/*
* Copyright 2010 Google Inc. All Rights Reserved.
* Author: dlaurie@google.com (Duncan Laurie)
*
* Re-worked to expose sysfs APIs by mikew@google.com (Mike Waychison)
*
* EFI SMI interface for Google platforms
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/ioctl.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/dmi.h>
#include <linux/kdebug.h>
#include <linux/reboot.h>
#include <linux/efi.h>
#include <linux/module.h>
#include <linux/ucs2_string.h>
#define GSMI_SHUTDOWN_CLEAN 0 /* Clean Shutdown */
/* TODO(mikew@google.com): Tie in HARDLOCKUP_DETECTOR with NMIWDT */
#define GSMI_SHUTDOWN_NMIWDT 1 /* NMI Watchdog */
#define GSMI_SHUTDOWN_PANIC 2 /* Panic */
#define GSMI_SHUTDOWN_OOPS 3 /* Oops */
#define GSMI_SHUTDOWN_DIE 4 /* Die -- No longer meaningful */
#define GSMI_SHUTDOWN_MCE 5 /* Machine Check */
#define GSMI_SHUTDOWN_SOFTWDT 6 /* Software Watchdog */
#define GSMI_SHUTDOWN_MBE 7 /* Uncorrected ECC */
#define GSMI_SHUTDOWN_TRIPLE 8 /* Triple Fault */
#define DRIVER_VERSION "1.0"
#define GSMI_GUID_SIZE 16
#define GSMI_BUF_SIZE 1024
#define GSMI_BUF_ALIGN sizeof(u64)
#define GSMI_CALLBACK 0xef
/* SMI return codes */
#define GSMI_SUCCESS 0x00
#define GSMI_UNSUPPORTED2 0x03
#define GSMI_LOG_FULL 0x0b
#define GSMI_VAR_NOT_FOUND 0x0e
#define GSMI_HANDSHAKE_SPIN 0x7d
#define GSMI_HANDSHAKE_CF 0x7e
#define GSMI_HANDSHAKE_NONE 0x7f
#define GSMI_INVALID_PARAMETER 0x82
#define GSMI_UNSUPPORTED 0x83
#define GSMI_BUFFER_TOO_SMALL 0x85
#define GSMI_NOT_READY 0x86
#define GSMI_DEVICE_ERROR 0x87
#define GSMI_NOT_FOUND 0x8e
#define QUIRKY_BOARD_HASH 0x78a30a50
/* Internally used commands passed to the firmware */
#define GSMI_CMD_GET_NVRAM_VAR 0x01
#define GSMI_CMD_GET_NEXT_VAR 0x02
#define GSMI_CMD_SET_NVRAM_VAR 0x03
#define GSMI_CMD_SET_EVENT_LOG 0x08
#define GSMI_CMD_CLEAR_EVENT_LOG 0x09
#define GSMI_CMD_CLEAR_CONFIG 0x20
#define GSMI_CMD_HANDSHAKE_TYPE 0xC1
/* Magic entry type for kernel events */
#define GSMI_LOG_ENTRY_TYPE_KERNEL 0xDEAD
/* SMI buffers must be in 32bit physical address space */
struct gsmi_buf {
u8 *start; /* start of buffer */
size_t length; /* length of buffer */
dma_addr_t handle; /* dma allocation handle */
u32 address; /* physical address of buffer */
};
struct gsmi_device {
struct platform_device *pdev; /* platform device */
struct gsmi_buf *name_buf; /* variable name buffer */
struct gsmi_buf *data_buf; /* generic data buffer */
struct gsmi_buf *param_buf; /* parameter buffer */
spinlock_t lock; /* serialize access to SMIs */
u16 smi_cmd; /* SMI command port */
int handshake_type; /* firmware handler interlock type */
struct dma_pool *dma_pool; /* DMA buffer pool */
} gsmi_dev;
/* Packed structures for communicating with the firmware */
struct gsmi_nvram_var_param {
efi_guid_t guid;
u32 name_ptr;
u32 attributes;
u32 data_len;
u32 data_ptr;
} __packed;
struct gsmi_get_next_var_param {
u8 guid[GSMI_GUID_SIZE];
u32 name_ptr;
u32 name_len;
} __packed;
struct gsmi_set_eventlog_param {
u32 data_ptr;
u32 data_len;
u32 type;
} __packed;
/* Event log formats */
struct gsmi_log_entry_type_1 {
u16 type;
u32 instance;
} __packed;
/*
* Some platforms don't have explicit SMI handshake
* and need to wait for SMI to complete.
