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

/*
 *  linux/drivers/mmc/host/mmci.c - ARM PrimeCell MMCI PL180/1 driver
 *
 *  Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
 *  Copyright (C) 2010 ST-Ericsson AB.
 *
 * 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/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/log2.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/amba/bus.h>
#include <linux/clk.h>
#include <linux/scatterlist.h>
#include <linux/gpio.h>
#include <linux/amba/mmci.h>
#include <linux/regulator/consumer.h>

#include <asm/div64.h>
#include <asm/io.h>
#include <asm/sizes.h>

#include "mmci.h"

#define DRIVER_NAME "mmci-pl18x"

static unsigned int fmax = 515633;

/**
 * struct variant_data - MMCI variant-specific quirks
 * @clkreg: default value for MCICLOCK register
 * @clkreg_enable: enable value for MMCICLOCK register
 * @datalength_bits: number of bits in the MMCIDATALENGTH register
 * @fifosize: number of bytes that can be written when MMCI_TXFIFOEMPTY
 *	      is asserted (likewise for RX)
 * @fifohalfsize: number of bytes that can be written when MCI_TXFIFOHALFEMPTY
 *		  is asserted (likewise for RX)
 * @sdio: variant supports SDIO
 * @st_clkdiv: true if using a ST-specific clock divider algorithm
 */
struct variant_data {
	unsigned int		clkreg;
	unsigned int		clkreg_enable;
	unsigned int		datalength_bits;
	unsigned int		fifosize;
	unsigned int		fifohalfsize;
	bool			sdio;
	bool			st_clkdiv;
};

static struct variant_data variant_arm = {
	.fifosize		= 16 * 4,
	.fifohalfsize		= 8 * 4,
	.datalength_bits	= 16,
};

static struct variant_data variant_u300 = {
	.fifosize		= 16 * 4,
	.fifohalfsize		= 8 * 4,
	.clkreg_enable		= 1 << 13, /* HWFCEN */
	.datalength_bits	= 16,
	.sdio			= true,
};

static struct variant_data variant_ux500 = {
	.fifosize		= 30 * 4,
	.fifohalfsize		= 8 * 4,
	.clkreg			= MCI_CLK_ENABLE,
	.clkreg_enable		= 1 << 14, /* HWFCEN */
	.datalength_bits	= 24,
	.sdio			= true,
	.st_clkdiv		= true,
};

/*
 * This must be called with host->lock held
 */
static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
{
	struct variant_data *variant = host->variant;
	u32 clk = variant->clkreg;

	if (desired) {
		if (desired >= host->mclk) {
			clk = MCI_CLK_BYPASS;
			host->cclk = host->mclk;
		} else if (variant->st_clkdiv) {
			/*
			 * DB8500 TRM says f = mclk / (clkdiv + 2)
			 * => clkdiv = (mclk / f) - 2
			 * Round the divider up so we don't exceed the max
			 * frequency
			 */
			clk = DIV_ROUND_UP(host->mclk, desired) - 2;
			if (clk >= 256)
				clk = 255;
			host->cclk = host->mclk / (clk + 2);
		} else {
			/*
			 * PL180 TRM says f = mclk / (2 * (clkdiv + 1))
			 * => clkdiv = mclk / (2 * f) - 1
			 */
			clk = host->mclk / (2 * desired) - 1;
			if (clk >= 256)
				clk = 255;
			host->cclk = host->mclk / (2 * (clk + 1));
		}

		clk |= variant->clkreg_enable;
		clk |= MCI_CLK_ENABLE;
		/* This hasn't proven to be worthwhile */
		/* clk |= MCI_CLK_PWRSAVE; */
	}

	if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_4)
		clk |= MCI_4BIT_BUS;
	if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_8)
		clk |= MCI_ST_8BIT_BUS;

	writel(clk, host->base + MMCICLOCK);
}

static void
mmci_request_end(struct mmci_host *host, struct mmc_request *mrq)
{
	writel(0, host->base + MMCICOMMAND);

	BUG_ON(host->data);

	host->mrq =