iommu/tegra-smmu: Store struct page pointer for page tables
Store the struct page pointer for the second level page tables, rather
than working back from the page directory entry. This is necessary as
we want to eliminate the use of physical addresses used with
arch-private functions, switching instead to use the streaming DMA API.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index bbff5b64..8ec5ac4 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -41,6 +41,7 @@
struct tegra_smmu *smmu;
unsigned int use_count;
struct page *count;
+ struct page **pts;
struct page *pd;
unsigned id;
u32 attr;
@@ -271,6 +272,14 @@
return NULL;
}
+ as->pts = kcalloc(SMMU_NUM_PDE, sizeof(*as->pts), GFP_KERNEL);
+ if (!as->pts) {
+ __free_page(as->count);
+ __free_page(as->pd);
+ kfree(as);
+ return NULL;
+ }
+
/* clear PDEs */
pd = page_address(as->pd);
SetPageReserved(as->pd);
@@ -487,14 +496,11 @@
{
unsigned int pd_index = iova_pd_index(iova);
struct page *pt_page;
- u32 *pd;
- pd = page_address(as->pd);
-
- if (!pd[pd_index])
+ pt_page = as->pts[pd_index];
+ if (!pt_page)
return NULL;
- pt_page = pfn_to_page(pd[pd_index] & as->smmu->pfn_mask);
*pagep = pt_page;
return tegra_smmu_pte_offset(pt_page, iova);
@@ -509,7 +515,7 @@
struct page *page;
unsigned int i;
- if (pd[pde] == 0) {
+ if (!as->pts[pde]) {
page = alloc_page(GFP_KERNEL | __GFP_DMA);
if (!page)
return NULL;
@@ -520,6 +526,8 @@
for (i = 0; i < SMMU_NUM_PTE; i++)
pt[i] = 0;
+ as->pts[pde] = page;
+
smmu->soc->ops->flush_dcache(page, 0, SMMU_SIZE_PT);
pd[pde] = SMMU_MK_PDE(page, SMMU_PDE_ATTR | SMMU_PDE_NEXT);
@@ -529,7 +537,7 @@
smmu_flush_tlb_section(smmu, as->id, iova);
smmu_flush(smmu);
} else {
- page = pfn_to_page(pd[pde] & smmu->pfn_mask);
+ page = as->pts[pde];
}
*pagep = page;
@@ -550,9 +558,7 @@
unsigned int pde = iova_pd_index(iova);
u32 *count = page_address(as->count);
u32 *pd = page_address(as->pd);
- struct page *page;
-
- page = pfn_to_page(pd[pde] & smmu->pfn_mask);
+ struct page *page = as->pts[pde];
/*
* When no entries in this page table are used anymore, return the
@@ -573,6 +579,7 @@
/* Finally, free the page */
ClearPageReserved(page);
__free_page(page);
+ as->pts[pde] = NULL;
}
}