[PATCH linux dev-4.10 v4 27/31] drivers: fsi: occ: Poll while receiving "command in progress"

[Eddie James <eajames@linux.vnet.ibm.com>]

From: "Edward A. James" <eajames@us.ibm.com>

Waiting for OCC to return something other than "command in progress"
should only be done in the worker function, instead of clients repeating
the entire transfer when they receive "command in progress." In this way
clients don't have to check for that return status.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
---
 drivers/fsi/occ.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/fsi/occ.c b/drivers/fsi/occ.c
index 3e27307..bd0ad98 100644
--- a/drivers/fsi/occ.c
+++ b/drivers/fsi/occ.c
@@ -23,6 +23,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/uaccess.h>
@@ -33,6 +34,9 @@
 #define OCC_CMD_DATA_BYTES	4090
 #define OCC_RESP_DATA_BYTES	4089
 
+#define OCC_TIMEOUT_MS		1000
+#define OCC_CMD_IN_PRG_WAIT_MS	50
+
 struct occ {
 	struct device *sbefifo;
 	char name[32];
@@ -588,6 +592,9 @@ static void occ_worker(struct work_struct *work)
 {
 	int rc = 0, empty, waiting, canceled;
 	u16 resp_data_length;
+	unsigned long start;
+	const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
+	const long int wait_time = msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
 	struct occ_xfr *xfr;
 	struct occ_response *resp;
 	struct occ_client *client;
@@ -609,6 +616,8 @@ static void occ_worker(struct work_struct *work)
 	spin_unlock_irq(&occ->list_lock);
 	mutex_lock(&occ->occ_lock);
 
+	start = jiffies;
+
 	/* write occ command */
 	rc = occ_putsram(sbefifo, 0xFFFBE000, xfr->buf,
 			 xfr->cmd_data_length);
@@ -620,9 +629,21 @@ static void occ_worker(struct work_struct *work)
 		goto done;
 
 	/* read occ response */
-	rc = occ_getsram(sbefifo, 0xFFFBF000, xfr->buf, 8);
-	if (rc)
-		goto done;
+	do {
+		rc = occ_getsram(sbefifo, 0xFFFBF000, xfr->buf, 8);
+		if (rc)
+			goto done;
+
+		if (resp->return_status == OCC_RESP_CMD_IN_PRG) {
+			rc = -EALREADY;
+
+			if (time_after(jiffies, start + timeout))
+				break;
+
+			set_current_state(TASK_INTERRUPTIBLE);
+			schedule_timeout(wait_time);
+		}
+	} while (rc);
 
 	resp_data_length = get_unaligned_be16(&resp->data_length);
 	if (resp_data_length > OCC_RESP_DATA_BYTES) {
-- 
1.8.3.1