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Diffstat (limited to 'drivers/gpu/drm/panfrost/panfrost_mmu.c')
-rw-r--r--drivers/gpu/drm/panfrost/panfrost_mmu.c30
1 files changed, 23 insertions, 7 deletions
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index f7f83cf63f42..f51d3f791a17 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -58,17 +58,33 @@ static int write_cmd(struct panfrost_device *pfdev, u32 as_nr, u32 cmd)
}
static void lock_region(struct panfrost_device *pfdev, u32 as_nr,
- u64 iova, u64 size)
+ u64 region_start, u64 size)
{
u8 region_width;
- u64 region = iova & PAGE_MASK;
+ u64 region;
+ u64 region_end = region_start + size;
- /* The size is encoded as ceil(log2) minus(1), which may be calculated
- * with fls. The size must be clamped to hardware bounds.
+ if (!size)
+ return;
+
+ /*
+ * The locked region is a naturally aligned power of 2 block encoded as
+ * log2 minus(1).
+ * Calculate the desired start/end and look for the highest bit which
+ * differs. The smallest naturally aligned block must include this bit
+ * change, the desired region starts with this bit (and subsequent bits)
+ * zeroed and ends with the bit (and subsequent bits) set to one.
*/
- size = max_t(u64, size, AS_LOCK_REGION_MIN_SIZE);
- region_width = fls64(size - 1) - 1;
- region |= region_width;
+ region_width = max(fls64(region_start ^ (region_end - 1)),
+ const_ilog2(AS_LOCK_REGION_MIN_SIZE)) - 1;
+
+ /*
+ * Mask off the low bits of region_start (which would be ignored by
+ * the hardware anyway)
+ */
+ region_start &= GENMASK_ULL(63, region_width);
+
+ region = region_width | region_start;
/* Lock the region that needs to be updated */
mmu_write(pfdev, AS_LOCKADDR_LO(as_nr), lower_32_bits(region));