1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * System Specific setup for PCEngines ALIX.
4 * At the moment this means setup of GPIO control of LEDs
5 * on Alix.2/3/6 boards.
6 *
7 * Copyright (C) 2008 Constantin Baranov <const@mimas.ru>
8 * Copyright (C) 2011 Ed Wildgoose <kernel@wildgooses.com>
9 * and Philip Prindeville <philipp@redfish-solutions.com>
10 *
11 * TODO: There are large similarities with leds-net5501.c
12 * by Alessandro Zummo <a.zummo@towertech.it>
13 * In the future leds-net5501.c should be migrated over to platform
14 */
15
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/io.h>
19#include <linux/string.h>
20#include <linux/moduleparam.h>
21#include <linux/dmi.h>
22
23#include <asm/geode.h>
24
25#include "geode-common.h"
26
27#define BIOS_SIGNATURE_TINYBIOS 0xf0000
28#define BIOS_SIGNATURE_COREBOOT 0x500
29#define BIOS_REGION_SIZE 0x10000
30
31/*
32 * This driver is not modular, but to keep back compatibility
33 * with existing use cases, continuing with module_param is
34 * the easiest way forward.
35 */
36static bool force = 0;
37module_param(force, bool, 0444);
38/* FIXME: Award bios is not automatically detected as Alix platform */
39MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3 platform");
40
41static const struct geode_led alix_leds[] __initconst = {
42 { 6, true },
43 { 25, false },
44 { 27, false },
45};
46
47static void __init register_alix(void)
48{
49 geode_create_restart_key(pin: 24);
50 geode_create_leds(label: "alix", leds: alix_leds, ARRAY_SIZE(alix_leds));
51}
52
53static bool __init alix_present(unsigned long bios_phys,
54 const char *alix_sig,
55 size_t alix_sig_len)
56{
57 const size_t bios_len = BIOS_REGION_SIZE;
58 const char *bios_virt;
59 const char *scan_end;
60 const char *p;
61 char name[64];
62
63 if (force) {
64 printk(KERN_NOTICE "%s: forced to skip BIOS test, "
65 "assume system is ALIX.2/ALIX.3\n",
66 KBUILD_MODNAME);
67 return true;
68 }
69
70 bios_virt = phys_to_virt(address: bios_phys);
71 scan_end = bios_virt + bios_len - (alix_sig_len + 2);
72 for (p = bios_virt; p < scan_end; p++) {
73 const char *tail;
74 char *a;
75
76 if (memcmp(p, q: alix_sig, size: alix_sig_len) != 0)
77 continue;
78
79 memcpy(name, p, sizeof(name));
80
81 /* remove the first \0 character from string */
82 a = strchr(name, '\0');
83 if (a)
84 *a = ' ';
85
86 /* cut the string at a newline */
87 a = strchr(name, '\r');
88 if (a)
89 *a = '\0';
90
91 tail = p + alix_sig_len;
92 if ((tail[0] == '2' || tail[0] == '3' || tail[0] == '6')) {
93 printk(KERN_INFO
94 "%s: system is recognized as \"%s\"\n",
95 KBUILD_MODNAME, name);
96 return true;
97 }
98 }
99
100 return false;
101}
102
103static bool __init alix_present_dmi(void)
104{
105 const char *vendor, *product;
106
107 vendor = dmi_get_system_info(field: DMI_SYS_VENDOR);
108 if (!vendor || strcmp(vendor, "PC Engines"))
109 return false;
110
111 product = dmi_get_system_info(field: DMI_PRODUCT_NAME);
112 if (!product || (strcmp(product, "ALIX.2D") && strcmp(product, "ALIX.6")))
113 return false;
114
115 printk(KERN_INFO "%s: system is recognized as \"%s %s\"\n",
116 KBUILD_MODNAME, vendor, product);
117
118 return true;
119}
120
121static int __init alix_init(void)
122{
123 const char tinybios_sig[] = "PC Engines ALIX.";
124 const char coreboot_sig[] = "PC Engines\0ALIX.";
125
126 if (!is_geode())
127 return 0;
128
129 if (alix_present(BIOS_SIGNATURE_TINYBIOS, alix_sig: tinybios_sig, alix_sig_len: sizeof(tinybios_sig) - 1) ||
130 alix_present(BIOS_SIGNATURE_COREBOOT, alix_sig: coreboot_sig, alix_sig_len: sizeof(coreboot_sig) - 1) ||
131 alix_present_dmi())
132 register_alix();
133
134 return 0;
135}
136device_initcall(alix_init);
137

source code of linux/arch/x86/platform/geode/alix.c