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