*/
#define GSMI_DEFAULT_SPINCOUNT 0x10000
static unsigned int spincount = GSMI_DEFAULT_SPINCOUNT;
module_param(spincount, uint, 0600);
MODULE_PARM_DESC(spincount,
"The number of loop iterations to use when using the spin handshake.");
static struct gsmi_buf *gsmi_buf_alloc(void)
{
struct gsmi_buf *smibuf;
smibuf = kzalloc(sizeof(*smibuf), GFP_KERNEL);
if (!smibuf) {
printk(KERN_ERR "gsmi: out of memory\n");
return NULL;
}
/* allocate buffer in 32bit address space */
smibuf->start = dma_pool_alloc(gsmi_dev.dma_pool, GFP_KERNEL,
&smibuf->handle);
if (!smibuf->start) {
printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
kfree(smibuf);
return NULL;
}
/* fill in the buffer handle */
smibuf->length = GSMI_BUF_SIZE;
smibuf->address = (u32)virt_to_phys(smibuf->start);
return smibuf;
}
static void gsmi_buf_free(struct gsmi_buf *smibuf)
{
if (smibuf) {
if (smibuf->start)
dma_pool_free(gsmi_dev.dma_pool, smibuf->start,
smibuf->handle);
kfree(smibuf);
}
}
/*
* Make a call to gsmi func(sub). GSMI error codes are translated to
* in-kernel errnos (0 on success, -ERRNO on error).
*/
static int gsmi_exec(u8 func, u8 sub)
{
u16 cmd = (sub << 8) | func;
u16 result = 0;
int rc = 0;
/*
* AH : Subfunction number
* AL : Function number
* EBX : Parameter block address
* DX : SMI command port
*
* Three protocols here. See also the comment in gsmi_init().
*/
if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_CF) {
/*
* If handshake_type == HANDSHAKE_CF then set CF on the
* way in and wait for the handler to clear it; this avoids
* corrupting register state on those chipsets which have
* a delay between writing the SMI trigger register and
* entering SMM.
*/
asm volatile (
"stc\n"
"outb %%al, %%dx\n"
"1: jc 1b\n"
: "=a" (result)
: "0" (cmd),
"d" (gsmi_dev.smi_cmd),
"b" (gsmi_dev.param_buf->address)
: "memory", "cc"
);
} else if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_SPIN) {
/*
* If handshake_type == HANDSHAKE_SPIN we spin a
* hundred-ish usecs to ensure the SMI has triggered.
*/
asm volatile (
"outb %%al, %%dx\n"
"1: loop 1b\n"
: "=a" (result)
: "0" (cmd),
"d" (gsmi_dev.smi_cmd),
"b" (gsmi_dev.param_buf->address),
"c" (spincount)
: "memory", "cc"
);
} else {
/*
* If handshake_type == HANDSHAKE_NONE we do nothing;
* either we don't need to or it's legacy firmware that
* doesn't understand the CF protocol.
