[PATCH] i2c: iproc: handle invalid slave state
roman.bacik at broadcom.com
roman.bacik at broadcom.com
Thu Aug 24 14:23:51 PDT 2023
From: Roman Bacik <roman.bacik at broadcom.com>
Add the code to handle an invalid state when both bits S_RX_EVENT
(indicating a transaction) and S_START_BUSY (indicating the end
of transaction - transition of START_BUSY from 1 to 0) are set in
the interrupt status register during a slave read.
Signed-off-by: Roman Bacik <roman.bacik at broadcom.com>
Fixes: 1ca1b4516088 ("i2c: iproc: handle Master aborted error")
---
drivers/i2c/busses/i2c-bcm-iproc.c | 133 ++++++++++++++++-------------
1 file changed, 75 insertions(+), 58 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
index 05c80680dff4..68438d4e5d73 100644
--- a/drivers/i2c/busses/i2c-bcm-iproc.c
+++ b/drivers/i2c/busses/i2c-bcm-iproc.c
@@ -316,26 +316,44 @@ static void bcm_iproc_i2c_slave_init(
iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
}
-static void bcm_iproc_i2c_check_slave_status(
- struct bcm_iproc_i2c_dev *iproc_i2c)
+static bool bcm_iproc_i2c_check_slave_status
+ (struct bcm_iproc_i2c_dev *iproc_i2c, u32 status)
{
u32 val;
+ bool recover = false;
- val = iproc_i2c_rd_reg(iproc_i2c, S_CMD_OFFSET);
- /* status is valid only when START_BUSY is cleared after it was set */
- if (val & BIT(S_CMD_START_BUSY_SHIFT))
- return;
+ /* check slave transmit status only if slave is transmitting */
+ if (!iproc_i2c->slave_rx_only) {
+ val = iproc_i2c_rd_reg(iproc_i2c, S_CMD_OFFSET);
+ /* status is valid only when START_BUSY is cleared */
+ if (!(val & BIT(S_CMD_START_BUSY_SHIFT))) {
+ val = (val >> S_CMD_STATUS_SHIFT) & S_CMD_STATUS_MASK;
+ if (val == S_CMD_STATUS_TIMEOUT ||
+ val == S_CMD_STATUS_MASTER_ABORT) {
+ dev_warn(iproc_i2c->device,
+ (val == S_CMD_STATUS_TIMEOUT) ?
+ "slave random stretch time timeout\n" :
+ "Master aborted read transaction\n");
+ recover = true;
+ }
+ }
+ }
+
+ /* RX_EVENT is not valid when START_BUSY is set */
+ if ((status & BIT(IS_S_RX_EVENT_SHIFT)) &&
+ (status & BIT(IS_S_START_BUSY_SHIFT))) {
+ dev_warn(iproc_i2c->device, "Slave aborted read transaction\n");
+ recover = true;
+ }
- val = (val >> S_CMD_STATUS_SHIFT) & S_CMD_STATUS_MASK;
- if (val == S_CMD_STATUS_TIMEOUT || val == S_CMD_STATUS_MASTER_ABORT) {
- dev_err(iproc_i2c->device, (val == S_CMD_STATUS_TIMEOUT) ?
- "slave random stretch time timeout\n" :
- "Master aborted read transaction\n");
+ if (recover) {
/* re-initialize i2c for recovery */
bcm_iproc_i2c_enable_disable(iproc_i2c, false);
bcm_iproc_i2c_slave_init(iproc_i2c, true);
bcm_iproc_i2c_enable_disable(iproc_i2c, true);
}
+
+ return recover;
}
static void bcm_iproc_i2c_slave_read(struct bcm_iproc_i2c_dev *iproc_i2c)
@@ -420,48 +438,6 @@ static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
u32 val;
u8 value;
- /*
- * Slave events in case of master-write, master-write-read and,
- * master-read
- *
- * Master-write : only IS_S_RX_EVENT_SHIFT event
- * Master-write-read: both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT
- * events
- * Master-read : both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT
- * events or only IS_S_RD_EVENT_SHIFT
- *
- * iproc has a slave rx fifo size of 64 bytes. Rx fifo full interrupt
- * (IS_S_RX_FIFO_FULL_SHIFT) will be generated when RX fifo becomes
- * full. This can happen if Master issues write requests of more than
- * 64 bytes.
