[PATCH v2] fpga: stratix10-soc: Fix SVC mailbox handling during reconfiguration

From: Tien Sung Ang <[email protected]>

Fix incorrect stratix10_svc_done() usage during FPGA reconfiguration.

Do not call stratix10_svc_done() at the end of write_init() on success, so
the SVC session remains active through write() and write_complete(). Call
stratix10_svc_done() on failure in write_init() and write() so the shared
SVC mailbox is released when reconfiguration aborts, allowing coexistence
with other SVC clients such as soc64-hwmon.

Fixes: e7eef1d7633a ("fpga: add intel stratix10 soc fpga manager driver")
Cc: [email protected] # 5.1+

Signed-off-by: Tien Sung Ang <[email protected]>
Signed-off-by: Tze Yee Ng <[email protected]>
---
Changes in v2:
- Add Fixes: e7eef1d7633a per maintainer review; the incorrect
  stratix10_svc_done() call in write_init() dates to the initial driver.
- Add Cc: [email protected] # 5.1+ for stable backport consideration.
- No code changes from v1.
---
 drivers/fpga/stratix10-soc.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/fpga/stratix10-soc.c b/drivers/fpga/stratix10-soc.c
index 0a295ccf1644..0d07d303bad1 100644
--- a/drivers/fpga/stratix10-soc.c
+++ b/drivers/fpga/stratix10-soc.c
@@ -195,20 +195,20 @@ static int s10_ops_write_init(struct fpga_manager *mgr,
 	ret = s10_svc_send_msg(priv, COMMAND_RECONFIG,
 			       &ctype, sizeof(ctype));
 	if (ret < 0)
-		goto init_done;
+		goto init_error;
 
 	ret = wait_for_completion_timeout(
 		&priv->status_return_completion, S10_RECONFIG_TIMEOUT);
 	if (!ret) {
 		dev_err(dev, "timeout waiting for RECONFIG_REQUEST\n");
 		ret = -ETIMEDOUT;
-		goto init_done;
+		goto init_error;
 	}
 
 	ret = 0;
 	if (!test_and_clear_bit(SVC_STATUS_OK, &priv->status)) {
 		ret = -ETIMEDOUT;
-		goto init_done;
+		goto init_error;
 	}
 
 	/* Allocate buffers from the service layer's pool. */
@@ -216,16 +216,19 @@ static int s10_ops_write_init(struct fpga_manager *mgr,
 		kbuf = stratix10_svc_allocate_memory(priv->chan, SVC_BUF_SIZE);
 		if (IS_ERR(kbuf)) {
 			s10_free_buffers(mgr);
-			ret = PTR_ERR(kbuf);
-			goto init_done;
+			ret = -ENOMEM;
+			goto init_error;
 		}
 
 		priv->svc_bufs[i].buf = kbuf;
 		priv->svc_bufs[i].lock = 0;
 	}
 
-init_done:
+	goto init_done;
+
+init_error:
 	stratix10_svc_done(priv->chan);
+init_done:
 	return ret;
 }
 
@@ -342,6 +345,9 @@ static int s10_ops_write(struct fpga_manager *mgr, const char *buf,
 	if (!s10_free_buffers(mgr))
 		dev_err(dev, "%s not all buffers were freed\n", __func__);
 
+	if (ret < 0)
+		stratix10_svc_done(priv->chan);
+
 	return ret;
 }
 
-- 
2.43.7