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: 701dc207bf
("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>
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@ -592,6 +592,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
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u8 port;
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int retval;
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mutex_lock(&piix4_mutex_sb800);
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/* Request the SMBUS semaphore, avoid conflicts with the IMC */
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smbslvcnt = inb_p(SMBSLVCNT);
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do {
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@ -605,10 +607,10 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
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usleep_range(1000, 2000);
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} while (--retries);
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/* SMBus is still owned by the IMC, we give up */
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if (!retries)
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if (!retries) {
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mutex_unlock(&piix4_mutex_sb800);
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return -EBUSY;
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mutex_lock(&piix4_mutex_sb800);
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}
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outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
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smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
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@ -623,11 +625,11 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
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outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
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mutex_unlock(&piix4_mutex_sb800);
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/* Release the semaphore */
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outb_p(smbslvcnt | 0x20, SMBSLVCNT);
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mutex_unlock(&piix4_mutex_sb800);
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return retval;
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}
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