drivers/gpu/drm/amd/amdgpu/amdgpu_ih.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  */
  23
  24 #include <drm/drmP.h>
  25 #include "amdgpu.h"
  26 #include "amdgpu_ih.h"
  27
  28 /**
  29  * amdgpu_ih_ring_init - initialize the IH state
  30  *
  31  * @adev: amdgpu_device pointer
  32  * @ih: ih ring to initialize
  33  * @ring_size: ring size to allocate
  34  * @use_bus_addr: true when we can use dma_alloc_coherent
  35  *
  36  * Initializes the IH state and allocates a buffer
  37  * for the IH ring buffer.
  38  * Returns 0 for success, errors for failure.
  39  */
  40 int amdgpu_ih_ring_init(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih,
  41                         unsigned ring_size, bool use_bus_addr)
  42 {
  43         u32 rb_bufsz;
  44         int r;
  45
  46         /* Align ring size */
  47         rb_bufsz = order_base_2(ring_size / 4);
  48         ring_size = (1 << rb_bufsz) * 4;
  49         ih->ring_size = ring_size;
  50         ih->ptr_mask = ih->ring_size - 1;
  51         ih->rptr = 0;
  52         ih->use_bus_addr = use_bus_addr;
  53
  54         if (use_bus_addr) {
  55                 dma_addr_t dma_addr;
  56
  57                 if (ih->ring)
  58                         return 0;
  59
  60                 /* add 8 bytes for the rptr/wptr shadows and
  61                  * add them to the end of the ring allocation.
  62                  */
  63                 ih->ring = dma_alloc_coherent(adev->dev, ih->ring_size + 8,
  64                                               &dma_addr, GFP_KERNEL);
  65                 if (ih->ring == NULL)
  66                         return -ENOMEM;
  67
  68                 memset((void *)ih->ring, 0, ih->ring_size + 8);
  69                 ih->gpu_addr = dma_addr;
  70                 ih->wptr_addr = dma_addr + ih->ring_size;
  71                 ih->wptr_cpu = &ih->ring[ih->ring_size / 4];
  72                 ih->rptr_addr = dma_addr + ih->ring_size + 4;
  73                 ih->rptr_cpu = &ih->ring[(ih->ring_size / 4) + 1];
  74         } else {
  75                 unsigned wptr_offs, rptr_offs;
  76
  77                 r = amdgpu_device_wb_get(adev, &wptr_offs);
  78                 if (r)
  79                         return r;
  80
  81                 r = amdgpu_device_wb_get(adev, &rptr_offs);
  82                 if (r) {
  83                         amdgpu_device_wb_free(adev, wptr_offs);
  84                         return r;
  85                 }
  86
  87                 r = amdgpu_bo_create_kernel(adev, ih->ring_size, PAGE_SIZE,
  88                                             AMDGPU_GEM_DOMAIN_GTT,
  89                                             &ih->ring_obj, &ih->gpu_addr,
  90                                             (void **)&ih->ring);
  91                 if (r) {
  92                         amdgpu_device_wb_free(adev, rptr_offs);
  93                         amdgpu_device_wb_free(adev, wptr_offs);
  94                         return r;
  95                 }
  96
  97                 ih->wptr_addr = adev->wb.gpu_addr + wptr_offs * 4;
  98                 ih->wptr_cpu = &adev->wb.wb[wptr_offs];
  99                 ih->rptr_addr = adev->wb.gpu_addr + rptr_offs * 4;
 100                 ih->rptr_cpu = &adev->wb.wb[rptr_offs];
 101         }
 102         return 0;
 103 }
 104
 105 /**
 106  * amdgpu_ih_ring_fini - tear down the IH state
 107  *
 108  * @adev: amdgpu_device pointer
 109  * @ih: ih ring to tear down
 110  *
 111  * Tears down the IH state and frees buffer
 112  * used for the IH ring buffer.
 113  */
 114 void amdgpu_ih_ring_fini(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih)
 115 {
 116         if (ih->use_bus_addr) {
 117                 if (!ih->ring)
 118                         return;
 119
 120                 /* add 8 bytes for the rptr/wptr shadows and
 121                  * add them to the end of the ring allocation.
 122                  */
 123                 dma_free_coherent(adev->dev, ih->ring_size + 8,
 124                                   (void *)ih->ring, ih->gpu_addr);
 125                 ih->ring = NULL;
 126         } else {
 127                 amdgpu_bo_free_kernel(&ih->ring_obj, &ih->gpu_addr,
 128                                       (void **)&ih->ring);
 129                 amdgpu_device_wb_free(adev, (ih->wptr_addr - ih->gpu_addr) / 4);
 130                 amdgpu_device_wb_free(adev, (ih->rptr_addr - ih->gpu_addr) / 4);
 131         }
 132 }
 133
 134 /**
 135  * amdgpu_ih_process - interrupt handler
 136  *
 137  * @adev: amdgpu_device pointer
 138  * @ih: ih ring to process
 139  *
 140  * Interrupt hander (VI), walk the IH ring.
 141  * Returns irq process return code.
 142  */
 143 int amdgpu_ih_process(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih)
 144 {
 145         u32 wptr;
 146
 147         if (!ih->enabled || adev->shutdown)
 148                 return IRQ_NONE;
 149
 150         wptr = amdgpu_ih_get_wptr(adev, ih);
 151
 152 restart_ih:
 153         /* is somebody else already processing irqs? */
 154         if (atomic_xchg(&ih->lock, 1))
 155                 return IRQ_NONE;
 156
 157         DRM_DEBUG("%s: rptr %d, wptr %d\n", __func__, ih->rptr, wptr);
 158
 159         /* Order reading of wptr vs. reading of IH ring data */
 160         rmb();
 161
 162         while (ih->rptr != wptr) {
 163                 amdgpu_irq_dispatch(adev, ih);
 164                 ih->rptr &= ih->ptr_mask;
 165         }
 166
 167         amdgpu_ih_set_rptr(adev, ih);
 168         atomic_set(&ih->lock, 0);
 169
 170         /* make sure wptr hasn't changed while processing */
 171         wptr = amdgpu_ih_get_wptr(adev, ih);
 172         if (wptr != ih->rptr)
 173                 goto restart_ih;
 174
 175         return IRQ_HANDLED;
 176 }
 177