[RFC PATCH 2/2] drm/panthor: add initial mt8196 support

Chia-I Wu
2025-09-03T22:55:11Z

Add panthor_soc_data to control custom ASN_HASH. Add compatible string
for "mediatek,mt8196-mali" and enable custom ASN_HASH for the soc.

Without custom ASN_HASH, FW fails to boot

panthor 48000000.gpu: [drm] *ERROR* Unhandled Page fault in AS0 at VA 0x0000000000000000
panthor 48000000.gpu: [drm] *ERROR* Failed to boot MCU (status=fatal)
panthor 48000000.gpu: probe with driver panthor failed with error -110

With custom ASN_HASH, panthor probes fine and userspace boots to ui just
fine as well

panthor 48000000.gpu: [drm] clock rate = 0
panthor 48000000.gpu: EM: created perf domain
panthor 48000000.gpu: [drm] Mali-G925-Immortalis id 0xd830 major 0x0 minor 0x1 status 0x5
panthor 48000000.gpu: [drm] Features: L2:0x8130306 Tiler:0x809 Mem:0x301 MMU:0x2830 AS:0xff
panthor 48000000.gpu: [drm] shader_present=0xee0077 l2_present=0x1 tiler_present=0x1
panthor 48000000.gpu: [drm] Firmware protected mode entry not be supported, ignoring
panthor 48000000.gpu: [drm] Firmware git sha: 27713280172c742d467a4b7d11180930094092ec
panthor 48000000.gpu: [drm] CSF FW using interface v3.13.0, Features 0x10 Instrumentation features 0x71
[drm] Initialized panthor 1.5.0 for 48000000.gpu on minor 1

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
---
drivers/gpu/drm/panthor/Kconfig | 6 +++++
drivers/gpu/drm/panthor/Makefile | 2 ++
drivers/gpu/drm/panthor/panthor_device.c | 2 ++
drivers/gpu/drm/panthor/panthor_device.h | 4 +++
drivers/gpu/drm/panthor/panthor_drv.c | 4 +++
drivers/gpu/drm/panthor/panthor_gpu.c | 26 +++++++++++++++++++-
drivers/gpu/drm/panthor/panthor_regs.h | 4 +++
drivers/gpu/drm/panthor/panthor_soc.h | 26 ++++++++++++++++++++
drivers/gpu/drm/panthor/panthor_soc_mt8196.c | 9 +++++++
9 files changed, 82 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/panthor/panthor_soc.h
create mode 100644 drivers/gpu/drm/panthor/panthor_soc_mt8196.c

diff --git a/drivers/gpu/drm/panthor/Kconfig b/drivers/gpu/drm/panthor/Kconfig
index 55b40ad07f3b0..a207962cb518d 100644
--- a/drivers/gpu/drm/panthor/Kconfig
+++ b/drivers/gpu/drm/panthor/Kconfig
@@ -21,3 +21,9 @@ config DRM_PANTHOR

Note that the Mali-G68 and Mali-G78, while Valhall architecture, will
be supported with the panfrost driver as they are not CSF GPUs.
+
+config DRM_PANTHOR_SOC_MT8196
+ bool "Enable MediaTek MT8196 support"
+ depends on DRM_PANTHOR
+ help
+ Enable SoC-specific code for MediaTek MT8196.
diff --git a/drivers/gpu/drm/panthor/Makefile b/drivers/gpu/drm/panthor/Makefile
index 02db21748c125..75e92c461304b 100644
--- a/drivers/gpu/drm/panthor/Makefile
+++ b/drivers/gpu/drm/panthor/Makefile
@@ -12,4 +12,6 @@ panthor-y := \
panthor_mmu.o \
panthor_sched.o

+panthor-$(CONFIG_DRM_PANTHOR_SOC_MT8196) += panthor_soc_mt8196.o
+
obj-$(CONFIG_DRM_PANTHOR) += panthor.o
diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index 81df49880bd87..c7033d82cef55 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -172,6 +172,8 @@ int panthor_device_init(struct panthor_device *ptdev)
struct page *p;
int ret;

+ ptdev->soc_data = of_device_get_match_data(ptdev->base.dev);
+
init_completion(&ptdev->unplug.done);
ret = drmm_mutex_init(&ptdev->base, &ptdev->unplug.lock);
if (ret)
diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index 4fc7cf2aeed57..160977834e017 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -28,6 +28,7 @@ struct panthor_job;
struct panthor_mmu;
struct panthor_fw;
struct panthor_perfcnt;
+struct panthor_soc_data;
struct panthor_vm;
struct panthor_vm_pool;

@@ -93,6 +94,9 @@ struct panthor_device {
/** @base: Base drm_device. */
struct drm_device base;

+ /** @soc_data: Optional SoC data. */
+ const struct panthor_soc_data *soc_data;
+
/** @phys_addr: Physical address of the iomem region. */
phys_addr_t phys_addr;

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 9256806eb6623..061ba38dd1bad 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -33,6 +33,7 @@
#include "panthor_mmu.h"
#include "panthor_regs.h"
#include "panthor_sched.h"
+#include "panthor_soc.h"

