120 lines
2.4 KiB
C
120 lines
2.4 KiB
C
// 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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if (!block)
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return -ENOMEM;
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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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