path: root/drivers/mmc/host/tmio_mmc.c

/*
 *  linux/drivers/mmc/tmio_mmc.c
 *
 *  Copyright (C) 2004 Ian Molton
 *  Copyright (C) 2007 Ian Molton
 *
 * 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.
 *
 * Driver for the MMC / SD / SDIO cell found in:
 *
 * TC6393XB TC6391XB TC6387XB T7L66XB ASIC3
 *
 * This driver draws mainly on scattered spec sheets, Reverse engineering
 * of the toshiba e800  SD driver and some parts of the 2.4 ASIC3 driver (4 bit
 * support). (Further 4 bit support from a later datasheet).
 *
 * TODO:
 *   Investigate using a workqueue for PIO transfers
 *   Eliminate FIXMEs
 *   SDIO support
 *   Better Power management
 *   Handle MMC errors better
 *   double buffer support
 *
 */
#include <linux/module.h>
#include <linux/irq.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/mmc/host.h>
#include <linux/mfd/core.h>
#include <linux/mfd/tmio.h>

#include "tmio_mmc.h"

static void tmio_mmc_set_clock(struct tmio_mmc_host *host, int new_clock)
{
	u32 clk = 0, clock;

	if (new_clock) {
		for (clock = host->mmc->f_min, clk = 0x80000080;
			new_clock >= (clock<<1); clk >>= 1)
			clock <<= 1;
		clk |= 0x100;
	}

	if (host->set_clk_div)
		host->set_clk_div(host->pdev, (clk>>22) & 1);

	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk & 0x1ff);
}

static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
{
	sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0000);
	msleep(10);
	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~0x0100 &
		sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
	msleep(10);
}

static void tmio_mmc_clk_start(struct tmio_mmc_host *host)
{
	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, 0x0100 |
		sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
	msleep(10);
	sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0100);
	msleep(10);
}

static void reset(struct tmio_mmc_host *host)
{
	/* FIXME - should we set stop clock reg here */
	sd_ctrl_write16(host, CTL_RESET_SD, 0x0000);
	sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0000);
	msleep(10);
	sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
	sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0001);
	msleep(10);
}

static void
tmio_mmc_finish_request(struct tmio_mmc_host *host)
{
	struct mmc_request *mrq = host->mrq;

	host->mrq = NULL;
	host->cmd = NULL;
	host->data = NULL;

	mmc_request_done(host->mmc, mrq);
}

/* These are the bitmasks the tmio chip requires to implement the MMC response
 * types. Note that R1 and R6 are the same in this scheme. */
#define APP_CMD        0x0040
#define RESP_NONE      0x0300
#define RESP_R1        0x0400
#define RESP_R1B       0x0500
#define RESP_R2        0x0600
#define RESP_R3        0x0700
#define DATA_PRESENT   0x0800
#define TRANSFER_READ  0x1000
#define TRANSFER_MULTI 0x2000
#define SECURITY_CMD   0x4000

static int
tmio_mmc_start_command(struct tmio_mmc_host *host, struct mmc_command *cmd)
{
	struct mmc_data *data = host->data;
	int c = cmd->opcode;

	/* Command 12 is handled by hardware */
	if (cmd->opcode == 12 && !cmd->arg) {
		sd_ctrl_write16(host, CTL_STOP_INTERNAL_ACTION, 0x001);
		return 0;
	}

	switch (mmc_resp_type(cmd)) {
	case MMC_RSP_NONE: c |= RESP_NONE; break;
	case MMC_RSP_R1:   c |= RESP_R1;   break;
	case MMC_RSP_R1B:  c |= RESP_R1B;  break;
	case MMC_RSP_R2:   c |= RESP_R2;   break;
	case MMC_RSP_R3:   c |= RESP_R3;   break;
	default:
		pr_debug("Unknown response type %d\n", mmc_resp_type(cmd));
		return -EINVAL;
	}

	host->cmd = cmd;

/* FIXME - this seems to be ok commented out but the spec suggest this bit
 *         should be set when issuing app commands.
 *	if(cmd->flags & MMC_FLAG_ACMD)
 *		c |= APP_CMD;
 */
	if (data) {
		c |= DATA_PRESENT;
		if (data->blocks > 1) {
			sd_ctrl_write16(host, CTL_STOP_INTERNAL_ACTION, 0x100);
			c |= TRANSFER_MULTI;
		}
		if (data->flags & MMC_DATA_READ)
			c |= TRANSFER_READ;
	}

	enable_mmc_irqs(host, TMIO_MASK_CMD);

	/* Fire off the command */
	sd_ctrl_write32(host, CTL_ARG_REG, cmd->arg);
	sd_ctrl_write16(host, CTL_SD_CMD, c);

	return 0;
}

/*
 * This chip always returns (at least?) as much data as you ask for.
 * I'm unsure what happens if you ask for less than a block. This should be
 * looked into to ensure that a funny length read doesnt hose the controller.
 */
static void tmio_mmc_pio_irq(struct tmio_mmc_host *host)
{
	struct mmc_data *data = host->data;
	unsigned short *buf;
	unsigned int count;
	unsigned long flags;

	if (!data) {
		pr_debug("Spurious PIO IRQ\n");
		return;
	}

	buf = (unsigned short *