path: root/drivers/mmc/imxmmc.c

/*
 *  linux/drivers/mmc/imxmmc.c - Motorola i.MX MMCI driver
 *
 *  Copyright (C) 2004 Sascha Hauer, Pengutronix <sascha@saschahauer.de>
 *  Copyright (C) 2006 Pavel Pisa, PiKRON <ppisa@pikron.com>
 *
 *  derived from pxamci.c by Russell King
 *
 * 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.
 *
 *  2005-04-17 Pavel Pisa <pisa@cmp.felk.cvut.cz>
 *             Changed to conform redesigned i.MX scatter gather DMA interface
 *
 *  2005-11-04 Pavel Pisa <pisa@cmp.felk.cvut.cz>
 *             Updated for 2.6.14 kernel
 *
 *  2005-12-13 Jay Monkman <jtm@smoothsmoothie.com>
 *             Found and corrected problems in the write path
 *
 *  2005-12-30 Pavel Pisa <pisa@cmp.felk.cvut.cz>
 *             The event handling rewritten right way in softirq.
 *             Added many ugly hacks and delays to overcome SDHC
 *             deficiencies
 *
 */

#ifdef CONFIG_MMC_DEBUG
#define DEBUG
#else
#undef  DEBUG
#endif

#include <linux/module.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/dma-mapping.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/protocol.h>
#include <linux/delay.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/sizes.h>
#include <asm/arch/mmc.h>
#include <asm/arch/imx-dma.h>

#include "imxmmc.h"

#define DRIVER_NAME "imx-mmc"

#define IMXMCI_INT_MASK_DEFAULT (INT_MASK_BUF_READY | INT_MASK_DATA_TRAN | \
	              INT_MASK_WRITE_OP_DONE | INT_MASK_END_CMD_RES | \
		      INT_MASK_AUTO_CARD_DETECT | INT_MASK_DAT0_EN | INT_MASK_SDIO)

struct imxmci_host {
	struct mmc_host		*mmc;
	spinlock_t		lock;
	struct resource		*res;
	int			irq;
	imx_dmach_t		dma;
	unsigned int		clkrt;
	unsigned int		cmdat;
	volatile unsigned int	imask;
	unsigned int		power_mode;
	unsigned int		present;
	struct imxmmc_platform_data *pdata;

	struct mmc_request	*req;
	struct mmc_command	*cmd;
	struct mmc_data		*data;

	struct timer_list	timer;
	struct tasklet_struct	tasklet;
	unsigned int		status_reg;
	unsigned long		pending_events;
	/* Next to fields are there for CPU driven transfers to overcome SDHC deficiencies */
	u16			*data_ptr;
	unsigned int		data_cnt;
	atomic_t		stuck_timeout;

	unsigned int		dma_nents;
	unsigned int		dma_size;
	unsigned int		dma_dir;
	int			dma_allocated;

	unsigned char		actual_bus_width;

	int			prev_cmd_code;
};

#define IMXMCI_PEND_IRQ_b	0
#define IMXMCI_PEND_DMA_END_b	1
#define IMXMCI_PEND_DMA_ERR_b	2
#define IMXMCI_PEND_WAIT_RESP_b	3
#define IMXMCI_PEND_DMA_DATA_b	4
#define IMXMCI_PEND_CPU_DATA_b	5
#define IMXMCI_PEND_CARD_XCHG_b	6
#define IMXMCI_PEND_SET_INIT_b	7
#define IMXMCI_PEND_STARTED_b	8

#define IMXMCI_PEND_IRQ_m	(1 << IMXMCI_PEND_IRQ_b)
#define IMXMCI_PEND_DMA_END_m	(1 << IMXMCI_PEND_DMA_END_b)
#define IMXMCI_PEND_DMA_ERR_m	(1 << IMXMCI_PEND_DMA_ERR_b)
#define IMXMCI_PEND_WAIT_RESP_m	(1 << IMXMCI_PEND_WAIT_RESP_b)
#define IMXMCI_PEND_DMA_DATA_m	(1 << IMXMCI_PEND_DMA_DATA_b)
#define IMXMCI_PEND_CPU_DATA_m	(1 << IMXMCI_PEND_CPU_DATA_b)
#define IMXMCI_PEND_CARD_XCHG_m	(1 << IMXMCI_PEND_CARD_XCHG_b)
#define IMXMCI_PEND_SET_INIT_m	(1 << IMXMCI_PEND_SET_INIT_b)
#define IMXMCI_PEND_STARTED_m	(1 << IMXMCI_PEND_STARTED_b)

static void imxmci_stop_clock(struct imxmci_host *host)
{
	int i = 0;
	MMC_STR_STP_CLK &= ~STR_STP_CLK_START_CLK;
	while(i < 0x1000) {
	        if(!(i & 0x7f))
			MMC_STR_STP_CLK |= STR_STP_CLK_STOP_CLK;

		if(!(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN)) {
			/* Check twice before cut */
			if(!(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN))
				return;
		}

		i++;
	}
	dev_dbg(mmc_dev(host->mmc), "imxmci_stop_clock blocked, no luck\n");
}

static int imxmci_start_clock(struct imxmci_host *host)
{
	unsigned int trials = 0;
	unsigned int delay_limit = 128;
	unsigned long flags;

	MMC_STR_STP_CLK &= ~STR_STP_CLK_STOP_CLK;

	clear_bit(IMXMCI_PEND_STARTED_b, &host->pending_events);

	/*
	 * Command start of the clock, this usually succeeds in less
	 * then 6 delay loops, but during card detection (low clockrate)
	 * it takes up to 5000 delay loops and sometimes fails for the first time
	 */
	MMC_STR_STP_CLK |= STR_STP_CLK_START_CLK;

	do {
		unsigned int delay = delay_limit;

		while(delay--){
			if(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN)
				/* Check twice before cut */
				if(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN)
					return 0;

			if(test_bit(IMXMCI_PEND_STARTED_b, &host->pending_events))
				return 0;
		}

		local_irq_save(flags);
		/*
		 * Ensure, that request is not doubled under all possible circumstances.
		 * It is possible, that cock running state is missed, because some other