mmc.c

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/*
 *  linux/drivers/mmc/mmc.c
 *
 *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
 *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
 *  SD support Copyright (C) 2005 Pierre Ossman, All Rights Reserved.
 *  MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
 *
 * 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/init.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <asm/scatterlist.h>
#include <linux/scatterlist.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/protocol.h>

#include "mmc.h"

#define CMD_RETRIES	3

/*
 * OCR Bit positions to 10s of Vdd mV.
 */
static const unsigned short mmc_ocr_bit_to_vdd[] = {
	150,	155,	160,	165,	170,	180,	190,	200,
	210,	220,	230,	240,	250,	260,	270,	280,
	290,	300,	310,	320,	330,	340,	350,	360
};

static const unsigned int tran_exp[] = {
	10000,		100000,		1000000,	10000000,
	0,		0,		0,		0
};

static const unsigned char tran_mant[] = {
	0,	10,	12,	13,	15,	20,	25,	30,
	35,	40,	45,	50,	55,	60,	70,	80,
};

static const unsigned int tacc_exp[] = {
	1,	10,	100,	1000,	10000,	100000,	1000000, 10000000,
};

static const unsigned int tacc_mant[] = {
	0,	10,	12,	13,	15,	20,	25,	30,
	35,	40,	45,	50,	55,	60,	70,	80,
};


/**
 *	mmc_request_done - finish processing an MMC request
 *	@host: MMC host which completed request
 *	@mrq: MMC request which request
 *
 *	MMC drivers should call this function when they have completed
 *	their processing of a request.
 */
void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
	struct mmc_command *cmd = mrq->cmd;
	int err = cmd->error;

	pr_debug("%s: req done (CMD%u): %d/%d/%d: %08x %08x %08x %08x\n",
		 mmc_hostname(host), cmd->opcode, err,
		 mrq->data ? mrq->data->error : 0,
		 mrq->stop ? mrq->stop->error : 0,
		 cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]);

	if (err && cmd->retries) {
		cmd->retries--;
		cmd->error = 0;
		host->ops->request(host, mrq);
	} else if (mrq->done) {
		mrq->done(mrq);
	}
}

EXPORT_SYMBOL(mmc_request_done);

/**
 *	mmc_start_request - start a command on a host
 *	@host: MMC host to start command on
 *	@mrq: MMC request to start
 *
 *	Queue a command on the specified host.  We expect the
 *	caller to be holding the host lock with interrupts disabled.
 */
void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
	pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
		 mmc_hostname(host), mrq->cmd->opcode,
		 mrq->cmd->arg, mrq->cmd->flags);

	WARN_ON(host->card_busy == NULL);

	mrq->cmd->error = 0;
	mrq->cmd->mrq = mrq;
	if (mrq->data) {
		mrq->cmd->data = mrq->data;
		mrq->data->error = 0;
		mrq->data->mrq = mrq;
		if (mrq->stop) {
			mrq->data->stop = mrq->stop;
			mrq->stop->error = 0;
			mrq->stop->mrq = mrq;
		}
	}
	host->ops->request(host, mrq);
}

EXPORT_SYMBOL(mmc_start_request);

static void mmc_wait_done(struct mmc_request *mrq)
{
	complete(mrq->done_data);
}

int mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
	DECLARE_COMPLETION_ONSTACK(complete);

	mrq->done_data = &complete;
	mrq->done = mmc_wait_done;

	mmc_start_request(host, mrq);

	wait_for_completion(&complete);

	return 0;
}

EXPORT_SYMBOL(mmc_wait_for_req);

/**
 *	mmc_wait_for_cmd - start a command and wait for completion
 *	@host: MMC host to start command
 *	@cmd: MMC command to start
 *	@retries: maximum number of retries
 *
 *	Start a new MMC command for a host, and wait for the command
 *	to complete.  Return any error that occurred while the command
 *	was executing.  Do not attempt to parse the response.
 */
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
	struct mmc_request mrq;

	BUG_ON(host->card_busy == NULL);

	memset(&mrq, 0, sizeof(struct mmc_request));

	memset(cmd->resp, 0, sizeof(cmd->resp));
	cmd->retries = retries;

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

	mmc_wait_for_req(host, &mrq);

	return cmd->error;
}

EXPORT_SYMBOL(mmc_wait_for_cmd);

/**
 *	mmc_wait_for_app_cmd - start an application command and wait for
 			       completion
 *	@host: MMC host to start command
 *	@rca: RCA to send MMC_APP_CMD to
 *	@cmd: MMC command to start
 *	@retries: maximum number of retries
 *
 *	Sends a MMC_APP_CMD, checks the card response, sends the command
 *	in the parameter and waits for it to complete. Return any error
 *	that occurred while the command was executing.  Do not attempt to
 *	parse the response.
 */
int mmc_wait_for_app_cmd(struct mmc_host *host, unsigned int rca,
	struct mmc_command *cmd, int retries)
{
	struct mmc_request mrq;
	struct mmc_command appcmd;

	int i, err;

