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

[Hiago De Franco <hiagofranco@gmail.com>]

From: Hiago De Franco <hiago.franco@toradex.com>

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.

But when M-core is started, the SCFW will automatically enable the clock
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 <ulf.hansson@linaro.org>
Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
---
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