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 "nouveau_drv.h"
  28 #include "nouveau_dma.h"
  29 #include "nouveau_vmm.h"
  30
  31 #include <nvif/user.h>
  32
  33 void
  34 OUT_RINGp(struct nouveau_channel *chan, const void *data, unsigned nr_dwords)
  35 {
  36         bool is_iomem;
  37         u32 *mem = ttm_kmap_obj_virtual(&chan->push.buffer->kmap, &is_iomem);
  38         mem = &mem[chan->dma.cur];
  39         if (is_iomem)
  40                 memcpy_toio((void __force __iomem *)mem, data, nr_dwords * 4);
  41         else
  42                 memcpy(mem, data, nr_dwords * 4);
  43         chan->dma.cur += nr_dwords;
  44 }
  45
  46 /* Fetch and adjust GPU GET pointer
  47  *
  48  * Returns:
  49  *  value >= 0, the adjusted GET pointer
  50  *  -EINVAL if GET pointer currently outside main push buffer
  51  *  -EBUSY if timeout exceeded
  52  */
  53 static inline int
  54 READ_GET(struct nouveau_channel *chan, uint64_t *prev_get, int *timeout)
  55 {
  56         uint64_t val;
  57
  58         val = nvif_rd32(&chan->user, chan->user_get);
  59         if (chan->user_get_hi)
  60                 val |= (uint64_t)nvif_rd32(&chan->user, chan->user_get_hi) << 32;
  61
  62         /* reset counter as long as GET is still advancing, this is
  63          * to avoid misdetecting a GPU lockup if the GPU happens to
  64          * just be processing an operation that takes a long time
  65          */
  66         if (val != *prev_get) {
  67                 *prev_get = val;
  68                 *timeout = 0;
  69         }
  70
  71         if ((++*timeout & 0xff) == 0) {
  72                 udelay(1);
  73                 if (*timeout > 100000)
  74                         return -EBUSY;
  75         }
  76
  77         if (val < chan->push.addr ||
  78             val > chan->push.addr + (chan->dma.max << 2))
  79                 return -EINVAL;
  80
  81         return (val - chan->push.addr) >> 2;
  82 }
  83
  84 void
  85 nv50_dma_push(struct nouveau_channel *chan, u64 offset, int length)
  86 {
  87         struct nvif_user *user = &chan->drm->client.device.user;
  88         struct nouveau_bo *pb = chan->push.buffer;
  89         int ip = (chan->dma.ib_put * 2) + chan->dma.ib_base;
  90
  91         BUG_ON(chan->dma.ib_free < 1);
  92
  93         nouveau_bo_wr32(pb, ip++, lower_32_bits(offset));
  94         nouveau_bo_wr32(pb, ip++, upper_32_bits(offset) | length << 8);
  95
  96         chan->dma.ib_put = (chan->dma.ib_put + 1) & chan->dma.ib_max;
  97
  98         mb();
  99         /* Flush writes. */
 100         nouveau_bo_rd32(pb, 0);
 101
 102         nvif_wr32(&chan->user, 0x8c, chan->dma.ib_put);
 103         if (user->func && user->func->doorbell)
 104                 user->func->doorbell(user, chan->token);
 105         chan->dma.ib_free--;
 106 }
 107
 108 static int
 109 nv50_dma_push_wait(struct nouveau_channel *chan, int count)
 110 {
 111         uint32_t cnt = 0, prev_get = 0;
 112
 113         while (chan->dma.ib_free < count) {
 114                 uint32_t get = nvif_rd32(&chan->user, 0x88);
 115                 if (get != prev_get) {
 116                         prev_get = get;
 117                         cnt = 0;
 118                 }
 119
 120                 if ((++cnt & 0xff) == 0) {
 121                         DRM_UDELAY(1);
 122                         if (cnt > 100000)
 123                                 return -EBUSY;
 124                 }
 125
 126                 chan->dma.ib_free = get - chan->dma.ib_put;
 127                 if (chan->dma.ib_free <= 0)
 128                         chan->dma.ib_free += chan->dma.ib_max;
 129         }
 130
 131         return 0;
 132 }
 133
 134 static int
 135 nv50_dma_wait(struct nouveau_channel *chan, int slots, int count)
 136 {
 137         uint64_t prev_get = 0;
 138         int ret, cnt = 0;
 139
 140         ret = nv50_dma_push_wait(chan, slots + 1);
 141         if (unlikely(ret))
 142                 return ret;
 143
 144         while (chan->dma.free < count) {
 145                 int get = READ_GET(chan, &prev_get, &cnt);
 146                 if (unlikely(get < 0)) {
 147                         if (get == -EINVAL)
 148                                 continue;
 149
 150                         return get;
 151                 }
 152
 153                 if (get <= chan->dma.cur) {
 154                         chan->dma.free = chan->dma.max - chan->dma.cur;
 155                         if (chan->dma.free >= count)
 156                                 break;
 157
 158                         FIRE_RING(chan);
 159                         do {
 160                                 get = READ_GET(chan, &prev_get, &cnt);
 161                                 if (unlikely(get < 0)) {
