[PATCH linux dev-4.7 v2 5/7] drivers/fsi: Add retry on bus error detect

[Christopher Bostic]

After each gpio master read/write check for bus errors.  If
errors detected then clean it up and retry the original operation
again.  If second attempt succeeds then don't report original
error to caller.

Signed-off-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>
---
 drivers/fsi/fsi-core.c        |  4 ++++
 drivers/fsi/fsi-master-gpio.c | 24 ++++++++++++++++++++++--
 drivers/fsi/fsi-master.h      |  3 +++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index 360c02a..428675f 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -639,6 +639,10 @@ static int fsi_master_break(struct fsi_master *master, int link)
 	return 0;
 }
 
+void fsi_master_handle_error(struct fsi_master *master, uint32_t addr)
+{
+}
+
 static int fsi_master_scan(struct fsi_master *master)
 {
 	int link, slave_id, rc;
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
index 8aec538..5b502eb 100644
--- a/drivers/fsi/fsi-master-gpio.c
+++ b/drivers/fsi/fsi-master-gpio.c
@@ -381,7 +381,17 @@ static int fsi_master_gpio_read(struct fsi_master *_master, int link,
 		return -ENODEV;
 
 	build_abs_ar_command(&cmd, FSI_GPIO_CMD_READ, slave, addr, size, NULL);
-	return send_command(master, &cmd, FSI_GPIO_RESP_ACKD, size, val);
+	rc = send_command(master, &cmd, FSI_GPIO_RESP_ACKD, size, val);
+	if (rc) {
+		fsi_master_handle_error(&master->master, addr);
+
+		/* Try again */
+		rc = send_command(master, &cmd, FSI_GPIO_RESP_ACKD, size, val);
+		if (rc)
+			fsi_master_handle_error(&master->master, addr);
+	}
+
+	return rc;
 }
 
 static int fsi_master_gpio_write(struct fsi_master *_master, int link,
@@ -395,7 +405,17 @@ static int fsi_master_gpio_write(struct fsi_master *_master, int link,
 		return -ENODEV;
 
 	build_abs_ar_command(&cmd, FSI_GPIO_CMD_WRITE, slave, addr, size, val);
-	return send_command(master, &cmd, FSI_GPIO_RESP_ACK, size, NULL);
+	rc = send_command(master, &cmd, FSI_GPIO_RESP_ACK, size, NULL);
+	if (rc) {
+		fsi_master_handle_error(&master->master, addr);
+
+		/* Try again */
+		rc = send_command(master, &cmd, FSI_GPIO_RESP_ACK, size, NULL);
+		if (rc)
+			fsi_master_handle_error(&master->master, addr);
+	}
+
+	return rc;
 }
 
 /*
diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
index 4a3176b..4ed416c 100644
--- a/drivers/fsi/fsi-master.h
+++ b/drivers/fsi/fsi-master.h
@@ -19,6 +19,8 @@
 
 #include <linux/device.h>
 
+#include "fsi-master.h"
+
 /* Control Registers */
 #define FSI_MMODE		0x0		/* R/W: mode */
 #define FSI_MDLYR		0x4		/* R/W: delay */
@@ -85,6 +87,7 @@ struct fsi_master {
 extern int fsi_master_register(struct fsi_master *master);
 extern void fsi_master_unregister(struct fsi_master *master);
 extern int fsi_master_start_ipoll(struct fsi_master *master);
+extern void fsi_master_handle_error(struct fsi_master *master, uint32_t addr);
 
 /**
  * crc4 helper: Given a starting crc4 state @c, calculate the crc4 vaue of @x,
-- 
1.8.2.2