[PATCH 4.9 08/32] drm/etnaviv: replace MMU flush marker with flush sequence

From: Greg Kroah-Hartman
Date: Sat Apr 11 2020 - 08:28:25 EST


From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>

commit 4900dda90af2cb13bc1d4c12ce94b98acc8fe64e upstream.

If a MMU is shared between multiple GPUs, all of them need to flush their
TLBs, so a single marker that gets reset on the first flush won't do.
Replace the flush marker with a sequence number, so that it's possible to
check if the TLB is in sync with the current page table state for each GPU.

Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Reviewed-by: Guido GÃnther <agx@xxxxxxxxxxx>
Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/gpu/drm/etnaviv/etnaviv_buffer.c | 10 ++++++----
drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 2 +-
drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 1 +
drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 6 +++---
drivers/gpu/drm/etnaviv/etnaviv_mmu.h | 2 +-
5 files changed, 12 insertions(+), 9 deletions(-)

--- a/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
@@ -257,6 +257,8 @@ void etnaviv_buffer_queue(struct etnaviv
unsigned int waitlink_offset = buffer->user_size - 16;
u32 return_target, return_dwords;
u32 link_target, link_dwords;
+ unsigned int new_flush_seq = READ_ONCE(gpu->mmu->flush_seq);
+ bool need_flush = gpu->flush_seq != new_flush_seq;

if (drm_debug & DRM_UT_DRIVER)
etnaviv_buffer_dump(gpu, buffer, 0, 0x50);
@@ -269,14 +271,14 @@ void etnaviv_buffer_queue(struct etnaviv
* need to append a mmu flush load state, followed by a new
* link to this buffer - a total of four additional words.
*/
- if (gpu->mmu->need_flush || gpu->switch_context) {
+ if (need_flush || gpu->switch_context) {
u32 target, extra_dwords;

/* link command */
extra_dwords = 1;

/* flush command */
- if (gpu->mmu->need_flush) {
+ if (need_flush) {
if (gpu->mmu->version == ETNAVIV_IOMMU_V1)
extra_dwords += 1;
else
@@ -289,7 +291,7 @@ void etnaviv_buffer_queue(struct etnaviv

target = etnaviv_buffer_reserve(gpu, buffer, extra_dwords);

- if (gpu->mmu->need_flush) {
+ if (need_flush) {
/* Add the MMU flush */
if (gpu->mmu->version == ETNAVIV_IOMMU_V1) {
CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_MMU,
@@ -309,7 +311,7 @@ void etnaviv_buffer_queue(struct etnaviv
SYNC_RECIPIENT_PE);
}

- gpu->mmu->need_flush = false;
+ gpu->flush_seq = new_flush_seq;
}

if (gpu->switch_context) {
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1313,7 +1313,7 @@ int etnaviv_gpu_submit(struct etnaviv_gp
gpu->active_fence = submit->fence;

if (gpu->lastctx != cmdbuf->ctx) {
- gpu->mmu->need_flush = true;
+ gpu->mmu->flush_seq++;
gpu->switch_context = true;
gpu->lastctx = cmdbuf->ctx;
}
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -135,6 +135,7 @@ struct etnaviv_gpu {
int irq;

struct etnaviv_iommu *mmu;
+ unsigned int flush_seq;

/* Power Control: */
struct clk *clk_bus;
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
@@ -134,7 +134,7 @@ static int etnaviv_iommu_find_iova(struc
*/
if (mmu->last_iova) {
mmu->last_iova = 0;
- mmu->need_flush = true;
+ mmu->flush_seq++;
continue;
}

@@ -197,7 +197,7 @@ static int etnaviv_iommu_find_iova(struc
* associated commit requesting this mapping, and retry the
* allocation one more time.
*/
- mmu->need_flush = true;
+ mmu->flush_seq++;
}

return ret;
@@ -354,7 +354,7 @@ u32 etnaviv_iommu_get_cmdbuf_va(struct e
* that the FE MMU prefetch won't load invalid entries.
*/
mmu->last_iova = buf->vram_node.start + buf->size + SZ_64K;
- gpu->mmu->need_flush = true;
+ mmu->flush_seq++;
mutex_unlock(&mmu->lock);

return (u32)buf->vram_node.start;
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
@@ -44,7 +44,7 @@ struct etnaviv_iommu {
struct list_head mappings;
struct drm_mm mm;
u32 last_iova;
- bool need_flush;
+ unsigned int flush_seq;
};

struct etnaviv_gem_object;