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authorRobin Murphy <robin.murphy@arm.com>2022-11-08 17:06:19 +0000
committerSteven Price <steven.price@arm.com>2022-11-09 14:17:39 +0000
commitf352262f727215553879705bacbcb208979f3eff (patch)
tree0d87abb0e00a47d3c71c4d791dab2dec959edd02
parente0b26b9482461e9528552f54fa662c2269f75b3f (diff)
drm/panfrost: Split io-pgtable requests properlydrm-misc-fixes-2022-11-09
Although we don't use 1GB block mappings, we still need to split map/unmap requests at 1GB boundaries to match what io-pgtable expects. Fix that, and add some explanation to make sense of it all. Fixes: 3740b081795a ("drm/panfrost: Update io-pgtable API") Reported-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Reviewed-by: Steven Price <steven.price@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Link: https://patchwork.freedesktop.org/patch/msgid/49e54bb4019cd06e01549b106d7ac37c3d182cd3.1667927179.git.robin.murphy@arm.com
-rw-r--r--drivers/gpu/drm/panfrost/panfrost_mmu.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index e246d914e7f6..4e83a1891f3e 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -250,13 +250,22 @@ void panfrost_mmu_reset(struct panfrost_device *pfdev)
static size_t get_pgsize(u64 addr, size_t size, size_t *count)
{
+ /*
+ * io-pgtable only operates on multiple pages within a single table
+ * entry, so we need to split at boundaries of the table size, i.e.
+ * the next block size up. The distance from address A to the next
+ * boundary of block size B is logically B - A % B, but in unsigned
+ * two's complement where B is a power of two we get the equivalence
+ * B - A % B == (B - A) % B == (n * B - A) % B, and choose n = 0 :)
+ */
size_t blk_offset = -addr % SZ_2M;
if (blk_offset || size < SZ_2M) {
*count = min_not_zero(blk_offset, size) / SZ_4K;
return SZ_4K;
}
- *count = size / SZ_2M;
+ blk_offset = -addr % SZ_1G ?: SZ_1G;
+ *count = min(blk_offset, size) / SZ_2M;
return SZ_2M;
}