xref: /linux/arch/x86/platform/geode/alix.c (revision 7a4ffec9fd54ea27395e24dff726dbf58e2fe06b)
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  */
36 static bool force = 0;
37 module_param(force, bool, 0444);
38 /* FIXME: Award bios is not automatically detected as Alix platform */
39 MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3 platform");
40 
41 static const struct geode_led alix_leds[] __initconst = {
42 	{ 6, true },
43 	{ 25, false },
44 	{ 27, false },
45 };
46 
47 static void __init register_alix(void)
48 {
49 	geode_create_restart_key(24);
50 	geode_create_leds("alix", alix_leds, ARRAY_SIZE(alix_leds));
51 }
52 
53 static 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(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, alix_sig, 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 
103 static bool __init alix_present_dmi(void)
104 {
105 	const char *vendor, *product;
106 
107 	vendor = dmi_get_system_info(DMI_SYS_VENDOR);
108 	if (!vendor || strcmp(vendor, "PC Engines"))
109 		return false;
110 
111 	product = dmi_get_system_info(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 
121 static 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, tinybios_sig, sizeof(tinybios_sig) - 1) ||
130 	    alix_present(BIOS_SIGNATURE_COREBOOT, coreboot_sig, sizeof(coreboot_sig) - 1) ||
131 	    alix_present_dmi())
132 		register_alix();
133 
134 	return 0;
135 }
136 device_initcall(alix_init);
137