/**
* DOC: user <-> kernel object copy helpers.
@@ -1683,6 +1684,9 @@ static struct attribute *panthor_attrs[] = {
ATTRIBUTE_GROUPS(panthor);

static const struct of_device_id dt_match[] = {
+#ifdef CONFIG_DRM_PANTHOR_SOC_MT8196
+ { .compatible = "mediatek,mt8196-mali", .data = &panthor_soc_data_mediatek_mt8196, },
+#endif
{ .compatible = "rockchip,rk3588-mali" },
{ .compatible = "arm,mali-valhall-csf" },
{}
diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
index db69449a5be09..e68001a330790 100644
--- a/drivers/gpu/drm/panthor/panthor_gpu.c
+++ b/drivers/gpu/drm/panthor/panthor_gpu.c
@@ -19,6 +19,7 @@
#include "panthor_device.h"
#include "panthor_gpu.h"
#include "panthor_regs.h"
+#include "panthor_soc.h"

/**
* struct panthor_gpu - GPU block management data.
@@ -52,6 +53,28 @@ static void panthor_gpu_coherency_set(struct panthor_device *ptdev)
ptdev->coherent ? GPU_COHERENCY_PROT_BIT(ACE_LITE) : GPU_COHERENCY_NONE);
}

+static void panthor_gpu_l2_config_set(struct panthor_device *ptdev)
+{
+ const struct panthor_soc_data *data = ptdev->soc_data;
+ u32 l2_config;
+ u32 i;
+
+ if (!data || !data->asn_hash_enable)
+ return;
+
+ if (GPU_ARCH_MAJOR(ptdev->gpu_info.gpu_id) < 11) {
+ drm_err(&ptdev->base, "Custom ASN hash not supported by the device");
+ return;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(data->asn_hash); i++)
+ gpu_write(ptdev, GPU_ASN_HASH(i), data->asn_hash[i]);
+
+ l2_config = gpu_read(ptdev, GPU_L2_CONFIG);
+ l2_config |= GPU_L2_CONFIG_ASN_HASH_ENABLE;
+ gpu_write(ptdev, GPU_L2_CONFIG, l2_config);
+}
+
static void panthor_gpu_irq_handler(struct panthor_device *ptdev, u32 status)
{
gpu_write(ptdev, GPU_INT_CLEAR, status);
@@ -241,8 +264,9 @@ int panthor_gpu_l2_power_on(struct panthor_device *ptdev)
hweight64(ptdev->gpu_info.shader_present));
}

- /* Set the desired coherency mode before the power up of L2 */
+ /* Set the desired coherency mode and L2 config before the power up of L2 */
panthor_gpu_coherency_set(ptdev);
+ panthor_gpu_l2_config_set(ptdev);

return panthor_gpu_power_on(ptdev, L2, 1, 20000);
}
diff --git a/drivers/gpu/drm/panthor/panthor_regs.h b/drivers/gpu/drm/panthor/panthor_regs.h
index 8bee76d01bf83..8fa69f33e911e 100644
--- a/drivers/gpu/drm/panthor/panthor_regs.h
+++ b/drivers/gpu/drm/panthor/panthor_regs.h
@@ -64,6 +64,8 @@

#define GPU_FAULT_STATUS 0x3C
#define GPU_FAULT_ADDR 0x40
+#define GPU_L2_CONFIG 0x48
+#define GPU_L2_CONFIG_ASN_HASH_ENABLE BIT(24)

#define GPU_PWR_KEY 0x50
#define GPU_PWR_KEY_UNLOCK 0x2968A819
@@ -110,6 +112,8 @@

#define GPU_REVID 0x280

+#define GPU_ASN_HASH(n) (0x2C0 + ((n) * 4))
+
#define GPU_COHERENCY_FEATURES 0x300
#define GPU_COHERENCY_PROT_BIT(name) BIT(GPU_COHERENCY_ ## name)

diff --git a/drivers/gpu/drm/panthor/panthor_soc.h b/drivers/gpu/drm/panthor/panthor_soc.h
new file mode 100644
index 0000000000000..784f4f359f0bb
--- /dev/null
+++ b/drivers/gpu/drm/panthor/panthor_soc.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+/* Copyright 2025 Google LLC */
+
+#ifndef __PANTHOR_SOC_H__
+#define __PANTHOR_SOC_H__
+
+#include <linux/types.h>
+
+struct panthor_device;
+
+/**
+ * struct panthor_soc_data - Panthor SoC Data
+ */
+struct panthor_soc_data {
+ /** @asn_hash_enable: True if GPU_L2_CONFIG_ASN_HASH_ENABLE must be set. */
+ bool asn_hash_enable;
+
+ /** @asn_hash: ASN_HASH values when asn_hash_enable is true. */
+ u32 asn_hash[3];
+};
+
+#ifdef CONFIG_DRM_PANTHOR_SOC_MT8196
+extern const struct panthor_soc_data panthor_soc_data_mediatek_mt8196;
+#endif
+
+#endif /* __PANTHOR_SOC_H__ */
diff --git a/drivers/gpu/drm/panthor/panthor_soc_mt8196.c b/drivers/gpu/drm/panthor/panthor_soc_mt8196.c
new file mode 100644
index 0000000000000..d85b2168c158c
--- /dev/null
+++ b/drivers/gpu/drm/panthor/panthor_soc_mt8196.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0 or MIT
+/* Copyright 2025 Google LLC */
+
+#include "panthor_soc.h"
+
+const struct panthor_soc_data panthor_soc_data_mediatek_mt8196 = {
+ .asn_hash_enable = true,
+ .asn_hash = { 0xb, 0xe, 0x0, },
+};
--
2.51.0.338.gd7d06c2dae-goog