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mmc: sh_mmcif: protect against a theoretical race

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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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <damm@opensource.se>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Guennadi Liakhovetski 2011-04-15 18:30:47 +00:00 committed by Chris Ball
parent 06e8935feb
commit 3b0beafc92
1 changed files with 42 additions and 8 deletions
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50
drivers/mmc/host/sh_mmcif.c
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@ -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);