[PATCH 2/5] I8K - use standard DMI functions

Dmitry Torokhov
2005-02-24T06:18:52Z

===================================================================

I8K: Change to use stock dmi infrastructure instead of homegrown
parsing code. The driver now requres box's DMI data to match
list of supported models so driver can be safely compiled-in
by default without fear of it poking into random SMM BIOS
code. DMI checks can be ignored with i8k.ignore_dmi option.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Documentation/kernel-parameters.txt | 3
arch/i386/kernel/dmi_scan.c | 1
drivers/char/i8k.c | 304 ++++++------------------------------
include/linux/dmi.h | 1
4 files changed, 60 insertions(+), 249 deletions(-)

Index: dtor/arch/i386/kernel/dmi_scan.c
===================================================================
--- dtor.orig/arch/i386/kernel/dmi_scan.c
+++ dtor/arch/i386/kernel/dmi_scan.c
@@ -416,6 +416,7 @@ static void __init dmi_decode(struct dmi
dmi_save_ident(dm, DMI_PRODUCT_VERSION, 6);
dmi_printk(("Serial Number: %s\n",
dmi_string(dm, data[7])));
+ dmi_save_ident(dm, DMI_PRODUCT_SERIAL, 7);
break;
case 2:
dmi_printk(("Board Vendor: %s\n",
Index: dtor/include/linux/dmi.h
===================================================================
--- dtor.orig/include/linux/dmi.h
+++ dtor/include/linux/dmi.h
@@ -9,6 +9,7 @@ enum dmi_field {
DMI_SYS_VENDOR,
DMI_PRODUCT_NAME,
DMI_PRODUCT_VERSION,
+ DMI_PRODUCT_SERIAL,
DMI_BOARD_VENDOR,
DMI_BOARD_NAME,
DMI_BOARD_VERSION,
Index: dtor/drivers/char/i8k.c
===================================================================
--- dtor.orig/drivers/char/i8k.c
+++ dtor/drivers/char/i8k.c
@@ -20,7 +20,7 @@
#include <linux/types.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
-#include <linux/apm_bios.h>
+#include <linux/dmi.h>
#include <asm/uaccess.h>
#include <asm/io.h>

@@ -52,18 +52,7 @@

#define I8K_TEMPERATURE_BUG 1

-#define DELL_SIGNATURE "Dell Computer"
-
-static char *supported_models[] = {
- "Inspiron",
- "Latitude",
- NULL
-};
-
-static char system_vendor[48] = "?";
-static char product_name[48] = "?";
-static char bios_version[4] = "?";
-static char serial_number[16] = "?";
+static char bios_version[4];

MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
@@ -73,6 +62,10 @@ static int force;
module_param(force, bool, 0);
MODULE_PARM_DESC(force, "Force loading without checking for supported models");

+static int ignore_dmi;
+module_param(ignore_dmi, bool, 0);
+MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
+
static int restricted;
module_param(restricted, bool, 0);
MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
@@ -99,11 +92,10 @@ typedef struct {
unsigned int edi __attribute__ ((packed));
} SMMRegisters;

-typedef struct {
- u8 type;
- u8 length;
- u16 handle;
-} DMIHeader;
+static inline char *i8k_get_dmi_data(int field)
+{
+ return dmi_get_system_info(field) ? : "N/A";
+}

/*
* Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
@@ -163,15 +155,6 @@ static int i8k_get_bios_version(void)
}

/*
- * Read the machine id.
- */
-static int i8k_get_serial_number(unsigned char *buff)
-{
- strlcpy(buff, serial_number, sizeof(serial_number));
- return 0;
-}
-
-/*
* Read the Fn key status.
*/
static int i8k_get_fn_status(void)
@@ -328,7 +311,7 @@ static int i8k_get_dell_signature(void)
static int i8k_ioctl(struct inode *ip, struct file *fp, unsigned int cmd,
unsigned long arg)
{
- int val;
+ int val = 0;
int speed;
unsigned char buff[16];
int __user *argp = (int __user *)arg;
@@ -343,7 +326,7 @@ static int i8k_ioctl(struct inode *ip, s

case I8K_MACHINE_ID:
memset(buff, 0, 16);
- val = i8k_get_serial_number(buff);
+ strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL), sizeof(buff));
break;

case I8K_FN_STATUS:
@@ -451,10 +434,10 @@ static int i8k_get_info(char *buffer, ch
n = sprintf(buffer, "%s %s %s %d %d %d %d %d %d %d\n",
I8K_PROC_FMT,
bios_version,
- serial_number,
+ dmi_get_system_info(DMI_PRODUCT_SERIAL) ? : "N/A",
cpu_temp,
- left_fan,
- right_fan, left_speed, right_speed, ac_power, fn_key);
+ left_fan, right_fan, left_speed, right_speed,
+ ac_power, fn_key);

return n;
}
@@ -486,201 +469,23 @@ static ssize_t i8k_read(struct file *f,
return len;
}

