root/arch/x86/platform/geode/alix.c

DEFINITIONS

1. register_alix
2. alix_present
3. alix_present_dmi
4. alix_init

   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/leds.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/input.h>
  24 #include <linux/gpio_keys.h>
  25 #include <linux/dmi.h>
  26 
  27 #include <asm/geode.h>
  28 
  29 #define BIOS_SIGNATURE_TINYBIOS         0xf0000
  30 #define BIOS_SIGNATURE_COREBOOT         0x500
  31 #define BIOS_REGION_SIZE                0x10000
  32 
  33 /*
  34  * This driver is not modular, but to keep back compatibility
  35  * with existing use cases, continuing with module_param is
  36  * the easiest way forward.
  37  */
  38 static bool force = 0;
  39 module_param(force, bool, 0444);
  40 /* FIXME: Award bios is not automatically detected as Alix platform */
  41 MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3 platform");
  42 
  43 static struct gpio_keys_button alix_gpio_buttons[] = {
  44         {
  45                 .code                   = KEY_RESTART,
  46                 .gpio                   = 24,
  47                 .active_low             = 1,
  48                 .desc                   = "Reset button",
  49                 .type                   = EV_KEY,
  50                 .wakeup                 = 0,
  51                 .debounce_interval      = 100,
  52                 .can_disable            = 0,
  53         }
  54 };
  55 static struct gpio_keys_platform_data alix_buttons_data = {
  56         .buttons                        = alix_gpio_buttons,
  57         .nbuttons                       = ARRAY_SIZE(alix_gpio_buttons),
  58         .poll_interval                  = 20,
  59 };
  60 
  61 static struct platform_device alix_buttons_dev = {
  62         .name                           = "gpio-keys-polled",
  63         .id                             = 1,
  64         .dev = {
  65                 .platform_data          = &alix_buttons_data,
  66         }
  67 };
  68 
  69 static struct gpio_led alix_leds[] = {
  70         {
  71                 .name = "alix:1",
  72                 .gpio = 6,
  73                 .default_trigger = "default-on",
  74                 .active_low = 1,
  75         },
  76         {
  77                 .name = "alix:2",
  78                 .gpio = 25,
  79                 .default_trigger = "default-off",
  80                 .active_low = 1,
  81         },
  82         {
  83                 .name = "alix:3",
  84                 .gpio = 27,
  85                 .default_trigger = "default-off",
  86                 .active_low = 1,
  87         },
  88 };
  89 
  90 static struct gpio_led_platform_data alix_leds_data = {
  91         .num_leds = ARRAY_SIZE(alix_leds),
  92         .leds = alix_leds,
  93 };
  94 
  95 static struct platform_device alix_leds_dev = {
  96         .name = "leds-gpio",
  97         .id = -1,
  98         .dev.platform_data = &alix_leds_data,
  99 };
 100 
 101 static struct platform_device *alix_devs[] __initdata = {
 102         &alix_buttons_dev,
 103         &alix_leds_dev,
 104 };
 105 
 106 static void __init register_alix(void)
 107 {
 108         /* Setup LED control through leds-gpio driver */
 109         platform_add_devices(alix_devs, ARRAY_SIZE(alix_devs));
 110 }
 111 
 112 static bool __init alix_present(unsigned long bios_phys,
 113                                 const char *alix_sig,
 114                                 size_t alix_sig_len)
 115 {
 116         const size_t bios_len = BIOS_REGION_SIZE;
 117         const char *bios_virt;
 118         const char *scan_end;
 119         const char *p;
 120         char name[64];
 121 
 122         if (force) {
 123                 printk(KERN_NOTICE "%s: forced to skip BIOS test, "
 124                        "assume system is ALIX.2/ALIX.3\n",
 125                        KBUILD_MODNAME);
 126                 return true;
 127         }
 128 
 129         bios_virt = phys_to_virt(bios_phys);
 130         scan_end = bios_virt + bios_len - (alix_sig_len + 2);
 131         for (p = bios_virt; p < scan_end; p++) {
 132                 const char *tail;
 133                 char *a;
 134 
 135                 if (memcmp(p, alix_sig, alix_sig_len) != 0)
 136                         continue;
 137 
 138                 memcpy(name, p, sizeof(name));
 139 
 140                 /* remove the first \0 character from string */
 141                 a = strchr(name, '\0');
 142                 if (a)
 143                         *a = ' ';
 144 
 145                 /* cut the string at a newline */
 146                 a = strchr(name, '\r');
 147                 if (a)
 148                         *a = '\0';
 149 
 150                 tail = p + alix_sig_len;
 151                 if ((tail[0] == '2' || tail[0] == '3' || tail[0] == '6')) {
 152                         printk(KERN_INFO
 153                                "%s: system is recognized as \"%s\"\n",
 154                                KBUILD_MODNAME, name);
 155                         return true;
 156                 }
 157         }
 158 
 159         return false;
 160 }
 161 
 162 static bool __init alix_present_dmi(void)
 163 {
 164         const char *vendor, *product;
 165 
 166         vendor = dmi_get_system_info(DMI_SYS_VENDOR);
 167         if (!vendor || strcmp(vendor, "PC Engines"))
 168                 return false;
 169 
 170         product = dmi_get_system_info(DMI_PRODUCT_NAME);
 171         if (!product || (strcmp(product, "ALIX.2D") && strcmp(product, "ALIX.6")))
 172                 return false;
 173 
 174         printk(KERN_INFO "%s: system is recognized as \"%s %s\"\n",
 175                KBUILD_MODNAME, vendor, product);
 176 
 177         return true;
 178 }
 179 
 180 static int __init alix_init(void)
 181 {
 182         const char tinybios_sig[] = "PC Engines ALIX.";
 183         const char coreboot_sig[] = "PC Engines\0ALIX.";
 184 
 185         if (!is_geode())
 186                 return 0;
 187 
 188         if (alix_present(BIOS_SIGNATURE_TINYBIOS, tinybios_sig, sizeof(tinybios_sig) - 1) ||
 189             alix_present(BIOS_SIGNATURE_COREBOOT, coreboot_sig, sizeof(coreboot_sig) - 1) ||
 190             alix_present_dmi())
 191                 register_alix();
 192 
 193         return 0;
 194 }
 195 device_initcall(alix_init);