[PATCH 6.1 0809/1146] iommu/sun50i: Fix reset release

Greg Kroah-Hartman
2022-12-28T16:32:52Z

From: Jernej Skrabec <jernej.skrabec@gmail.com>

[ Upstream commit 9ad0c1252e84dbc664f0462707182245ed603237 ]

Reset signal is asserted by writing 0 to the corresponding locations of
masters we want to reset. So in order to deassert all reset signals, we
should write 1's to all locations.

Current code writes 1's to locations of masters which were just reset
which is good. However, at the same time it also writes 0's to other
locations and thus asserts reset signals of remaining masters. Fix code
by writing all 1's when we want to deassert all reset signals.

This bug was discovered when working with Cedrus (video decoder). When
it faulted, display went blank due to reset signal assertion.

Fixes: 4100b8c229b3 ("iommu: Add Allwinner H6 IOMMU driver")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20221025165415.307591-2-jernej.skrabec@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/sun50i-iommu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index cd9b74ee24de..270204a6ec4a 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -27,6 +27,7 @@
#include <linux/types.h>

#define IOMMU_RESET_REG 0x010
+#define IOMMU_RESET_RELEASE_ALL 0xffffffff
#define IOMMU_ENABLE_REG 0x020
#define IOMMU_ENABLE_ENABLE BIT(0)

@@ -893,7 +894,7 @@ static irqreturn_t sun50i_iommu_irq(int irq, void *dev_id)
iommu_write(iommu, IOMMU_INT_CLR_REG, status);

iommu_write(iommu, IOMMU_RESET_REG, ~status);
- iommu_write(iommu, IOMMU_RESET_REG, status);
+ iommu_write(iommu, IOMMU_RESET_REG, IOMMU_RESET_RELEASE_ALL);

spin_unlock(&iommu->iommu_lock);

--
2.35.1