2 * Copyright 2014 Advanced Micro Devices, Inc.
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24 #include <linux/mman.h>
25 #include <linux/slab.h>
27 #include <linux/idr.h>
30 * This extension supports a kernel level doorbells management for the
31 * kernel queues using the first doorbell page reserved for the kernel.
35 * Each device exposes a doorbell aperture, a PCI MMIO aperture that
36 * receives 32-bit writes that are passed to queues as wptr values.
37 * The doorbells are intended to be written by applications as part
38 * of queueing work on user-mode queues.
39 * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
40 * We map the doorbell address space into user-mode when a process creates
41 * its first queue on each device.
42 * Although the mapping is done by KFD, it is equivalent to an mmap of
43 * the /dev/kfd with the particular device encoded in the mmap offset.
44 * There will be other uses for mmap of /dev/kfd, so only a range of
45 * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
48 /* # of doorbell bytes allocated for each process. */
49 size_t kfd_doorbell_process_slice(struct kfd_dev *kfd)
51 return roundup(kfd->device_info->doorbell_size *
52 KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
56 /* Doorbell calculations for device init. */
57 int kfd_doorbell_init(struct kfd_dev *kfd)
59 size_t doorbell_start_offset;
60 size_t doorbell_aperture_size;
61 size_t doorbell_process_limit;
64 * We start with calculations in bytes because the input data might
65 * only be byte-aligned.
66 * Only after we have done the rounding can we assume any alignment.
69 doorbell_start_offset =
70 roundup(kfd->shared_resources.doorbell_start_offset,
71 kfd_doorbell_process_slice(kfd));
73 doorbell_aperture_size =
74 rounddown(kfd->shared_resources.doorbell_aperture_size,
75 kfd_doorbell_process_slice(kfd));
77 if (doorbell_aperture_size > doorbell_start_offset)
78 doorbell_process_limit =
79 (doorbell_aperture_size - doorbell_start_offset) /
80 kfd_doorbell_process_slice(kfd);
84 if (!kfd->max_doorbell_slices ||
85 doorbell_process_limit < kfd->max_doorbell_slices)
86 kfd->max_doorbell_slices = doorbell_process_limit;
88 kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
89 doorbell_start_offset;
91 kfd->doorbell_base_dw_offset = doorbell_start_offset / sizeof(u32);
93 kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
94 kfd_doorbell_process_slice(kfd));
96 if (!kfd->doorbell_kernel_ptr)
99 pr_debug("Doorbell initialization:\n");
100 pr_debug("doorbell base == 0x%08lX\n",
101 (uintptr_t)kfd->doorbell_base);
103 pr_debug("doorbell_base_dw_offset == 0x%08lX\n",
104 kfd->doorbell_base_dw_offset);
106 pr_debug("doorbell_process_limit == 0x%08lX\n",
107 doorbell_process_limit);
109 pr_debug("doorbell_kernel_offset == 0x%08lX\n",
110 (uintptr_t)kfd->doorbell_base);
112 pr_debug("doorbell aperture size == 0x%08lX\n",
113 kfd->shared_resources.doorbell_aperture_size);
115 pr_debug("doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);
120 void kfd_doorbell_fini(struct kfd_dev *kfd)
122 if (kfd->doorbell_kernel_ptr)
123 iounmap(kfd->doorbell_kernel_ptr);
126 int kfd_doorbell_mmap(struct kfd_dev *dev, struct kfd_process *process,
127 struct vm_area_struct *vma)
130 struct kfd_process_device *pdd;
133 * For simplicitly we only allow mapping of the entire doorbell
134 * allocation of a single device & process.
136 if (vma->vm_end - vma->vm_start != kfd_doorbell_process_slice(dev))
139 pdd = kfd_get_process_device_data(dev, process);
143 /* Calculate physical address of doorbell */
144 address = kfd_get_process_doorbells(pdd);
145 vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE |
146 VM_DONTDUMP | VM_PFNMAP;
148 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
150 pr_debug("Mapping doorbell page\n"
151 " target user address == 0x%08llX\n"
152 " physical address == 0x%08llX\n"
153 " vm_flags == 0x%04lX\n"
154 " size == 0x%04lX\n",
155 (unsigned long long) vma->vm_start, address, vma->vm_flags,
156 kfd_doorbell_process_slice(dev));
159 return io_remap_pfn_range(vma,
161 address >> PAGE_SHIFT,
162 kfd_doorbell_process_slice(dev),
167 /* get kernel iomem pointer for a doorbell */
168 void __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
169 unsigned int *doorbell_off)
173 mutex_lock(&kfd->doorbell_mutex);
174 inx = find_first_zero_bit(kfd->doorbell_available_index,
175 KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);
177 __set_bit(inx, kfd->doorbell_available_index);
178 mutex_unlock(&kfd->doorbell_mutex);
180 if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
183 inx *= kfd->device_info->doorbell_size / sizeof(u32);
186 * Calculating the kernel doorbell offset using the first
189 *doorbell_off = kfd->doorbell_base_dw_offset + inx;
191 pr_debug("Get kernel queue doorbell\n"
192 " doorbell offset == 0x%08X\n"
193 " doorbell index == 0x%x\n",
196 return kfd->doorbell_kernel_ptr + inx;
199 void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
203 inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr)
204 * sizeof(u32) / kfd->device_info->doorbell_size;
206 mutex_lock(&kfd->doorbell_mutex);
207 __clear_bit(inx, kfd->doorbell_available_index);
208 mutex_unlock(&kfd->doorbell_mutex);
211 void write_kernel_doorbell(void __iomem *db, u32 value)
215 pr_debug("Writing %d to doorbell address %p\n", value, db);
219 void write_kernel_doorbell64(void __iomem *db, u64 value)
222 WARN(((unsigned long)db & 7) != 0,
223 "Unaligned 64-bit doorbell");
224 writeq(value, (u64 __iomem *)db);
225 pr_debug("writing %llu to doorbell address %p\n", value, db);
229 unsigned int kfd_get_doorbell_dw_offset_in_bar(struct kfd_dev *kfd,
230 struct kfd_process_device *pdd,
231 unsigned int doorbell_id)
234 * doorbell_base_dw_offset accounts for doorbells taken by KGD.
235 * index * kfd_doorbell_process_slice/sizeof(u32) adjusts to
236 * the process's doorbells. The offset returned is in dword
237 * units regardless of the ASIC-dependent doorbell size.
239 return kfd->doorbell_base_dw_offset +
241 * kfd_doorbell_process_slice(kfd) / sizeof(u32) +
242 doorbell_id * kfd->device_info->doorbell_size / sizeof(u32);
245 uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
247 uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
248 kfd->shared_resources.doorbell_start_offset) /
249 kfd_doorbell_process_slice(kfd) + 1;
255 phys_addr_t kfd_get_process_doorbells(struct kfd_process_device *pdd)
257 return pdd->dev->doorbell_base +
258 pdd->doorbell_index * kfd_doorbell_process_slice(pdd->dev);
261 int kfd_alloc_process_doorbells(struct kfd_dev *kfd, unsigned int *doorbell_index)
263 int r = ida_simple_get(&kfd->doorbell_ida, 1, kfd->max_doorbell_slices,
271 void kfd_free_process_doorbells(struct kfd_dev *kfd, unsigned int doorbell_index)
274 ida_simple_remove(&kfd->doorbell_ida, doorbell_index);