*/
asm volatile (
"outb %%al, %%dx\n\t"
: "=a" (result)
: "0" (cmd),
"d" (gsmi_dev.smi_cmd),
"b" (gsmi_dev.param_buf->address)
: "memory", "cc"
);
}
/* check return code from SMI handler */
switch (result) {
case GSMI_SUCCESS:
break;
case GSMI_VAR_NOT_FOUND:
/* not really an error, but let the caller know */
rc = 1;
break;
case GSMI_INVALID_PARAMETER:
printk(KERN_ERR "gsmi: exec 0x%04x: Invalid parameter\n", cmd);
rc = -EINVAL;
break;
case GSMI_BUFFER_TOO_SMALL:
printk(KERN_ERR "gsmi: exec 0x%04x: Buffer too small\n", cmd);
rc = -ENOMEM;
break;
case GSMI_UNSUPPORTED:
case GSMI_UNSUPPORTED2:
if (sub != GSMI_CMD_HANDSHAKE_TYPE)
printk(KERN_ERR "gsmi: exec 0x%04x: Not supported\n",
cmd);
rc = -ENOSYS;
break;
case GSMI_NOT_READY:
printk(KERN_ERR "gsmi: exec 0x%04x: Not ready\n", cmd);
rc = -EBUSY;
break;
case GSMI_DEVICE_ERROR:
printk(KERN_ERR "gsmi: exec 0x%04x: Device error\n", cmd);
rc = -EFAULT;
break;
case GSMI_NOT_FOUND:
printk(KERN_ERR "gsmi: exec 0x%04x: Data not found\n", cmd);
rc = -ENOENT;
break;
case GSMI_LOG_FULL:
printk(KERN_ERR "gsmi: exec 0x%04x: Log full\n", cmd);
rc = -ENOSPC;
break;
case GSMI_HANDSHAKE_CF:
case GSMI_HANDSHAKE_SPIN:
case GSMI_HANDSHAKE_NONE:
rc = result;
break;
default:
printk(KERN_ERR "gsmi: exec 0x%04x: Unknown error 0x%04x\n",
cmd, result);
rc = -ENXIO;
}
return rc;
}
static efi_status_t gsmi_get_variable(efi_char16_t *name,
efi_guid_t *vendor, u32 *attr,
unsigned long *data_size,
void *data)
{
struct gsmi_nvram_var_param param = {
.name_ptr = gsmi_dev.name_buf->address,
.data_ptr = gsmi_dev.data_buf->address,
.data_len = (u32)*data_size,
};
efi_status_t ret = EFI_SUCCESS;
unsigned long flags;
size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2);
int rc;
if (name_len >= GSMI_BUF_SIZE / 2)
return EFI_BAD_BUFFER_SIZE;
spin_lock_irqsave(&gsmi_dev.lock, flags);
/* Vendor guid */
memcpy(¶m.guid, vendor, sizeof(param.guid));
/* variable name, already in UTF-16 */
memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length);
memcpy(gsmi_dev.name_buf->start, name, name_len * 2);
/* data pointer */
memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
/* parameter buffer */
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NVRAM_VAR);
if (rc < 0) {
printk(KERN_ERR "gsmi: Get Variable failed\n");
ret = EFI_LOAD_ERROR;
} else if (rc == 1) {
/* variable was not found */
ret = EFI_NOT_FOUND;
} else {
/* Get the arguments back */
memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param));
/* The size reported is the min of all of our buffers */
*data_size = min_t(unsigned long, *data_size,
gsmi_dev.data_buf->length);
*data_size = min_t(unsigned long, *data_size, param.data_len);
/* Copy data back to return buffer. */
memcpy(data, gsmi_dev.data_buf->start, *data_size);
/* All variables are have the following attributes */
*attr = EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS;
}
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
return ret;
}
static efi_status_t gsmi_get_next_variable(unsigned long *name_size,
efi_char16_t *name,
efi_guid_t *vendor)
{
struct gsmi_get_next_var_param param = {
.name_ptr = gsmi_dev.name_buf->address,
.name_len = gsmi_dev.name_buf->length,
};
efi_status_t ret = EFI_SUCCESS;
int rc;
unsigned long flags;
/* For the moment, only support buffers that exactly match in size */
if (*name_size != GSMI_BUF_SIZE)
return EFI_BAD_BUFFER_SIZE;
/* Let's make sure the thing is at least null-terminated */
if (ucs2_strnlen(name, GSMI_BUF_SIZE / 2) == GSMI_BUF_SIZE / 2)
return EFI_INVALID_PARAMETER;
