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authorRicardo Ribalda <ricardo.ribalda@gmail.com>2017-02-02 20:15:16 +0100
committerWolfram Sang <wsa@the-dreams.de>2017-02-09 17:13:01 +0100
commitbbb27fc33d44e7b8d96369810654df4ee1837566 (patch)
treeb769e165ad52c0021054f1a048b62bd7e4fbec47 /drivers/i2c
parenti2c: piix4: Fix request_region size (diff)
downloadlinux-bbb27fc33d44e7b8d96369810654df4ee1837566.tar.xz
linux-bbb27fc33d44e7b8d96369810654df4ee1837566.zip
i2c: piix4: Request the SMBUS semaphore inside the mutex
SMBSLVCNT must be protected with the piix4_mutex_sb800 in order to avoid multiple buses accessing to the semaphore at the same time. Fixes: 701dc207bf55 ("i2c: piix4: Avoid race conditions with IMC") Reported-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-piix4.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 73cc6799cc59..c21ca7bf2efe 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -592,6 +592,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
u8 port;
int retval;
+ mutex_lock(&piix4_mutex_sb800);
+
/* Request the SMBUS semaphore, avoid conflicts with the IMC */
smbslvcnt = inb_p(SMBSLVCNT);
do {
@@ -605,10 +607,10 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
usleep_range(1000, 2000);
} while (--retries);
/* SMBus is still owned by the IMC, we give up */
- if (!retries)
+ if (!retries) {
+ mutex_unlock(&piix4_mutex_sb800);
return -EBUSY;
-
- mutex_lock(&piix4_mutex_sb800);
+ }
outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
@@ -623,11 +625,11 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
- mutex_unlock(&piix4_mutex_sb800);
-
/* Release the semaphore */
outb_p(smbslvcnt | 0x20, SMBSLVCNT);
+ mutex_unlock(&piix4_mutex_sb800);
+
return retval;
}