- */
- if (status & BIT(IS_S_RX_EVENT_SHIFT) ||
- status & BIT(IS_S_RD_EVENT_SHIFT) ||
- status & BIT(IS_S_RX_FIFO_FULL_SHIFT)) {
- /* disable slave interrupts */
- val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
- val &= ~iproc_i2c->slave_int_mask;
- iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
-
- if (status & BIT(IS_S_RD_EVENT_SHIFT))
- /* Master-write-read request */
- iproc_i2c->slave_rx_only = false;
- else
- /* Master-write request only */
- iproc_i2c->slave_rx_only = true;
-
- /* schedule tasklet to read data later */
- tasklet_schedule(&iproc_i2c->slave_rx_tasklet);
-
- /*
- * clear only IS_S_RX_EVENT_SHIFT and
- * IS_S_RX_FIFO_FULL_SHIFT interrupt.
- */
- val = BIT(IS_S_RX_EVENT_SHIFT);
- if (status & BIT(IS_S_RX_FIFO_FULL_SHIFT))
- val |= BIT(IS_S_RX_FIFO_FULL_SHIFT);
- iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, val);
- }
if (status & BIT(IS_S_TX_UNDERRUN_SHIFT)) {
iproc_i2c->tx_underrun++;
@@ -493,8 +469,9 @@ static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
* less than PKT_LENGTH bytes were output on the SMBUS
*/
iproc_i2c->slave_int_mask &= ~BIT(IE_S_TX_UNDERRUN_SHIFT);
- iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET,
- iproc_i2c->slave_int_mask);
+ val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
+ val &= ~BIT(IE_S_TX_UNDERRUN_SHIFT);
+ iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
/* End of SMBUS for Master Read */
val = BIT(S_TX_WR_STATUS_SHIFT);
@@ -515,9 +492,49 @@ static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
BIT(IS_S_START_BUSY_SHIFT));
}
- /* check slave transmit status only if slave is transmitting */
- if (!iproc_i2c->slave_rx_only)
- bcm_iproc_i2c_check_slave_status(iproc_i2c);
+ /* if the controller has been reset, immediately return from the ISR */
+ if (bcm_iproc_i2c_check_slave_status(iproc_i2c, status))
+ return true;
+
+ /*
+ * Slave events in case of master-write, master-write-read and,
+ * master-read
+ *
+ * Master-write : only IS_S_RX_EVENT_SHIFT event
+ * Master-write-read: both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT
+ * events
+ * Master-read : both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT
+ * events or only IS_S_RD_EVENT_SHIFT
+ *
+ * iproc has a slave rx fifo size of 64 bytes. Rx fifo full interrupt
+ * (IS_S_RX_FIFO_FULL_SHIFT) will be generated when RX fifo becomes
+ * full. This can happen if Master issues write requests of more than
+ * 64 bytes.
+ */
+ if (status & BIT(IS_S_RX_EVENT_SHIFT) ||
+ status & BIT(IS_S_RD_EVENT_SHIFT) ||
+ status & BIT(IS_S_RX_FIFO_FULL_SHIFT)) {
+ /* disable slave interrupts */
+ val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
+ val &= ~iproc_i2c->slave_int_mask;
+ iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
+
+ if (status & BIT(IS_S_RD_EVENT_SHIFT))
+ /* Master-write-read request */
+ iproc_i2c->slave_rx_only = false;
+ else
+ /* Master-write request only */
+ iproc_i2c->slave_rx_only = true;
+
+ /* schedule tasklet to read data later */
+ tasklet_schedule(&iproc_i2c->slave_rx_tasklet);
+
+ /* clear IS_S_RX_FIFO_FULL_SHIFT interrupt */
+ if (status & BIT(IS_S_RX_FIFO_FULL_SHIFT)) {
+ val = BIT(IS_S_RX_FIFO_FULL_SHIFT);
+ iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, val);
+ }
+ }
return true;
}
--
2.41.0
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