[PATCH v7 1/6] drm/panthor: Expose GPU page sizes to UM

Adrián Larumbe
2026-04-15T11:29:28Z

In future commits that will implement repeated mappings, only repeat
values multiple of GPU page sizes will be tolerated. That means these
values must be made known to UM. Do it through a queriable GPU info
value.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
---
drivers/gpu/drm/panthor/panthor_device.h | 3 +++
drivers/gpu/drm/panthor/panthor_drv.c | 8 ++++++++
drivers/gpu/drm/panthor/panthor_mmu.c | 9 ++++++++-
include/uapi/drm/panthor_drm.h | 13 +++++++++++++
4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index 5cba272f9b4d..d856a4fe1d61 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -158,6 +158,9 @@ struct panthor_device {
/** @csif_info: Command stream interface information. */
struct drm_panthor_csif_info csif_info;

+ /** @mmu_info: MMU info */
+ struct drm_panthor_mmu_info mmu_info;
+
/** @hw: GPU-specific data. */
struct panthor_hw *hw;

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 73fc983dc9b4..a8090bc4e33c 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -175,6 +175,7 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
_Generic(_obj_name, \
PANTHOR_UOBJ_DECL(struct drm_panthor_gpu_info, tiler_present), \
PANTHOR_UOBJ_DECL(struct drm_panthor_csif_info, pad), \
+ PANTHOR_UOBJ_DECL(struct drm_panthor_mmu_info, page_size_bitmap), \
PANTHOR_UOBJ_DECL(struct drm_panthor_timestamp_info, current_timestamp), \
PANTHOR_UOBJ_DECL(struct drm_panthor_group_priorities_info, pad), \
PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
@@ -946,6 +947,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
args->size = sizeof(ptdev->csif_info);
return 0;

+ case DRM_PANTHOR_DEV_QUERY_MMU_INFO:
+ args->size = sizeof(ptdev->mmu_info);
+ return 0;
+
case DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO:
args->size = sizeof(timestamp_info);
return 0;
@@ -966,6 +971,9 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
case DRM_PANTHOR_DEV_QUERY_CSIF_INFO:
return PANTHOR_UOBJ_SET(args->pointer, args->size, ptdev->csif_info);

+ case DRM_PANTHOR_DEV_QUERY_MMU_INFO:
+ return PANTHOR_UOBJ_SET(args->pointer, args->size, ptdev->mmu_info);
+
case DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO:
ret = copy_struct_from_user(&timestamp_info,
sizeof(timestamp_info),
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index bd41c892beb7..01577be88933 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -2769,7 +2769,7 @@ panthor_vm_create(struct panthor_device *ptdev, bool for_mcu,
refcount_set(&vm->as.active_cnt, 0);

pgtbl_cfg = (struct io_pgtable_cfg) {
- .pgsize_bitmap = SZ_4K | SZ_2M,
+ .pgsize_bitmap = ptdev->mmu_info.page_size_bitmap,
.ias = va_bits,
.oas = pa_bits,
.coherent_walk = ptdev->coherent,
@@ -3214,6 +3214,11 @@ static void panthor_mmu_release_wq(struct drm_device *ddev, void *res)
destroy_workqueue(res);
}

+static void panthor_mmu_info_init(struct panthor_device *ptdev)
+{
+ ptdev->mmu_info.page_size_bitmap = SZ_4K | SZ_2M;
+}
+
/**
* panthor_mmu_init() - Initialize the MMU logic.
* @ptdev: Device.
@@ -3226,6 +3231,8 @@ int panthor_mmu_init(struct panthor_device *ptdev)
struct panthor_mmu *mmu;
int ret, irq;

+ panthor_mmu_info_init(ptdev);
+
mmu = drmm_kzalloc(&ptdev->base, sizeof(*mmu), GFP_KERNEL);
if (!mmu)
return -ENOMEM;
diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
index 0e455d91e77d..dc2704fc2829 100644
--- a/include/uapi/drm/panthor_drm.h
+++ b/include/uapi/drm/panthor_drm.h
@@ -246,6 +246,9 @@ enum drm_panthor_dev_query_type {
/** @DRM_PANTHOR_DEV_QUERY_CSIF_INFO: Query command-stream interface information. */
DRM_PANTHOR_DEV_QUERY_CSIF_INFO,

+ /** @DRM_PANTHOR_DEV_QUERY_MMU_INFO: Query MMU information. */
+ DRM_PANTHOR_DEV_QUERY_MMU_INFO,
+
/** @DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO: Query timestamp information. */
DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO,

@@ -487,6 +490,16 @@ struct drm_panthor_timestamp_info {
__u64 cpu_timestamp_nsec;
};

+/**
+ * struct drm_panthor_mmu_info - MMU information
+ *
+ * Structure grouping all queryable information relating to the MMU.
+ */
+struct drm_panthor_mmu_info {
+ /** @page_size_bitmap: Allowed page sizes */
+ __u64 page_size_bitmap;
+};
+
/**
* struct drm_panthor_group_priorities_info - Group priorities information
*
--
2.53.0