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116 lines
2.4 KiB
116 lines
2.4 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* An example software sink buffer for Intel TH MSU. |
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* |
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* Copyright (C) 2019 Intel Corporation. |
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*/ |
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#include <linux/intel_th.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/device.h> |
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#include <linux/dma-mapping.h> |
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#define MAX_SGTS 16 |
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struct msu_sink_private { |
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struct device *dev; |
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struct sg_table **sgts; |
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unsigned int nr_sgts; |
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}; |
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static void *msu_sink_assign(struct device *dev, int *mode) |
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{ |
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struct msu_sink_private *priv; |
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priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return NULL; |
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priv->sgts = kcalloc(MAX_SGTS, sizeof(void *), GFP_KERNEL); |
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if (!priv->sgts) { |
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kfree(priv); |
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return NULL; |
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} |
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priv->dev = dev; |
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*mode = MSC_MODE_MULTI; |
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return priv; |
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} |
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static void msu_sink_unassign(void *data) |
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{ |
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struct msu_sink_private *priv = data; |
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kfree(priv->sgts); |
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kfree(priv); |
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} |
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/* See also: msc.c: __msc_buffer_win_alloc() */ |
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static int msu_sink_alloc_window(void *data, struct sg_table **sgt, size_t size) |
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{ |
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struct msu_sink_private *priv = data; |
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unsigned int nents; |
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struct scatterlist *sg_ptr; |
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void *block; |
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int ret, i; |
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if (priv->nr_sgts == MAX_SGTS) |
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return -ENOMEM; |
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nents = DIV_ROUND_UP(size, PAGE_SIZE); |
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ret = sg_alloc_table(*sgt, nents, GFP_KERNEL); |
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if (ret) |
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return -ENOMEM; |
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priv->sgts[priv->nr_sgts++] = *sgt; |
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for_each_sg((*sgt)->sgl, sg_ptr, nents, i) { |
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block = dma_alloc_coherent(priv->dev->parent->parent, |
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PAGE_SIZE, &sg_dma_address(sg_ptr), |
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GFP_KERNEL); |
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sg_set_buf(sg_ptr, block, PAGE_SIZE); |
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} |
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return nents; |
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} |
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/* See also: msc.c: __msc_buffer_win_free() */ |
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static void msu_sink_free_window(void *data, struct sg_table *sgt) |
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{ |
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struct msu_sink_private *priv = data; |
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struct scatterlist *sg_ptr; |
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int i; |
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for_each_sg(sgt->sgl, sg_ptr, sgt->nents, i) { |
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dma_free_coherent(priv->dev->parent->parent, PAGE_SIZE, |
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sg_virt(sg_ptr), sg_dma_address(sg_ptr)); |
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} |
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sg_free_table(sgt); |
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priv->nr_sgts--; |
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} |
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static int msu_sink_ready(void *data, struct sg_table *sgt, size_t bytes) |
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{ |
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struct msu_sink_private *priv = data; |
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intel_th_msc_window_unlock(priv->dev, sgt); |
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return 0; |
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} |
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static const struct msu_buffer sink_mbuf = { |
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.name = "sink", |
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.assign = msu_sink_assign, |
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.unassign = msu_sink_unassign, |
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.alloc_window = msu_sink_alloc_window, |
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.free_window = msu_sink_free_window, |
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.ready = msu_sink_ready, |
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}; |
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module_intel_th_msu_buffer(sink_mbuf); |
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MODULE_LICENSE("GPL v2");
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