-static char *__init string_trim(char *s, int size)
-{
- int len;
- char *p;
-
- if ((len = strlen(s)) > size) {
- len = size;
- }
-
- for (p = s + len - 1; len && (*p == ' '); len--, p--) {
- *p = '\0';
- }
-
- return s;
-}
-
-/* DMI code, stolen from arch/i386/kernel/dmi_scan.c */
-
-/*
- * |<-- dmi->length -->|
- * | |
- * |dmi header s=N | string1,\0, ..., stringN,\0, ..., \0
- * | |
- * +-----------------------+
- */
-static char *__init dmi_string(DMIHeader * dmi, u8 s)
-{
- u8 *p;
-
- if (!s) {
- return "";
- }
- s--;
-
- p = (u8 *) dmi + dmi->length;
- while (s > 0) {
- p += strlen(p);
- p++;
- s--;
- }
-
- return p;
-}
-
-static void __init dmi_decode(DMIHeader * dmi)
-{
- u8 *data = (u8 *) dmi;
- char *p;
-
-#ifdef I8K_DEBUG
- int i;
- printk("%08x ", (int)data);
- for (i = 0; i < data[1] && i < 64; i++) {
- printk("%02x ", data[i]);
- }
- printk("\n");
-#endif
-
- switch (dmi->type) {
- case 0: /* BIOS Information */
- p = dmi_string(dmi, data[5]);
- if (*p) {
- strlcpy(bios_version, p, sizeof(bios_version));
- string_trim(bios_version, sizeof(bios_version));
- }
- break;
- case 1: /* System Information */
- p = dmi_string(dmi, data[4]);
- if (*p) {
- strlcpy(system_vendor, p, sizeof(system_vendor));
- string_trim(system_vendor, sizeof(system_vendor));
- }
- p = dmi_string(dmi, data[5]);
- if (*p) {
- strlcpy(product_name, p, sizeof(product_name));
- string_trim(product_name, sizeof(product_name));
- }
- p = dmi_string(dmi, data[7]);
- if (*p) {
- strlcpy(serial_number, p, sizeof(serial_number));
- string_trim(serial_number, sizeof(serial_number));
- }
- break;
- }
-}
-
-static int __init dmi_table(u32 base, int len, int num,
- void (*fn) (DMIHeader *))
-{
- u8 *buf;
- u8 *data;
- DMIHeader *dmi;
- int i = 1;
-
- buf = ioremap(base, len);
- if (buf == NULL) {
- return -1;
- }
- data = buf;
-
- /*
- * Stop when we see al the items the table claimed to have
- * or we run off the end of the table (also happens)
- */
- while ((i < num) && ((data - buf) < len)) {
- dmi = (DMIHeader *) data;
- /*
- * Avoid misparsing crud if the length of the last
- * record is crap
- */
- if ((data - buf + dmi->length) >= len) {
- break;
- }
- fn(dmi);
- data += dmi->length;
- /*
- * Don't go off the end of the data if there is
- * stuff looking like string fill past the end
- */
- while (((data - buf) < len) && (*data || data[1])) {
- data++;
- }
- data += 2;
- i++;
- }
- iounmap(buf);
-
- return 0;
-}
-
-static int __init dmi_iterate(void (*decode) (DMIHeader *))
-{
- unsigned char buf[20];
- void __iomem *p = ioremap(0xe0000, 0x20000), *q;
-
- if (!p)
- return -1;
-
- for (q = p; q < p + 0x20000; q += 16) {
- memcpy_fromio(buf, q, 20);
- if (memcmp(buf, "_DMI_", 5) == 0) {
- u16 num = buf[13] << 8 | buf[12];
- u16 len = buf[7] << 8 | buf[6];
- u32 base = buf[11] << 24 | buf[10] << 16 | buf[9] << 8 | buf[8];
-#ifdef I8K_DEBUG
- printk(KERN_INFO "DMI %d.%d present.\n",
- buf[14] >> 4, buf[14] & 0x0F);
- printk(KERN_INFO "%d structures occupying %d bytes.\n",
- buf[13] << 8 | buf[12], buf[7] << 8 | buf[6]);
- printk(KERN_INFO "DMI table at 0x%08X.\n",
- buf[11] << 24 | buf[10] << 16 | buf[9] << 8 |
- buf[8]);
-#endif
- if (dmi_table(base, len, num, decode) == 0) {
- iounmap(p);
- return 0;
- }
- }
- }
- iounmap(p);
- return -1;
-}
-
-/* end of DMI code */
-
-/*
- * Get DMI information.
- */
-static int __init i8k_dmi_probe(void)
-{
- char **p;
-
- if (dmi_iterate(dmi_decode) != 0) {
- printk(KERN_INFO "i8k: unable to get DMI information\n");
- return -ENODEV;
- }
-
- if (strncmp(system_vendor, DELL_SIGNATURE, strlen(DELL_SIGNATURE)) != 0) {
- printk(KERN_INFO "i8k: not running on a Dell system\n");
- return -ENODEV;
- }
-
- for (p = supported_models;; p++) {
- if (!*p) {
- printk(KERN_INFO "i8k: unsupported model: %s\n",
- product_name);
- return -ENODEV;
- }
- if (strncmp(product_name, *p, strlen(*p)) == 0) {
- break;
- }
- }
-
- return 0;
-}
+static struct dmi_system_id __initdata i8k_dmi_table[] = {
+ {
+ .ident = "Dell Inspiron",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
+ },
+ },
+ {
+ .ident = "Dell Latitude",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
+ },
+ },
+ { }
+};

