0cd61b68c3
Untested, but this should fix up the bulk of the totally mechanical issues, and should make the actual detail fixing easier. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
244 lines
4.8 KiB
C
244 lines
4.8 KiB
C
/*
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* linux/arch/arm/mach-sa1100/ssp.c
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*
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* Copyright (C) 2003 Russell King.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Generic SSP driver. This provides the generic core for simple
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* IO-based SSP applications.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/ioport.h>
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#include <linux/init.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include <asm/hardware.h>
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#include <asm/hardware/ssp.h>
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#define TIMEOUT 100000
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static irqreturn_t ssp_interrupt(int irq, void *dev_id)
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{
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unsigned int status = Ser4SSSR;
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if (status & SSSR_ROR) {
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printk(KERN_WARNING "SSP: receiver overrun\n");
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}
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Ser4SSSR = SSSR_ROR;
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return status ? IRQ_HANDLED : IRQ_NONE;
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}
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/**
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* ssp_write_word - write a word to the SSP port
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* @data: 16-bit, MSB justified data to write.
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*
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* Wait for a free entry in the SSP transmit FIFO, and write a data
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* word to the SSP port. Wait for the SSP port to start sending
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* the data.
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*
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* The caller is expected to perform the necessary locking.
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*
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* Returns:
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* %-ETIMEDOUT timeout occurred
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* 0 success
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*/
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int ssp_write_word(u16 data)
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{
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int timeout = TIMEOUT;
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while (!(Ser4SSSR & SSSR_TNF)) {
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if (!--timeout)
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return -ETIMEDOUT;
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cpu_relax();
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}
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Ser4SSDR = data;
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timeout = TIMEOUT;
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while (!(Ser4SSSR & SSSR_BSY)) {
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if (!--timeout)
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return -ETIMEDOUT;
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cpu_relax();
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}
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return 0;
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}
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/**
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* ssp_read_word - read a word from the SSP port
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*
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* Wait for a data word in the SSP receive FIFO, and return the
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* received data. Data is LSB justified.
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*
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* Note: Currently, if data is not expected to be received, this
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* function will wait for ever.
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*
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* The caller is expected to perform the necessary locking.
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*
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* Returns:
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* %-ETIMEDOUT timeout occurred
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* 16-bit data success
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*/
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int ssp_read_word(u16 *data)
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{
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int timeout = TIMEOUT;
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while (!(Ser4SSSR & SSSR_RNE)) {
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if (!--timeout)
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return -ETIMEDOUT;
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cpu_relax();
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}
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*data = (u16)Ser4SSDR;
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return 0;
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}
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/**
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* ssp_flush - flush the transmit and receive FIFOs
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*
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* Wait for the SSP to idle, and ensure that the receive FIFO
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* is empty.
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*
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* The caller is expected to perform the necessary locking.
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*
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* Returns:
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* %-ETIMEDOUT timeout occurred
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* 0 success
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*/
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int ssp_flush(void)
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{
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int timeout = TIMEOUT * 2;
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do {
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while (Ser4SSSR & SSSR_RNE) {
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if (!--timeout)
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return -ETIMEDOUT;
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(void) Ser4SSDR;
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}
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if (!--timeout)
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return -ETIMEDOUT;
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} while (Ser4SSSR & SSSR_BSY);
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return 0;
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}
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/**
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* ssp_enable - enable the SSP port
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*
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* Turn on the SSP port.
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*/
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void ssp_enable(void)
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{
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Ser4SSCR0 |= SSCR0_SSE;
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}
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/**
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* ssp_disable - shut down the SSP port
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*
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* Turn off the SSP port, optionally powering it down.
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*/
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void ssp_disable(void)
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{
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Ser4SSCR0 &= ~SSCR0_SSE;
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}
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/**
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* ssp_save_state - save the SSP configuration
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* @ssp: pointer to structure to save SSP configuration
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*
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* Save the configured SSP state for suspend.
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*/
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void ssp_save_state(struct ssp_state *ssp)
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{
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ssp->cr0 = Ser4SSCR0;
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ssp->cr1 = Ser4SSCR1;
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Ser4SSCR0 &= ~SSCR0_SSE;
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}
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/**
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* ssp_restore_state - restore a previously saved SSP configuration
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* @ssp: pointer to configuration saved by ssp_save_state
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*
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* Restore the SSP configuration saved previously by ssp_save_state.
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*/
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void ssp_restore_state(struct ssp_state *ssp)
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{
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Ser4SSSR = SSSR_ROR;
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Ser4SSCR0 = ssp->cr0 & ~SSCR0_SSE;
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Ser4SSCR1 = ssp->cr1;
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Ser4SSCR0 = ssp->cr0;
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}
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/**
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* ssp_init - setup the SSP port
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*
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* initialise and claim resources for the SSP port.
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*
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* Returns:
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* %-ENODEV if the SSP port is unavailable
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* %-EBUSY if the resources are already in use
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* %0 on success
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*/
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int ssp_init(void)
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{
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int ret;
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if (!(PPAR & PPAR_SPR) && (Ser4MCCR0 & MCCR0_MCE))
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return -ENODEV;
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if (!request_mem_region(__PREG(Ser4SSCR0), 0x18, "SSP")) {
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return -EBUSY;
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}
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Ser4SSSR = SSSR_ROR;
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ret = request_irq(IRQ_Ser4SSP, ssp_interrupt, 0, "SSP", NULL);
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if (ret)
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goto out_region;
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return 0;
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out_region:
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release_mem_region(__PREG(Ser4SSCR0), 0x18);
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return ret;
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}
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/**
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* ssp_exit - undo the effects of ssp_init
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*
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* release and free resources for the SSP port.
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*/
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void ssp_exit(void)
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{
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Ser4SSCR0 &= ~SSCR0_SSE;
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free_irq(IRQ_Ser4SSP, NULL);
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release_mem_region(__PREG(Ser4SSCR0), 0x18);
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}
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MODULE_AUTHOR("Russell King");
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MODULE_DESCRIPTION("SA11x0 SSP PIO driver");
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MODULE_LICENSE("GPL");
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EXPORT_SYMBOL(ssp_write_word);
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EXPORT_SYMBOL(ssp_read_word);
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EXPORT_SYMBOL(ssp_flush);
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EXPORT_SYMBOL(ssp_enable);
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EXPORT_SYMBOL(ssp_disable);
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EXPORT_SYMBOL(ssp_save_state);
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EXPORT_SYMBOL(ssp_restore_state);
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EXPORT_SYMBOL(ssp_init);
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EXPORT_SYMBOL(ssp_exit);
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