[PATCH v5 3/3 DO NOT MERGE] drm/tyr: enable runtime PM

[Beata Michalska <beata.michalska@arm.com>]

Add runtime PM support to the Tyr platform driver. Move the clocks
and regulators used by runtime suspend and resume into the PM
payload, register the PM callbacks, configure autosuspend,
and let DRM paths take a PM usage reference while querying
device state.

Signed-off-by: Beata Michalska <beata.michalska@arm.com>
---
 drivers/gpu/drm/tyr/driver.rs | 110 +++++++++++++++++++++++++++-------
 drivers/gpu/drm/tyr/file.rs   |   3 +
 2 files changed, 93 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs
index c2b99d67369f..de18470f0bd6 100644
--- a/drivers/gpu/drm/tyr/driver.rs
+++ b/drivers/gpu/drm/tyr/driver.rs
@@ -21,17 +21,15 @@
         poll,
         Io, //
     },
-    new_mutex,
     of,
     platform,
+    pm,
+    pm::*,
     prelude::*,
     regulator,
     regulator::Regulator,
     sizes::SZ_2M,
-    sync::{
-        Arc,
-        Mutex, //
-    },
+    sync::Arc,
     time, //
 };
 
@@ -59,6 +57,9 @@
 pub(crate) struct TyrPlatformDriverData<'bound> {
     #[pin]
     _reg: drm::Registration<'bound, TyrDrmDriver>,
+    // This needs to be dropped after drm::Registration as that one
+    // borrows PMContext.
+    pub(crate) pm: pm::Registration<'bound, TyrPlatformDriver>,
 }
 
 /// Data owned by the DRM [`Registration`].
@@ -73,11 +74,8 @@ pub(crate) struct TyrDrmRegistrationData<'drm> {
     /// Firmware sections.
     pub(crate) fw: Firmware<'drm>,
 
-    #[pin]
-    clks: Mutex<Clocks>,
-
-    #[pin]
-    regulators: Mutex<Regulators>,
+    /// Runtime PM context owned by the PM Registration
+    pub(crate) pm: PMContext<'drm, TyrPlatformDriver>,
 
     /// GPU MMIO register mapping.
     pub(crate) iomem: Arc<IoMem<'drm>>,
@@ -113,6 +111,8 @@ impl platform::Driver for TyrPlatformDriver {
     type IdInfo = ();
     type Data<'bound> = TyrPlatformDriverData<'bound>;
     const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+    const DEV_PM_OPS: Option<pm::DevPMOpsRef<'static, platform::Adapter<Self>>> =
+        Some(TYR_PM_OPS.pm_ops());
 
     fn probe<'bound>(
         pdev: &'bound platform::Device<Core<'_>>,
@@ -130,6 +130,37 @@ fn probe<'bound>(
             let mali_regulator = Regulator::<regulator::Enabled>::get(pdev.as_ref(), c"mali")?;
             let sram_regulator = Regulator::<regulator::Enabled>::get(pdev.as_ref(), c"sram")?;
 
+            let runtime_payload = TyrRuntimePMPayload {
+                clks: Clocks {
+                    core: core_clk,
+                    stacks: stacks_clk,
+                    coregroup: coregroup_clk,
+                },
+                _regulators: Regulators {
+                    _mali: mali_regulator,
+                    _sram: sram_regulator,
+                },
+            };
+
+            let mut pm_configs = KVec::<PMConfig>::with_capacity(2, GFP_KERNEL)?;
+            pm_configs.push(PMConfig::AutoSuspend(true), GFP_KERNEL)?;
+            pm_configs.push(PMConfig::AutoSuspendDelay(300), GFP_KERNEL)?;
+
+            // SAFETY: `pm_registration` is stored in `TyrPlatformDriverData`
+            // and dropped when the driver is
+            // unbound; it is never forgotten.
+            let pm_registration = unsafe {
+                pm::Registration::new(
+                    pdev.as_ref(),
+                    &TYR_PM_OPS,
+                    None,
+                    Some(pm_configs),
+                    runtime_payload,
+                )
+            }?;
+
+            let pm_context = pm_registration.ctx().clone();
+
             let request = pdev.io_request_by_index(0).ok_or(ENODEV)?;
 
