arch/x86/platform/geode/alix.c

   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);