net: ipa: support retries on generic GSI commands

When stopping an AP RX channel, there can be a transient period
while the channel enters STOP_IN_PROC state before reaching the
final STOPPED state.  In that case we make another attempt to stop
the channel.

Similarly, when stopping a modem channel (using a GSI generic
command issued from the AP), it's possible that multiple attempts
will be required before the channel reaches STOPPED state.

Add a field to the GSI structure to record an errno representing the
result code provided when a generic command completes.  If the
result learned in gsi_isr_gp_int1() is RETRY, record -EAGAIN in the
result code, otherwise record 0 for success, or -EIO for any other
result.

If we time out nf gsi_generic_command() waiting for the command to
complete, return -ETIMEDOUT (as before).  Otherwise return the
result stashed by gsi_isr_gp_int1().

Add a loop in gsi_modem_channel_halt() to reissue the HALT command
if the result code indicates -EAGAIN.  Limit this to 10 retries
(after the initial attempt).

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/ipa/gsi.h b/drivers/net/ipa/gsi.h
index ecc784e3a812..96c9aed397aa 100644
--- a/drivers/net/ipa/gsi.h
+++ b/drivers/net/ipa/gsi.h
@@ -161,6 +161,7 @@ struct gsi {
 	u32 type_enabled_bitmap;	/* GSI IRQ types enabled */
 	u32 ieob_enabled_bitmap;	/* IEOB IRQ enabled (event rings) */
 	struct completion completion;	/* for global EE commands */
+	int result;			/* Negative errno (generic commands) */
 	struct mutex mutex;		/* protects commands, programming */
 };