android/android_kernel_samsung_sm8650
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

iommu: Improve the performance for direct_mapping

Browse Source 
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/iommu/iommu.c
View File

@ -739,6 +739,7 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
/* We need to consider overlapping regions for different devices */
list_for_each_entry(entry, &mappings, list) {
dma_addr_t start, end, addr;
size_t map_size = 0;
if (domain->ops->apply_resv_region)
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)
continue;
for (addr = start; addr < end; addr += pg_size) {
for (addr = start; addr <= end; addr += pg_size) {
phys_addr_t phys_addr;
phys_addr = iommu_iova_to_phys(domain, addr);
if (phys_addr)
continue;
if (addr == end)
goto map_end;
ret = iommu_map(domain, addr, addr, pg_size, entry->prot);
if (ret)
goto out;
phys_addr = iommu_iova_to_phys(domain, addr);
if (!phys_addr) {
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;
}
}
}