
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