1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * An example software sink buffer for Intel TH MSU.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2019 Intel Corporation.
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/intel_th.h>
9*4882a593Smuzhiyun #include <linux/module.h>
10*4882a593Smuzhiyun #include <linux/slab.h>
11*4882a593Smuzhiyun #include <linux/device.h>
12*4882a593Smuzhiyun #include <linux/dma-mapping.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #define MAX_SGTS 16
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun struct msu_sink_private {
17*4882a593Smuzhiyun struct device *dev;
18*4882a593Smuzhiyun struct sg_table **sgts;
19*4882a593Smuzhiyun unsigned int nr_sgts;
20*4882a593Smuzhiyun };
21*4882a593Smuzhiyun
msu_sink_assign(struct device * dev,int * mode)22*4882a593Smuzhiyun static void *msu_sink_assign(struct device *dev, int *mode)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun struct msu_sink_private *priv;
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun priv = kzalloc(sizeof(*priv), GFP_KERNEL);
27*4882a593Smuzhiyun if (!priv)
28*4882a593Smuzhiyun return NULL;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun priv->sgts = kcalloc(MAX_SGTS, sizeof(void *), GFP_KERNEL);
31*4882a593Smuzhiyun if (!priv->sgts) {
32*4882a593Smuzhiyun kfree(priv);
33*4882a593Smuzhiyun return NULL;
34*4882a593Smuzhiyun }
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun priv->dev = dev;
37*4882a593Smuzhiyun *mode = MSC_MODE_MULTI;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun return priv;
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun
msu_sink_unassign(void * data)42*4882a593Smuzhiyun static void msu_sink_unassign(void *data)
43*4882a593Smuzhiyun {
44*4882a593Smuzhiyun struct msu_sink_private *priv = data;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun kfree(priv->sgts);
47*4882a593Smuzhiyun kfree(priv);
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun /* See also: msc.c: __msc_buffer_win_alloc() */
msu_sink_alloc_window(void * data,struct sg_table ** sgt,size_t size)51*4882a593Smuzhiyun static int msu_sink_alloc_window(void *data, struct sg_table **sgt, size_t size)
52*4882a593Smuzhiyun {
53*4882a593Smuzhiyun struct msu_sink_private *priv = data;
54*4882a593Smuzhiyun unsigned int nents;
55*4882a593Smuzhiyun struct scatterlist *sg_ptr;
56*4882a593Smuzhiyun void *block;
57*4882a593Smuzhiyun int ret, i;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun if (priv->nr_sgts == MAX_SGTS)
60*4882a593Smuzhiyun return -ENOMEM;
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun nents = DIV_ROUND_UP(size, PAGE_SIZE);
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun ret = sg_alloc_table(*sgt, nents, GFP_KERNEL);
65*4882a593Smuzhiyun if (ret)
66*4882a593Smuzhiyun return -ENOMEM;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun priv->sgts[priv->nr_sgts++] = *sgt;
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun for_each_sg((*sgt)->sgl, sg_ptr, nents, i) {
71*4882a593Smuzhiyun block = dma_alloc_coherent(priv->dev->parent->parent,
72*4882a593Smuzhiyun PAGE_SIZE, &sg_dma_address(sg_ptr),
73*4882a593Smuzhiyun GFP_KERNEL);
74*4882a593Smuzhiyun if (!block)
75*4882a593Smuzhiyun return -ENOMEM;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun sg_set_buf(sg_ptr, block, PAGE_SIZE);
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun return nents;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun /* See also: msc.c: __msc_buffer_win_free() */
msu_sink_free_window(void * data,struct sg_table * sgt)84*4882a593Smuzhiyun static void msu_sink_free_window(void *data, struct sg_table *sgt)
85*4882a593Smuzhiyun {
86*4882a593Smuzhiyun struct msu_sink_private *priv = data;
87*4882a593Smuzhiyun struct scatterlist *sg_ptr;
88*4882a593Smuzhiyun int i;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun for_each_sg(sgt->sgl, sg_ptr, sgt->nents, i) {
91*4882a593Smuzhiyun dma_free_coherent(priv->dev->parent->parent, PAGE_SIZE,
92*4882a593Smuzhiyun sg_virt(sg_ptr), sg_dma_address(sg_ptr));
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun sg_free_table(sgt);
96*4882a593Smuzhiyun priv->nr_sgts--;
97*4882a593Smuzhiyun }
98*4882a593Smuzhiyun
msu_sink_ready(void * data,struct sg_table * sgt,size_t bytes)99*4882a593Smuzhiyun static int msu_sink_ready(void *data, struct sg_table *sgt, size_t bytes)
100*4882a593Smuzhiyun {
101*4882a593Smuzhiyun struct msu_sink_private *priv = data;
102*4882a593Smuzhiyun
103*4882a593Smuzhiyun intel_th_msc_window_unlock(priv->dev, sgt);
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun return 0;
106*4882a593Smuzhiyun }
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun static const struct msu_buffer sink_mbuf = {
109*4882a593Smuzhiyun .name = "sink",
110*4882a593Smuzhiyun .assign = msu_sink_assign,
111*4882a593Smuzhiyun .unassign = msu_sink_unassign,
112*4882a593Smuzhiyun .alloc_window = msu_sink_alloc_window,
113*4882a593Smuzhiyun .free_window = msu_sink_free_window,
114*4882a593Smuzhiyun .ready = msu_sink_ready,
115*4882a593Smuzhiyun };
116*4882a593Smuzhiyun
117*4882a593Smuzhiyun module_intel_th_msu_buffer(sink_mbuf);
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
120