drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c - linux - Git at Google

 /*
  * Copyright 2014 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */
 #include "kfd_priv.h"
 #include <linux/mm.h>
 #include <linux/mman.h>
 #include <linux/slab.h>
 #include <linux/io.h>

 /*
  * This extension supports a kernel level doorbells management for
  * the kernel queues.
  * Basically the last doorbells page is devoted to kernel queues
  * and that's assures that any user process won't get access to the
  * kernel doorbells page
  */

 #define KERNEL_DOORBELL_PASID 1
 #define KFD_SIZE_OF_DOORBELL_IN_BYTES 4

 /*
  * Each device exposes a doorbell aperture, a PCI MMIO aperture that
  * receives 32-bit writes that are passed to queues as wptr values.
  * The doorbells are intended to be written by applications as part
  * of queueing work on user-mode queues.
  * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
  * We map the doorbell address space into user-mode when a process creates
  * its first queue on each device.
  * Although the mapping is done by KFD, it is equivalent to an mmap of
  * the /dev/kfd with the particular device encoded in the mmap offset.
  * There will be other uses for mmap of /dev/kfd, so only a range of
  * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
  */

 /* # of doorbell bytes allocated for each process. */
 static inline size_t doorbell_process_allocation(void)
 {
 	return roundup(KFD_SIZE_OF_DOORBELL_IN_BYTES *
 			KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
 			PAGE_SIZE);
 }

 /* Doorbell calculations for device init. */
 void kfd_doorbell_init(struct kfd_dev *kfd)
 {
 	size_t doorbell_start_offset;
 	size_t doorbell_aperture_size;
 	size_t doorbell_process_limit;

 	/*
 	 * We start with calculations in bytes because the input data might
 	 * only be byte-aligned.
 	 * Only after we have done the rounding can we assume any alignment.
 	 */

 	doorbell_start_offset =
 			roundup(kfd->shared_resources.doorbell_start_offset,
 					doorbell_process_allocation());

 	doorbell_aperture_size =
 			rounddown(kfd->shared_resources.doorbell_aperture_size,
 					doorbell_process_allocation());

 	if (doorbell_aperture_size > doorbell_start_offset)
 		doorbell_process_limit =
 			(doorbell_aperture_size - doorbell_start_offset) /
 						doorbell_process_allocation();
 	else
 		doorbell_process_limit = 0;

 	kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
 				doorbell_start_offset;

 	kfd->doorbell_id_offset = doorbell_start_offset / sizeof(u32);
 	kfd->doorbell_process_limit = doorbell_process_limit - 1;

 	kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
 						doorbell_process_allocation());

 	BUG_ON(!kfd->doorbell_kernel_ptr);

 	pr_debug("kfd: doorbell initialization:\n");
 	pr_debug("kfd: doorbell base           == 0x%08lX\n",
 			(uintptr_t)kfd->doorbell_base);

 	pr_debug("kfd: doorbell_id_offset      == 0x%08lX\n",
 			kfd->doorbell_id_offset);

 	pr_debug("kfd: doorbell_process_limit  == 0x%08lX\n",
 			doorbell_process_limit);

 	pr_debug("kfd: doorbell_kernel_offset  == 0x%08lX\n",
 			(uintptr_t)kfd->doorbell_base);

 	pr_debug("kfd: doorbell aperture size  == 0x%08lX\n",
 			kfd->shared_resources.doorbell_aperture_size);

 	pr_debug("kfd: doorbell kernel address == 0x%08lX\n",
 			(uintptr_t)kfd->doorbell_kernel_ptr);
 }

 int kfd_doorbell_mmap(struct kfd_process *process, struct vm_area_struct *vma)
 {
 	phys_addr_t address;
 	struct kfd_dev *dev;

 	/*
 	 * For simplicitly we only allow mapping of the entire doorbell
 	 * allocation of a single device & process.
 	 */
 	if (vma->vm_end - vma->vm_start != doorbell_process_allocation())
 		return -EINVAL;

 	/* Find kfd device according to gpu id */
 	dev = kfd_device_by_id(vma->vm_pgoff);
 	if (dev == NULL)
 		return -EINVAL;

 	/* Calculate physical address of doorbell */
 	address = kfd_get_process_doorbells(dev, process);

 	vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE |
 				VM_DONTDUMP | VM_PFNMAP;

 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

 	pr_debug("mapping doorbell page:\n");
 	pr_debug("     target user address == 0x%08llX\n",
 			(unsigned long long) vma->vm_start);
 	pr_debug("     physical address    == 0x%08llX\n", address);
 	pr_debug("     vm_flags            == 0x%04lX\n", vma->vm_flags);
 	pr_debug("     size                == 0x%04lX\n",
 			 doorbell_process_allocation());

 	return io_remap_pfn_range(vma,
 				vma->vm_start,
 				address >> PAGE_SHIFT,
 				doorbell_process_allocation(),
 				vma->vm_page_prot);
 }


 /* get kernel iomem pointer for a doorbell */
 u32 __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
 					unsigned int *doorbell_off)
 {
 	u32 inx;

