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 /* Fetch and adjust GPU GET pointer
34 *
35 * Returns:
36 * value >= 0, the adjusted GET pointer
37 * -EINVAL if GET pointer currently outside main push buffer
38 * -EBUSY if timeout exceeded
39 */
40 static inline int
READ_GET(struct nouveau_channel * chan,uint64_t * prev_get,int * timeout)41 READ_GET(struct nouveau_channel *chan, uint64_t *prev_get, int *timeout)
42 {
43 uint64_t val;
44
45 val = nvif_rd32(chan->userd, chan->user_get);
46 if (chan->user_get_hi)
47 val |= (uint64_t)nvif_rd32(chan->userd, chan->user_get_hi) << 32;
48
49 /* reset counter as long as GET is still advancing, this is
50 * to avoid misdetecting a GPU lockup if the GPU happens to
51 * just be processing an operation that takes a long time
52 */
53 if (val != *prev_get) {
54 *prev_get = val;
55 *timeout = 0;
56 }
57
58 if ((++*timeout & 0xff) == 0) {
59 udelay(1);
60 if (*timeout > 100000)
61 return -EBUSY;
62 }
63
64 if (val < chan->push.addr ||
65 val > chan->push.addr + (chan->dma.max << 2))
66 return -EINVAL;
67
68 return (val - chan->push.addr) >> 2;
69 }
70
71 void
nv50_dma_push(struct nouveau_channel * chan,u64 offset,u32 length,bool no_prefetch)72 nv50_dma_push(struct nouveau_channel *chan, u64 offset, u32 length,
73 bool no_prefetch)
74 {
75 struct nvif_user *user = &chan->drm->client.device.user;
76 struct nouveau_bo *pb = chan->push.buffer;
77 int ip = (chan->dma.ib_put * 2) + chan->dma.ib_base;
78
79 BUG_ON(chan->dma.ib_free < 1);
80 WARN_ON(length > NV50_DMA_PUSH_MAX_LENGTH);
81
82 nouveau_bo_wr32(pb, ip++, lower_32_bits(offset));
83 nouveau_bo_wr32(pb, ip++, upper_32_bits(offset) | length << 8 |
84 (no_prefetch ? (1 << 31) : 0));
85
86 chan->dma.ib_put = (chan->dma.ib_put + 1) & chan->dma.ib_max;
87
88 mb();
89 /* Flush writes. */
90 nouveau_bo_rd32(pb, 0);
91
92 nvif_wr32(chan->userd, 0x8c, chan->dma.ib_put);
93 if (user->func && user->func->doorbell)
94 user->func->doorbell(user, chan->token);
95 chan->dma.ib_free--;
96 }
97
98 static int
nv50_dma_push_wait(struct nouveau_channel * chan,int count)99 nv50_dma_push_wait(struct nouveau_channel *chan, int count)
100 {
101 uint32_t cnt = 0, prev_get = 0;
102
103 while (chan->dma.ib_free < count) {
104 uint32_t get = nvif_rd32(chan->userd, 0x88);
105 if (get != prev_get) {
106 prev_get = get;
107 cnt = 0;
108 }
109
110 if ((++cnt & 0xff) == 0) {
111 udelay(1);
112 if (cnt > 100000)
113 return -EBUSY;
114 }
115
116 chan->dma.ib_free = get - chan->dma.ib_put;
117 if (chan->dma.ib_free <= 0)
118 chan->dma.ib_free += chan->dma.ib_max;
119 }
120
121 return 0;
122 }
123
124 static int
nv50_dma_wait(struct nouveau_channel * chan,int slots,int count)125 nv50_dma_wait(struct nouveau_channel *chan, int slots, int count)
126 {
127 uint64_t prev_get = 0;
128 int ret, cnt = 0;
129
130 ret = nv50_dma_push_wait(chan, slots + 1);
131 if (unlikely(ret))
132 return ret;
133
134 while (chan->dma.free < count) {
135 int get = READ_GET(chan, &prev_get, &cnt);
136 if (unlikely(get < 0)) {
137 if (get == -EINVAL)
138 continue;
139
140 return get;
141 }
142
143 if (get <= chan->dma.cur) {
