From: Karol Wachowski <karol.wachowski@xxxxxxxxxxxxxxx>
Previously using dma_alloc_wc() API we created cache coherent
(mapped as write-back) mappings.
Because we disable MMU600 snooping it was required to do costly
page walk and cache flushes after each page table modification.
With write-combined buffers it's possible to do a single write memory
barrier to flush write-combined buffer to memory which simplifies the
driver and significantly reduce time of map/unmap operations.
Mapping time of 255 MB is reduced from 2.5 ms to 500 us.
Signed-off-by: Karol Wachowski <karol.wachowski@xxxxxxxxxxxxxxx>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
---
drivers/accel/ivpu/ivpu_mmu_context.c | 115 ++++++++++++++------------
1 file changed, 63 insertions(+), 52 deletions(-)
diff --git a/drivers/accel/ivpu/ivpu_mmu_context.c b/drivers/accel/ivpu/ivpu_mmu_context.c
index 0c8c65351919..7d8005bc78d2 100644
--- a/drivers/accel/ivpu/ivpu_mmu_context.c
+++ b/drivers/accel/ivpu/ivpu_mmu_context.c
@@ -5,6 +5,9 @@
#include <linux/bitfield.h>
#include <linux/highmem.h>
+#include <linux/set_memory.h>
+
+#include <drm/drm_cache.h>
#include "ivpu_drv.h"
#include "ivpu_hw.h"
@@ -38,12 +41,57 @@
#define IVPU_MMU_ENTRY_MAPPED (IVPU_MMU_ENTRY_FLAG_AF | IVPU_MMU_ENTRY_FLAG_USER | \
IVPU_MMU_ENTRY_FLAG_NG | IVPU_MMU_ENTRY_VALID)
+static void *ivpu_pgtable_alloc_page(struct ivpu_device *vdev, dma_addr_t *dma)
+{
+ dma_addr_t dma_addr;
+ struct page *page;
+ void *cpu;
+
+ page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
+ if (!page)
+ return NULL;
+
+ set_pages_array_wc(&page, 1);
+
+ dma_addr = dma_map_page(vdev->drm.dev, page, 0, PAGE_SIZE, DMA_BIDIRECTIONAL);
+ if (dma_mapping_error(vdev->drm.dev, dma_addr))
+ goto err_free_page;
+
+ cpu = vmap(&page, 1, VM_MAP, pgprot_writecombine(PAGE_KERNEL));
+ if (!cpu)
+ goto err_dma_unmap_page;
+
+
+ *dma = dma_addr;
+ return cpu;
+
+err_dma_unmap_page:
+ dma_unmap_page(vdev->drm.dev, dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);
+
+err_free_page:
+ put_page(page);
+ return NULL;
+}
+
+static void ivpu_pgtable_free_page(struct ivpu_device *vdev, u64 *cpu_addr, dma_addr_t dma_addr)
+{
+ struct page *page;
+
+ if (cpu_addr) {
+ page = vmalloc_to_page(cpu_addr);
+ vunmap(cpu_addr);
+ dma_unmap_page(vdev->drm.dev, dma_addr & ~IVPU_MMU_ENTRY_FLAGS_MASK, PAGE_SIZE,
+ DMA_BIDIRECTIONAL);
+ set_pages_array_wb(&page, 1);
+ put_page(page);
+ }
+}
+
static int ivpu_mmu_pgtable_init(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable)
{
dma_addr_t pgd_dma;
- pgtable->pgd_dma_ptr = dma_alloc_coherent(vdev->drm.dev, IVPU_MMU_PGTABLE_SIZE, &pgd_dma,
