Commit 3b0beafc authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
Browse files

mmc: sh_mmcif: protect against a theoretical race 



The MMC subsystem does not guarantee that host driver .request() and
.set_ios() callbacks are serialised. Such concurrent calls, however,
do not have to be meaningfully supported, drivers just have to make
sure to avoid any severe problems.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <damm@opensource.se>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 06e8935f

drivers/mmc/host/sh_mmcif.c

+42 −8
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/mmc/sh_mmcif.h>

#include <linux/pagemap.h>

#include <linux/platform_device.h>

#include <linux/spinlock.h>



#define DRIVER_NAME	"sh_mmcif"

#define DRIVER_VERSION	"2010-04-28"
@@ -153,6 +154,12 @@ 
#define CLKDEV_MMC_DATA		20000000 /* 20MHz */

#define CLKDEV_INIT		400000   /* 400 KHz */



enum mmcif_state {

	STATE_IDLE,

	STATE_REQUEST,

	STATE_IOS,

};



struct sh_mmcif_host {

	struct mmc_host *mmc;

	struct mmc_data *data;
@@ -164,6 +171,8 @@ struct sh_mmcif_host { 
	long timeout;

	void __iomem *addr;

	struct completion intr_wait;

	enum mmcif_state state;

	spinlock_t lock;



	/* DMA support */

	struct dma_chan		*chan_rx;
@@ -798,17 +807,31 @@ static void sh_mmcif_stop_cmd(struct sh_mmcif_host *host, 
static void sh_mmcif_request(struct mmc_host *mmc, struct mmc_request *mrq)

{

	struct sh_mmcif_host *host = mmc_priv(mmc);

	unsigned long flags;



	spin_lock_irqsave(&host->lock, flags);

	if (host->state != STATE_IDLE) {

		spin_unlock_irqrestore(&host->lock, flags);

		mrq->cmd->error = -EAGAIN;

		mmc_request_done(mmc, mrq);

		return;

	}



	host->state = STATE_REQUEST;

	spin_unlock_irqrestore(&host->lock, flags);



	switch (mrq->cmd->opcode) {

	/* MMCIF does not support SD/SDIO command */

	case SD_IO_SEND_OP_COND:

	case MMC_APP_CMD:

		host->state = STATE_IDLE;

		mrq->cmd->error = -ETIMEDOUT;

		mmc_request_done(mmc, mrq);

		return;

	case MMC_SEND_EXT_CSD: /* = SD_SEND_IF_COND (8) */

		if (!mrq->data) {

			/* send_if_cond cmd (not support) */

			host->state = STATE_IDLE;

			mrq->cmd->error = -ETIMEDOUT;

			mmc_request_done(mmc, mrq);

			return;
@@ -830,12 +853,9 @@ static void sh_mmcif_request(struct mmc_host *mmc, struct mmc_request *mrq) 
	sh_mmcif_start_cmd(host, mrq, mrq->cmd);

	host->data = NULL;



	if (mrq->cmd->error != 0) {

		mmc_request_done(mmc, mrq);

		return;

	}

	if (mrq->stop)

	if (!mrq->cmd->error && mrq->stop)

		sh_mmcif_stop_cmd(host, mrq, mrq->stop);

	host->state = STATE_IDLE;

	mmc_request_done(mmc, mrq);

}
@@ -843,6 +863,16 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
{

	struct sh_mmcif_host *host = mmc_priv(mmc);

	struct sh_mmcif_plat_data *p = host->pd->dev.platform_data;

	unsigned long flags;



	spin_lock_irqsave(&host->lock, flags);

	if (host->state != STATE_IDLE) {

		spin_unlock_irqrestore(&host->lock, flags);

		return;

	}



	host->state = STATE_IOS;

	spin_unlock_irqrestore(&host->lock, flags);



	if (ios->power_mode == MMC_POWER_UP) {

		if (p->set_pwr)
@@ -852,6 +882,7 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
		sh_mmcif_clock_control(host, 0);

		if (ios->power_mode == MMC_POWER_OFF && p->down_pwr)

			p->down_pwr(host->pd);

		host->state = STATE_IDLE;

		return;

	}
@@ -859,6 +890,7 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
		sh_mmcif_clock_control(host, ios->clock);



	host->bus_width = ios->bus_width;

	host->state = STATE_IDLE;

}



static int sh_mmcif_get_cd(struct mmc_host *mmc)
@@ -996,6 +1028,7 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev) 
	host->pd = pdev;



	init_completion(&host->intr_wait);

	spin_lock_init(&host->lock);



	mmc->ops = &sh_mmcif_ops;

	mmc->f_max = host->clk;
@@ -1025,6 +1058,8 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev) 


	mmc_add_host(mmc);



	sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);



	ret = request_irq(irq[0], sh_mmcif_intr, 0, "sh_mmc:error", host);

	if (ret) {

		dev_err(&pdev->dev, "request_irq error (sh_mmc:error)\n");
@@ -1037,7 +1072,6 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev) 
		goto clean_up2;

	}



	sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);

	sh_mmcif_detect(host->mmc);



	dev_info(&pdev->dev, "driver version %s\n", DRIVER_VERSION);
@@ -1063,11 +1097,11 @@ static int __devexit sh_mmcif_remove(struct platform_device *pdev) 
	mmc_remove_host(host->mmc);

	sh_mmcif_release_dma(host);



	sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);



	if (host->addr)

		iounmap(host->addr);



	sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);



	irq[0] = platform_get_irq(pdev, 0);

	irq[1] = platform_get_irq(pdev, 1);

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