drm/panthor: Make MMU cache maintenance use FLUSH_CACHES command

As the FLUSH_MEM and FLUSH_PT MMU_AS commands are deprecated in GPUs
from Mali-Gx20 onwards, this patch adds support for performing cache
maintenance via the FLUSH_CACHES command in GPU_COMMAND in place of
FLUSH_MEM and FLUSH_PT commands.

Mali-Gx10 and Mali-Gx15 GPUs also has support for the FLUSH_CACHES
command and will also use this by default going forward.

Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Karunika Choo <karunika.choo@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250807162633.3666310-7-karunika.choo@arm.com

diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index 4140f697ba5af5769492d3bbb378e18aec8ade98..367c89aca558d426e7b7392cf73a188edb7d2aeb 100644 (file)
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -29,6 +29,7 @@
 
 #include "panthor_device.h"
 #include "panthor_gem.h"
+#include "panthor_gpu.h"
 #include "panthor_heap.h"
 #include "panthor_mmu.h"
 #include "panthor_regs.h"
@@ -568,6 +569,35 @@ 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)
+{
+       const u32 l2_flush_op = CACHE_CLEAN | CACHE_INV;
+       u32 lsc_flush_op = 0;
+       int ret;
+
+       if (op == AS_COMMAND_FLUSH_MEM)
+               lsc_flush_op = CACHE_CLEAN | CACHE_INV;
+
+       ret = wait_ready(ptdev, as_nr);
+       if (ret)
+               return ret;
+
+       ret = panthor_gpu_flush_caches(ptdev, l2_flush_op, lsc_flush_op, 0);
+       if (ret)
+               return ret;
+
+       /*
+        * Explicitly unlock the region as the AS is not unlocked automatically
+        * at the end of the GPU_CONTROL cache flush command, unlike
+        * AS_COMMAND_FLUSH_MEM or AS_COMMAND_FLUSH_PT.
+        */
+       write_cmd(ptdev, as_nr, AS_COMMAND_UNLOCK);
+
+       /* Wait for the unlock command to complete */
+       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)
 {
@@ -585,6 +615,9 @@ static int mmu_hw_do_operation_locked(struct panthor_device *ptdev, int as_nr,
        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);