On 20/08/2021 22:31, Alyssa Rosenzweig wrote:
When locking a region, we currently clamp to a PAGE_SIZE as the minimum lock region. While this is valid for Midgard, it is invalid for Bifrost,
While the spec does seem to state it's invalid for Bifrost - kbase didn't bother with a lower clamp for a long time. I actually think this is in many ways more of a spec bug: i.e. implementation details of the round-up that the hardware does. But it's much safer following the spec ;) And it seems like kbase eventually caught up too.
where the minimum locking size is 8x larger than the 4k page size. Add a hardware definition for the minimum lock region size (corresponding to KBASE_LOCK_REGION_MIN_SIZE_LOG2 in kbase) and respect it.
Signed-off-by: Alyssa Rosenzweig alyssa.rosenzweig@collabora.com Tested-by: Chris Morgan macromorgan@hotmail.com Cc: stable@vger.kernel.org
Reviewed-by: Steven Price steven.price@arm.com
drivers/gpu/drm/panfrost/panfrost_mmu.c | 2 +- drivers/gpu/drm/panfrost/panfrost_regs.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c index 3a795273e505..dfe5f1d29763 100644 --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c @@ -66,7 +66,7 @@ static void lock_region(struct panfrost_device *pfdev, u32 as_nr, /* The size is encoded as ceil(log2) minus(1), which may be calculated * with fls. The size must be clamped to hardware bounds. */
- size = max_t(u64, size, PAGE_SIZE);
- size = max_t(u64, size, AS_LOCK_REGION_MIN_SIZE); region_width = fls64(size - 1) - 1; region |= region_width;
diff --git a/drivers/gpu/drm/panfrost/panfrost_regs.h b/drivers/gpu/drm/panfrost/panfrost_regs.h index 1940ff86e49a..6c5a11ef1ee8 100644 --- a/drivers/gpu/drm/panfrost/panfrost_regs.h +++ b/drivers/gpu/drm/panfrost/panfrost_regs.h @@ -316,6 +316,8 @@ #define AS_FAULTSTATUS_ACCESS_TYPE_READ (0x2 << 8) #define AS_FAULTSTATUS_ACCESS_TYPE_WRITE (0x3 << 8) +#define AS_LOCK_REGION_MIN_SIZE (1ULL << 15)
#define gpu_write(dev, reg, data) writel(data, dev->iomem + reg) #define gpu_read(dev, reg) readl(dev->iomem + reg)