Thread (13 messages) 13 messages, 5 authors, 2025-06-24

Re: [PATCH v5 2/3] remoteproc: imx_rproc: skip clock enable when M-core is managed by the SCU

From: Mathieu Poirier <mathieu.poirier@linaro.org>
Date: 2025-06-23 15:15:55
Also in: imx, linux-pm, linux-remoteproc, lkml

Hi Hiago,

On Tue, Jun 17, 2025 at 04:34:49PM -0300, Hiago De Franco wrote:
From: Hiago De Franco <redacted>

For the i.MX8X and i.MX8 family SoCs, when the M-core is powered up
by the bootloader, M-core and Linux are in same SCFW (System Controller
Firmware) partition, so linux has permission to control M-core.
Ok
But when M-core is started, the SCFW will automatically enable the clock
I find the "But when M-core is started" part confusing.  Started by who?  And
are you making a distinction between "powered up" and "started"?  It is not
possible for someone that doesn't have HW documentation to understand what is
going on. 
quoted hunk ↗ jump to hunk
and configure the rate, and any users that want to enable the clock will
get error 'LOCKED' from SCFW. So current imx_rproc.c probe function
fails because clk_prepare_enable also fails. With that, the M-core power
domain is powered off when it is still running, causing a SCU (System
Controller Unit) fault reset, and the system restarts.

To address the issue, ignore handling the clk for i.MX8X and i.MX8 M-core,
because SCFW will automatically enable and configure the clock.

Suggested-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Ulf Hansson <redacted>
Signed-off-by: Hiago De Franco <redacted>
---
v4 -> v5:
 - Unchanged.
v3 -> v4:
 - Unchanged.
v2 -> v3:
 - Unchanged.
v1 -> v2:
 - Commit description updated, as suggested. Fixed Peng Fan email.
---
 drivers/remoteproc/imx_rproc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 74299af1d7f1..627e57a88db2 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -1029,8 +1029,8 @@ static int imx_rproc_clk_enable(struct imx_rproc *priv)
 	struct device *dev = priv->dev;
 	int ret;
 
-	/* Remote core is not under control of Linux */
-	if (dcfg->method == IMX_RPROC_NONE)
+	/* Remote core is not under control of Linux or it is managed by SCU API */
+	if (dcfg->method == IMX_RPROC_NONE || dcfg->method == IMX_RPROC_SCU_API)
 		return 0;
 
 	priv->clk = devm_clk_get(dev, NULL);
-- 
2.39.5
  
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