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 */
 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(24);
 50	geode_create_leds("alix", 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(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
103static 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
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, 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}
136device_initcall(alix_init);