2 * Copyright 2014 Advanced Micro Devices, Inc.
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24 #include <linux/mman.h>
25 #include <linux/slab.h>
29 * This extension supports a kernel level doorbells management for
31 * Basically the last doorbells page is devoted to kernel queues
32 * and that's assures that any user process won't get access to the
33 * kernel doorbells page
36 #define KERNEL_DOORBELL_PASID 1
37 #define KFD_SIZE_OF_DOORBELL_IN_BYTES 4
40 * Each device exposes a doorbell aperture, a PCI MMIO aperture that
41 * receives 32-bit writes that are passed to queues as wptr values.
42 * The doorbells are intended to be written by applications as part
43 * of queueing work on user-mode queues.
44 * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
45 * We map the doorbell address space into user-mode when a process creates
46 * its first queue on each device.
47 * Although the mapping is done by KFD, it is equivalent to an mmap of
48 * the /dev/kfd with the particular device encoded in the mmap offset.
49 * There will be other uses for mmap of /dev/kfd, so only a range of
50 * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
53 /* # of doorbell bytes allocated for each process. */
54 static inline size_t doorbell_process_allocation(void)
56 return roundup(KFD_SIZE_OF_DOORBELL_IN_BYTES *
57 KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
61 /* Doorbell calculations for device init. */
62 int kfd_doorbell_init(struct kfd_dev *kfd)
64 size_t doorbell_start_offset;
65 size_t doorbell_aperture_size;
66 size_t doorbell_process_limit;
69 * We start with calculations in bytes because the input data might
70 * only be byte-aligned.
71 * Only after we have done the rounding can we assume any alignment.
74 doorbell_start_offset =
75 roundup(kfd->shared_resources.doorbell_start_offset,
76 doorbell_process_allocation());
78 doorbell_aperture_size =
79 rounddown(kfd->shared_resources.doorbell_aperture_size,
80 doorbell_process_allocation());
82 if (doorbell_aperture_size > doorbell_start_offset)
83 doorbell_process_limit =
84 (doorbell_aperture_size - doorbell_start_offset) /
85 doorbell_process_allocation();
87 doorbell_process_limit = 0;
89 kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
90 doorbell_start_offset;
92 kfd->doorbell_id_offset = doorbell_start_offset / sizeof(u32);
93 kfd->doorbell_process_limit = doorbell_process_limit - 1;
95 kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
96 doorbell_process_allocation());
98 if (!kfd->doorbell_kernel_ptr)
101 pr_debug("Doorbell initialization:\n");
102 pr_debug("doorbell base == 0x%08lX\n",
103 (uintptr_t)kfd->doorbell_base);
105 pr_debug("doorbell_id_offset == 0x%08lX\n",
106 kfd->doorbell_id_offset);
108 pr_debug("doorbell_process_limit == 0x%08lX\n",
109 doorbell_process_limit);
111 pr_debug("doorbell_kernel_offset == 0x%08lX\n",
112 (uintptr_t)kfd->doorbell_base);
114 pr_debug("doorbell aperture size == 0x%08lX\n",
115 kfd->shared_resources.doorbell_aperture_size);
117 pr_debug("doorbell kernel address == 0x%08lX\n",
118 (uintptr_t)kfd->doorbell_kernel_ptr);
123 void kfd_doorbell_fini(struct kfd_dev *kfd)
125 if (kfd->doorbell_kernel_ptr)
126 iounmap(kfd->doorbell_kernel_ptr);
129 int kfd_doorbell_mmap(struct kfd_process *process, struct vm_area_struct *vma)
135 * For simplicitly we only allow mapping of the entire doorbell
136 * allocation of a single device & process.
138 if (vma->vm_end - vma->vm_start != doorbell_process_allocation())
141 /* Find kfd device according to gpu id */
142 dev = kfd_device_by_id(vma->vm_pgoff);
146 /* Calculate physical address of doorbell */
147 address = kfd_get_process_doorbells(dev, process);
149 vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE |
150 VM_DONTDUMP | VM_PFNMAP;
152 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
154 pr_debug("Mapping doorbell page\n"
155 " target user address == 0x%08llX\n"
156 " physical address == 0x%08llX\n"
157 " vm_flags == 0x%04lX\n"
158 " size == 0x%04lX\n",
159 (unsigned long long) vma->vm_start, address, vma->vm_flags,
160 doorbell_process_allocation());
163 return io_remap_pfn_range(vma,
165 address >> PAGE_SHIFT,
166 doorbell_process_allocation(),
171 /* get kernel iomem pointer for a doorbell */
172 u32 __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
173 unsigned int *doorbell_off)
177 mutex_lock(&kfd->doorbell_mutex);
178 inx = find_first_zero_bit(kfd->doorbell_available_index,
179 KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);
181 __set_bit(inx, kfd->doorbell_available_index);
182 mutex_unlock(&kfd->doorbell_mutex);
184 if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
188 * Calculating the kernel doorbell offset using "faked" kernel
189 * pasid that allocated for kernel queues only
191 *doorbell_off = KERNEL_DOORBELL_PASID * (doorbell_process_allocation() /
194 pr_debug("Get kernel queue doorbell\n"
195 " doorbell offset == 0x%08X\n"
196 " kernel address == 0x%08lX\n",
197 *doorbell_off, (uintptr_t)(kfd->doorbell_kernel_ptr + inx));
199 return kfd->doorbell_kernel_ptr + inx;
202 void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
206 inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr);
208 mutex_lock(&kfd->doorbell_mutex);
209 __clear_bit(inx, kfd->doorbell_available_index);
210 mutex_unlock(&kfd->doorbell_mutex);
213 inline void write_kernel_doorbell(u32 __iomem *db, u32 value)
217 pr_debug("Writing %d to doorbell address 0x%p\n", value, db);
222 * queue_ids are in the range [0,MAX_PROCESS_QUEUES) and are mapped 1:1
223 * to doorbells with the process's doorbell page
225 unsigned int kfd_queue_id_to_doorbell(struct kfd_dev *kfd,
226 struct kfd_process *process,
227 unsigned int queue_id)
230 * doorbell_id_offset accounts for doorbells taken by KGD.
231 * pasid * doorbell_process_allocation/sizeof(u32) adjusts
232 * to the process's doorbells
234 return kfd->doorbell_id_offset +
235 process->pasid * (doorbell_process_allocation()/sizeof(u32)) +
239 uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
241 uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
242 kfd->shared_resources.doorbell_start_offset) /
243 doorbell_process_allocation() + 1;
249 phys_addr_t kfd_get_process_doorbells(struct kfd_dev *dev,
250 struct kfd_process *process)
252 return dev->doorbell_base +
253 process->pasid * doorbell_process_allocation();