On a CRC error while using hardware-supported PEC, an additional error bit is set in the auxiliary status register. If this bit isn't cleared, all subsequent operations will fail, essentially hanging the controller.
The fix is simple: clear the bit at the same time we clear the error bits in the main status register. Signed-off-by: Ellen Wang <[email protected]> --- drivers/i2c/busses/i2c-i801.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 5ecbb3f..7f3331e 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -129,6 +129,10 @@ #define SMBAUXCTL_CRC 1 #define SMBAUXCTL_E32B 2 +/* Auxiliary status register bits, ICH4+ only */ +#define SMBAUXSTS_CRCE 1 +#define SMBAUXSTS_STCO 2 + /* Other settings */ #define MAX_RETRIES 400 @@ -164,6 +168,8 @@ #define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \ STATUS_ERROR_FLAGS) +#define AUXSTS_ERROR_FLAGS SMBAUXSTS_CRCE + /* Older devices have their ID defined in <linux/pci_ids.h> */ #define PCI_DEVICE_ID_INTEL_BAYTRAIL_SMBUS 0x0f12 #define PCI_DEVICE_ID_INTEL_BRASWELL_SMBUS 0x2292 @@ -509,6 +515,21 @@ static irqreturn_t i801_isr(int irq, void *dev_id) i801_isr_byte_done(priv); /* + * Clear error condition in aux status that may have come from + * a PEC error. The main status register also should be showing + * an error. That should be sufficient for reporting purposes. + */ + if (priv->features & FEATURE_SMBUS_PEC) { + u8 auxsts = inb_p(SMBAUXSTS(priv)); + + if (auxsts & AUXSTS_ERROR_FLAGS) { + dev_dbg(&priv->pci_dev->dev, "irq: auxsts = %02x\n", + auxsts); + outb_p(auxsts & AUXSTS_ERROR_FLAGS, SMBAUXSTS(priv)); + } + } + + /* * Clear irq sources and report transaction result. * ->status must be cleared before the next transaction is started. */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
