linux-kernel - [PATCH v2] fpga: altera-cvp: allow interrupt to continue next time

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Message-Id: <20220601014027.2547481-1-tien.sung.ang@intel.com>
Date:   Wed,  1 Jun 2022 09:40:27 +0800
From:   tien.sung.ang@...el.com
To:     yilun.xu@...el.com
Cc:     hao.wu@...el.com, linux-fpga@...r.kernel.org,
        linux-kernel@...r.kernel.org, mdf@...nel.org,
        tien.sung.ang@...el.com, trix@...hat.com, dinh.nguyen@...el.com
Subject: [PATCH v2] fpga: altera-cvp: allow interrupt to continue next time

From: Dinh Nguyen <dinh.nguyen@...el.com>

The main objective of this change is to perform error handling
if the CvP firmware becomes unresponsive. The error_path flow
resets the CvP mode and HIP_CLK_SEL bit.

CFG_READY signal/bit may time-out due to firmware not responding
within the given time-out. This time varies due to numerous
factors like size of bitstream and others.
This time-out error may or may not impact the result of the CvP
previous transactions. The CvP driver shall then, respond with
EAGAIN instead Time out error.

Signed-off-by: Dinh Nguyen <dinh.nguyen@...el.com>
Signed-off-by: Ang Tien Sung <tien.sung.ang@...el.com>
---

changelog v2:
* Amend the commit message

---
 drivers/fpga/altera-cvp.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
index 4ffb9da537d8..d74ff63c61e8 100644
--- a/drivers/fpga/altera-cvp.c
+++ b/drivers/fpga/altera-cvp.c
@@ -309,10 +309,22 @@ static int altera_cvp_teardown(struct fpga_manager *mgr,
 	/* STEP 15 - poll CVP_CONFIG_READY bit for 0 with 10us timeout */
 	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0,
 				     conf->priv->poll_time_us);
-	if (ret)
+	if (ret) {
 		dev_err(&mgr->dev, "CFG_RDY == 0 timeout\n");
+		goto error_path;
+	}
 
 	return ret;
+
+error_path:
+	/* reset CVP_MODE and HIP_CLK_SEL bit */
+	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
+	val &= ~VSE_CVP_MODE_CTRL_HIP_CLK_SEL;
+	val &= ~VSE_CVP_MODE_CTRL_CVP_MODE;
+	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
+
+	return -EAGAIN;
+
 }
 
 static int altera_cvp_write_init(struct fpga_manager *mgr,
-- 
2.25.1