drm/amdkfd: Clean up KFD_MMAP_ offset handling

Use bit-rotate for better clarity and remove _MASK from the #defines as
these represent mmap types.

Centralize all the parsing of the mmap offset in kfd_mmap and add device
parameter to doorbell and reserved_mem map functions.

Encode gpu_id into upper bits of vm_pgoff. This frees up the lower bits
for encoding the the doorbell ID on Vega10.

Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -292,7 +292,8 @@ static int kfd_ioctl_create_queue(struct file *filep, struct kfd_process *p,
 
 
 	/* Return gpu_id as doorbell offset for mmap usage */
-	args->doorbell_offset = (KFD_MMAP_DOORBELL_MASK | args->gpu_id);
+	args->doorbell_offset = KFD_MMAP_TYPE_DOORBELL;
+	args->doorbell_offset |= KFD_MMAP_GPU_ID(args->gpu_id);
 	args->doorbell_offset <<= PAGE_SHIFT;
 
 	mutex_unlock(&p->mutex);
@@ -1644,23 +1645,33 @@ err_i1:
 static int kfd_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct kfd_process *process;
+	struct kfd_dev *dev = NULL;
+	unsigned long vm_pgoff;
+	unsigned int gpu_id;
 
 	process = kfd_get_process(current);
 	if (IS_ERR(process))
 		return PTR_ERR(process);
 
-	if ((vma->vm_pgoff & KFD_MMAP_DOORBELL_MASK) ==
-			KFD_MMAP_DOORBELL_MASK) {
-		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_DOORBELL_MASK;
-		return kfd_doorbell_mmap(process, vma);
-	} else if ((vma->vm_pgoff & KFD_MMAP_EVENTS_MASK) ==
-			KFD_MMAP_EVENTS_MASK) {
-		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_EVENTS_MASK;
+	vm_pgoff = vma->vm_pgoff;
+	vma->vm_pgoff = KFD_MMAP_OFFSET_VALUE_GET(vm_pgoff);
+	gpu_id = KFD_MMAP_GPU_ID_GET(vm_pgoff);
+	if (gpu_id)
+		dev = kfd_device_by_id(gpu_id);
+
+	switch (vm_pgoff & KFD_MMAP_TYPE_MASK) {
+	case KFD_MMAP_TYPE_DOORBELL:
+		if (!dev)
+			return -ENODEV;
+		return kfd_doorbell_mmap(dev, process, vma);
+
+	case KFD_MMAP_TYPE_EVENTS:
 		return kfd_event_mmap(process, vma);
-	} else if ((vma->vm_pgoff & KFD_MMAP_RESERVED_MEM_MASK) ==
-			KFD_MMAP_RESERVED_MEM_MASK) {
-		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_RESERVED_MEM_MASK;
-		return kfd_reserved_mem_mmap(process, vma);
+
+	case KFD_MMAP_TYPE_RESERVED_MEM:
+		if (!dev)
+			return -ENODEV;
+		return kfd_reserved_mem_mmap(dev, process, vma);
 	}
 
 	return -EFAULT;

drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c

@@ -126,15 +126,10 @@ void kfd_doorbell_fini(struct kfd_dev *kfd)
 		iounmap(kfd->doorbell_kernel_ptr);
 }
 
-int kfd_doorbell_mmap(struct kfd_process *process, struct vm_area_struct *vma)
+int kfd_doorbell_mmap(struct kfd_dev *dev, struct kfd_process *process,
+		      struct vm_area_struct *vma)
 {
 	phys_addr_t address;
-	struct kfd_dev *dev;
-
-	/* Find kfd device according to gpu id */
-	dev = kfd_device_by_id(vma->vm_pgoff);
-	if (!dev)
-		return -EINVAL;
 
 	/*
 	 * For simplicitly we only allow mapping of the entire doorbell

drivers/gpu/drm/amd/amdkfd/kfd_events.c

@@ -345,7 +345,7 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
 	case KFD_EVENT_TYPE_DEBUG:
 		ret = create_signal_event(devkfd, p, ev);
 		if (!ret) {
-			*event_page_offset = KFD_MMAP_EVENTS_MASK;
+			*event_page_offset = KFD_MMAP_TYPE_EVENTS;
 			*event_page_offset <<= PAGE_SHIFT;
 			*event_slot_index = ev->event_id;
 		}

