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authorGuennadi Liakhovetski <g.liakhovetski@gmx.de>2011-04-15 18:30:47 +0000
committerChris Ball <cjb@laptop.org>2011-05-24 23:53:50 -0400
commit3b0beafc92406b98cbc2749b8db736f313d390b1 (patch)
treed782fec514beb5dbb4281adc6d6ec28b7c5915da /drivers/mmc
parent06e8935febe687e2a561707d4c7ca4245d261dbe (diff)
downloadlinux-3b0beafc92406b98cbc2749b8db736f313d390b1.tar.bz2
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: 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>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/sh_mmcif.c50
1 files changed, 42 insertions, 8 deletions
diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index af97015a2fc7..d3871b67f77b 100644
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -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);