	BUG_ON(host->card_busy == NULL);
	BUG_ON(retries < 0);

	err = MMC_ERR_INVALID;

	/*
	 * We have to resend MMC_APP_CMD for each attempt so
	 * we cannot use the retries field in mmc_command.
	 */
	for (i = 0;i <= retries;i++) {
		memset(&mrq, 0, sizeof(struct mmc_request));

		appcmd.opcode = MMC_APP_CMD;
		appcmd.arg = rca << 16;
		appcmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
		appcmd.retries = 0;
		memset(appcmd.resp, 0, sizeof(appcmd.resp));
		appcmd.data = NULL;

		mrq.cmd = &appcmd;
		appcmd.data = NULL;

		mmc_wait_for_req(host, &mrq);

		if (appcmd.error) {
			err = appcmd.error;
			continue;
		}

		/* Check that card supported application commands */
		if (!(appcmd.resp[0] & R1_APP_CMD))
			return MMC_ERR_FAILED;

		memset(&mrq, 0, sizeof(struct mmc_request));

		memset(cmd->resp, 0, sizeof(cmd->resp));
		cmd->retries = 0;

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

		mmc_wait_for_req(host, &mrq);

		err = cmd->error;
		if (cmd->error == MMC_ERR_NONE)
			break;
	}

	return err;
}

EXPORT_SYMBOL(mmc_wait_for_app_cmd);

/**
 *	mmc_set_data_timeout - set the timeout for a data command
 *	@data: data phase for command
 *	@card: the MMC card associated with the data transfer
 *	@write: flag to differentiate reads from writes
 */
void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card,
			  int write)
{
	unsigned int mult;

	/*
	 * SD cards use a 100 multiplier rather than 10
	 */
	mult = mmc_card_sd(card) ? 100 : 10;

	/*
	 * Scale up the multiplier (and therefore the timeout) by
	 * the r2w factor for writes.
	 */
	if (write)
		mult <<= card->csd.r2w_factor;

	data->timeout_ns = card->csd.tacc_ns * mult;
	data->timeout_clks = card->csd.tacc_clks * mult;

	/*
	 * SD cards also have an upper limit on the timeout.
	 */
	if (mmc_card_sd(card)) {
		unsigned int timeout_us, limit_us;

		timeout_us = data->timeout_ns / 1000;
		timeout_us += data->timeout_clks * 1000 /
			(card->host->ios.clock / 1000);

		if (write)
			limit_us = 250000;
		else
			limit_us = 100000;

		if (timeout_us > limit_us) {
			data->timeout_ns = limit_us * 1000;
			data->timeout_clks = 0;
		}
	}
}
EXPORT_SYMBOL(mmc_set_data_timeout);

static int mmc_select_card(struct mmc_host *host, struct mmc_card *card);

/**
 *	__mmc_claim_host - exclusively claim a host
 *	@host: mmc host to claim
 *	@card: mmc card to claim host for
 *
 *	Claim a host for a set of operations.  If a valid card
 *	is passed and this wasn't the last card selected, select
 *	the card before returning.
 *
 *	Note: you should use mmc_card_claim_host or mmc_claim_host.
 */
int __mmc_claim_host(struct mmc_host *host, struct mmc_card *card)
{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long flags;
	int err = 0;

	add_wait_queue(&host->wq, &wait);
	spin_lock_irqsave(&host->lock, flags);
	while (1) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (host->card_busy == NULL)
			break;
		spin_unlock_irqrestore(&host->lock, flags);
		schedule();
		spin_lock_irqsave(&host->lock, flags);
	}
	set_current_state(TASK_RUNNING);
	host->card_busy = card;
	spin_unlock_irqrestore(&host->lock, flags);
	remove_wait_queue(&host->wq, &wait);

	if (card != (void *)-1) {
		err = mmc_select_card(host, card);
		if (err != MMC_ERR_NONE)
			return err;
	}

	return err;
}

EXPORT_SYMBOL(__mmc_claim_host);

/**
 *	mmc_release_host - release a host
 *	@host: mmc host to release
 *
 *	Release a MMC host, allowing others to claim the host
 *	for their operations.
 */
void mmc_release_host(struct mmc_host *host)
{
	unsigned long flags;

	BUG_ON(host->card_busy == NULL);

	spin_lock_irqsave(&host->lock, flags);
	host->card_busy = NULL;
	spin_unlock_irqrestore(&host->lock, flags);

	wake_up(&host->wq);
}

EXPORT_SYMBOL(mmc_release_host);

static inline void mmc_set_ios(struct mmc_host *host)
{
	struct mmc_ios *ios = &host->ios;

	pr_debug("%s: clock %uHz busmode %u powermode %u cs %u Vdd %u width %u\n",
		 mmc_hostname(host), ios->clock, ios->bus_mode,
		 ios->power_mode, ios->chip_select, ios->vdd,
		 ios->bus_width);
	
	host->ops->set_ios(host, ios);
}

static int mmc_select_card(struct mmc_host *host, struct mmc_card *card)
{
	int err;
	struct mmc_command cmd;