144 chan->dma.free = chan->dma.max - chan->dma.cur;
145 if (chan->dma.free >= count)
146 break;
147
148 FIRE_RING(chan);
149 do {
150 get = READ_GET(chan, &prev_get, &cnt);
151 if (unlikely(get < 0)) {
152 if (get == -EINVAL)
153 continue;
154 return get;
155 }
156 } while (get == 0);
157 chan->dma.cur = 0;
158 chan->dma.put = 0;
159 }
160
161 chan->dma.free = get - chan->dma.cur - 1;
162 }
163
164 return 0;
165 }
166
167 int
nouveau_dma_wait(struct nouveau_channel * chan,int slots,int size)168 nouveau_dma_wait(struct nouveau_channel *chan, int slots, int size)
169 {
170 uint64_t prev_get = 0;
171 int cnt = 0, get;
172
173 if (chan->dma.ib_max)
174 return nv50_dma_wait(chan, slots, size);
175
176 while (chan->dma.free < size) {
177 get = READ_GET(chan, &prev_get, &cnt);
178 if (unlikely(get == -EBUSY))
179 return -EBUSY;
180
181 /* loop until we have a usable GET pointer. the value
182 * we read from the GPU may be outside the main ring if
183 * PFIFO is processing a buffer called from the main ring,
184 * discard these values until something sensible is seen.
185 *
186 * the other case we discard GET is while the GPU is fetching
187 * from the SKIPS area, so the code below doesn't have to deal
188 * with some fun corner cases.
189 */
190 if (unlikely(get == -EINVAL) || get < NOUVEAU_DMA_SKIPS)
191 continue;
192
193 if (get <= chan->dma.cur) {
194 /* engine is fetching behind us, or is completely
195 * idle (GET == PUT) so we have free space up until
196 * the end of the push buffer
197 *
198 * we can only hit that path once per call due to
199 * looping back to the beginning of the push buffer,
200 * we'll hit the fetching-ahead-of-us path from that
201 * point on.
202 *
203 * the *one* exception to that rule is if we read
204 * GET==PUT, in which case the below conditional will
205 * always succeed and break us out of the wait loop.
206 */
207 chan->dma.free = chan->dma.max - chan->dma.cur;
208 if (chan->dma.free >= size)
209 break;
210
211 /* not enough space left at the end of the push buffer,
212 * instruct the GPU to jump back to the start right
213 * after processing the currently pending commands.
214 */
215 OUT_RING(chan, chan->push.addr | 0x20000000);
216
217 /* wait for GET to depart from the skips area.
218 * prevents writing GET==PUT and causing a race
219 * condition that causes us to think the GPU is
220 * idle when it's not.
221 */
222 do {
223 get = READ_GET(chan, &prev_get, &cnt);
224 if (unlikely(get == -EBUSY))
225 return -EBUSY;
226 if (unlikely(get == -EINVAL))
227 continue;
228 } while (get <= NOUVEAU_DMA_SKIPS);
229 WRITE_PUT(NOUVEAU_DMA_SKIPS);
230
231 /* we're now submitting commands at the start of
232 * the push buffer.
233 */
234 chan->dma.cur =
235 chan->dma.put = NOUVEAU_DMA_SKIPS;
236 }
237
238 /* engine fetching ahead of us, we have space up until the
239 * current GET pointer. the "- 1" is to ensure there's
240 * space left to emit a jump back to the beginning of the
241 * push buffer if we require it. we can never get GET == PUT
242 * here, so this is safe.
243 */
244 chan->dma.free = get - chan->dma.cur - 1;
245 }
246
247 return 0;
248 }
249
250