88b333b0ed
Currently the value written to CP_RB_WPTR is calculated on the fly as (rb->next - rb->start). But as the code is designed rb->next is wrapped before writing the commands so if a series of commands happened to fit perfectly in the ringbuffer, rb->next would end up being equal to rb->size / 4 and thus result in an out of bounds address to CP_RB_WPTR. The easiest way to fix this is to mask WPTR when writing it to the hardware; it makes the hardware happy and the rest of the ringbuffer math appears to work and there isn't any point in upsetting anything. Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> [squash in is_power_of_2() check] Signed-off-by: Rob Clark <robdclark@gmail.com>
69 lines
1.6 KiB
C
69 lines
1.6 KiB
C
/*
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* Copyright (C) 2013 Red Hat
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* Author: Rob Clark <robdclark@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "msm_ringbuffer.h"
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#include "msm_gpu.h"
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struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int size)
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{
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struct msm_ringbuffer *ring;
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int ret;
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if (WARN_ON(!is_power_of_2(size)))
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return ERR_PTR(-EINVAL);
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ring = kzalloc(sizeof(*ring), GFP_KERNEL);
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if (!ring) {
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ret = -ENOMEM;
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goto fail;
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}
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ring->gpu = gpu;
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ring->bo = msm_gem_new(gpu->dev, size, MSM_BO_WC);
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if (IS_ERR(ring->bo)) {
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ret = PTR_ERR(ring->bo);
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ring->bo = NULL;
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goto fail;
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}
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ring->start = msm_gem_get_vaddr_locked(ring->bo);
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if (IS_ERR(ring->start)) {
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ret = PTR_ERR(ring->start);
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goto fail;
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}
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ring->end = ring->start + (size / 4);
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ring->cur = ring->start;
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ring->size = size;
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return ring;
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fail:
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if (ring)
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msm_ringbuffer_destroy(ring);
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return ERR_PTR(ret);
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}
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void msm_ringbuffer_destroy(struct msm_ringbuffer *ring)
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{
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if (ring->bo) {
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msm_gem_put_vaddr(ring->bo);
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drm_gem_object_unreference_unlocked(ring->bo);
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}
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kfree(ring);
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}
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