From bbb27fc33d44e7b8d96369810654df4ee1837566 Mon Sep 17 00:00:00 2001 From: Ricardo Ribalda Date: Thu, 2 Feb 2017 20:15:16 +0100 Subject: 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 Signed-off-by: Ricardo Ribalda Delgado Signed-off-by: Jean Delvare Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-piix4.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c index 73cc679..c21ca7b 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; } -- cgit v1.1