drivers/gpu/drm/nouveau/nouveau_dma.c

   1 /*
   2  * Copyright (C) 2007 Ben Skeggs.
   3  * All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining
   6  * a copy of this software and associated documentation files (the
   7  * "Software"), to deal in the Software without restriction, including
   8  * without limitation the rights to use, copy, modify, merge, publish,
   9  * distribute, sublicense, and/or sell copies of the Software, and to
  10  * permit persons to whom the Software is furnished to do so, subject to
  11  * the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the
  14  * next paragraph) shall be included in all copies or substantial
  15  * portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  20  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
  21  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  22  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  23  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  */
  26
  27 #include <core/client.h>
  28
  29 #include "nouveau_drm.h"
  30 #include "nouveau_dma.h"
  31
  32 void
  33 OUT_RINGp(struct nouveau_channel *chan, const void *data, unsigned nr_dwords)
  34 {
  35         bool is_iomem;
  36         u32 *mem = ttm_kmap_obj_virtual(&chan->push.buffer->kmap, &is_iomem);
  37         mem = &mem[chan->dma.cur];
  38         if (is_iomem)
  39                 memcpy_toio((void __force __iomem *)mem, data, nr_dwords * 4);
  40         else
  41                 memcpy(mem, data, nr_dwords * 4);
  42         chan->dma.cur += nr_dwords;
  43 }
  44
  45 /* Fetch and adjust GPU GET pointer
  46  *
  47  * Returns:
  48  *  value >= 0, the adjusted GET pointer
  49  *  -EINVAL if GET pointer currently outside main push buffer
  50  *  -EBUSY if timeout exceeded
  51  */
  52 static inline int
  53 READ_GET(struct nouveau_channel *chan, uint64_t *prev_get, int *timeout)
  54 {
  55         uint64_t val;
  56
  57         val = nv_ro32(chan->object, chan->user_get);
  58         if (chan->user_get_hi)
  59                 val |= (uint64_t)nv_ro32(chan->object, chan->user_get_hi) << 32;
  60
  61         /* reset counter as long as GET is still advancing, this is
  62          * to avoid misdetecting a GPU lockup if the GPU happens to
  63          * just be processing an operation that takes a long time
  64          */
  65         if (val != *prev_get) {
  66                 *prev_get = val;
  67                 *timeout = 0;
  68         }
  69
  70         if ((++*timeout & 0xff) == 0) {
  71                 udelay(1);
  72                 if (*timeout > 100000)
  73                         return -EBUSY;
  74         }
  75
  76         if (val < chan->push.vma.offset ||
  77             val > chan->push.vma.offset + (chan->dma.max << 2))
  78                 return -EINVAL;
  79
  80         return (val - chan->push.vma.offset) >> 2;
  81 }
  82
  83 void
  84 nv50_dma_push(struct nouveau_channel *chan, struct nouveau_bo *bo,
  85               int delta, int length)
  86 {
  87         struct nouveau_bo *pb = chan->push.buffer;
  88         struct nouveau_vma *vma;
  89         int ip = (chan->dma.ib_put * 2) + chan->dma.ib_base;
  90         u64 offset;
  91
  92         vma = nouveau_bo_vma_find(bo, nv_client(chan->cli)->vm);
  93         BUG_ON(!vma);
  94         offset = vma->offset + delta;
  95
  96         BUG_ON(chan->dma.ib_free < 1);
  97
  98         nouveau_bo_wr32(pb, ip++, lower_32_bits(offset));
  99         nouveau_bo_wr32(pb, ip++, upper_32_bits(offset) | length << 8);
 100
 101         chan->dma.ib_put = (chan->dma.ib_put + 1) & chan->dma.ib_max;
 102
 103         DRM_MEMORYBARRIER();
 104         /* Flush writes. */
 105         nouveau_bo_rd32(pb, 0);
 106
 107         nv_wo32(chan->object, 0x8c, chan->dma.ib_put);
 108         chan->dma.ib_free--;
 109 }
 110
 111 static int
 112 nv50_dma_push_wait(struct nouveau_channel *chan, int count)
 113 {
 114         uint32_t cnt = 0, prev_get = 0;
 115
 116         while (chan->dma.ib_free < count) {
 117                 uint32_t get = nv_ro32(chan->object, 0x88);
 118                 if (get != prev_get) {
 119                         prev_get = get;
 120                         cnt = 0;
 121                 }
 122
 123                 if ((++cnt & 0xff) == 0) {
 124                         DRM_UDELAY(1);
 125                         if (cnt > 100000)
 126                                 return -EBUSY;
 127                 }
 128
 129                 chan->dma.ib_free = get - chan->dma.ib_put;
 130                 if (chan->dma.ib_free <= 0)
 131                         chan->dma.ib_free += chan->dma.ib_max;
 132         }
 133
 134         return 0;
 135 }
 136
 137 static int
 138 nv50_dma_wait(struct nouveau_channel *chan, int slots, int count)
 139 {
 140         uint64_t prev_get = 0;
 141         int ret, cnt = 0;
 142
 143         ret = nv50_dma_push_wait(chan, slots + 1);
 144         if (unlikely(ret))
 145                 return ret;
 146
 147         while (chan->dma.free < count) {
 148                 int get = READ_GET(chan, &prev_get, &cnt);
 149                 if (unlikely(get < 0)) {
 150                         if (get == -EINVAL)
 151                                 continue;
