cregit-Linux how code gets into the kernel

Release 4.11 drivers/gpu/drm/nouveau/nouveau_dma.c

/*
 * Copyright (C) 2007 Ben Skeggs.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include "nouveau_drv.h"
#include "nouveau_dma.h"


void OUT_RINGp(struct nouveau_channel *chan, const void *data, unsigned nr_dwords) { bool is_iomem; u32 *mem = ttm_kmap_obj_virtual(&chan->push.buffer->kmap, &is_iomem); mem = &mem[chan->dma.cur]; if (is_iomem) memcpy_toio((void __force __iomem *)mem, data, nr_dwords * 4); else memcpy(mem, data, nr_dwords * 4); chan->dma.cur += nr_dwords; }

Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs93100.00%2100.00%
Total93100.00%2100.00%

/* Fetch and adjust GPU GET pointer * * Returns: * value >= 0, the adjusted GET pointer * -EINVAL if GET pointer currently outside main push buffer * -EBUSY if timeout exceeded */
static inline int READ_GET(struct nouveau_channel *chan, uint64_t *prev_get, int *timeout) { uint64_t val; val = nvif_rd32(&chan->user, chan->user_get); if (chan->user_get_hi) val |= (uint64_t)nvif_rd32(&chan->user, chan->user_get_hi) << 32; /* reset counter as long as GET is still advancing, this is * to avoid misdetecting a GPU lockup if the GPU happens to * just be processing an operation that takes a long time */ if (val != *prev_get) { *prev_get = val; *timeout = 0; } if ((++*timeout & 0xff) == 0) { udelay(1); if (*timeout > 100000) return -EBUSY; } if (val < chan->push.vma.offset || val > chan->push.vma.offset + (chan->dma.max << 2)) return -EINVAL; return (val - chan->push.vma.offset) >> 2; }

Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs13985.28%685.71%
Francisco Jerez2414.72%114.29%
Total163100.00%7100.00%


void nv50_dma_push(struct nouveau_channel *chan, struct nouveau_bo *bo, int delta, int length) { struct nouveau_cli *cli = (void *)chan->user.client; struct nouveau_bo *pb = chan->push.buffer; struct nvkm_vma *vma; int ip = (chan->dma.ib_put * 2) + chan->dma.ib_base; u64 offset; vma = nouveau_bo_vma_find(bo, cli->vm); BUG_ON(!vma); offset = vma->offset + delta; BUG_ON(chan->dma.ib_free < 1); nouveau_bo_wr32(pb, ip++, lower_32_bits(offset)); nouveau_bo_wr32(pb, ip++, upper_32_bits(offset) | length << 8); chan->dma.ib_put = (chan->dma.ib_put + 1) & chan->dma.ib_max; mb(); /* Flush writes. */ nouveau_bo_rd32(pb, 0); nvif_wr32(&chan->user, 0x8c, chan->dma.ib_put); chan->dma.ib_free--; }

Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs18594.39%1184.62%
Maarten Maathuis105.10%17.69%
Daniel Vetter10.51%17.69%
Total196100.00%13100.00%


static int nv50_dma_push_wait(struct nouveau_channel *chan, int count) { uint32_t cnt = 0, prev_get = 0; while (chan->dma.ib_free < count) { uint32_t get = nvif_rd32(&chan->user, 0x88); if (get != prev_get) { prev_get = get; cnt = 0; } if ((++cnt & 0xff) == 0) { DRM_UDELAY(1); if (cnt > 100000) return -EBUSY; } chan->dma.ib_free = get - chan->dma.ib_put; if (chan->dma.ib_free <= 0) chan->dma.ib_free += chan->dma.ib_max; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs131100.00%5100.00%
Total131100.00%5100.00%


static int nv50_dma_wait(struct nouveau_channel *chan, int slots, int count) { uint64_t prev_get = 0; int ret, cnt = 0; ret = nv50_dma_push_wait(chan, slots + 1); if (unlikely(ret)) return ret; while (chan->dma.free < count) { int get = READ_GET(chan, &prev_get, &cnt); if (unlikely(get < 0)) { if (get == -EINVAL) continue; return get; } if (get <= chan->dma.cur) { chan->dma.free = chan->dma.max - chan->dma.cur; if (chan->dma.free >= count) break; FIRE_RING(chan); do { get = READ_GET(chan, &prev_get, &cnt); if (unlikely(get < 0)) { if (get == -EINVAL) continue; return get; } } while (get == 0); chan->dma.cur = 0; chan->dma.put = 0; } chan->dma.free = get - chan->dma.cur - 1; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs21997.77%150.00%
Francisco Jerez52.23%150.00%
Total224100.00%2100.00%


int nouveau_dma_wait(struct nouveau_channel *chan, int slots, int size) { uint64_t prev_get = 0; int cnt = 0, get; if (chan->dma.ib_max) return nv50_dma_wait(chan, slots, size); while (chan->dma.free < size) { get = READ_GET(chan, &prev_get, &cnt); if (unlikely(get == -EBUSY)) return -EBUSY; /* loop until we have a usable GET pointer. the value * we read from the GPU may be outside the main ring if * PFIFO is processing a buffer called from the main ring, * discard these values until something sensible is seen. * * the other case we discard GET is while the GPU is fetching * from the SKIPS area, so the code below doesn't have to deal * with some fun corner cases. */ if (unlikely(get == -EINVAL) || get < NOUVEAU_DMA_SKIPS) continue; if (get <= chan->dma.cur) { /* engine is fetching behind us, or is completely * idle (GET == PUT) so we have free space up until * the end of the push buffer * * we can only hit that path once per call due to * looping back to the beginning of the push buffer, * we'll hit the fetching-ahead-of-us path from that * point on. * * the *one* exception to that rule is if we read * GET==PUT, in which case the below conditional will * always succeed and break us out of the wait loop. */ chan->dma.free = chan->dma.max - chan->dma.cur; if (chan->dma.free >= size) break; /* not enough space left at the end of the push buffer, * instruct the GPU to jump back to the start right * after processing the currently pending commands. */ OUT_RING(chan, chan->push.vma.offset | 0x20000000); /* wait for GET to depart from the skips area. * prevents writing GET==PUT and causing a race * condition that causes us to think the GPU is * idle when it's not. */ do { get = READ_GET(chan, &prev_get, &cnt); if (unlikely(get == -EBUSY)) return -EBUSY; if (unlikely(get == -EINVAL)) continue; } while (get <= NOUVEAU_DMA_SKIPS); WRITE_PUT(NOUVEAU_DMA_SKIPS); /* we're now submitting commands at the start of * the push buffer. */ chan->dma.cur = chan->dma.put = NOUVEAU_DMA_SKIPS; } /* engine fetching ahead of us, we have space up until the * current GET pointer. the "- 1" is to ensure there's * space left to emit a jump back to the beginning of the * push buffer if we require it. we can never get GET == PUT * here, so this is safe. */ chan->dma.free = get - chan->dma.cur - 1; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs24498.39%480.00%
Francisco Jerez41.61%120.00%
Total248100.00%5100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Ben Skeggs101995.86%1482.35%
Francisco Jerez333.10%15.88%
Maarten Maathuis100.94%15.88%
Daniel Vetter10.09%15.88%
Total1063100.00%17100.00%
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