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>
 #include <linux/idr.h>

 /*
  * This extension supports a kernel level doorbells management for the
  * kernel queues using the first doorbell page reserved for the kernel.
  */

 static DEFINE_IDA(doorbell_ida);
 static unsigned int max_doorbell_slices;

 /*
  * 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. */
 size_t kfd_doorbell_process_slice(struct kfd_dev *kfd)
 {
 	return roundup(kfd->device_info->doorbell_size *
 			KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
 			PAGE_SIZE);
 }

 /* Doorbell calculations for device init. */
 int 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,
 					kfd_doorbell_process_slice(kfd));

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

 	if (doorbell_aperture_size > doorbell_start_offset)
 		doorbell_process_limit =
 			(doorbell_aperture_size - doorbell_start_offset) /
 						kfd_doorbell_process_slice(kfd);
 	else
 		return -ENOSPC;

 	if (!max_doorbell_slices ||
 	    doorbell_process_limit < max_doorbell_slices)
 		max_doorbell_slices = doorbell_process_limit;

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

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

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

 	if (!kfd->doorbell_kernel_ptr)
 		return -ENOMEM;

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

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

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

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

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

 	pr_debug("doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);

 	return 0;
 }

 void kfd_doorbell_fini(struct kfd_dev *kfd)
 {
 	if (kfd->doorbell_kernel_ptr)
 		iounmap(kfd->doorbell_kernel_ptr);
 }

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

 	/*
 	 * For simplicitly we only allow mapping of the entire doorbell
 	 * allocation of a single device & process.
 	 */
 	if (vma->vm_end - vma->vm_start != kfd_doorbell_process_slice(dev))
 		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"
 		 "     target user address == 0x%08llX\n"
 		 "     physical address    == 0x%08llX\n"
 		 "     vm_flags            == 0x%04lX\n"
 		 "     size                == 0x%04lX\n",
 		 (unsigned long long) vma->vm_start, address, vma->vm_flags,
 		 kfd_doorbell_process_slice(dev));


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


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

 	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;

 	inx *= kfd->device_info->doorbell_size / sizeof(u32);

 	/*
 	 * Calculating the kernel doorbell offset using the first
 	 * doorbell page.
 	 */
 	*doorbell_off = kfd->doorbell_id_offset + inx;

 	pr_debug("Get kernel queue doorbell\n"
 			"     doorbell offset   == 0x%08X\n"
 			"     doorbell index    == 0x%x\n",
 		*doorbell_off, inx);

 	return kfd->doorbell_kernel_ptr + inx;
 }

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

 	inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr)
 		* sizeof(u32) / kfd->device_info->doorbell_size;

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

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

 void write_kernel_doorbell64(void __iomem *db, u64 value)
 {
 	if (db) {
 		WARN(((unsigned long)db & 7) != 0,
 		     "Unaligned 64-bit doorbell");
 		writeq(value, (u64 __iomem *)db);
 		pr_debug("writing %llu to doorbell address %p\n", value, db);
 	}
 }

 unsigned int kfd_doorbell_id_to_offset(struct kfd_dev *kfd,
 					struct kfd_process *process,
 					unsigned int doorbell_id)
 {
 	/*
 	 * doorbell_id_offset accounts for doorbells taken by KGD.
 	 * index * kfd_doorbell_process_slice/sizeof(u32) adjusts to
 	 * the process's doorbells. The offset returned is in dword
 	 * units regardless of the ASIC-dependent doorbell size.
 	 */
 	return kfd->doorbell_id_offset +
 		process->doorbell_index
 		* kfd_doorbell_process_slice(kfd) / sizeof(u32) +
 		doorbell_id * kfd->device_info->doorbell_size / sizeof(u32);
 }

 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) /
 					kfd_doorbell_process_slice(kfd) + 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->doorbell_index * kfd_doorbell_process_slice(dev);
 }

 int kfd_alloc_process_doorbells(struct kfd_process *process)
 {
 	int r = ida_simple_get(&doorbell_ida, 1, max_doorbell_slices,
 				GFP_KERNEL);
 	if (r > 0)
 		process->doorbell_index = r;

 	return r;
 }

 void kfd_free_process_doorbells(struct kfd_process *process)
 {
 	if (process->doorbell_index)
 		ida_simple_remove(&doorbell_ida, process->doorbell_index);
 }
	/*
	* 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>
	#include <linux/idr.h>