- GFP_KERNEL);
+ pgtable->pgd_dma_ptr = ivpu_pgtable_alloc_page(vdev, &pgd_dma);
if (!pgtable->pgd_dma_ptr)
return -ENOMEM;
@@ -52,13 +100,6 @@ static int ivpu_mmu_pgtable_init(struct ivpu_device *vdev, struct ivpu_mmu_pgtab
return 0;
}
-static void ivpu_mmu_pgtable_free(struct ivpu_device *vdev, u64 *cpu_addr, dma_addr_t dma_addr)
-{
- if (cpu_addr)
- dma_free_coherent(vdev->drm.dev, IVPU_MMU_PGTABLE_SIZE, cpu_addr,
- dma_addr & ~IVPU_MMU_ENTRY_FLAGS_MASK);
-}
-
static void ivpu_mmu_pgtables_free(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable)
{
int pgd_idx, pud_idx, pmd_idx;
@@ -83,19 +124,19 @@ static void ivpu_mmu_pgtables_free(struct ivpu_device *vdev, struct ivpu_mmu_pgt
pte_dma_ptr = pgtable->pte_ptrs[pgd_idx][pud_idx][pmd_idx];
pte_dma = pgtable->pmd_ptrs[pgd_idx][pud_idx][pmd_idx];
- ivpu_mmu_pgtable_free(vdev, pte_dma_ptr, pte_dma);
+ ivpu_pgtable_free_page(vdev, pte_dma_ptr, pte_dma);
}
kfree(pgtable->pte_ptrs[pgd_idx][pud_idx]);
- ivpu_mmu_pgtable_free(vdev, pmd_dma_ptr, pmd_dma);
+ ivpu_pgtable_free_page(vdev, pmd_dma_ptr, pmd_dma);
}
kfree(pgtable->pmd_ptrs[pgd_idx]);
kfree(pgtable->pte_ptrs[pgd_idx]);
- ivpu_mmu_pgtable_free(vdev, pud_dma_ptr, pud_dma);
+ ivpu_pgtable_free_page(vdev, pud_dma_ptr, pud_dma);
}
- ivpu_mmu_pgtable_free(vdev, pgtable->pgd_dma_ptr, pgtable->pgd_dma);
+ ivpu_pgtable_free_page(vdev, pgtable->pgd_dma_ptr, pgtable->pgd_dma);
}
static u64*
@@ -107,7 +148,7 @@ ivpu_mmu_ensure_pud(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable,
if (pud_dma_ptr)
return pud_dma_ptr;
- pud_dma_ptr = dma_alloc_wc(vdev->drm.dev, IVPU_MMU_PGTABLE_SIZE, &pud_dma, GFP_KERNEL);
+ pud_dma_ptr = ivpu_pgtable_alloc_page(vdev, &pud_dma);
if (!pud_dma_ptr)
return NULL;
@@ -130,7 +171,7 @@ ivpu_mmu_ensure_pud(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable,
kfree(pgtable->pmd_ptrs[pgd_idx]);
err_free_pud_dma_ptr:
- ivpu_mmu_pgtable_free(vdev, pud_dma_ptr, pud_dma);
+ ivpu_pgtable_free_page(vdev, pud_dma_ptr, pud_dma);
return NULL;
}
@@ -144,7 +185,7 @@ ivpu_mmu_ensure_pmd(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable,
if (pmd_dma_ptr)
return pmd_dma_ptr;
- pmd_dma_ptr = dma_alloc_wc(vdev->drm.dev, IVPU_MMU_PGTABLE_SIZE, &pmd_dma, GFP_KERNEL);
+ pmd_dma_ptr = ivpu_pgtable_alloc_page(vdev, &pmd_dma);
if (!pmd_dma_ptr)
return NULL;
@@ -159,7 +200,7 @@ ivpu_mmu_ensure_pmd(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable,
return pmd_dma_ptr;
err_free_pmd_dma_ptr:
- ivpu_mmu_pgtable_free(vdev, pmd_dma_ptr, pmd_dma);
+ ivpu_pgtable_free_page(vdev, pmd_dma_ptr, pmd_dma);
