2020-04-02 17:13:44

by Bob Beckett

Subject: [PATCH v4.19.y] drm/etnaviv: replace MMU flush marker with flush sequence

From: Lucas Stach <[email protected]>

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 <[email protected]>
Reviewed-by: Philipp Zabel <[email protected]>
Reviewed-by: Guido Günther <[email protected]>
Signed-off-by: Robert Beckett <[email protected]>
---
drivers/gpu/drm/etnaviv/etnaviv_buffer.c | 10 ++++++----
drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 1 +
drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 6 +++---
drivers/gpu/drm/etnaviv/etnaviv_mmu.h | 2 +-
4 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_buffer.c b/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
index 7fea74861a87..c83655b008b9 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
@@ -311,6 +311,8 @@ void etnaviv_buffer_queue(struct etnaviv_gpu *gpu, u32 exec_state,
u32 return_target, return_dwords;
u32 link_target, link_dwords;
bool switch_context = gpu->exec_state != exec_state;
+ unsigned int new_flush_seq = READ_ONCE(gpu->mmu->flush_seq);
+ bool need_flush = gpu->flush_seq != new_flush_seq;

lockdep_assert_held(&gpu->lock);

@@ -325,14 +327,14 @@ void etnaviv_buffer_queue(struct etnaviv_gpu *gpu, u32 exec_state,
* 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 || switch_context) {
+ if (need_flush || 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
@@ -345,7 +347,7 @@ void etnaviv_buffer_queue(struct etnaviv_gpu *gpu, u32 exec_state,

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,
@@ -365,7 +367,7 @@ void etnaviv_buffer_queue(struct etnaviv_gpu *gpu, u32 exec_state,
SYNC_RECIPIENT_PE);
}

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

if (switch_context) {
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
index 90f17ff7888e..4efc45304dce 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -139,6 +139,7 @@ struct etnaviv_gpu {

struct etnaviv_iommu *mmu;
struct etnaviv_cmdbuf_suballoc *cmdbuf_suballoc;
+ unsigned int flush_seq;

/* Power Control: */
struct clk *clk_bus;
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
index 8069f9f36a2e..e132dccedf88 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
@@ -261,7 +261,7 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu *mmu,
}

list_add_tail(&mapping->mmu_node, &mmu->mappings);
- mmu->need_flush = true;
+ mmu->flush_seq++;
unlock:
mutex_unlock(&mmu->lock);

@@ -280,7 +280,7 @@ void etnaviv_iommu_unmap_gem(struct etnaviv_iommu *mmu,
etnaviv_iommu_remove_mapping(mmu, mapping);

list_del(&mapping->mmu_node);
- mmu->need_flush = true;
+ mmu->flush_seq++;
mutex_unlock(&mmu->lock);
}

@@ -357,7 +357,7 @@ int etnaviv_iommu_get_suballoc_va(struct etnaviv_gpu *gpu, dma_addr_t paddr,
mutex_unlock(&mmu->lock);
return ret;
}
- gpu->mmu->need_flush = true;
+ mmu->flush_seq++;
mutex_unlock(&mmu->lock);

*iova = (u32)vram_node->start;
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.h b/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
index a0db17ffb686..348a94d9695b 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
@@ -48,7 +48,7 @@ struct etnaviv_iommu {
struct mutex lock;
struct list_head mappings;
struct drm_mm mm;
- bool need_flush;
+ unsigned int flush_seq;
};

struct etnaviv_gem_object;
--
2.20.1