[Skiboot] [PATCH] p8-i2c: Send stop bit on timeouts
Benjamin Herrenschmidt
benh at kernel.crashing.org
Thu Jan 21 13:49:21 AEDT 2016
Some devices otherwise can leave the bus in a held state. We also clean
things up a bit by using the same path as the normal error path using
a pseudo-error status bit.
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
hw/p8-i2c.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/hw/p8-i2c.c b/hw/p8-i2c.c
index 66510f1..5dd407d 100644
--- a/hw/p8-i2c.c
+++ b/hw/p8-i2c.c
@@ -140,13 +140,17 @@ DEFINE_LOG_ENTRY(OPAL_RC_I2C_RESET, OPAL_INPUT_OUTPUT_ERR_EVT, OPAL_I2C,
#define I2C_STAT_SDA_INPUT_LEVEL PPC_BIT(21)
#define I2C_STAT_PORT_BUSY PPC_BIT(22)
#define I2C_STAT_INTERFACE_BUSY PPC_BIT(23)
-#define I2C_STAT_FIFO_ENTRY_COUNT PPC_BITMASK(24, 31)
+#define I2C_STAT_FIFO_ENTRY_COUNT PPC_BITMASK(24, 31)
#define I2C_STAT_ANY_ERR (I2C_STAT_INVALID_CMD | I2C_STAT_LBUS_PARITY_ERR | \
I2C_STAT_BKEND_OVERRUN_ERR | \
I2C_STAT_BKEND_ACCESS_ERR | I2C_STAT_ARBT_LOST_ERR | \
I2C_STAT_NACK_RCVD_ERR | I2C_STAT_STOP_ERR)
+/* Pseudo-status used for timeouts */
+#define I2C_STAT_PSEUDO_TIMEOUT PPC_BIT(63)
+
+
/* I2C extended status register */
#define I2C_EXTD_STAT_REG 0xc
#define I2C_EXTD_STAT_FIFO_SIZE PPC_BITMASK(0, 7)
@@ -452,6 +456,8 @@ static void p8_i2c_translate_error(struct i2c_request *req, uint64_t status)
req->result = OPAL_I2C_ARBT_LOST;
else if (status & I2C_STAT_STOP_ERR)
req->result = OPAL_I2C_STOP_ERR;
+ else if (status & I2C_STAT_PSEUDO_TIMEOUT)
+ req->result = OPAL_I2C_TIMEOUT;
}
static void p8_i2c_status_error(struct p8_i2c_master_port *port,
@@ -461,10 +467,11 @@ static void p8_i2c_status_error(struct p8_i2c_master_port *port,
struct p8_i2c_master *master = port->master;
int rc;
- /* Display any error other than I2C_INTR_NACK_RCVD_ERR since
- * getting NACK's is normal if Linux is probing the bus
+ /* Display any error other than I2C_INTR_NACK_RCVD_ERR or
+ * timeout since getting NACK's is normal if Linux is probing
+ * the bus and timeouts will have already logged something.
*/
- if (!(status & I2C_STAT_NACK_RCVD_ERR)) {
+ if (!(status & (I2C_STAT_NACK_RCVD_ERR | I2C_STAT_PSEUDO_TIMEOUT))) {
log_simple_error(&e_info(OPAL_RC_I2C_TRANSFER),
"I2C: Transfer error occurred\n");
p8_i2c_print_debug_info(port, req);
@@ -761,9 +768,12 @@ static void p8_i2c_check_status(struct p8_i2c_master *master)
/* Handle the status in that order: errors, data requests and
* command completion.
*/
- if (status & I2C_STAT_ANY_ERR)
- p8_i2c_status_error(port, req, status);
- else if (status & I2C_STAT_DATA_REQ)
+ if (status & I2C_STAT_ANY_ERR) {
+ /* Mask status to avoid some unrelated bit overwriting
+ * our pseudo-status "timeout" bit 63
+ */
+ p8_i2c_status_error(port, req, status & I2C_STAT_ANY_ERR);
+ } else if (status & I2C_STAT_DATA_REQ)
p8_i2c_status_data_request(master, req, status);
else if (status & I2C_STAT_CMD_COMP)
p8_i2c_status_cmd_completion(master, req);
@@ -1087,12 +1097,8 @@ static void p8_i2c_timeout(struct timer *t __unused, void *data, uint64_t now)
"I2C: Request timeout !\n");
p8_i2c_print_debug_info(port, req);
- /* Reset the engine */
- p8_i2c_engine_reset(port);
-
- /* Should we send a stop ? For now just complete */
- p8_i2c_complete_request(master, req, OPAL_I2C_TIMEOUT);
-
+ /* Use the standard error path */
+ p8_i2c_status_error(port, req, I2C_STAT_PSEUDO_TIMEOUT);
exit:
unlock(&master->lock);
}
--
2.5.0
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