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iommu: Improve the performance for direct_mapping

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Currently direct_mapping always use the smallest pgsize which is SZ_4K
normally to mapping. This is unnecessary. we could gather the size, and
call iommu_map then, iommu_map could decide how to map better with the
just right pgsize.

>From the original comment, we should take care overlap, otherwise,
iommu_map may return -EEXIST. In this overlap case, we should map the
previous region before overlap firstly. then map the left part.

Each a iommu device will call this direct_mapping when its iommu
initialize, This patch is effective to improve the boot/initialization
time especially while it only needs level 1 mapping.

Signed-off-by: Anan Sun <anan.sun@mediatek.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Link: https://lore.kernel.org/r/20201207093553.8635-1-yong.wu@mediatek.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Yong Wu
2020-12-07 17:35:53 +08:00
committed by Will Deacon
parent 058236eef6
commit 093b32a849
1 changed files with 19 additions and 7 deletions
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26
drivers/iommu/iommu.c
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@@ -739,6 +739,7 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
/* We need to consider overlapping regions for different devices */ /* We need to consider overlapping regions for different devices */
list_for_each_entry(entry, &mappings, list) { list_for_each_entry(entry, &mappings, list) {
dma_addr_t start, end, addr; dma_addr_t start, end, addr;
size_t map_size = 0;
if (domain->ops->apply_resv_region) if (domain->ops->apply_resv_region)
domain->ops->apply_resv_region(dev, domain, entry); domain->ops->apply_resv_region(dev, domain, entry);
@@ -750,16 +751,27 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
entry->type != IOMMU_RESV_DIRECT_RELAXABLE) entry->type != IOMMU_RESV_DIRECT_RELAXABLE)
continue; continue;
for (addr = start; addr < end; addr += pg_size) { for (addr = start; addr <= end; addr += pg_size) {
phys_addr_t phys_addr; phys_addr_t phys_addr;
phys_addr = iommu_iova_to_phys(domain, addr); if (addr == end)
if (phys_addr) goto map_end;
continue;
ret = iommu_map(domain, addr, addr, pg_size, entry->prot); phys_addr = iommu_iova_to_phys(domain, addr);
if (ret) if (!phys_addr) {
goto out; map_size += pg_size;
continue;
}
map_end:
if (map_size) {
ret = iommu_map(domain, addr - map_size,
addr - map_size, map_size,
entry->prot);
if (ret)
goto out;
map_size = 0;
}
} }
} }