Mali v15 exposes a 64-bit GPU_ID register with a different field layout
from earlier GPUs.

Add the register definitions and decoding helpers for the new format,
read GPU_WIDE_ID when the compatibility value indicates a v15 GPU, and
populate both the cached GPU_ID fields and the uAPI gpu_id_hi field.

This allows userspace and the driver to identify v15 GPUs correctly.

Signed-off-by: Karunika Choo <[email protected]>
---
 .../drm/panthor/panthor_gpu_discover_regs.h   | 17 +++++++++
 drivers/gpu/drm/panthor/panthor_hw.c          | 38 ++++++++++++++-----
 include/uapi/drm/panthor_drm.h                | 10 +++++
 3 files changed, 56 insertions(+), 9 deletions(-)
 create mode 100644 drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h

diff --git a/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h 
b/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h
new file mode 100644
index 000000000000..54bb104902ee
--- /dev/null
+++ b/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+/* Copyright 2026 ARM Limited. All rights reserved. */
+
+#ifndef __PANTHOR_GPU_DISCOVER_REGS_H__
+#define __PANTHOR_GPU_DISCOVER_REGS_H__
+
+#define GPU_WIDE_ID                                    0x0
+#define   GPU_WIDE_COMPAT                              0xF
+#define   GPU_WIDE_ARCH_MAJOR(x)                       (((x) & GENMASK(63, 
56)) >> 56)
+#define   GPU_WIDE_ARCH_MINOR(x)                       (((x) & GENMASK(55, 
48)) >> 48)
+#define   GPU_WIDE_ARCH_REV(x)                         (((x) & GENMASK(47, 
40)) >> 40)
+#define   GPU_WIDE_PROD_MAJOR(x)                       (((x) & GENMASK(39, 
32)) >> 32)
+#define   GPU_WIDE_VER_MAJOR(x)                                (((x) & 
GENMASK(23, 16)) >> 16)
+#define   GPU_WIDE_VER_MINOR(x)                                (((x) & 
GENMASK(15, 8)) >> 8)
+#define   GPU_WIDE_VER_STATUS(x)                       ((x) & GENMASK(7, 0))
+
+#endif /* __PANTHOR_GPU_DISCOVER_REGS_H__ */
diff --git a/drivers/gpu/drm/panthor/panthor_hw.c 
b/drivers/gpu/drm/panthor/panthor_hw.c
index 3570e2889584..833d10cbb2d6 100644
--- a/drivers/gpu/drm/panthor/panthor_hw.c
+++ b/drivers/gpu/drm/panthor/panthor_hw.c
@@ -9,6 +9,7 @@
 #include "panthor_device.h"
 #include "panthor_device_io.h"
 #include "panthor_gpu.h"
+#include "panthor_gpu_discover_regs.h"
 #include "panthor_gpu_regs.h"
 #include "panthor_hw.h"
 #include "panthor_pwr.h"
@@ -297,18 +298,37 @@ static int panthor_hw_bind_device(struct panthor_device 
*ptdev)
 static int panthor_hw_gpu_id_init(struct panthor_device *ptdev)
 {
        struct panthor_gpu_id *gpu_id = &ptdev->gpu_id;
-       ptdev->gpu_info.gpu_id = gpu_read(ptdev->iomem, GPU_ID);
+       u32 gpu_id32 = gpu_read(ptdev->iomem, GPU_ID);
 
-       if (!ptdev->gpu_info.gpu_id)
+       if (!gpu_id32)
                return -ENXIO;
 
-       gpu_id->arch.major = GPU_ARCH_MAJOR(ptdev->gpu_info.gpu_id);
-       gpu_id->arch.minor = GPU_ARCH_MINOR(ptdev->gpu_info.gpu_id);
-       gpu_id->arch.rev = GPU_ARCH_REV(ptdev->gpu_info.gpu_id);
-       gpu_id->prod_major = GPU_PROD_MAJOR(ptdev->gpu_info.gpu_id);
-       gpu_id->ver.major = GPU_VER_MAJOR(ptdev->gpu_info.gpu_id);
-       gpu_id->ver.minor = GPU_VER_MINOR(ptdev->gpu_info.gpu_id);
-       gpu_id->ver.status = GPU_VER_STATUS(ptdev->gpu_info.gpu_id);
+       ptdev->gpu_info.gpu_id = gpu_id32;
+
+       gpu_id->arch.major = GPU_ARCH_MAJOR(gpu_id32);
+       gpu_id->arch.minor = GPU_ARCH_MINOR(gpu_id32);
+       gpu_id->arch.rev = GPU_ARCH_REV(gpu_id32);
+       gpu_id->prod_major = GPU_PROD_MAJOR(gpu_id32);
+       gpu_id->ver.major = GPU_VER_MAJOR(gpu_id32);
+       gpu_id->ver.minor = GPU_VER_MINOR(gpu_id32);
+       gpu_id->ver.status = GPU_VER_STATUS(gpu_id32);
+
+       if (GPU_ARCH_MAJOR(gpu_id32) == GPU_WIDE_COMPAT) {
+               u64 gpu_id64 = gpu_read64(ptdev->iomem, GPU_WIDE_ID);
+               if (!gpu_id64)
+                       return -ENXIO;
+
+               ptdev->gpu_info.gpu_wide_id = gpu_id64;
+               ptdev->gpu_info.gpu_id = 0;
+
+               gpu_id->arch.major = GPU_WIDE_ARCH_MAJOR(gpu_id64);
+               gpu_id->arch.minor = GPU_WIDE_ARCH_MINOR(gpu_id64);
+               gpu_id->arch.rev = GPU_WIDE_ARCH_REV(gpu_id64);
+               gpu_id->prod_major = GPU_WIDE_PROD_MAJOR(gpu_id64);
+               gpu_id->ver.major = GPU_WIDE_VER_MAJOR(gpu_id64);
+               gpu_id->ver.minor = GPU_WIDE_VER_MINOR(gpu_id64);
+               gpu_id->ver.status = GPU_WIDE_VER_STATUS(gpu_id64);
+       }
 
        return 0;
 }
diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
index 0e455d91e77d..04fc9f133152 100644
--- a/include/uapi/drm/panthor_drm.h
+++ b/include/uapi/drm/panthor_drm.h
@@ -373,6 +373,16 @@ struct drm_panthor_gpu_info {
 
        /** @gpu_features: Bitmask describing supported GPU-wide features */
        __u64 gpu_features;
+
+       /** @gpu_wide_id: 64-bit GPU_ID for v15 onwards. */
+       __u64 gpu_wide_id;
+#define DRM_PANTHOR_WIDE_ARCH_MAJOR(x)         (((x) >> 56) & 0xff)
+#define DRM_PANTHOR_WIDE_ARCH_MINOR(x)         (((x) >> 48) & 0xff)
+#define DRM_PANTHOR_WIDE_ARCH_REV(x)           (((x) >> 40) & 0xff)
+#define DRM_PANTHOR_WIDE_PRODUCT_MAJOR(x)      (((x) >> 32) & 0xff)
+#define DRM_PANTHOR_WIDE_VERSION_MAJOR(x)      (((x) >> 16) & 0xff)
+#define DRM_PANTHOR_WIDE_VERSION_MINOR(x)      (((x) >> 8) & 0xff)
+#define DRM_PANTHOR_WIDE_VERSION_STATUS(x)     ((x) & 0xff)
 };
 
 /**
-- 
2.43.0

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