diff options
| author | Ricardo Ribalda <ricardo.ribalda@gmail.com> | 2017-05-23 21:53:44 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-17 06:41:50 +0200 |
| commit | c1a4306f24a092f55ee9bbdff0c0a8741e9c833c (patch) | |
| tree | 69ac1e24fbacc8241a05005a057a1fac2b7db642 /drivers/i2c | |
| parent | 7a6fcf38fabb404dd6fa589fa257c104c217c662 (diff) | |
i2c: piix4: Request the SMBUS semaphore inside the mutex
[ Upstream commit bbb27fc33d44e7b8d96369810654df4ee1837566 ]
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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-piix4.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c index e34d82e79b98..1250e5bc46b7 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; } |