	/*
	* This extension supports a kernel level doorbells management for the
	* kernel queues using the first doorbell page reserved for the kernel.
	*/

	static DEFINE_IDA(doorbell_ida);
	static unsigned int max_doorbell_slices;

	/*
	* 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. */
	size_t kfd_doorbell_process_slice(struct kfd_dev *kfd)
	{
	return roundup(kfd->device_info->doorbell_size *
	KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
	PAGE_SIZE);
	}

	/* Doorbell calculations for device init. */
	int 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,
	kfd_doorbell_process_slice(kfd));

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

	if (doorbell_aperture_size > doorbell_start_offset)
	doorbell_process_limit =
	(doorbell_aperture_size - doorbell_start_offset) /
	kfd_doorbell_process_slice(kfd);
	else
	return -ENOSPC;

	if (!max_doorbell_slices \|\|
	doorbell_process_limit < max_doorbell_slices)
	max_doorbell_slices = doorbell_process_limit;

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

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

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

	if (!kfd->doorbell_kernel_ptr)
	return -ENOMEM;

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

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

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

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

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

	pr_debug("doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);

	return 0;
	}

	void kfd_doorbell_fini(struct kfd_dev *kfd)
	{
	if (kfd->doorbell_kernel_ptr)
	iounmap(kfd->doorbell_kernel_ptr);
	}

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

	/*
	* For simplicitly we only allow mapping of the entire doorbell
	* allocation of a single device & process.
	*/
	if (vma->vm_end - vma->vm_start != kfd_doorbell_process_slice(dev))
	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"
	" target user address == 0x%08llX\n"
	" physical address == 0x%08llX\n"
	" vm_flags == 0x%04lX\n"
	" size == 0x%04lX\n",
	(unsigned long long) vma->vm_start, address, vma->vm_flags,
	kfd_doorbell_process_slice(dev));


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


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

	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;

	inx *= kfd->device_info->doorbell_size / sizeof(u32);

	/*
	* Calculating the kernel doorbell offset using the first
	* doorbell page.
	*/
	*doorbell_off = kfd->doorbell_id_offset + inx;

	pr_debug("Get kernel queue doorbell\n"
	" doorbell offset == 0x%08X\n"
	" doorbell index == 0x%x\n",
	*doorbell_off, inx);

	return kfd->doorbell_kernel_ptr + inx;
	}

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

	inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr)
	* sizeof(u32) / kfd->device_info->doorbell_size;

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

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

	void write_kernel_doorbell64(void __iomem *db, u64 value)
	{
	if (db) {
	WARN(((unsigned long)db & 7) != 0,
	"Unaligned 64-bit doorbell");
	writeq(value, (u64 __iomem *)db);
	pr_debug("writing %llu to doorbell address %p\n", value, db);
	}
	}

	unsigned int kfd_doorbell_id_to_offset(struct kfd_dev *kfd,
	struct kfd_process *process,
	unsigned int doorbell_id)
	{
	/*
	* doorbell_id_offset accounts for doorbells taken by KGD.
	* index * kfd_doorbell_process_slice/sizeof(u32) adjusts to
	* the process's doorbells. The offset returned is in dword
	* units regardless of the ASIC-dependent doorbell size.
	*/
	return kfd->doorbell_id_offset +
	process->doorbell_index
	* kfd_doorbell_process_slice(kfd) / sizeof(u32) +
	doorbell_id * kfd->device_info->doorbell_size / sizeof(u32);
	}

	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) /
	kfd_doorbell_process_slice(kfd) + 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->doorbell_index * kfd_doorbell_process_slice(dev);
	}

	int kfd_alloc_process_doorbells(struct kfd_process *process)
	{
	int r = ida_simple_get(&doorbell_ida, 1, max_doorbell_slices,
	GFP_KERNEL);
	if (r > 0)
	process->doorbell_index = r;

	return r;
	}

	void kfd_free_process_doorbells(struct kfd_process *process)
	{
	if (process->doorbell_index)
	ida_simple_remove(&doorbell_ida, process->doorbell_index);
	}