diff mbox series

[3/8] drm/panthor: Map doorbell pages

Message ID 20240828172605.19176-4-mihail.atanassov@arm.com (mailing list archive)
State New, archived
Headers show
Series drm/panthor: Add user submission | expand

Commit Message

Mihail Atanassov Aug. 28, 2024, 5:25 p.m. UTC 
From: Ketil Johnsen <ketil.johnsen@arm.com>

Dinging the doorbell directly from userspace allows the user driver to
bypass the kernel if the group is already assigned and active.

Signed-off-by: Ketil Johnsen <ketil.johnsen@arm.com>
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
---
 drivers/gpu/drm/panthor/panthor_device.c | 66 ++++++++++++++++++------
 drivers/gpu/drm/panthor/panthor_device.h |  7 ++-
 drivers/gpu/drm/panthor/panthor_drv.c    |  3 +-
 drivers/gpu/drm/panthor/panthor_fw.c     |  2 +-
 drivers/gpu/drm/panthor/panthor_sched.c  | 46 ++++++++++++++++-
 drivers/gpu/drm/panthor/panthor_sched.h  |  2 +
 6 files changed, 104 insertions(+), 22 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index 4082c8f2951d..3c376e21bd2e 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -179,6 +179,14 @@  int panthor_device_init(struct panthor_device *ptdev)
 	if (ret)
 		return ret;
 
+	ptdev->dummy_doorbell_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!ptdev->dummy_doorbell_page)
+		return -ENOMEM;
+
+	ret = drmm_add_action_or_reset(&ptdev->base, panthor_device_free_page,
+				       page_address(ptdev->dummy_doorbell_page));
+	if (ret)
+		return ret;
 	/*
 	 * Set the dummy page holding the latest flush to 1. This will cause the
 	 * flush to avoided as we know it isn't necessary if the submission
@@ -343,41 +351,58 @@  const char *panthor_exception_name(struct panthor_device *ptdev, u32 exception_c
 static vm_fault_t panthor_mmio_vm_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
-	struct panthor_device *ptdev = vma->vm_private_data;
+	struct panthor_file *pfile = vma->vm_private_data;
+	struct panthor_device *ptdev = pfile->ptdev;
 	u64 offset = (u64)vma->vm_pgoff << PAGE_SHIFT;
 	unsigned long pfn;
 	pgprot_t pgprot;
 	vm_fault_t ret;
 	bool active;
 	int cookie;
+	u32 group_handle;
+	u8 doorbell_id;
 
 	if (!drm_dev_enter(&ptdev->base, &cookie))
 		return VM_FAULT_SIGBUS;
 
-	mutex_lock(&ptdev->pm.mmio_lock);
-	active = atomic_read(&ptdev->pm.state) == PANTHOR_DEVICE_PM_STATE_ACTIVE;
-
 	switch (offset) {
 	case DRM_PANTHOR_USER_FLUSH_ID_MMIO_OFFSET:
-		if (active)
+		mutex_lock(&ptdev->pm.mmio_lock);
+
+		pgprot = vma->vm_page_prot;
+
+		active = atomic_read(&ptdev->pm.state) == PANTHOR_DEVICE_PM_STATE_ACTIVE;
+		if (active) {
 			pfn = __phys_to_pfn(ptdev->phys_addr + CSF_GPU_LATEST_FLUSH_ID);
-		else
+			pgprot = pgprot_noncached(pgprot);
+		} else {
 			pfn = page_to_pfn(ptdev->pm.dummy_latest_flush);
+		}
+
+		ret = vmf_insert_pfn_prot(vma, vmf->address, pfn, pgprot);
+
+		mutex_unlock(&ptdev->pm.mmio_lock);
+
+		break;
+
+	case PANTHOR_DOORBELL_OFFSET_START ... (PANTHOR_DOORBELL_OFFSET_END - 1):
+		group_handle = PANTHOR_DOORBELL_GROUP_FROM_OFFSET(offset) + 1;
+
+		doorbell_id = panthor_sched_doorbell_id(pfile, group_handle);
+		if (doorbell_id != (u8)-1)
+			pfn = PHYS_PFN(ptdev->phys_addr + CSF_DOORBELL(doorbell_id));
+		else
+			pfn = page_to_pfn(ptdev->dummy_doorbell_page);
+
+		ret = vmf_insert_pfn_prot(vma, vmf->address, pfn,
+					  pgprot_device(vma->vm_page_prot));
+
 		break;
 
 	default:
 		ret = VM_FAULT_SIGBUS;
-		goto out_unlock;
 	}
 
-	pgprot = vma->vm_page_prot;
-	if (active)
-		pgprot = pgprot_noncached(pgprot);
-
-	ret = vmf_insert_pfn_prot(vma, vmf->address, pfn, pgprot);
-
-out_unlock:
-	mutex_unlock(&ptdev->pm.mmio_lock);
 	drm_dev_exit(cookie);
 	return ret;
 }
@@ -386,7 +411,7 @@  static const struct vm_operations_struct panthor_mmio_vm_ops = {
 	.fault = panthor_mmio_vm_fault,
 };
 
