Linux kernel mirror (for testing)
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linux
1/*
2 * Support for Core System Resources Table (CSRT)
3 *
4 * Copyright (C) 2013, Intel Corporation
5 * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
6 * Andy Shevchenko <andriy.shevchenko@linux.intel.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#define pr_fmt(fmt) "ACPI: CSRT: " fmt
14
15#include <linux/acpi.h>
16#include <linux/device.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/sizes.h>
21
22ACPI_MODULE_NAME("CSRT");
23
24static int __init acpi_csrt_parse_shared_info(struct platform_device *pdev,
25 const struct acpi_csrt_group *grp)
26{
27 const struct acpi_csrt_shared_info *si;
28 struct resource res[3];
29 size_t nres;
30 int ret;
31
32 memset(res, 0, sizeof(res));
33 nres = 0;
34
35 si = (const struct acpi_csrt_shared_info *)&grp[1];
36 /*
37 * The peripherals that are listed on CSRT typically support only
38 * 32-bit addresses so we only use the low part of MMIO base for
39 * now.
40 */
41 if (!si->mmio_base_high && si->mmio_base_low) {
42 /*
43 * There is no size of the memory resource in shared_info
44 * so we assume that it is 4k here.
45 */
46 res[nres].start = si->mmio_base_low;
47 res[nres].end = res[0].start + SZ_4K - 1;
48 res[nres++].flags = IORESOURCE_MEM;
49 }
50
51 if (si->gsi_interrupt) {
52 int irq = acpi_register_gsi(NULL, si->gsi_interrupt,
53 si->interrupt_mode,
54 si->interrupt_polarity);
55 res[nres].start = irq;
56 res[nres].end = irq;
57 res[nres++].flags = IORESOURCE_IRQ;
58 }
59
60 if (si->base_request_line || si->num_handshake_signals) {
61 /*
62 * We pass the driver a DMA resource describing the range
63 * of request lines the device supports.
64 */
65 res[nres].start = si->base_request_line;
66 res[nres].end = res[nres].start + si->num_handshake_signals - 1;
67 res[nres++].flags = IORESOURCE_DMA;
68 }
69
70 ret = platform_device_add_resources(pdev, res, nres);
71 if (ret) {
72 if (si->gsi_interrupt)
73 acpi_unregister_gsi(si->gsi_interrupt);
74 return ret;
75 }
76
77 return 0;
78}
79
80static int __init
81acpi_csrt_parse_resource_group(const struct acpi_csrt_group *grp)
82{
83 struct platform_device *pdev;
84 char vendor[5], name[16];
85 int ret, i;
86
87 vendor[0] = grp->vendor_id;
88 vendor[1] = grp->vendor_id >> 8;
89 vendor[2] = grp->vendor_id >> 16;
90 vendor[3] = grp->vendor_id >> 24;
91 vendor[4] = '\0';
92
93 if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
94 return -ENODEV;
95
96 snprintf(name, sizeof(name), "%s%04X", vendor, grp->device_id);
97 pdev = platform_device_alloc(name, PLATFORM_DEVID_AUTO);
98 if (!pdev)
99 return -ENOMEM;
100
101 /* Add resources based on the shared info */
102 ret = acpi_csrt_parse_shared_info(pdev, grp);
103 if (ret)
104 goto fail;
105
106 ret = platform_device_add(pdev);
107 if (ret)
108 goto fail;
109
110 for (i = 0; i < pdev->num_resources; i++)
111 dev_dbg(&pdev->dev, "%pR\n", &pdev->resource[i]);
112
113 return 0;
114
115fail:
116 platform_device_put(pdev);
117 return ret;
118}
119
120/*
121 * CSRT or Core System Resources Table is a proprietary ACPI table
122 * introduced by Microsoft. This table can contain devices that are not in
123 * the system DSDT table. In particular DMA controllers might be described
124 * here.
125 *
126 * We present these devices as normal platform devices that don't have ACPI
127 * IDs or handle. The platform device name will be something like
128 * <VENDOR><DEVID>.<n>.auto for example: INTL9C06.0.auto.
129 */
130void __init acpi_csrt_init(void)
131{
132 struct acpi_csrt_group *grp, *end;
133 struct acpi_table_csrt *csrt;
134 acpi_status status;
135 int ret;
136
137 status = acpi_get_table(ACPI_SIG_CSRT, 0,
138 (struct acpi_table_header **)&csrt);
139 if (ACPI_FAILURE(status)) {
140 if (status != AE_NOT_FOUND)
141 pr_warn("failed to get the CSRT table\n");
142 return;
143 }
144
145 pr_debug("parsing CSRT table for devices\n");
146
147 grp = (struct acpi_csrt_group *)(csrt + 1);
148 end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
149
150 while (grp < end) {
151 ret = acpi_csrt_parse_resource_group(grp);
152 if (ret) {
153 pr_warn("error in parsing resource group: %d\n", ret);
154 return;
155 }
156
157 grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
158 }
159}