 	BUG_ON(!kfd || !doorbell_off);

 	mutex_lock(&kfd->doorbell_mutex);
 	inx = find_first_zero_bit(kfd->doorbell_available_index,
 					KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);

 	__set_bit(inx, kfd->doorbell_available_index);
 	mutex_unlock(&kfd->doorbell_mutex);

 	if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
 		return NULL;

 	/*
 	 * Calculating the kernel doorbell offset using "faked" kernel
 	 * pasid that allocated for kernel queues only
 	 */
 	*doorbell_off = KERNEL_DOORBELL_PASID * (doorbell_process_allocation() /
 							sizeof(u32)) + inx;

 	pr_debug("kfd: get kernel queue doorbell\n"
 			 "     doorbell offset   == 0x%08d\n"
 			 "     kernel address    == 0x%08lX\n",
 		*doorbell_off, (uintptr_t)(kfd->doorbell_kernel_ptr + inx));

 	return kfd->doorbell_kernel_ptr + inx;
 }

 void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
 {
 	unsigned int inx;

 	BUG_ON(!kfd || !db_addr);

 	inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr);

 	mutex_lock(&kfd->doorbell_mutex);
 	__clear_bit(inx, kfd->doorbell_available_index);
 	mutex_unlock(&kfd->doorbell_mutex);
 }

 inline void write_kernel_doorbell(u32 __iomem *db, u32 value)
 {
 	if (db) {
 		writel(value, db);
 		pr_debug("writing %d to doorbell address 0x%p\n", value, db);
 	}
 }

 /*
  * queue_ids are in the range [0,MAX_PROCESS_QUEUES) and are mapped 1:1
  * to doorbells with the process's doorbell page
  */
 unsigned int kfd_queue_id_to_doorbell(struct kfd_dev *kfd,
 					struct kfd_process *process,
 					unsigned int queue_id)
 {
 	/*
 	 * doorbell_id_offset accounts for doorbells taken by KGD.
 	 * pasid * doorbell_process_allocation/sizeof(u32) adjusts
 	 * to the process's doorbells
 	 */
 	return kfd->doorbell_id_offset +
 		process->pasid * (doorbell_process_allocation()/sizeof(u32)) +
 		queue_id;
 }

 uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
 {
 	uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
 				kfd->shared_resources.doorbell_start_offset) /
 					doorbell_process_allocation() + 1;

 	return num_of_elems;

 }

 phys_addr_t kfd_get_process_doorbells(struct kfd_dev *dev,
 					struct kfd_process *process)
 {
 	return dev->doorbell_base +
 		process->pasid * doorbell_process_allocation();
 }
	/*
	* Copyright 2014 Advanced Micro Devices, Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*/
	#include "kfd_priv.h"
	#include <linux/mm.h>
	#include <linux/mman.h>
	#include <linux/slab.h>
	#include <linux/io.h>

	/*
	* This extension supports a kernel level doorbells management for
	* the kernel queues.
	* Basically the last doorbells page is devoted to kernel queues
	* and that's assures that any user process won't get access to the
	* kernel doorbells page
	*/

	#define KERNEL_DOORBELL_PASID 1
	#define KFD_SIZE_OF_DOORBELL_IN_BYTES 4

	/*
	* Each device exposes a doorbell aperture, a PCI MMIO aperture that
	* receives 32-bit writes that are passed to queues as wptr values.
	* The doorbells are intended to be written by applications as part
	* of queueing work on user-mode queues.
	* We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
	* We map the doorbell address space into user-mode when a process creates
	* its first queue on each device.
	* Although the mapping is done by KFD, it is equivalent to an mmap of
	* the /dev/kfd with the particular device encoded in the mmap offset.
	* There will be other uses for mmap of /dev/kfd, so only a range of
	* offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
	*/

	/* # of doorbell bytes allocated for each process. */
	static inline size_t doorbell_process_allocation(void)
	{
	return roundup(KFD_SIZE_OF_DOORBELL_IN_BYTES *
	KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
	PAGE_SIZE);
	}

	/* Doorbell calculations for device init. */
	void kfd_doorbell_init(struct kfd_dev *kfd)
	{
	size_t doorbell_start_offset;
	size_t doorbell_aperture_size;
	size_t doorbell_process_limit;

	/*
	* We start with calculations in bytes because the input data might
	* only be byte-aligned.
	* Only after we have done the rounding can we assume any alignment.
	*/

	doorbell_start_offset =
	roundup(kfd->shared_resources.doorbell_start_offset,
	doorbell_process_allocation());

	doorbell_aperture_size =
	rounddown(kfd->shared_resources.doorbell_aperture_size,
	doorbell_process_allocation());

	if (doorbell_aperture_size > doorbell_start_offset)
	doorbell_process_limit =
	(doorbell_aperture_size - doorbell_start_offset) /
	doorbell_process_allocation();
	else
	doorbell_process_limit = 0;

	kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
	doorbell_start_offset;

	kfd->doorbell_id_offset = doorbell_start_offset / sizeof(u32);
	kfd->doorbell_process_limit = doorbell_process_limit - 1;

	kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
	doorbell_process_allocation());