	BUG_ON(host->card_busy == NULL);

	if (host->card_selected == card)
		return MMC_ERR_NONE;

	host->card_selected = card;

	cmd.opcode = MMC_SELECT_CARD;
	cmd.arg = card->rca << 16;
	cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;

	err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
	if (err != MMC_ERR_NONE)
		return err;

	/*
	 * We can only change the bus width of SD cards when
	 * they are selected so we have to put the handling
	 * here.
	 *
	 * The card is in 1 bit mode by default so
	 * we only need to change if it supports the
	 * wider version.
	 */
	if (mmc_card_sd(card) &&
		(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {

		/*
		* Default bus width is 1 bit.
		*/
		host->ios.bus_width = MMC_BUS_WIDTH_1;

		if (host->caps & MMC_CAP_4_BIT_DATA) {
			struct mmc_command cmd;
			cmd.opcode = SD_APP_SET_BUS_WIDTH;
			cmd.arg = SD_BUS_WIDTH_4;
			cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;

			err = mmc_wait_for_app_cmd(host, card->rca, &cmd,
				CMD_RETRIES);
			if (err != MMC_ERR_NONE)
				return err;

			host->ios.bus_width = MMC_BUS_WIDTH_4;
		}
	}

	mmc_set_ios(host);

	return MMC_ERR_NONE;
}

/*
 * Ensure that no card is selected.
 */
static void mmc_deselect_cards(struct mmc_host *host)
{
	struct mmc_command cmd;

	if (host->card_selected) {
		host->card_selected = NULL;

		cmd.opcode = MMC_SELECT_CARD;
		cmd.arg = 0;
		cmd.flags = MMC_RSP_NONE | MMC_CMD_AC;

		mmc_wait_for_cmd(host, &cmd, 0);
	}
}


static inline void mmc_delay(unsigned int ms)
{
	if (ms < 1000 / HZ) {
		cond_resched();
		mdelay(ms);
	} else {
		msleep(ms);
	}
}

/*
 * Mask off any voltages we don't support and select
 * the lowest voltage
 */
static u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
{
	int bit;

	ocr &= host->ocr_avail;

	bit = ffs(ocr);
	if (bit) {
		bit -= 1;

		ocr &= 3 << bit;

		host->ios.vdd = bit;
		mmc_set_ios(host);
	} else {
		ocr = 0;
	}

	return ocr;
}

#define UNSTUFF_BITS(resp,start,size)					\
	({								\
		const int __size = size;				\
		const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1;	\
		const int __off = 3 - ((start) / 32);			\
		const int __shft = (start) & 31;			\
		u32 __res;						\
									\
		__res = resp[__off] >> __shft;				\
		if (__size + __shft > 32)				\
			__res |= resp[__off-1] << ((32 - __shft) % 32);	\
		__res & __mask;						\
	})

/*
 * Given the decoded CSD structure, decode the raw CID to our CID structure.
 */
static void mmc_decode_cid(struct mmc_card *card)
{
	u32 *resp = card->raw_cid;

	memset(&card->cid, 0, sizeof(struct mmc_cid));

	if (mmc_card_sd(card)) {
		/*
		 * SD doesn't currently have a version field so we will
		 * have to assume we can parse this.
		 */
		card->cid.manfid		= UNSTUFF_BITS(resp, 120, 8);
		card->cid.oemid			= UNSTUFF_BITS(resp, 104, 16);
		card->cid.prod_name[0]		= UNSTUFF_BITS(resp, 96, 8);
		card->cid.prod_name[1]		= UNSTUFF_BITS(resp, 88, 8);
		card->cid.prod_name[2]		= UNSTUFF_BITS(resp, 80, 8);
		card->cid.prod_name[3]		= UNSTUFF_BITS(resp, 72, 8);
		card->cid.prod_name[4]		= UNSTUFF_BITS(resp, 64, 8);
		card->cid.hwrev			= UNSTUFF_BITS(resp, 60, 4);
		card->cid.fwrev			= UNSTUFF_BITS(resp, 56, 4);
		card->cid.serial		= UNSTUFF_BITS(resp, 24, 32);
		card->cid.year			= UNSTUFF_BITS(resp, 12, 8);
		card->cid.month			= UNSTUFF_BITS(resp, 8, 4);

		card->cid.year += 2000; /* SD cards year offset */
	} else {
		/*
		 * The selection of the format here is based upon published
		 * specs from sandisk and from what people have reported.
		 */
		switch (card->csd.mmca_vsn) {
		case 0: /* MMC v1.0 - v1.2 */
		case 1: /* MMC v1.4 */
			card->cid.manfid	= UNSTUFF_BITS(resp, 104, 24);
			card->cid.prod_name[0]	= UNSTUFF_BITS(resp, 96, 8);