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -41,9 +41,33 @@
 
 #define KFD_SYSFS_FILE_MODE 0444
 
-#define KFD_MMAP_DOORBELL_MASK 0x8000000000000ull
-#define KFD_MMAP_EVENTS_MASK 0x4000000000000ull
-#define KFD_MMAP_RESERVED_MEM_MASK 0x2000000000000ull
+/* GPU ID hash width in bits */
+#define KFD_GPU_ID_HASH_WIDTH 16
+
+/* Use upper bits of mmap offset to store KFD driver specific information.
+ * BITS[63:62] - Encode MMAP type
+ * BITS[61:46] - Encode gpu_id. To identify to which GPU the offset belongs to
+ * BITS[45:0]  - MMAP offset value
+ *
+ * NOTE: struct vm_area_struct.vm_pgoff uses offset in pages. Hence, these
+ *  defines are w.r.t to PAGE_SIZE
+ */
+#define KFD_MMAP_TYPE_SHIFT	(62 - PAGE_SHIFT)
+#define KFD_MMAP_TYPE_MASK	(0x3ULL << KFD_MMAP_TYPE_SHIFT)
+#define KFD_MMAP_TYPE_DOORBELL	(0x3ULL << KFD_MMAP_TYPE_SHIFT)
+#define KFD_MMAP_TYPE_EVENTS	(0x2ULL << KFD_MMAP_TYPE_SHIFT)
+#define KFD_MMAP_TYPE_RESERVED_MEM	(0x1ULL << KFD_MMAP_TYPE_SHIFT)
+
+#define KFD_MMAP_GPU_ID_SHIFT (46 - PAGE_SHIFT)
+#define KFD_MMAP_GPU_ID_MASK (((1ULL << KFD_GPU_ID_HASH_WIDTH) - 1) \
+				<< KFD_MMAP_GPU_ID_SHIFT)
+#define KFD_MMAP_GPU_ID(gpu_id) ((((uint64_t)gpu_id) << KFD_MMAP_GPU_ID_SHIFT)\
+				& KFD_MMAP_GPU_ID_MASK)
+#define KFD_MMAP_GPU_ID_GET(offset)    ((offset & KFD_MMAP_GPU_ID_MASK) \
+				>> KFD_MMAP_GPU_ID_SHIFT)
+
+#define KFD_MMAP_OFFSET_VALUE_MASK	(0x3FFFFFFFFFFFULL >> PAGE_SHIFT)
+#define KFD_MMAP_OFFSET_VALUE_GET(offset) (offset & KFD_MMAP_OFFSET_VALUE_MASK)
 
 /*
  * When working with cp scheduler we should assign the HIQ manually or via
@@ -55,9 +79,6 @@
 #define KFD_CIK_HIQ_PIPE 4
 #define KFD_CIK_HIQ_QUEUE 0
 
-/* GPU ID hash width in bits */
-#define KFD_GPU_ID_HASH_WIDTH 16
-
 /* Macro for allocating structures */
 #define kfd_alloc_struct(ptr_to_struct)	\
 	((typeof(ptr_to_struct)) kzalloc(sizeof(*ptr_to_struct), GFP_KERNEL))
@@ -698,7 +719,7 @@ struct kfd_process_device *kfd_get_process_device_data(struct kfd_dev *dev,
 struct kfd_process_device *kfd_create_process_device_data(struct kfd_dev *dev,
 							struct kfd_process *p);
 
-int kfd_reserved_mem_mmap(struct kfd_process *process,
+int kfd_reserved_mem_mmap(struct kfd_dev *dev, struct kfd_process *process,
 			  struct vm_area_struct *vma);
 
 /* KFD process API for creating and translating handles */
@@ -728,7 +749,8 @@ void kfd_pasid_free(unsigned int pasid);
 /* Doorbells */
 int kfd_doorbell_init(struct kfd_dev *kfd);
 void kfd_doorbell_fini(struct kfd_dev *kfd);
-int kfd_doorbell_mmap(struct kfd_process *process, struct vm_area_struct *vma);
+int kfd_doorbell_mmap(struct kfd_dev *dev, struct kfd_process *process,
+		      struct vm_area_struct *vma);
 void __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
 					unsigned int *doorbell_off);
 void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr);

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -451,7 +451,8 @@ static int kfd_process_init_cwsr_apu(struct kfd_process *p, struct file *filep)
 		if (!dev->cwsr_enabled || qpd->cwsr_kaddr || qpd->cwsr_base)
 			continue;
 
-		offset = (dev->id | KFD_MMAP_RESERVED_MEM_MASK) << PAGE_SHIFT;
+		offset = (KFD_MMAP_TYPE_RESERVED_MEM | KFD_MMAP_GPU_ID(dev->id))
+			<< PAGE_SHIFT;
 		qpd->tba_addr = (int64_t)vm_mmap(filep, 0,
 			KFD_CWSR_TBA_TMA_SIZE, PROT_READ | PROT_EXEC,
 			MAP_SHARED, offset);
@@ -989,15 +990,12 @@ int kfd_resume_all_processes(void)
 	return ret;
 }
 
-int kfd_reserved_mem_mmap(struct kfd_process *process,
+int kfd_reserved_mem_mmap(struct kfd_dev *dev, struct kfd_process *process,
 			  struct vm_area_struct *vma)
 {
-	struct kfd_dev *dev = kfd_device_by_id(vma->vm_pgoff);
 	struct kfd_process_device *pdd;
 	struct qcm_process_device *qpd;
 
-	if (!dev)
-		return -EINVAL;
 	if ((vma->vm_end - vma->vm_start) != KFD_CWSR_TBA_TMA_SIZE) {
 		pr_err("Incorrect CWSR mapping size.\n");
 		return -EINVAL;