	BUG_ON(!kfd->doorbell_kernel_ptr);

	pr_debug("kfd: doorbell initialization:\n");
	pr_debug("kfd: doorbell base == 0x%08lX\n",
	(uintptr_t)kfd->doorbell_base);

	pr_debug("kfd: doorbell_id_offset == 0x%08lX\n",
	kfd->doorbell_id_offset);

	pr_debug("kfd: doorbell_process_limit == 0x%08lX\n",
	doorbell_process_limit);

	pr_debug("kfd: doorbell_kernel_offset == 0x%08lX\n",
	(uintptr_t)kfd->doorbell_base);

	pr_debug("kfd: doorbell aperture size == 0x%08lX\n",
	kfd->shared_resources.doorbell_aperture_size);

	pr_debug("kfd: doorbell kernel address == 0x%08lX\n",
	(uintptr_t)kfd->doorbell_kernel_ptr);
	}

	int kfd_doorbell_mmap(struct kfd_process process, struct vm_area_struct vma)
	{
	phys_addr_t address;
	struct kfd_dev *dev;

	/*
	* For simplicitly we only allow mapping of the entire doorbell
	* allocation of a single device & process.
	*/
	if (vma->vm_end - vma->vm_start != doorbell_process_allocation())
	return -EINVAL;

	/* Find kfd device according to gpu id */
	dev = kfd_device_by_id(vma->vm_pgoff);
	if (dev == NULL)
	return -EINVAL;

	/* Calculate physical address of doorbell */
	address = kfd_get_process_doorbells(dev, process);

	vma->vm_flags \|= VM_IO \| VM_DONTCOPY \| VM_DONTEXPAND \| VM_NORESERVE \|
	VM_DONTDUMP \| VM_PFNMAP;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	pr_debug("mapping doorbell page:\n");
	pr_debug(" target user address == 0x%08llX\n",
	(unsigned long long) vma->vm_start);
	pr_debug(" physical address == 0x%08llX\n", address);
	pr_debug(" vm_flags == 0x%04lX\n", vma->vm_flags);
	pr_debug(" size == 0x%04lX\n",
	doorbell_process_allocation());

	return io_remap_pfn_range(vma,
	vma->vm_start,
	address >> PAGE_SHIFT,
	doorbell_process_allocation(),
	vma->vm_page_prot);
	}


	/* get kernel iomem pointer for a doorbell */
	u32 __iomem kfd_get_kernel_doorbell(struct kfd_dev kfd,
	unsigned int *doorbell_off)
	{
	u32 inx;

	BUG_ON(!kfd \|\| !doorbell_off);

	mutex_lock(&kfd->doorbell_mutex);
	inx = find_first_zero_bit(kfd->doorbell_available_index,
	KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);

	__set_bit(inx, kfd->doorbell_available_index);
	mutex_unlock(&kfd->doorbell_mutex);

	if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
	return NULL;

	/*
	* Calculating the kernel doorbell offset using "faked" kernel
	* pasid that allocated for kernel queues only
	*/
	doorbell_off = KERNEL_DOORBELL_PASID (doorbell_process_allocation() /
	sizeof(u32)) + inx;

	pr_debug("kfd: get kernel queue doorbell\n"
	" doorbell offset == 0x%08d\n"
	" kernel address == 0x%08lX\n",
	*doorbell_off, (uintptr_t)(kfd->doorbell_kernel_ptr + inx));

	return kfd->doorbell_kernel_ptr + inx;
	}

	void kfd_release_kernel_doorbell(struct kfd_dev kfd, u32 __iomem db_addr)
	{
	unsigned int inx;

	BUG_ON(!kfd \|\| !db_addr);

	inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr);

	mutex_lock(&kfd->doorbell_mutex);
	__clear_bit(inx, kfd->doorbell_available_index);
	mutex_unlock(&kfd->doorbell_mutex);
	}

	inline void write_kernel_doorbell(u32 __iomem *db, u32 value)
	{
	if (db) {
	writel(value, db);
	pr_debug("writing %d to doorbell address 0x%p\n", value, db);
	}
	}

	/*
	* queue_ids are in the range [0,MAX_PROCESS_QUEUES) and are mapped 1:1
	* to doorbells with the process's doorbell page
	*/
	unsigned int kfd_queue_id_to_doorbell(struct kfd_dev *kfd,
	struct kfd_process *process,
	unsigned int queue_id)
	{
	/*
	* doorbell_id_offset accounts for doorbells taken by KGD.
	* pasid * doorbell_process_allocation/sizeof(u32) adjusts
	* to the process's doorbells
	*/
	return kfd->doorbell_id_offset +
	process->pasid * (doorbell_process_allocation()/sizeof(u32)) +
	queue_id;
	}

	uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
	{
	uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
	kfd->shared_resources.doorbell_start_offset) /
	doorbell_process_allocation() + 1;

	return num_of_elems;

	}

	phys_addr_t kfd_get_process_doorbells(struct kfd_dev *dev,
	struct kfd_process *process)
	{
	return dev->doorbell_base +
	process->pasid * doorbell_process_allocation();
	}