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

   1 /*
   2  * Copyright 2014 Advanced Micro Devices, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  */
  22 #include "kfd_priv.h"
  23 #include <linux/mm.h>
  24 #include <linux/mman.h>
  25 #include <linux/slab.h>
  26 #include <linux/io.h>
  27 #include <linux/idr.h>
  28
  29 /*
  30  * This extension supports a kernel level doorbells management for the
  31  * kernel queues using the first doorbell page reserved for the kernel.
  32  */
  33
  34 static DEFINE_IDA(doorbell_ida);
  35 static unsigned int max_doorbell_slices;
  36 #define KFD_SIZE_OF_DOORBELL_IN_BYTES 4
  37
  38 /*
  39  * Each device exposes a doorbell aperture, a PCI MMIO aperture that
  40  * receives 32-bit writes that are passed to queues as wptr values.
  41  * The doorbells are intended to be written by applications as part
  42  * of queueing work on user-mode queues.
  43  * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
  44  * We map the doorbell address space into user-mode when a process creates
  45  * its first queue on each device.
  46  * Although the mapping is done by KFD, it is equivalent to an mmap of
  47  * the /dev/kfd with the particular device encoded in the mmap offset.
  48  * There will be other uses for mmap of /dev/kfd, so only a range of
  49  * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
  50  */
  51
  52 /* # of doorbell bytes allocated for each process. */
  53 static inline size_t doorbell_process_allocation(void)
  54 {
  55         return roundup(KFD_SIZE_OF_DOORBELL_IN_BYTES *
  56                         KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
  57                         PAGE_SIZE);
  58 }
  59
  60 /* Doorbell calculations for device init. */
  61 int kfd_doorbell_init(struct kfd_dev *kfd)
  62 {
  63         size_t doorbell_start_offset;
  64         size_t doorbell_aperture_size;
  65         size_t doorbell_process_limit;
  66
  67         /*
  68          * We start with calculations in bytes because the input data might
  69          * only be byte-aligned.
  70          * Only after we have done the rounding can we assume any alignment.
  71          */
  72
  73         doorbell_start_offset =
  74                         roundup(kfd->shared_resources.doorbell_start_offset,
  75                                         doorbell_process_allocation());
  76
  77         doorbell_aperture_size =
  78                         rounddown(kfd->shared_resources.doorbell_aperture_size,
  79                                         doorbell_process_allocation());
  80
  81         if (doorbell_aperture_size > doorbell_start_offset)
  82                 doorbell_process_limit =
  83                         (doorbell_aperture_size - doorbell_start_offset) /
  84                                                 doorbell_process_allocation();
  85         else
  86                 return -ENOSPC;
  87
  88         if (!max_doorbell_slices ||
  89             doorbell_process_limit < max_doorbell_slices)
  90                 max_doorbell_slices = doorbell_process_limit;
  91
  92         kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
  93                                 doorbell_start_offset;
  94
  95         kfd->doorbell_id_offset = doorbell_start_offset / sizeof(u32);
  96
  97         kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
  98                                                 doorbell_process_allocation());
  99
 100         if (!kfd->doorbell_kernel_ptr)
 101                 return -ENOMEM;
 102
 103         pr_debug("Doorbell initialization:\n");
 104         pr_debug("doorbell base           == 0x%08lX\n",
 105                         (uintptr_t)kfd->doorbell_base);
 106
 107         pr_debug("doorbell_id_offset      == 0x%08lX\n",
 108                         kfd->doorbell_id_offset);
 109
 110         pr_debug("doorbell_process_limit  == 0x%08lX\n",
 111                         doorbell_process_limit);
 112
 113         pr_debug("doorbell_kernel_offset  == 0x%08lX\n",
 114                         (uintptr_t)kfd->doorbell_base);
 115
 116         pr_debug("doorbell aperture size  == 0x%08lX\n",
 117                         kfd->shared_resources.doorbell_aperture_size);
 118
 119         pr_debug("doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);
 120
 121         return 0;
 122 }
 123
 124 void kfd_doorbell_fini(struct kfd_dev *kfd)
 125 {
 126         if (kfd->doorbell_kernel_ptr)
 127                 iounmap(kfd->doorbell_kernel_ptr);
 128 }
 129
 130 int kfd_doorbell_mmap(struct kfd_process *process, struct vm_area_struct *vma)
 131 {
 132         phys_addr_t address;
 133         struct kfd_dev *dev;
 134
 135         /*
 136          * For simplicitly we only allow mapping of the entire doorbell
 137          * allocation of a single device & process.
