[PATCH v3 3/4] i2c: pasemi: Improve error recovery

[Sven Peter via B4 Relay]

From: Hector Martin <mar...@marcan.st>

Add handling for all the missing error condition, and better recovery in
pasemi_smb_clear().

Reviewed-by: Alyssa Rosenzweig <aly...@rosenzweig.io>
Reviewed-by: Neal Gompa <n...@gompa.dev>
Signed-off-by: Hector Martin <mar...@marcan.st>
Co-developed-by: Sven Peter <s...@svenpeter.dev>
Signed-off-by: Sven Peter <s...@svenpeter.dev>
---
 drivers/i2c/busses/i2c-pasemi-core.c | 61 +++++++++++++++++++++++++++++++-----
 1 file changed, 54 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pasemi-core.c 
b/drivers/i2c/busses/i2c-pasemi-core.c
index 
ee38e8a1e1f5d062384e85a2fd49d7da9257aacc..dad20ee0c6689eda309cb0374aa75b42669cbcdc
 100644
--- a/drivers/i2c/busses/i2c-pasemi-core.c
+++ b/drivers/i2c/busses/i2c-pasemi-core.c
@@ -87,12 +87,31 @@ static void pasemi_reset(struct pasemi_smbus *smbus)
        reinit_completion(&smbus->irq_completion);
 }
 
-static void pasemi_smb_clear(struct pasemi_smbus *smbus)
+static int pasemi_smb_clear(struct pasemi_smbus *smbus)
 {
        unsigned int status;
+       int ret;
 
-       status = reg_read(smbus, REG_SMSTA);
+       /* First wait for the bus to go idle */
+       ret = readx_poll_timeout(ioread32, smbus->ioaddr + REG_SMSTA,
+                                status, !(status & (SMSTA_XIP | SMSTA_JAM)),
+                                USEC_PER_MSEC,
+                                USEC_PER_MSEC * PASEMI_TRANSFER_TIMEOUT_MS);
+
+       if (ret < 0) {
+               dev_err(smbus->dev, "Bus is still stuck (status 0x%08x)\n", 
status);
+               return -EIO;
+       }
+
+       /* If any badness happened or there is data in the FIFOs, reset the 
FIFOs */
+       if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | 
SMSTA_MTN | SMSTA_MTA)) ||
+           !(status & SMSTA_MTE))
+               pasemi_reset(smbus);
+
+       /* Clear the flags */
        reg_write(smbus, REG_SMSTA, status);
+
+       return 0;
 }
 
 static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
@@ -130,9 +149,35 @@ static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
                }
        }
 
+       /* Controller timeout? */
+       if (status & SMSTA_TOM) {
+               dev_err(smbus->dev, "Controller timeout, status 0x%08x\n", 
status);
+               return -EIO;
+       }
+
+       /* Peripheral timeout? */
+       if (status & SMSTA_MTO) {
+               dev_err(smbus->dev, "Peripheral timeout, status 0x%08x\n", 
status);
+               return -ETIME;
+       }
+
+       /* Still stuck in a transaction? */
+       if (status & SMSTA_XIP) {
+               dev_err(smbus->dev, "Bus stuck, status 0x%08x\n", status);
+               return -EIO;
+       }
+
+       /* Arbitration loss? */
+       if (status & SMSTA_MTA) {
+               dev_err(smbus->dev, "Arbitration loss, status 0x%08x\n", 
status);
+               return -EBUSY;
+       }
+
        /* Got NACK? */
-       if (status & SMSTA_MTN)
+       if (status & SMSTA_MTN) {
+               dev_err(smbus->dev, "NACK, status 0x%08x\n", status);
                return -ENXIO;
+       }
 
        /* Clear XEN */
        reg_write(smbus, REG_SMSTA, SMSTA_XEN);
@@ -194,9 +239,9 @@ static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
        struct pasemi_smbus *smbus = adapter->algo_data;
        int ret, i;
 
-       pasemi_smb_clear(smbus);
-
-       ret = 0;
+       ret = pasemi_smb_clear(smbus);
+       if (ret)
+               return ret;
 
        for (i = 0; i < num && !ret; i++)
                ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));
@@ -217,7 +262,9 @@ static int pasemi_smb_xfer(struct i2c_adapter *adapter,
        addr <<= 1;
        read_flag = read_write == I2C_SMBUS_READ;
 
-       pasemi_smb_clear(smbus);
+       err = pasemi_smb_clear(smbus);
+       if (err)
+               return err;
 
        switch (size) {
        case I2C_SMBUS_QUICK:

-- 
2.34.1