hwtracing/intel_th/msu-sink.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * An example software sink buffer for Intel TH MSU.
0004  *
0005  * Copyright (C) 2019 Intel Corporation.
0006  */
0007
0008 #include <linux/intel_th.h>
0009 #include <linux/module.h>
0010 #include <linux/slab.h>
0011 #include <linux/device.h>
0012 #include <linux/dma-mapping.h>
0013
0014 #define MAX_SGTS 16
0015
0016 struct msu_sink_private {
0017     struct device   *dev;
0018     struct sg_table **sgts;
0019     unsigned int    nr_sgts;
0020 };
0021
0022 static void *msu_sink_assign(struct device *dev, int *mode)
0023 {
0024     struct msu_sink_private *priv;
0025
0026     priv = kzalloc(sizeof(*priv), GFP_KERNEL);
0027     if (!priv)
0028         return NULL;
0029
0030     priv->sgts = kcalloc(MAX_SGTS, sizeof(void *), GFP_KERNEL);
0031     if (!priv->sgts) {
0032         kfree(priv);
0033         return NULL;
0034     }
0035
0036     priv->dev = dev;
0037     *mode = MSC_MODE_MULTI;
0038
0039     return priv;
0040 }
0041
0042 static void msu_sink_unassign(void *data)
0043 {
0044     struct msu_sink_private *priv = data;
0045
0046     kfree(priv->sgts);
0047     kfree(priv);
0048 }
0049
0050 /* See also: msc.c: __msc_buffer_win_alloc() */
0051 static int msu_sink_alloc_window(void *data, struct sg_table **sgt, size_t size)
0052 {
0053     struct msu_sink_private *priv = data;
0054     unsigned int nents;
0055     struct scatterlist *sg_ptr;
0056     void *block;
0057     int ret, i;
0058
0059     if (priv->nr_sgts == MAX_SGTS)
0060         return -ENOMEM;
0061
0062     nents = DIV_ROUND_UP(size, PAGE_SIZE);
0063
0064     ret = sg_alloc_table(*sgt, nents, GFP_KERNEL);
0065     if (ret)
0066         return -ENOMEM;
0067
0068     priv->sgts[priv->nr_sgts++] = *sgt;
0069
0070     for_each_sg((*sgt)->sgl, sg_ptr, nents, i) {
0071         block = dma_alloc_coherent(priv->dev->parent->parent,
0072                        PAGE_SIZE, &sg_dma_address(sg_ptr),
0073                        GFP_KERNEL);
0074         if (!block)
0075             return -ENOMEM;
0076
0077         sg_set_buf(sg_ptr, block, PAGE_SIZE);
0078     }
0079
0080     return nents;
0081 }
0082
0083 /* See also: msc.c: __msc_buffer_win_free() */
0084 static void msu_sink_free_window(void *data, struct sg_table *sgt)
0085 {
0086     struct msu_sink_private *priv = data;
0087     struct scatterlist *sg_ptr;
0088     int i;
0089
0090     for_each_sg(sgt->sgl, sg_ptr, sgt->nents, i) {
0091         dma_free_coherent(priv->dev->parent->parent, PAGE_SIZE,
0092                   sg_virt(sg_ptr), sg_dma_address(sg_ptr));
0093     }
0094
0095     sg_free_table(sgt);
0096     priv->nr_sgts--;
0097 }
0098
0099 static int msu_sink_ready(void *data, struct sg_table *sgt, size_t bytes)
0100 {
0101     struct msu_sink_private *priv = data;
0102
0103     intel_th_msc_window_unlock(priv->dev, sgt);
0104
0105     return 0;
0106 }
0107
0108 static const struct msu_buffer sink_mbuf = {
0109     .name       = "sink",
0110     .assign     = msu_sink_assign,
0111     .unassign   = msu_sink_unassign,
0112     .alloc_window   = msu_sink_alloc_window,
0113     .free_window    = msu_sink_free_window,
0114     .ready      = msu_sink_ready,
0115 };
0116
0117 module_intel_th_msu_buffer(sink_mbuf);
0118
0119 MODULE_LICENSE("GPL v2");