path: root/drivers/mmc/host/atmel-mci.c

/*
 * Atmel MultiMedia Card Interface driver
 *
 * Copyright (C) 2004-2008 Atmel Corporation
 *
 * 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.
 */
#include <linux/blkdev.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>

#include <linux/mmc/host.h>

#include <asm/atmel-mci.h>
#include <asm/io.h>
#include <asm/unaligned.h>

#include <asm/arch/board.h>
#include <asm/arch/gpio.h>

#include "atmel-mci-regs.h"

#define ATMCI_DATA_ERROR_FLAGS	(MCI_DCRCE | MCI_DTOE | MCI_OVRE | MCI_UNRE)

enum {
	EVENT_CMD_COMPLETE = 0,
	EVENT_DATA_ERROR,
	EVENT_DATA_COMPLETE,
	EVENT_STOP_SENT,
	EVENT_STOP_COMPLETE,
	EVENT_XFER_COMPLETE,
};

struct atmel_mci {
	struct mmc_host		*mmc;
	void __iomem		*regs;

	struct scatterlist	*sg;
	unsigned int		pio_offset;

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

	u32			cmd_status;
	u32			data_status;
	u32			stop_status;
	u32			stop_cmdr;

	u32			mode_reg;
	u32			sdc_reg;

	struct tasklet_struct	tasklet;
	unsigned long		pending_events;
	unsigned long		completed_events;

	int			present;
	int			detect_pin;
	int			wp_pin;

	/* For detect pin debouncing */
	struct timer_list	detect_timer;

	unsigned long		bus_hz;
	unsigned long		mapbase;
	struct clk		*mck;
	struct platform_device	*pdev;
};

#define atmci_is_completed(host, event)				\
	test_bit(event, &host->completed_events)
#define atmci_test_and_clear_pending(host, event)		\
	test_and_clear_bit(event, &host->pending_events)
#define atmci_test_and_set_completed(host, event)		\
	test_and_set_bit(event, &host->completed_events)
#define atmci_set_completed(host, event)			\
	set_bit(event, &host->completed_events)
#define atmci_set_pending(host, event)				\
	set_bit(event, &host->pending_events)
#define atmci_clear_pending(host, event)			\
	clear_bit(event, &host->pending_events)


static void atmci_enable(struct atmel_mci *host)
{
	clk_enable(host->mck);
	mci_writel(host, CR, MCI_CR_MCIEN);
	mci_writel(host, MR, host->mode_reg);
	mci_writel(host, SDCR, host->sdc_reg);
}

static void atmci_disable(struct atmel_mci *host)
{
	mci_writel(host, CR, MCI_CR_SWRST);

	/* Stall until write is complete, then disable the bus clock */
	mci_readl(host, SR);
	clk_disable(host->mck);
}

static inline unsigned int ns_to_clocks(struct atmel_mci *host,
					unsigned int ns)
{
	return (ns * (host->bus_hz / 1000000) + 999) / 1000;
}

static void atmci_set_timeout(struct atmel_mci *host,
			      struct mmc_data *data)
{
	static unsigned	dtomul_to_shift[] = {
		0, 4, 7, 8, 10, 12, 16, 20
	};
	unsigned	timeout;
	unsigned	dtocyc;
	unsigned	dtomul;

	timeout = ns_to_clocks(host, data->timeout_ns) + data->timeout_clks;

	for (dtomul = 0; dtomul < 8; dtomul++) {
		unsigned shift = dtomul_to_shift[dtomul];
		dtocyc = (timeout + (1 << shift) - 1) >> shift;
		if (dtocyc < 15)
			break;
	}

	if (dtomul >= 8) {
		dtomul = 7;
		dtocyc = 15;
	}

	dev_vdbg(&host->mmc->class_dev, "setting timeout to %u cycles\n",
			dtocyc << dtomul_to_shift[dtomul]);
	mci_writel(host, DTOR, (MCI_DTOMUL(dtomul) | MCI_DTOCYC(dtocyc)));
}

/*
 * Return mask with command flags to be enabled for this command.
 */
static u32 atmci_prepare_command(struct mmc_host *mmc,
				 struct mmc_command *cmd)
{
	struct mmc_data	*data;
	u32		cmdr;

	cmd->error = -EINPROGRESS;

	cmdr = MCI_CMDR_CMDNB(cmd->opcode);

	if (cmd->flags & MMC_RSP_PRESENT) {
		if (cmd->flags & MMC_RSP_136)
			cmdr |= MCI_CMDR_RSPTYP_136BIT;
		else
			cmdr |= MCI_CMDR_RSPTYP_48BIT;
	}

	/*
	 * This should really be MAXLAT_5 for CMD2 and ACMD41, but
	 * it's too difficult to determine whether this is an ACMD or
	 * not. Better make it 64.
	 */
	cmdr |= MCI_CMDR_MAXLAT_64CYC;

	if (mmc->ios.bus_mode == MMC_BUSMODE_OPENDRAIN)
		cmdr |= MCI_CMDR_OPDCMD;

	data = cmd->data;
	if (data) {
		cmdr |= MCI_CMDR_START_XFER;
		if (data->flags