fsi/fsi-master-gpio: Implement CRC error recovery

The FSI protocol defines two modes of recovery from CRC errors,
this implements both:

 - If the device returns an ECRC (it detected a CRC error in the
   command), then we simply issue the command again.

 - If the master detects a CRC error in the response, we send
   an E_POLL command which requests a resend of the response
   without actually re-executing the command (which could otherwise
   have unwanted side effects such as dequeuing a FIFO twice).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
---

Note: This was actually tested by removing some of my fixes, thus
causing us to hit occasional CRC errors during high LPC activity.

1 files changed, 27 insertions, 0 deletions

diff --git a/include/trace/events/fsi_master_gpio.h b/include/trace/events/fsi_master_gpio.h
index 33e928c5acf3..389082132433 100644
--- a/include/trace/events/fsi_master_gpio.h
+++ b/include/trace/events/fsi_master_gpio.h
@@ -64,6 +64,33 @@ TRACE_EVENT(fsi_master_gpio_break,
         )
 );
 
+TRACE_EVENT(fsi_master_gpio_crc_cmd_error,
+        TP_PROTO(const struct fsi_master_gpio *master),
+        TP_ARGS(master),
+        TP_STRUCT__entry(
+                __field(int,    master_idx)
+        ),
+        TP_fast_assign(
+                __entry->master_idx = master->master.idx;
+        ),
+        TP_printk("fsi-gpio%d ----CRC command retry---",
+                __entry->master_idx
+        )
+);
+
+TRACE_EVENT(fsi_master_gpio_crc_rsp_error,
+        TP_PROTO(const struct fsi_master_gpio *master),
+        TP_ARGS(master),
+        TP_STRUCT__entry(
+                __field(int,    master_idx)
+        ),
+        TP_fast_assign(
+                __entry->master_idx = master->master.idx;
+        ),
+        TP_printk("fsi-gpio%d ----CRC response---",
+                __entry->master_idx
+        )
+);
 
 TRACE_EVENT(fsi_master_gpio_poll_response_busy,
         TP_PROTO(const struct fsi_master_gpio *master, int busy),