spin_lock_irqsave(&gsmi_dev.lock, flags);
/* guid */
memcpy(¶m.guid, vendor, sizeof(param.guid));
/* variable name, already in UTF-16 */
memcpy(gsmi_dev.name_buf->start, name, *name_size);
/* parameter buffer */
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NEXT_VAR);
if (rc < 0) {
printk(KERN_ERR "gsmi: Get Next Variable Name failed\n");
ret = EFI_LOAD_ERROR;
} else if (rc == 1) {
/* variable not found -- end of list */
ret = EFI_NOT_FOUND;
} else {
/* copy variable data back to return buffer */
memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param));
/* Copy the name back */
memcpy(name, gsmi_dev.name_buf->start, GSMI_BUF_SIZE);
*name_size = ucs2_strnlen(name, GSMI_BUF_SIZE / 2) * 2;
/* copy guid to return buffer */
memcpy(vendor, ¶m.guid, sizeof(param.guid));
ret = EFI_SUCCESS;
}
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
return ret;
}
static efi_status_t gsmi_set_variable(efi_char16_t *name,
efi_guid_t *vendor,
u32 attr,
unsigned long data_size,
void *data)
{
struct gsmi_nvram_var_param param = {
.name_ptr = gsmi_dev.name_buf->address,
.data_ptr = gsmi_dev.data_buf->address,
.data_len = (u32)data_size,
.attributes = EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
};
size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2);
efi_status_t ret = EFI_SUCCESS;
int rc;
unsigned long flags;
if (name_len >= GSMI_BUF_SIZE / 2)
return EFI_BAD_BUFFER_SIZE;
spin_lock_irqsave(&gsmi_dev.lock, flags);
/* guid */
memcpy(¶m.guid, vendor, sizeof(param.guid));
/* variable name, already in UTF-16 */
memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length);
memcpy(gsmi_dev.name_buf->start, name, name_len * 2);
/* data pointer */
memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
memcpy(gsmi_dev.data_buf->start, data, data_size);
/* parameter buffer */
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_NVRAM_VAR);
if (rc < 0) {
printk(KERN_ERR "gsmi: Set Variable failed\n");
ret = EFI_INVALID_PARAMETER;
}
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
return ret;
}
static const struct efivar_operations efivar_ops = {
.get_variable = gsmi_get_variable,
.set_variable = gsmi_set_variable,
.get_next_variable = gsmi_get_next_variable,
};
static ssize_t eventlog_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
{
struct gsmi_set_eventlog_param param = {
.data_ptr = gsmi_dev.data_buf->address,
};
int rc = 0;
unsigned long flags;
/* Pull the type out */
if (count < sizeof(u32))
return -EINVAL;
param.type = *(u32 *)buf;
count -= sizeof(u32);
buf += sizeof(u32);
/* The remaining buffer is the data payload */
if (count > gsmi_dev.data_buf->length)
return -EINVAL;
param.data_len = count - sizeof(u32);
spin_lock_irqsave(&gsmi_dev.lock, flags);
/* data pointer */
memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
memcpy(gsmi_dev.data_buf->start, buf, param.data_len);
/* parameter buffer */
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG);
if (rc < 0)
printk(KERN_ERR "gsmi: Set Event Log failed\n");
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
return rc;
}
static struct bin_attribute eventlog_bin_attr = {
.attr = {.name = "append_to_eventlog", .mode = 0200},
.write = eventlog_write,
};
static ssize_t gsmi_clear_eventlog_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int rc;
unsigned long flags;
unsigned long val;
struct {
u32 percentage;
u32 data_type;
} param;
rc = strict_strtoul(buf, 0, &val);
if (rc)
return rc;
/*
* Value entered is a percentage, 0 through 100, anything else
* is invalid.