return NULL;
}
@@ -173,7 +214,7 @@ ivpu_mmu_ensure_pte(struct ivpu_device *vdev, struct ivpu_mmu_pgtable *pgtable,
if (pte_dma_ptr)
return pte_dma_ptr;
- pte_dma_ptr = dma_alloc_wc(vdev->drm.dev, IVPU_MMU_PGTABLE_SIZE, &pte_dma, GFP_KERNEL);
+ pte_dma_ptr = ivpu_pgtable_alloc_page(vdev, &pte_dma);
if (!pte_dma_ptr)
return NULL;
@@ -248,38 +289,6 @@ static void ivpu_mmu_context_unmap_page(struct ivpu_mmu_context *ctx, u64 vpu_ad
ctx->pgtable.pte_ptrs[pgd_idx][pud_idx][pmd_idx][pte_idx] = IVPU_MMU_ENTRY_INVALID;
}
-static void
-ivpu_mmu_context_flush_page_tables(struct ivpu_mmu_context *ctx, u64 vpu_addr, size_t size)
-{
- struct ivpu_mmu_pgtable *pgtable = &ctx->pgtable;
- u64 end_addr = vpu_addr + size;
-
- /* Align to PMD entry (2 MB) */
- vpu_addr &= ~(IVPU_MMU_PTE_MAP_SIZE - 1);
-
- while (vpu_addr < end_addr) {
- int pgd_idx = FIELD_GET(IVPU_MMU_PGD_INDEX_MASK, vpu_addr);
- u64 pud_end = (pgd_idx + 1) * (u64)IVPU_MMU_PUD_MAP_SIZE;
-
- while (vpu_addr < end_addr && vpu_addr < pud_end) {
- int pud_idx = FIELD_GET(IVPU_MMU_PUD_INDEX_MASK, vpu_addr);
- u64 pmd_end = (pud_idx + 1) * (u64)IVPU_MMU_PMD_MAP_SIZE;
-
- while (vpu_addr < end_addr && vpu_addr < pmd_end) {
- int pmd_idx = FIELD_GET(IVPU_MMU_PMD_INDEX_MASK, vpu_addr);
-
- clflush_cache_range(pgtable->pte_ptrs[pgd_idx][pud_idx][pmd_idx],
- IVPU_MMU_PGTABLE_SIZE);
- vpu_addr += IVPU_MMU_PTE_MAP_SIZE;
- }
- clflush_cache_range(pgtable->pmd_ptrs[pgd_idx][pud_idx],
- IVPU_MMU_PGTABLE_SIZE);
- }
- clflush_cache_range(pgtable->pud_ptrs[pgd_idx], IVPU_MMU_PGTABLE_SIZE);
- }
- clflush_cache_range(pgtable->pgd_dma_ptr, IVPU_MMU_PGTABLE_SIZE);
-}
-
static int
ivpu_mmu_context_map_pages(struct ivpu_device *vdev, struct ivpu_mmu_context *ctx,
u64 vpu_addr, dma_addr_t dma_addr, size_t size, u64 prot)
@@ -352,10 +361,11 @@ ivpu_mmu_context_map_sgt(struct ivpu_device *vdev, struct ivpu_mmu_context *ctx,
mutex_unlock(&ctx->lock);
return ret;
}
- ivpu_mmu_context_flush_page_tables(ctx, vpu_addr, size);
vpu_addr += size;
}
+ /* Ensure page table modifications are flushed from wc buffers to memory */
+ wmb();
mutex_unlock(&ctx->lock);
ret = ivpu_mmu_invalidate_tlb(vdev, ctx->id);
@@ -381,10 +391,11 @@ ivpu_mmu_context_unmap_sgt(struct ivpu_device *vdev, struct ivpu_mmu_context *ct
size_t size = sg_dma_len(sg) + sg->offset;
ivpu_mmu_context_unmap_pages(ctx, vpu_addr, size);
- ivpu_mmu_context_flush_page_tables(ctx, vpu_addr, size);
vpu_addr += size;
}
+ /* Ensure page table modifications are flushed from wc buffers to memory */
+ wmb();
mutex_unlock(&ctx->lock);
ret = ivpu_mmu_invalidate_tlb(vdev, ctx->id);
--
2.25.1