/*
* Probe for the presence of a supported laptop.
@@ -689,23 +494,30 @@ static int __init i8k_probe(void)
{
char buff[4];
int version;
- int smm_found = 0;

/*
* Get DMI information
*/
- if (i8k_dmi_probe() != 0) {
+ if (!dmi_check_system(i8k_dmi_table)) {
+ if (!ignore_dmi && !force)
+ return -ENODEV;
+
+ printk(KERN_INFO "i8k: not running on a supported Dell system.\n");
printk(KERN_INFO "i8k: vendor=%s, model=%s, version=%s\n",
- system_vendor, product_name, bios_version);
+ i8k_get_dmi_data(DMI_SYS_VENDOR),
+ i8k_get_dmi_data(DMI_PRODUCT_NAME),
+ i8k_get_dmi_data(DMI_BIOS_VERSION));
}

+ strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION), sizeof(bios_version));
+
/*
* Get SMM Dell signature
*/
if (i8k_get_dell_signature() != 0) {
- printk(KERN_INFO "i8k: unable to get SMM Dell signature\n");
- } else {
- smm_found = 1;
+ printk(KERN_ERR "i8k: unable to get SMM Dell signature\n");
+ if (!force)
+ return -ENODEV;
}

/*
@@ -713,9 +525,10 @@ static int __init i8k_probe(void)
*/
version = i8k_get_bios_version();
if (version <= 0) {
- printk(KERN_INFO "i8k: unable to get SMM BIOS version\n");
+ printk(KERN_ERR "i8k: unable to get SMM BIOS version\n");
+ if (!force)
+ return -ENODEV;
} else {
- smm_found = 1;
buff[0] = (version >> 16) & 0xff;
buff[1] = (version >> 8) & 0xff;
buff[2] = (version) & 0xff;
@@ -723,21 +536,15 @@ static int __init i8k_probe(void)
/*
* If DMI BIOS version is unknown use SMM BIOS version.
*/
- if (bios_version[0] == '?') {
- strcpy(bios_version, buff);
- }
+ if (!dmi_get_system_info(DMI_BIOS_VERSION))
+ strlcpy(bios_version, buff, sizeof(bios_version));
+
/*
* Check if the two versions match.
*/
- if (strncmp(buff, bios_version, sizeof(bios_version)) != 0) {
- printk(KERN_INFO
- "i8k: BIOS version mismatch: %s != %s\n", buff,
- bios_version);
- }
- }
-
- if (!smm_found && !force) {
- return -ENODEV;
+ if (strncmp(buff, bios_version, sizeof(bios_version)) != 0)
+ printk(KERN_WARNING "i8k: BIOS version mismatch: %s != %s\n",
+ buff, bios_version);
}

return 0;
@@ -751,9 +558,8 @@ int __init i8k_init(void)
struct proc_dir_entry *proc_i8k;

/* Are we running on an supported laptop? */
- if (i8k_probe() != 0) {
+ if (i8k_probe())
return -ENODEV;
- }

/* Register the proc entry */
proc_i8k = create_proc_info_entry("i8k", 0, NULL, i8k_get_info);
Index: dtor/Documentation/kernel-parameters.txt
===================================================================
--- dtor.orig/Documentation/kernel-parameters.txt
+++ dtor/Documentation/kernel-parameters.txt
@@ -528,6 +528,9 @@ running once the system is up.

i810= [HW,DRM]

+ i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
+ indicates that the driver is running on unsupported
+ hardware.
i8k.force [HW] Activate i8k driver even if SMM BIOS signature
does not match list of supported models.
i8k.power_status