*/
if (val > 100)
return -EINVAL;
/* data_type here selects the smbios event log. */
param.percentage = val;
param.data_type = 0;
spin_lock_irqsave(&gsmi_dev.lock, flags);
/* parameter buffer */
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_EVENT_LOG);
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
if (rc)
return rc;
return count;
}
static struct kobj_attribute gsmi_clear_eventlog_attr = {
.attr = {.name = "clear_eventlog", .mode = 0200},
.store = gsmi_clear_eventlog_store,
};
static ssize_t gsmi_clear_config_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int rc;
unsigned long flags;
spin_lock_irqsave(&gsmi_dev.lock, flags);
/* clear parameter buffer */
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_CONFIG);
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
if (rc)
return rc;
return count;
}
static struct kobj_attribute gsmi_clear_config_attr = {
.attr = {.name = "clear_config", .mode = 0200},
.store = gsmi_clear_config_store,
};
static const struct attribute *gsmi_attrs[] = {
&gsmi_clear_config_attr.attr,
&gsmi_clear_eventlog_attr.attr,
NULL,
};
static int gsmi_shutdown_reason(int reason)
{
struct gsmi_log_entry_type_1 entry = {
.type = GSMI_LOG_ENTRY_TYPE_KERNEL,
.instance = reason,
};
struct gsmi_set_eventlog_param param = {
.data_len = sizeof(entry),
.type = 1,
};
static int saved_reason;
int rc = 0;
unsigned long flags;
/* avoid duplicate entries in the log */
if (saved_reason & (1 << reason))
return 0;
spin_lock_irqsave(&gsmi_dev.lock, flags);
saved_reason |= (1 << reason);
/* data pointer */
memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length);
memcpy(gsmi_dev.data_buf->start, &entry, sizeof(entry));
/* parameter buffer */
param.data_ptr = gsmi_dev.data_buf->address;
memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length);
memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param));
rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG);
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
if (rc < 0)
printk(KERN_ERR "gsmi: Log Shutdown Reason failed\n");
else
printk(KERN_EMERG "gsmi: Log Shutdown Reason 0x%02x\n",
reason);
return rc;
}
static int gsmi_reboot_callback(struct notifier_block *nb,
unsigned long reason, void *arg)
{
gsmi_shutdown_reason(GSMI_SHUTDOWN_CLEAN);
return NOTIFY_DONE;
}
static struct notifier_block gsmi_reboot_notifier = {
.notifier_call = gsmi_reboot_callback
};
static int gsmi_die_callback(struct notifier_block *nb,
unsigned long reason, void *arg)
{
if (reason == DIE_OOPS)
gsmi_shutdown_reason(GSMI_SHUTDOWN_OOPS);
return NOTIFY_DONE;
}
static struct notifier_block gsmi_die_notifier = {
.notifier_call = gsmi_die_callback
};
static int gsmi_panic_callback(struct notifier_block *nb,
unsigned long reason, void *arg)
{
gsmi_shutdown_reason(GSMI_SHUTDOWN_PANIC);
return NOTIFY_DONE;
}
static struct notifier_block gsmi_panic_notifier = {
.notifier_call = gsmi_panic_callback,
};
/*
* This hash function was blatantly copied from include/linux/hash.h.
* It is used by this driver to obfuscate a board name that requires a
* quirk within this driver.
*
* Please do not remove this copy of the function as any changes to the
* global utility hash_64() function would break this driver's ability
* to identify a board and provide the appropriate quirk -- mikew@google.com
*/
static u64 __init local_hash_64(u64 val, unsigned bits)
{
u64 hash = val;
/* Sigh, gcc can't optimise this alone like it does for 32 bits. */
u64 n = hash;
n <<= 18;
hash -= n;
n <<= 33;
hash -= n;
n <<= 3;
hash += n;
n <<= 3;
hash -= n;
n <<= 4;
hash += n;
n <<= 2;
hash += n;
/* High bits are more random, so use them. */
return hash >> (64 - bits);
}
static u32 __init hash_oem_table_id(char s[8])
{
u64 input;
memcpy(&input, s, 8);
return local_hash_64(input, 32);
}
static struct dmi_system_id gsmi_dmi_table[] __initdata = {
{
.ident = "Google Board",
.matches = {
DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."),
},
},
{}
};
MODULE_DEVICE_TABLE(dmi, gsmi_dmi_table);
static __init int gsmi_system_valid(void)
{
u32 hash;
if (!dmi_check_system(gsmi_dmi_table))
return -ENODEV;
/*
* Only newer firmware supports the gsmi interface. All older
* firmware that didn't support this interface used to plug the
* table name in the first four bytes of the oem_table_id field.