-int panthor_device_mmap_io(struct panthor_device *ptdev, struct vm_area_struct *vma)
+int panthor_device_mmap_io(struct panthor_file *pfile, struct vm_area_struct *vma)
 {
 	u64 offset = (u64)vma->vm_pgoff << PAGE_SHIFT;
 
@@ -398,12 +423,19 @@  int panthor_device_mmap_io(struct panthor_device *ptdev, struct vm_area_struct *
 
 		break;
 
+	case PANTHOR_DOORBELL_OFFSET_START ... (PANTHOR_DOORBELL_OFFSET_END - 1):
+		if (vma->vm_end - vma->vm_start != PAGE_SIZE ||
+		    (vma->vm_flags & (VM_READ | VM_EXEC)))
+			return -EINVAL;
+
+		break;
+
 	default:
 		return -EINVAL;
 	}
 
 	/* Defer actual mapping to the fault handler. */
-	vma->vm_private_data = ptdev;
+	vma->vm_private_data = pfile;
 	vma->vm_ops = &panthor_mmio_vm_ops;
 	vm_flags_set(vma,
 		     VM_IO | VM_DONTCOPY | VM_DONTEXPAND |
diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index 7c27dbba8270..87cce384e36a 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -162,6 +162,9 @@  struct panthor_device {
 		 */
 		struct page *dummy_latest_flush;
 	} pm;
+
+	/** @dummy_doorbell_page: dummy doorbell page when queue is not on HW */
+	struct page *dummy_doorbell_page;
 };
 
 /**
@@ -204,7 +207,7 @@  static inline bool panthor_device_reset_is_pending(struct panthor_device *ptdev)
 	return atomic_read(&ptdev->reset.pending) != 0;
 }
 
-int panthor_device_mmap_io(struct panthor_device *ptdev,
+int panthor_device_mmap_io(struct panthor_file *pfile,
 			   struct vm_area_struct *vma);
 
 int panthor_device_resume(struct device *dev);
@@ -376,6 +379,8 @@  static int panthor_request_ ## __name ## _irq(struct panthor_device *ptdev,			\
 					((group) << DRM_PANTHOR_MAX_PAGE_SHIFT))
 #define PANTHOR_DOORBELL_OFFSET_START PANTHOR_DOORBELL_OFFSET(0)
 #define PANTHOR_DOORBELL_OFFSET_END PANTHOR_DOORBELL_OFFSET(MAX_GROUPS_PER_POOL)
+#define PANTHOR_DOORBELL_GROUP_FROM_OFFSET(offset) \
+	((offset - PANTHOR_PRIVATE_MMIO_OFFSET) >> DRM_PANTHOR_MAX_PAGE_SHIFT)
 
 extern struct workqueue_struct *panthor_cleanup_wq;
 
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 0bd600c464b8..e391ab6aaab2 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1381,7 +1381,6 @@  static int panthor_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct drm_file *file = filp->private_data;
 	struct panthor_file *pfile = file->driver_priv;
-	struct panthor_device *ptdev = pfile->ptdev;
 	u64 offset = (u64)vma->vm_pgoff << PAGE_SHIFT;
 	int ret, cookie;
 
