[PATCH] I8K: use standard DMI interface

I8K: Change to use stock dmi infrastructure instead of homegrown
     parsing code. The driver now requires 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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 60 insertions, 252 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4924d387a657..86db43fd6b0f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -548,6 +548,9 @@ 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
diff --git a/arch/i386/kernel/dmi_scan.c b/arch/i386/kernel/dmi_scan.c
index 6ed7e28f306c..3facd20212bb 100644
--- a/arch/i386/kernel/dmi_scan.c
+++ b/arch/i386/kernel/dmi_scan.c
@@ -414,6 +414,7 @@ static void __init dmi_decode(struct dmi_header *dm)
                         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",
@@ -470,7 +471,6 @@ fail:		d++;
 
         return count;
 }
-
 EXPORT_SYMBOL(dmi_check_system);
 
 /**
@@ -480,8 +480,8 @@ EXPORT_SYMBOL(dmi_check_system);
  *      Returns one DMI data value, can be used to perform
  *      complex DMI data checks.
  */
-char * dmi_get_system_info(int field)
+char *dmi_get_system_info(int field)
 {
         return dmi_ident[field];
 }
-
+EXPORT_SYMBOL(dmi_get_system_info);
diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index bf5e43beca62..81d2f675fb77 100644
--- a/drivers/char/i8k.c
+++ b/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, struct file *fp, unsigned int cmd,
 
         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, char **start, off_t fpos, int length)
         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, char __user * buffer, size_t len,
         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 +525,8 @@ 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_WARNING "i8k: unable to get SMM BIOS version\n");
         } else {
-                smm_found = 1;
                 buff[0] = (version >> 16) & 0xff;
                 buff[1] = (version >> 8) & 0xff;
                 buff[2] = (version) & 0xff;
@@ -723,21 +534,15 @@ 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 +556,8 @@ 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);
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index d2bcf556088b..5e93e6dce9a4 100644
--- a/include/linux/dmi.h
+++ b/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,