[PATCH V3 2/3] memory: tegra: Wire up system sleep PM ops

Ashish Mhetre
2026-04-30T09:52:45Z

The tegra-mc platform driver does not register any dev_pm_ops, so the
SoC-specific ->resume() is never invoked (e.g. tegra186_mc_resume) on
system wake. On Tegra186 and later this means MC client Stream-ID
override registers are not reprogrammed, and clients behind the ARM
SMMU fault on the first DMA after resume.

Register a dev_pm_ops on the tegra-mc driver and route the system
resume callback into mc->soc->ops->resume() so the existing SID
restore path runs again on wake.

No suspend callback is needed as the resume path reprograms all MC
state from the static SoC tables, so there is nothing to save.

Fixes: fe3b082a6eb8 ("memory: tegra: Add SID override programming for MC clients")
Signed-off-by: Ashish Mhetre <amhetre@nvidia.com>
---
drivers/memory/tegra/mc.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index d620660da331..64e41338cdf2 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -13,6 +13,7 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/tegra-icc.h>
@@ -1010,10 +1011,23 @@ static void tegra_mc_sync_state(struct device *dev)
icc_sync_state(dev);
}

+static int tegra_mc_resume(struct device *dev)
+{
+ struct tegra_mc *mc = dev_get_drvdata(dev);
+
+ if (mc->soc->ops && mc->soc->ops->resume)
+ mc->soc->ops->resume(mc);
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(tegra_mc_pm_ops, NULL, tegra_mc_resume);
+
static struct platform_driver tegra_mc_driver = {
.driver = {
.name = "tegra-mc",
.of_match_table = tegra_mc_of_match,
+ .pm = pm_sleep_ptr(&tegra_mc_pm_ops),
.suppress_bind_attrs = true,
.sync_state = tegra_mc_sync_state,
},
--
2.50.1