@@ -1404,7 +1403,7 @@  static int panthor_mmap(struct file *filp, struct vm_area_struct *vma)
 #endif
 
 	if (offset >= DRM_PANTHOR_USER_MMIO_OFFSET)
-		ret = panthor_device_mmap_io(ptdev, vma);
+		ret = panthor_device_mmap_io(pfile, vma);
 	else
 		ret = drm_gem_mmap(filp, vma);
 
diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index ef232c0c2049..ce51f75a419b 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -444,7 +444,7 @@  panthor_fw_alloc_queue_iface_mem(struct panthor_device *ptdev,
 	int ret;
 
 	mem = panthor_kernel_bo_create(ptdev, ptdev->fw->vm, SZ_8K,
-				       DRM_PANTHOR_BO_NO_MMAP,
+				       0,
 				       DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC |
 				       DRM_PANTHOR_VM_BIND_OP_MAP_UNCACHED,
 				       PANTHOR_VM_KERNEL_AUTO_VA);
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index ad160a821957..471bb8f2b44c 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -954,6 +954,10 @@  group_bind_locked(struct panthor_group *group, u32 csg_id)
 	for (u32 i = 0; i < group->queue_count; i++)
 		group->queues[i]->doorbell_id = csg_id + 1;
 
+	/* Unmap the dummy doorbell page (if mapped) */
+	unmap_mapping_range(ptdev->base.anon_inode->i_mapping,
+			    PANTHOR_DOORBELL_OFFSET(group->handle - 1), 0, 1);
+
 	csg_slot->group = group;
 
 	return 0;
@@ -990,6 +994,10 @@  group_unbind_locked(struct panthor_group *group)
 	for (u32 i = 0; i < group->queue_count; i++)
 		group->queues[i]->doorbell_id = -1;
 
+	/* Unmap the dummy doorbell page (if mapped) */
+	unmap_mapping_range(ptdev->base.anon_inode->i_mapping,
+			    PANTHOR_DOORBELL_OFFSET(group->handle - 1), 0, 1);
+
 	slot->group = NULL;
 
 	group_put(group);
@@ -1726,6 +1734,41 @@  void panthor_sched_report_fw_events(struct panthor_device *ptdev, u32 events)
 	sched_queue_work(ptdev->scheduler, fw_events);
 }
 
+/**
+ * panthor_sched_doorbell_id() - Get the doorbell ID for a given group.
+ * @pfile: Panthor file.
+ * @group_handle: group slot id
+ *
+ * Return: a doorbell ID if valid, -1 otherwise
+ */
+u8 panthor_sched_doorbell_id(struct panthor_file *pfile, u32 group_handle)
+{
+	struct panthor_group_pool *gpool = pfile->groups;
+	struct panthor_scheduler *sched = pfile->ptdev->scheduler;
+	u8 doorbell_id;
+	struct panthor_group *group;
+
+	group = group_get(xa_load(&gpool->xa, group_handle));
+	if (!group)
+		return -1;
+
+	if (!group->queue_count) {
+		doorbell_id = -1;
+		goto err_put_group;
+	}
+
+	mutex_lock(&sched->lock);
+
+	/* In current implementation, all queues of same group share same doorbell page. */
+	doorbell_id = group->queues[0]->doorbell_id;
+
+	mutex_unlock(&sched->lock);
+
+err_put_group:
+	group_put(group);
+	return doorbell_id;
+}
+
 static const char *fence_get_driver_name(struct dma_fence *fence)
 {
 	return "panthor";
@@ -3057,6 +3100,7 @@  group_create_queue(struct panthor_group *group,
 	if (!queue)
 		return ERR_PTR(-ENOMEM);
 
+	queue->doorbell_id = -1;
 	queue->fence_ctx.id = dma_fence_context_alloc(1);
 	spin_lock_init(&queue->fence_ctx.lock);
 	INIT_LIST_HEAD(&queue->fence_ctx.in_flight_jobs);
@@ -3065,7 +3109,7 @@  group_create_queue(struct panthor_group *group,
 
 	queue->ringbuf = panthor_kernel_bo_create(group->ptdev, group->vm,
 						  args->ringbuf_size,
-						  DRM_PANTHOR_BO_NO_MMAP,
+						  0,
 						  DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC |
 						  DRM_PANTHOR_VM_BIND_OP_MAP_UNCACHED,
 						  PANTHOR_VM_KERNEL_AUTO_VA);
diff --git a/drivers/gpu/drm/panthor/panthor_sched.h b/drivers/gpu/drm/panthor/panthor_sched.h
index 55b6534fa390..0b3a2ee2a0ad 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.h
+++ b/drivers/gpu/drm/panthor/panthor_sched.h
@@ -47,4 +47,6 @@  void panthor_sched_resume(struct panthor_device *ptdev);
 void panthor_sched_report_mmu_fault(struct panthor_device *ptdev);
 void panthor_sched_report_fw_events(struct panthor_device *ptdev, u32 events);
 
+u8 panthor_sched_doorbell_id(struct panthor_file *pfile, u32 group_handle);
+
 #endif