spi_txx9.c

/*
 * linux/arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c
 * Copyright (C) 2000-2001 Toshiba Corporation
 *
 * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
 * terms of the GNU General Public License version 2. This program is
 * licensed "as is" without any warranty of any kind, whether express
 * or implied.
 *
 * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
 */
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <asm/tx4938/spi.h>
#include <asm/tx4938/tx4938.h>

static int (*txx9_spi_cs_func)(int chipid, int on);
static DEFINE_SPINLOCK(txx9_spi_lock);

extern unsigned int txx9_gbus_clock;

#define SPI_FIFO_SIZE	4

void __init txx9_spi_init(unsigned long base, int (*cs_func)(int chipid, int on))
{
	txx9_spi_cs_func = cs_func;
	/* enter config mode */
	tx4938_spiptr->mcr = TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR;
}

static DECLARE_WAIT_QUEUE_HEAD(txx9_spi_wait);
static void txx9_spi_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	/* disable rx intr */
	tx4938_spiptr->cr0 &= ~TXx9_SPCR0_RBSIE;
	wake_up(&txx9_spi_wait);
}
static struct irqaction txx9_spi_action = {
	txx9_spi_interrupt, 0, 0, "spi", NULL, NULL,
};

void __init txx9_spi_irqinit(int irc_irq)
{
	setup_irq(irc_irq, &txx9_spi_action);
}

int txx9_spi_io(int chipid, struct spi_dev_desc *desc,
		unsigned char **inbufs, unsigned int *incounts,
		unsigned char **outbufs, unsigned int *outcounts,
		int cansleep)
{
	unsigned int incount, outcount;
	unsigned char *inp, *outp;
	int ret;
	unsigned long flags;

	spin_lock_irqsave(&txx9_spi_lock, flags);
	if ((tx4938_spiptr->mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE) {
		spin_unlock_irqrestore(&txx9_spi_lock, flags);
		return -EBUSY;
	}
	/* enter config mode */
	tx4938_spiptr->mcr = TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR;
	tx4938_spiptr->cr0 =
		(desc->byteorder ? TXx9_SPCR0_SBOS : 0) |
		(desc->polarity ? TXx9_SPCR0_SPOL : 0) |
		(desc->phase ? TXx9_SPCR0_SPHA : 0) |
		0x08;
	tx4938_spiptr->cr1 =
		(((TXX9_IMCLK + desc->baud) / (2 * desc->baud) - 1) << 8) |
		0x08 /* 8 bit only */;
	/* enter active mode */
	tx4938_spiptr->mcr = TXx9_SPMCR_ACTIVE;
	spin_unlock_irqrestore(&txx9_spi_lock, flags);

	/* CS ON */
	if ((ret = txx9_spi_cs_func(chipid, 1)) < 0) {
		spin_unlock_irqrestore(&txx9_spi_lock, flags);
		return ret;
	}
	udelay(desc->tcss);

	/* do scatter IO */
	inp = inbufs ? *inbufs : NULL;
	outp = outbufs ? *outbufs : NULL;
	incount = 0;
	outcount = 0;
	while (1) {
		unsigned char data;
		unsigned int count;
		int i;
		if (!incount) {
			incount = incounts ? *incounts++ : 0;
			inp = (incount && inbufs) ? *inbufs++ : NULL;
		}
		if (!outcount) {
			outcount = outcounts ? *outcounts++ : 0;
			outp = (outcount && outbufs) ? *outbufs++ : NULL;
		}
		if (!inp && !outp)
			break;
		count = SPI_FIFO_SIZE;
		if (incount)
			count = min(count, incount);
		if (outcount)
			count = min(count, outcount);

		/* now tx must be idle... */
		while (!(tx4938_spiptr->sr & TXx9_SPSR_SIDLE))
			;

		tx4938_spiptr->cr0 =
			(tx4938_spiptr->cr0 & ~TXx9_SPCR0_RXIFL_MASK) |
			((count - 1) << 12);
		if (cansleep) {
			/* enable rx intr */
			tx4938_spiptr->cr0 |= TXx9_SPCR0_RBSIE;
		}
		/* send */
		for (i = 0; i < count; i++)
			tx4938_spiptr->dr = inp ? *inp++ : 0;
		/* wait all rx data */
		if (cansleep) {
			wait_event(txx9_spi_wait,
				   tx4938_spiptr->sr & TXx9_SPSR_SRRDY);
		} else {
			while (!(tx4938_spiptr->sr & TXx9_SPSR_RBSI))
				;
		}
		/* receive */
		for (i = 0; i < count; i++) {
			data = tx4938_spiptr->dr;
			if (outp)
				*outp++ = data;
		}
		if (incount)
			incount -= count;
		if (outcount)
			outcount -= count;
	}

	/* CS OFF */
	udelay(desc->tcsh);
	txx9_spi_cs_func(chipid, 0);
	udelay(desc->tcsr);

	spin_lock_irqsave(&txx9_spi_lock, flags);
	/* enter config mode */
	tx4938_spiptr->mcr = TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR;
	spin_unlock_irqrestore(&txx9_spi_lock, flags);

	return 0;
}