 152
 153                         return get;
 154                 }
 155
 156                 if (get <= chan->dma.cur) {
 157                         chan->dma.free = chan->dma.max - chan->dma.cur;
 158                         if (chan->dma.free >= count)
 159                                 break;
 160
 161                         FIRE_RING(chan);
 162                         do {
 163                                 get = READ_GET(chan, &prev_get, &cnt);
 164                                 if (unlikely(get < 0)) {
 165                                         if (get == -EINVAL)
 166                                                 continue;
 167                                         return get;
 168                                 }
 169                         } while (get == 0);
 170                         chan->dma.cur = 0;
 171                         chan->dma.put = 0;
 172                 }
 173
 174                 chan->dma.free = get - chan->dma.cur - 1;
 175         }
 176
 177         return 0;
 178 }
 179
 180 int
 181 nouveau_dma_wait(struct nouveau_channel *chan, int slots, int size)
 182 {
 183         uint64_t prev_get = 0;
 184         int cnt = 0, get;
 185
 186         if (chan->dma.ib_max)
 187                 return nv50_dma_wait(chan, slots, size);
 188
 189         while (chan->dma.free < size) {
 190                 get = READ_GET(chan, &prev_get, &cnt);
 191                 if (unlikely(get == -EBUSY))
 192                         return -EBUSY;
 193
 194                 /* loop until we have a usable GET pointer.  the value
 195                  * we read from the GPU may be outside the main ring if
 196                  * PFIFO is processing a buffer called from the main ring,
 197                  * discard these values until something sensible is seen.
 198                  *
 199                  * the other case we discard GET is while the GPU is fetching
 200                  * from the SKIPS area, so the code below doesn't have to deal
 201                  * with some fun corner cases.
 202                  */
 203                 if (unlikely(get == -EINVAL) || get < NOUVEAU_DMA_SKIPS)
 204                         continue;
 205
 206                 if (get <= chan->dma.cur) {
 207                         /* engine is fetching behind us, or is completely
 208                          * idle (GET == PUT) so we have free space up until
 209                          * the end of the push buffer
 210                          *
 211                          * we can only hit that path once per call due to
 212                          * looping back to the beginning of the push buffer,
 213                          * we'll hit the fetching-ahead-of-us path from that
 214                          * point on.
 215                          *
 216                          * the *one* exception to that rule is if we read
 217                          * GET==PUT, in which case the below conditional will
 218                          * always succeed and break us out of the wait loop.
 219                          */
 220                         chan->dma.free = chan->dma.max - chan->dma.cur;
 221                         if (chan->dma.free >= size)
 222                                 break;
 223
 224                         /* not enough space left at the end of the push buffer,
 225                          * instruct the GPU to jump back to the start right
 226                          * after processing the currently pending commands.
 227                          */
 228                         OUT_RING(chan, chan->push.vma.offset | 0x20000000);
 229
 230                         /* wait for GET to depart from the skips area.
 231                          * prevents writing GET==PUT and causing a race
 232                          * condition that causes us to think the GPU is
 233                          * idle when it's not.
 234                          */
 235                         do {
 236                                 get = READ_GET(chan, &prev_get, &cnt);
 237                                 if (unlikely(get == -EBUSY))
 238                                         return -EBUSY;
 239                                 if (unlikely(get == -EINVAL))
 240                                         continue;
 241                         } while (get <= NOUVEAU_DMA_SKIPS);
 242                         WRITE_PUT(NOUVEAU_DMA_SKIPS);
 243
 244                         /* we're now submitting commands at the start of
 245                          * the push buffer.
 246                          */
 247                         chan->dma.cur  =
 248                         chan->dma.put  = NOUVEAU_DMA_SKIPS;
 249                 }
 250
 251                 /* engine fetching ahead of us, we have space up until the
 252                  * current GET pointer.  the "- 1" is to ensure there's
 253                  * space left to emit a jump back to the beginning of the
 254                  * push buffer if we require it.  we can never get GET == PUT
 255                  * here, so this is safe.
 256                  */
 257                 chan->dma.free = get - chan->dma.cur - 1;
 258         }
 259
 260         return 0;
 261 }
 262