Re: [PATCH] remoteproc: xlnx: avoid RPU force power down

[Tanmay Shah]

On 4/22/25 10:59 AM, Mathieu Poirier wrote:
Good morning,

On Mon, Apr 14, 2025 at 11:46:01AM -0700, Tanmay Shah wrote:
Powering off RPU using force_pwrdwn call results in system failure
if there are multiple users of that RPU node. Better mechanism is to use
request_node and release_node EEMI calls. With use of these EEMI calls,
platform management controller will take-care of powering off RPU
when there is no user.

Signed-off-by: Tanmay Shah <tanmay.s...@amd.com>
---
  drivers/remoteproc/xlnx_r5_remoteproc.c | 29 ++++++++++++++++++++++++-
  1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/remoteproc/xlnx_r5_remoteproc.c 
b/drivers/remoteproc/xlnx_r5_remoteproc.c
index 5aeedeaf3c41..3597359c0fc8 100644
--- a/drivers/remoteproc/xlnx_r5_remoteproc.c
+++ b/drivers/remoteproc/xlnx_r5_remoteproc.c
@@ -380,6 +380,18 @@ static int zynqmp_r5_rproc_start(struct rproc *rproc)
        dev_dbg(r5_core->dev, "RPU boot addr 0x%llx from %s.", rproc->bootaddr,
                bootmem == PM_RPU_BOOTMEM_HIVEC ? "OCM" : "TCM");
  
+	/* Request node before starting RPU core if new version of API is supported */
+       if (zynqmp_pm_feature(PM_REQUEST_NODE) > 1) {
+               ret = zynqmp_pm_request_node(r5_core->pm_domain_id,
+                                            ZYNQMP_PM_CAPABILITY_ACCESS, 0,
+                                            ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+               if (ret < 0) {
+                       dev_err(r5_core->dev, "failed to request 0x%x",
+                               r5_core->pm_domain_id);
+                       return ret;
+               }
+       }
+
        ret = zynqmp_pm_request_wake(r5_core->pm_domain_id, 1,
                                     bootmem, ZYNQMP_PM_REQUEST_ACK_NO);
        if (ret)
@@ -401,10 +413,25 @@ static int zynqmp_r5_rproc_stop(struct rproc *rproc)
        struct zynqmp_r5_core *r5_core = rproc->priv;
        int ret;
  
+	/* Use release node API to stop core if new version of API is supported */
+       if (zynqmp_pm_feature(PM_RELEASE_NODE) > 1) {
+               ret = zynqmp_pm_release_node(r5_core->pm_domain_id);
+               if (ret)
+                       dev_err(r5_core->dev, "failed to stop remoteproc RPU 
%d\n", ret);
+               return ret;
+       }
+
+       if (zynqmp_pm_feature(PM_FORCE_POWERDOWN) < 1) {
+               dev_dbg(r5_core->dev, "EEMI interface %d not supported\n",
+                       PM_FORCE_POWERDOWN);
+               return -EOPNOTSUPP;
+       }

Here I have to guess, because it is not documented, that it is the check to see
if zynqmp_pm_force_pwrdwn() is available.  I'm not sure why it is needed because
zynqmp_pm_force_pwrdwn() returns and error code.

Hello,

Thanks for reviews. Yes you are correct. Actually instead, the check 
should be for version 1 of PM_FORCE_POWER_DOWN. If version 1 is 
supported, only then execute the call otherwise print the error.
Hence, the check should be something like:

if (zynqmp_pm_feature(PM_FORCE_POWERDOWN) != 1) {
        error out.
}

I will fix and add comment as well.

Thanks,
Mathieu

+
+       /* maintain force pwr down for backward compatibility */
        ret = zynqmp_pm_force_pwrdwn(r5_core->pm_domain_id,
                                     ZYNQMP_PM_REQUEST_ACK_BLOCKING);
        if (ret)
-               dev_err(r5_core->dev, "failed to stop remoteproc RPU %d\n", 
ret);
+               dev_err(r5_core->dev, "core force power down failed\n");
  
  	return ret;
  }

base-commit: 8532691d0a85ab2a826808207e904f7d62a9d804
--
2.34.1