* Newer firmware doesn't do that though, so use that as the
* discriminant factor. We have to do this in order to
* whitewash our board names out of the public driver.
*/
if (!strncmp(acpi_gbl_FADT.header.oem_table_id, "FACP", 4)) {
printk(KERN_INFO "gsmi: Board is too old\n");
return -ENODEV;
}
/* Disable on board with 1.0 BIOS due to Google bug 2602657 */
hash = hash_oem_table_id(acpi_gbl_FADT.header.oem_table_id);
if (hash == QUIRKY_BOARD_HASH) {
const char *bios_ver = dmi_get_system_info(DMI_BIOS_VERSION);
if (strncmp(bios_ver, "1.0", 3) == 0) {
pr_info("gsmi: disabled on this board's BIOS %s\n",
bios_ver);
return -ENODEV;
}
}
/* check for valid SMI command port in ACPI FADT */
if (acpi_gbl_FADT.smi_command == 0) {
pr_info("gsmi: missing smi_command\n");
return -ENODEV;
}
/* Found */
return 0;
}
static struct kobject *gsmi_kobj;
static struct efivars efivars;
static __init int gsmi_init(void)
{
unsigned long flags;
int ret;
ret = gsmi_system_valid();
if (ret)
return ret;
gsmi_dev.smi_cmd = acpi_gbl_FADT.smi_command;
/* register device */
gsmi_dev.pdev = platform_device_register_simple("gsmi", -1, NULL, 0);
if (IS_ERR(gsmi_dev.pdev)) {
printk(KERN_ERR "gsmi: unable to register platform device\n");
return PTR_ERR(gsmi_dev.pdev);
}
/* SMI access needs to be serialized */
spin_lock_init(&gsmi_dev.lock);
/* SMI callbacks require 32bit addresses */
gsmi_dev.pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
gsmi_dev.pdev->dev.dma_mask =
&gsmi_dev.pdev->dev.coherent_dma_mask;
ret = -ENOMEM;
gsmi_dev.dma_pool = dma_pool_create("gsmi", &gsmi_dev.pdev->dev,
GSMI_BUF_SIZE, GSMI_BUF_ALIGN, 0);
if (!gsmi_dev.dma_pool)
goto out_err;
/*
* pre-allocate buffers because sometimes we are called when
* this is not feasible: oops, panic, die, mce, etc
*/
gsmi_dev.name_buf = gsmi_buf_alloc();
if (!gsmi_dev.name_buf) {
printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
goto out_err;
}
gsmi_dev.data_buf = gsmi_buf_alloc();
if (!gsmi_dev.data_buf) {
printk(KERN_ERR "gsmi: failed to allocate data buffer\n");
goto out_err;
}
gsmi_dev.param_buf = gsmi_buf_alloc();
if (!gsmi_dev.param_buf) {
printk(KERN_ERR "gsmi: failed to allocate param buffer\n");
goto out_err;
}
/*
* Determine type of handshake used to serialize the SMI
* entry. See also gsmi_exec().
*
* There's a "behavior" present on some chipsets where writing the
* SMI trigger register in the southbridge doesn't result in an
* immediate SMI. Rather, the processor can execute "a few" more
* instructions before the SMI takes effect. To ensure synchronous
* behavior, implement a handshake between the kernel driver and the
* firmware handler to spin until released. This ioctl determines
* the type of handshake.
*
* NONE: The firmware handler does not implement any
* handshake. Either it doesn't need to, or it's legacy firmware
* that doesn't know it needs to and never will.
*
* CF: The firmware handler will clear the CF in the saved
* state before returning. The driver may set the CF and test for
* it to clear before proceeding.