             let iomem = Arc::new(request.iomap_sized::<SZ_2M>()?, GFP_KERNEL)?;
@@ -171,20 +202,14 @@ fn probe<'bound>(
                     pin_init!(TyrDrmRegistrationData {
                         pdev,
                         fw: firmware,
-                        clks <- new_mutex!(Clocks {
-                            core: core_clk,
-                            stacks: stacks_clk,
-                            coregroup: coregroup_clk,
-                        }),
-                        regulators <- new_mutex!(Regulators {
-                            _mali: mali_regulator,
-                            _sram: sram_regulator,
-                        }),
+                        pm: pm_context,
                         iomem,
                         gpu_info,
                     }),
                 )},
-                _: { dev_dbg!(pdev, "Tyr initialized correctly.") },
+                pm: pm_registration,
+                _: { pm.ctx().enable(RuntimePMState::Resumed)?;
+                    dev_dbg!(pdev, "Tyr initialized correctly.") },
             }))
         })
     }
@@ -239,3 +264,48 @@ struct Regulators {
     _mali: Regulator<regulator::Enabled>,
     _sram: Regulator<regulator::Enabled>,
 }
+
+pub(crate) struct TyrRuntimePMPayload {
+    clks: Clocks,
+    _regulators: Regulators,
+}
+
+static TYR_PM_OPS: pm::DevPMOps<TyrPlatformDriver> = pm::DevPMOps::new();
+
+#[vtable]
+impl PMOps for TyrPlatformDriver {
+    type Adapter = platform::Adapter<TyrPlatformDriver>;
+    type DeviceType = platform::Device<kernel::device::Bound>;
+    type RuntimePayloadType = TyrRuntimePMPayload;
+
+    fn runtime_suspend<'a>(
+        _dev: &'a Self::DeviceType,
+        payload: TyrRuntimePMPayload,
+    ) -> Result<TyrRuntimePMPayload, (TyrRuntimePMPayload, Error)> {
+        payload.clks.coregroup.disable_unprepare();
+        payload.clks.stacks.disable_unprepare();
+        payload.clks.core.disable_unprepare();
+        Ok(payload)
+    }
+    fn runtime_resume<'a>(
+        _dev: &'a Self::DeviceType,
+        payload: TyrRuntimePMPayload,
+    ) -> Result<TyrRuntimePMPayload, (TyrRuntimePMPayload, Error)> {
+        if let Err(e) = payload.clks.core.prepare_enable() {
+            return Err((payload, e));
+        }
+
+        if let Err(e) = payload.clks.stacks.prepare_enable() {
+            payload.clks.core.disable_unprepare();
+            return Err((payload, e));
+        }
+
+        if let Err(e) = payload.clks.coregroup.prepare_enable() {
+            payload.clks.stacks.disable_unprepare();
+            payload.clks.core.disable_unprepare();
+            return Err((payload, e));
+        }
+
+        Ok(payload)
+    }
+}
diff --git a/drivers/gpu/drm/tyr/file.rs b/drivers/gpu/drm/tyr/file.rs
index 9f60a90d4948..111cd4ccf87c 100644
--- a/drivers/gpu/drm/tyr/file.rs
+++ b/drivers/gpu/drm/tyr/file.rs
@@ -5,6 +5,7 @@
         self,
         Registered, //
     },
+    pm::PMProfile,
     prelude::*,
     uaccess::UserSlice,
     uapi, //
@@ -37,6 +38,8 @@ pub(crate) fn dev_query(
         devquery: &mut uapi::drm_panthor_dev_query,
         _file: &TyrDrmFile,
     ) -> Result<u32> {
+        // Runtime suspend called when pm_scope gets dropped
+        let _pm_scope = reg_data.pm.get(PMProfile::new())?;
         if devquery.pointer == 0 {
             match devquery.type_ {
                 uapi::drm_panthor_dev_query_type_DRM_PANTHOR_DEV_QUERY_GPU_INFO => {
-- 
2.43.0