 138          */
 139         if (vma->vm_end - vma->vm_start != doorbell_process_allocation())
 140                 return -EINVAL;
 141
 142         /* Find kfd device according to gpu id */
 143         dev = kfd_device_by_id(vma->vm_pgoff);
 144         if (!dev)
 145                 return -EINVAL;
 146
 147         /* Calculate physical address of doorbell */
 148         address = kfd_get_process_doorbells(dev, process);
 149
 150         vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE |
 151                                 VM_DONTDUMP | VM_PFNMAP;
 152
 153         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 154
 155         pr_debug("Mapping doorbell page\n"
 156                  "     target user address == 0x%08llX\n"
 157                  "     physical address    == 0x%08llX\n"
 158                  "     vm_flags            == 0x%04lX\n"
 159                  "     size                == 0x%04lX\n",
 160                  (unsigned long long) vma->vm_start, address, vma->vm_flags,
 161                  doorbell_process_allocation());
 162
 163
 164         return io_remap_pfn_range(vma,
 165                                 vma->vm_start,
 166                                 address >> PAGE_SHIFT,
 167                                 doorbell_process_allocation(),
 168                                 vma->vm_page_prot);
 169 }
 170
 171
 172 /* get kernel iomem pointer for a doorbell */
 173 u32 __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
 174                                         unsigned int *doorbell_off)
 175 {
 176         u32 inx;
 177
 178         mutex_lock(&kfd->doorbell_mutex);
 179         inx = find_first_zero_bit(kfd->doorbell_available_index,
 180                                         KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);
 181
 182         __set_bit(inx, kfd->doorbell_available_index);
 183         mutex_unlock(&kfd->doorbell_mutex);
 184
 185         if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
 186                 return NULL;
 187
 188         /*
 189          * Calculating the kernel doorbell offset using the first
 190          * doorbell page.
 191          */
 192         *doorbell_off = kfd->doorbell_id_offset + inx;
 193
 194         pr_debug("Get kernel queue doorbell\n"
 195                          "     doorbell offset   == 0x%08X\n"
 196                          "     kernel address    == %p\n",
 197                 *doorbell_off, (kfd->doorbell_kernel_ptr + inx));
 198
 199         return kfd->doorbell_kernel_ptr + inx;
 200 }
 201
 202 void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
 203 {
 204         unsigned int inx;
 205
 206         inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr);
 207
 208         mutex_lock(&kfd->doorbell_mutex);
 209         __clear_bit(inx, kfd->doorbell_available_index);
 210         mutex_unlock(&kfd->doorbell_mutex);
 211 }
 212
 213 inline void write_kernel_doorbell(u32 __iomem *db, u32 value)
 214 {
 215         if (db) {
 216                 writel(value, db);
 217                 pr_debug("Writing %d to doorbell address %p\n", value, db);
 218         }
 219 }
 220
 221 /*
 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
 224  */
 225 unsigned int kfd_queue_id_to_doorbell(struct kfd_dev *kfd,
 226                                         struct kfd_process *process,
 227                                         unsigned int queue_id)
 228 {
 229         /*
 230          * doorbell_id_offset accounts for doorbells taken by KGD.
 231          * index * doorbell_process_allocation/sizeof(u32) adjusts to
 232          * the process's doorbells.
 233          */
 234         return kfd->doorbell_id_offset +
 235                 process->doorbell_index
 236                 * doorbell_process_allocation() / sizeof(u32) +
 237                 queue_id;
 238 }
 239
 240 uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
 241 {
 242         uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
 243                                 kfd->shared_resources.doorbell_start_offset) /
 244                                         doorbell_process_allocation() + 1;
 245
 246         return num_of_elems;
 247
 248 }
 249
 250 phys_addr_t kfd_get_process_doorbells(struct kfd_dev *dev,
 251                                         struct kfd_process *process)
 252 {
 253         return dev->doorbell_base +
 254                 process->doorbell_index * doorbell_process_allocation();
 255 }
 256
 257 int kfd_alloc_process_doorbells(struct kfd_process *process)
 258 {
 259         int r = ida_simple_get(&doorbell_ida, 1, max_doorbell_slices,
 260                                 GFP_KERNEL);
 261         if (r > 0)
 262                 process->doorbell_index = r;
 263
 264         return r;
 265 }
 266
 267 void kfd_free_process_doorbells(struct kfd_process *process)
 268 {
 269         if (process->doorbell_index)
 270                 ida_simple_remove(&doorbell_ida, process->doorbell_index);
 271 }