*
* SPIN: The firmware handler does not implement any handshake
* but the driver should spin for a hundred or so microseconds
* to ensure the SMI has triggered.
*
* Finally, the handler will return -ENOSYS if
* GSMI_CMD_HANDSHAKE_TYPE is unimplemented, which implies
* HANDSHAKE_NONE.
*/
spin_lock_irqsave(&gsmi_dev.lock, flags);
gsmi_dev.handshake_type = GSMI_HANDSHAKE_SPIN;
gsmi_dev.handshake_type =
gsmi_exec(GSMI_CALLBACK, GSMI_CMD_HANDSHAKE_TYPE);
if (gsmi_dev.handshake_type == -ENOSYS)
gsmi_dev.handshake_type = GSMI_HANDSHAKE_NONE;
spin_unlock_irqrestore(&gsmi_dev.lock, flags);
/* Remove and clean up gsmi if the handshake could not complete. */
if (gsmi_dev.handshake_type == -ENXIO) {
printk(KERN_INFO "gsmi version " DRIVER_VERSION
" failed to load\n");
ret = -ENODEV;
goto out_err;
}
/* Register in the firmware directory */
ret = -ENOMEM;
gsmi_kobj = kobject_create_and_add("gsmi", firmware_kobj);
if (!gsmi_kobj) {
printk(KERN_INFO "gsmi: Failed to create firmware kobj\n");
goto out_err;
}
/* Setup eventlog access */
ret = sysfs_create_bin_file(gsmi_kobj, &eventlog_bin_attr);
if (ret) {
printk(KERN_INFO "gsmi: Failed to setup eventlog");
goto out_err;
}
/* Other attributes */
ret = sysfs_create_files(gsmi_kobj, gsmi_attrs);
if (ret) {
printk(KERN_INFO "gsmi: Failed to add attrs");
goto out_remove_bin_file;
}
ret = efivars_register(&efivars, &efivar_ops, gsmi_kobj);
if (ret) {
printk(KERN_INFO "gsmi: Failed to register efivars\n");
goto out_remove_sysfs_files;
}
ret = efivars_sysfs_init();
if (ret) {
printk(KERN_INFO "gsmi: Failed to create efivars files\n");
efivars_unregister(&efivars);
goto out_remove_sysfs_files;
}
register_reboot_notifier(&gsmi_reboot_notifier);
register_die_notifier(&gsmi_die_notifier);
atomic_notifier_chain_register(&panic_notifier_list,
&gsmi_panic_notifier);
printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n");
return 0;
out_remove_sysfs_files:
sysfs_remove_files(gsmi_kobj, gsmi_attrs);
out_remove_bin_file:
sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr);
out_err:
kobject_put(gsmi_kobj);
gsmi_buf_free(gsmi_dev.param_buf);
gsmi_buf_free(gsmi_dev.data_buf);
gsmi_buf_free(gsmi_dev.name_buf);
if (gsmi_dev.dma_pool)
dma_pool_destroy(gsmi_dev.dma_pool);
platform_device_unregister(gsmi_dev.pdev);
pr_info("gsmi: failed to load: %d\n", ret);
return ret;
}
static void __exit gsmi_exit(void)
{
unregister_reboot_notifier(&gsmi_reboot_notifier);
unregister_die_notifier(&gsmi_die_notifier);
atomic_notifier_chain_unregister(&panic_notifier_list,
&gsmi_panic_notifier);
efivars_unregister(&efivars);
sysfs_remove_files(gsmi_kobj, gsmi_attrs);
sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr);
kobject_put(gsmi_kobj);
gsmi_buf_free(gsmi_dev.param_buf);
gsmi_buf_free(gsmi_dev.data_buf);
gsmi_buf_free(gsmi_dev.name_buf);
dma_pool_destroy(gsmi_dev.dma_pool);
platform_device_unregister(gsmi_dev.pdev);
}
module_init(gsmi_init);
module_exit(gsmi_exit);
MODULE_AUTHOR("Google, Inc.");
MODULE_LICENSE("GPL");