[PATCH net-next 8/9] ptp: ocp: tolerate a latched FAILED when entering configuration mode

[Sagi Maimon]

The first status wait after EN_CFG_TP used adva_x1_cpld_wait_ready(),
which turns a set CPLD_STATUS_FAILED into -EIO.  FAILED is latched across
operations and nothing in the driver clears it - the failure path only
sends DIS_CFG - so once a part had failed an operation, every later
"devlink dev flash ... component fw.cpld" would return -EIO at the enable
step, before reaching the ERASE and REFRESH that would put the part back
into a defined state.

That contradicts the recovery this driver relies on elsewhere: the page
loop documents an aborted update as recoverable because fw.cpld stays
advertised so the image can be written again.

Use adva_x1_cpld_wait_idle(), which waits the operation out whatever its
outcome, and let the CPLD_STATUS_ENAB check that follows decide whether
the part actually entered configuration mode.  machxo2_write_init() in
drivers/fpga/machxo2-spi.c tests FAIL the same way, after the enable has
completed rather than as a precondition for it.

Fixes: a4b7c15aa78f ("ptp: ocp: add TAP CPLD flashing via devlink")
Signed-off-by: Sagi Maimon <maimon.sagi@xxxxxxxxx>
---
 drivers/ptp/ptp_ocp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 0d6d0c02882c..4f2bf54a23c2 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -5018,9 +5018,16 @@ static int adva_x1_cpld_flash(struct ptp_ocp *bp, struct devlink *devlink,
 	 */
 	bp->cpld_in_config_mode = true;
 
+	/* wait_idle(), not wait_ready(): FAILED is latched across operations
+	 * and nothing here clears it, so treating it as fatal at the enable
+	 * step would make every later flash of a part that has failed once
+	 * return -EIO before reaching the ERASE and REFRESH that put it back
+	 * into a defined state.  ENAB below is what says the enable worked;
+	 * machxo2-spi.c likewise tests FAIL only after ISC_ENABLE completes.
+	 */
 	err = adva_x1_cpld_write(bp, CPLD_CMD_EN_CFG_TP);
 	if (!err)
-		err = adva_x1_cpld_wait_ready(bp, 5000);
+		err = adva_x1_cpld_wait_idle(bp, 5000);
 	if (err)
 		goto exit_config;
 
-- 
2.47.0