drm/malidp: Enable MMU prefetch on Mali-DP650

Mali-DP650 supports warming up the SMMU translations, by sending
requsts to the SMMU before a buffer is read.

There are two modes supported:

- PARTIAL: could be enabled when the buffer is composed of 4K or 64K
  pages, the display hardware will send a configurable number of
  requests before the actual reading.

- FULL: could be enabled when the buffer is composed of 1M or 2M
  pages, the display hardware will send requests before reading for
  all pages composing the buffer.

This patch adds a mechanism for detecting the page size and set the
MMU prefetch mode if possible.

Changes since v1:
 - For imported buffers use the already populated
   drm_gem_cma_object.sgt instead of calling
   driver.gem_prime_get_sg_table, which works just for buffers
   allocated through the gem_cma API.

Signed-off-by: Jamie Fox <jamie.fox@arm.com>
Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
[rebased and re-ordered functions]
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/arm/malidp_drv.h b/drivers/gpu/drm/arm/malidp_drv.h
index e3eb0cb1f385..b76c86f18a56 100644
--- a/drivers/gpu/drm/arm/malidp_drv.h
+++ b/drivers/gpu/drm/arm/malidp_drv.h
@@ -55,6 +55,12 @@ struct malidp_plane {
 	const struct malidp_layer *layer;
 };
 
+enum mmu_prefetch_mode {
+	MALIDP_PREFETCH_MODE_NONE,
+	MALIDP_PREFETCH_MODE_PARTIAL,
+	MALIDP_PREFETCH_MODE_FULL,
+};
+
 struct malidp_plane_state {
 	struct drm_plane_state base;
 
@@ -63,6 +69,8 @@ struct malidp_plane_state {
 	/* internal format ID */
 	u8 format;
 	u8 n_planes;
+	enum mmu_prefetch_mode mmu_prefetch_mode;
+	u32 mmu_prefetch_pgsize;
 };
 
 #define to_malidp_plane(x) container_of(x, struct malidp_plane, base)