[PATCH 6.18 085/314] media: verisilicon: Avoid G2 bus error while decoding H.264 and HEVC

Sasha Levin
2026-03-10T11:26:01Z

From: Ming Qian <ming.qian@oss.nxp.com>

[ Upstream commit e0203ddf9af7c8e170e1e99ce83b4dc07f0cd765 ]

For the i.MX8MQ platform, there is a hardware limitation: the g1 VPU and
g2 VPU cannot decode simultaneously; otherwise, it will cause below bus
error and produce corrupted pictures, even potentially lead to system hang.

[ 110.527986] hantro-vpu 38310000.video-codec: frame decode timed out.
[ 110.583517] hantro-vpu 38310000.video-codec: bus error detected.

Therefore, it is necessary to ensure that g1 and g2 operate alternately.
This allows for successful multi-instance decoding of H.264 and HEVC.

To achieve this, g1 and g2 share the same v4l2_m2m_dev, and then the
v4l2_m2m_dev can handle the scheduling.

Fixes: cb5dd5a0fa518 ("media: hantro: Introduce G2/HEVC decoder")
Cc: stable@vger.kernel.org
Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Co-developed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/platform/verisilicon/hantro.h | 2 +
.../media/platform/verisilicon/hantro_drv.c | 42 +++++++++++++++++--
.../media/platform/verisilicon/imx8m_vpu_hw.c | 8 ++++
3 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/verisilicon/hantro.h b/drivers/media/platform/verisilicon/hantro.h
index e0fdc4535b2d7..0353de154a1ec 100644
--- a/drivers/media/platform/verisilicon/hantro.h
+++ b/drivers/media/platform/verisilicon/hantro.h
@@ -77,6 +77,7 @@ struct hantro_irq {
* @double_buffer: core needs double buffering
* @legacy_regs: core uses legacy register set
* @late_postproc: postproc must be set up at the end of the job
+ * @shared_devices: an array of device ids that cannot run concurrently
*/
struct hantro_variant {
unsigned int enc_offset;
@@ -101,6 +102,7 @@ struct hantro_variant {
unsigned int double_buffer : 1;
unsigned int legacy_regs : 1;
unsigned int late_postproc : 1;
+ const struct of_device_id *shared_devices;
};

/**
diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c
index e0c11fe8b55ca..418cfe3a14146 100644
--- a/drivers/media/platform/verisilicon/hantro_drv.c
+++ b/drivers/media/platform/verisilicon/hantro_drv.c
@@ -13,6 +13,7 @@
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
@@ -1035,6 +1036,41 @@ static int hantro_disable_multicore(struct hantro_dev *vpu)
return 0;
}

+static struct v4l2_m2m_dev *hantro_get_v4l2_m2m_dev(struct hantro_dev *vpu)
+{
+ struct device_node *node;
+ struct hantro_dev *shared_vpu;
+
+ if (!vpu->variant || !vpu->variant->shared_devices)
+ goto init_new_m2m_dev;
+
+ for_each_matching_node(node, vpu->variant->shared_devices) {
+ struct platform_device *pdev;
+ struct v4l2_m2m_dev *m2m_dev;
+
+ pdev = of_find_device_by_node(node);
+ if (!pdev)
+ continue;
+
+ shared_vpu = platform_get_drvdata(pdev);
+ if (IS_ERR_OR_NULL(shared_vpu) || shared_vpu == vpu) {
+ platform_device_put(pdev);
+ continue;
+ }
+
+ v4l2_m2m_get(shared_vpu->m2m_dev);
+ m2m_dev = shared_vpu->m2m_dev;
+ platform_device_put(pdev);
+
+ of_node_put(node);
+
+ return m2m_dev;
+ }
+
+init_new_m2m_dev:
+ return v4l2_m2m_init(&vpu_m2m_ops);
+}
+
static int hantro_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
@@ -1186,7 +1222,7 @@ static int hantro_probe(struct platform_device *pdev)
}
platform_set_drvdata(pdev, vpu);

- vpu->m2m_dev = v4l2_m2m_init(&vpu_m2m_ops);
+ vpu->m2m_dev = hantro_get_v4l2_m2m_dev(vpu);
if (IS_ERR(vpu->m2m_dev)) {
v4l2_err(&vpu->v4l2_dev, "Failed to init mem2mem device\n");
ret = PTR_ERR(vpu->m2m_dev);
@@ -1225,7 +1261,7 @@ static int hantro_probe(struct platform_device *pdev)
hantro_remove_enc_func(vpu);
err_m2m_rel:
media_device_cleanup(&vpu->mdev);
- v4l2_m2m_release(vpu->m2m_dev);
+ v4l2_m2m_put(vpu->m2m_dev);
err_v4l2_unreg:
v4l2_device_unregister(&vpu->v4l2_dev);
err_clk_unprepare:
@@ -1248,7 +1284,7 @@ static void hantro_remove(struct platform_device *pdev)
hantro_remove_dec_func(vpu);
hantro_remove_enc_func(vpu);
media_device_cleanup(&vpu->mdev);
- v4l2_m2m_release(vpu->m2m_dev);
+ v4l2_m2m_put(vpu->m2m_dev);
v4l2_device_unregister(&vpu->v4l2_dev);
clk_bulk_unprepare(vpu->variant->num_clocks, vpu->clocks);
reset_control_assert(vpu->resets);
diff --git a/drivers/media/platform/verisilicon/imx8m_vpu_hw.c b/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
index 5be0e2e76882f..6f8e43b7f1575 100644
--- a/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
+++ b/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
@@ -343,6 +343,12 @@ const struct hantro_variant imx8mq_vpu_variant = {
.num_regs = ARRAY_SIZE(imx8mq_reg_names)
};

+static const struct of_device_id imx8mq_vpu_shared_resources[] __initconst = {
+ { .compatible = "nxp,imx8mq-vpu-g1", },
+ { .compatible = "nxp,imx8mq-vpu-g2", },
+ { /* sentinel */ }
+};
+
const struct hantro_variant imx8mq_vpu_g1_variant = {
.dec_fmts = imx8m_vpu_dec_fmts,
.num_dec_fmts = ARRAY_SIZE(imx8m_vpu_dec_fmts),
@@ -356,6 +362,7 @@ const struct hantro_variant imx8mq_vpu_g1_variant = {
.num_irqs = ARRAY_SIZE(imx8mq_irqs),
.clk_names = imx8mq_g1_clk_names,
.num_clocks = ARRAY_SIZE(imx8mq_g1_clk_names),
+ .shared_devices = imx8mq_vpu_shared_resources,
};

const struct hantro_variant imx8mq_vpu_g2_variant = {
@@ -371,6 +378,7 @@ const struct hantro_variant imx8mq_vpu_g2_variant = {
.num_irqs = ARRAY_SIZE(imx8mq_g2_irqs),
.clk_names = imx8mq_g2_clk_names,
.num_clocks = ARRAY_SIZE(imx8mq_g2_clk_names),
+ .shared_devices = imx8mq_vpu_shared_resources,
};

const struct hantro_variant imx8mm_vpu_g1_variant = {
--
2.51.0