drm/panthor: Simplify mmu_hw_do_operation_locked

The only callers to mmu_hw_do_operation_locked() pass an 'op' of either
AS_COMAND_FLUSH_MEM or AS_COMMAND_FLUSH_PT. This means the code paths
after that are dead. Removing those paths means the
mmu_hw_do_flush_on_gpu_ctrl() function might has well be inlined.

Simplify everything by having a switch statement for the type of 'op'
(warning if we get an unexpected value) and removing the dead cases.

Suggested-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Steven Price <steven.price@arm.com>
Reviewed-by: Karunika Choo <karunika.choo@arm.com>
Link: https://lore.kernel.org/r/20250815134226.57703-1-steven.price@arm.com

diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index ee9e94448b76ffd31a97d82a857fa925c4cf0cb5..bad720f23eb7014da571ffc657ef7ce564421ed0 100644 (file)
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -569,15 +569,37 @@ static void lock_region(struct panthor_device *ptdev, u32 as_nr,
        write_cmd(ptdev, as_nr, AS_COMMAND_LOCK);
 }
 
-static int mmu_hw_do_flush_on_gpu_ctrl(struct panthor_device *ptdev, int as_nr,
-                                      u32 op)
+static int mmu_hw_do_operation_locked(struct panthor_device *ptdev, int as_nr,
+                                     u64 iova, u64 size, u32 op)
 {
        const u32 l2_flush_op = CACHE_CLEAN | CACHE_INV;
-       u32 lsc_flush_op = 0;
+       u32 lsc_flush_op;
        int ret;
 
-       if (op == AS_COMMAND_FLUSH_MEM)
+       lockdep_assert_held(&ptdev->mmu->as.slots_lock);
+
+       switch (op) {
+       case AS_COMMAND_FLUSH_MEM:
                lsc_flush_op = CACHE_CLEAN | CACHE_INV;
+               break;
+       case AS_COMMAND_FLUSH_PT:
+               lsc_flush_op = 0;
+               break;
+       default:
+               drm_WARN(&ptdev->base, 1, "Unexpected AS_COMMAND: %d", op);
+               return -EINVAL;
+       }
+
+       if (as_nr < 0)
+               return 0;
+
+       /*
+        * If the AS number is greater than zero, then we can be sure
+        * the device is up and running, so we don't need to explicitly
+        * power it up
+        */
+
+       lock_region(ptdev, as_nr, iova, size);
 
        ret = wait_ready(ptdev, as_nr);
        if (ret)
@@ -598,33 +620,6 @@ static int mmu_hw_do_flush_on_gpu_ctrl(struct panthor_device *ptdev, int as_nr,
        return wait_ready(ptdev, as_nr);
 }
 
-static int mmu_hw_do_operation_locked(struct panthor_device *ptdev, int as_nr,
-                                     u64 iova, u64 size, u32 op)
-{
-       lockdep_assert_held(&ptdev->mmu->as.slots_lock);
-
-       if (as_nr < 0)
-               return 0;
-
-       /*
-        * If the AS number is greater than zero, then we can be sure
-        * the device is up and running, so we don't need to explicitly
-        * power it up
-        */
-
-       if (op != AS_COMMAND_UNLOCK)
-               lock_region(ptdev, as_nr, iova, size);
-
-       if (op == AS_COMMAND_FLUSH_MEM || op == AS_COMMAND_FLUSH_PT)
-               return mmu_hw_do_flush_on_gpu_ctrl(ptdev, as_nr, op);
-
-       /* Run the MMU operation */
-       write_cmd(ptdev, as_nr, op);
-
-       /* Wait for the flush to complete */
-       return wait_ready(ptdev, as_nr);
-}
-
 static int mmu_hw_do_operation(struct panthor_vm *vm,
                               u64 iova, u64 size, u32 op)
 {