 162                                         if (get == -EINVAL)
 163                                                 continue;
 164                                         return get;
 165                                 }
 166                         } while (get == 0);
 167                         chan->dma.cur = 0;
 168                         chan->dma.put = 0;
 169                 }
 170
 171                 chan->dma.free = get - chan->dma.cur - 1;
 172         }
 173
 174         return 0;
 175 }
 176
 177 int
 178 nouveau_dma_wait(struct nouveau_channel *chan, int slots, int size)
 179 {
 180         uint64_t prev_get = 0;
 181         int cnt = 0, get;
 182
 183         if (chan->dma.ib_max)
 184                 return nv50_dma_wait(chan, slots, size);
 185
 186         while (chan->dma.free < size) {
 187                 get = READ_GET(chan, &prev_get, &cnt);
 188                 if (unlikely(get == -EBUSY))
 189                         return -EBUSY;
 190
 191                 /* loop until we have a usable GET pointer.  the value
 192                  * we read from the GPU may be outside the main ring if
 193                  * PFIFO is processing a buffer called from the main ring,
 194                  * discard these values until something sensible is seen.
 195                  *
 196                  * the other case we discard GET is while the GPU is fetching
 197                  * from the SKIPS area, so the code below doesn't have to deal
 198                  * with some fun corner cases.
 199                  */
 200                 if (unlikely(get == -EINVAL) || get < NOUVEAU_DMA_SKIPS)
 201                         continue;
 202
 203                 if (get <= chan->dma.cur) {
 204                         /* engine is fetching behind us, or is completely
 205                          * idle (GET == PUT) so we have free space up until
 206                          * the end of the push buffer
 207                          *
 208                          * we can only hit that path once per call due to
 209                          * looping back to the beginning of the push buffer,
 210                          * we'll hit the fetching-ahead-of-us path from that
 211                          * point on.
 212                          *
 213                          * the *one* exception to that rule is if we read
 214                          * GET==PUT, in which case the below conditional will
 215                          * always succeed and break us out of the wait loop.
 216                          */
 217                         chan->dma.free = chan->dma.max - chan->dma.cur;
 218                         if (chan->dma.free >= size)
 219                                 break;
 220
 221                         /* not enough space left at the end of the push buffer,
 222                          * instruct the GPU to jump back to the start right
 223                          * after processing the currently pending commands.
 224                          */
 225                         OUT_RING(chan, chan->push.addr | 0x20000000);
 226
 227                         /* wait for GET to depart from the skips area.
 228                          * prevents writing GET==PUT and causing a race
 229                          * condition that causes us to think the GPU is
 230                          * idle when it's not.
 231                          */
 232                         do {
 233                                 get = READ_GET(chan, &prev_get, &cnt);
 234                                 if (unlikely(get == -EBUSY))
 235                                         return -EBUSY;
 236                                 if (unlikely(get == -EINVAL))
 237                                         continue;
 238                         } while (get <= NOUVEAU_DMA_SKIPS);
 239                         WRITE_PUT(NOUVEAU_DMA_SKIPS);
 240
 241                         /* we're now submitting commands at the start of
 242                          * the push buffer.
 243                          */
 244                         chan->dma.cur  =
 245                         chan->dma.put  = NOUVEAU_DMA_SKIPS;
 246                 }
 247
 248                 /* engine fetching ahead of us, we have space up until the
 249                  * current GET pointer.  the "- 1" is to ensure there's
 250                  * space left to emit a jump back to the beginning of the
 251                  * push buffer if we require it.  we can never get GET == PUT
 252                  * here, so this is safe.
 253                  */
 254                 chan->dma.free = get - chan->dma.cur - 1;
 255         }
 256
 257         return 0;
 258 }
 259