mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
145 lines
3.5 KiB
145 lines
3.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Slim Bootloader(SBL) firmware update signaling driver |
|
* |
|
* Slim Bootloader is a small, open-source, non UEFI compliant, boot firmware |
|
* optimized for running on certain Intel platforms. |
|
* |
|
* SBL exposes an ACPI-WMI device via /sys/bus/wmi/devices/<INTEL_WMI_SBL_GUID>. |
|
* This driver further adds "firmware_update_request" device attribute. |
|
* This attribute normally has a value of 0 and userspace can signal SBL |
|
* to update firmware, on next reboot, by writing a value of 1. |
|
* |
|
* More details of SBL firmware update process is available at: |
|
* https://slimbootloader.github.io/security/firmware-update.html |
|
*/ |
|
|
|
#include <linux/acpi.h> |
|
#include <linux/device.h> |
|
#include <linux/module.h> |
|
#include <linux/slab.h> |
|
#include <linux/sysfs.h> |
|
#include <linux/wmi.h> |
|
|
|
#define INTEL_WMI_SBL_GUID "44FADEB1-B204-40F2-8581-394BBDC1B651" |
|
|
|
static int get_fwu_request(struct device *dev, u32 *out) |
|
{ |
|
struct acpi_buffer result = {ACPI_ALLOCATE_BUFFER, NULL}; |
|
union acpi_object *obj; |
|
acpi_status status; |
|
|
|
status = wmi_query_block(INTEL_WMI_SBL_GUID, 0, &result); |
|
if (ACPI_FAILURE(status)) { |
|
dev_err(dev, "wmi_query_block failed\n"); |
|
return -ENODEV; |
|
} |
|
|
|
obj = (union acpi_object *)result.pointer; |
|
if (!obj || obj->type != ACPI_TYPE_INTEGER) { |
|
dev_warn(dev, "wmi_query_block returned invalid value\n"); |
|
kfree(obj); |
|
return -EINVAL; |
|
} |
|
|
|
*out = obj->integer.value; |
|
kfree(obj); |
|
|
|
return 0; |
|
} |
|
|
|
static int set_fwu_request(struct device *dev, u32 in) |
|
{ |
|
struct acpi_buffer input; |
|
acpi_status status; |
|
u32 value; |
|
|
|
value = in; |
|
input.length = sizeof(u32); |
|
input.pointer = &value; |
|
|
|
status = wmi_set_block(INTEL_WMI_SBL_GUID, 0, &input); |
|
if (ACPI_FAILURE(status)) { |
|
dev_err(dev, "wmi_set_block failed\n"); |
|
return -ENODEV; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static ssize_t firmware_update_request_show(struct device *dev, |
|
struct device_attribute *attr, |
|
char *buf) |
|
{ |
|
u32 val; |
|
int ret; |
|
|
|
ret = get_fwu_request(dev, &val); |
|
if (ret) |
|
return ret; |
|
|
|
return sprintf(buf, "%d\n", val); |
|
} |
|
|
|
static ssize_t firmware_update_request_store(struct device *dev, |
|
struct device_attribute *attr, |
|
const char *buf, size_t count) |
|
{ |
|
unsigned int val; |
|
int ret; |
|
|
|
ret = kstrtouint(buf, 0, &val); |
|
if (ret) |
|
return ret; |
|
|
|
/* May later be extended to support values other than 0 and 1 */ |
|
if (val > 1) |
|
return -ERANGE; |
|
|
|
ret = set_fwu_request(dev, val); |
|
if (ret) |
|
return ret; |
|
|
|
return count; |
|
} |
|
static DEVICE_ATTR_RW(firmware_update_request); |
|
|
|
static struct attribute *firmware_update_attrs[] = { |
|
&dev_attr_firmware_update_request.attr, |
|
NULL |
|
}; |
|
ATTRIBUTE_GROUPS(firmware_update); |
|
|
|
static int intel_wmi_sbl_fw_update_probe(struct wmi_device *wdev, |
|
const void *context) |
|
{ |
|
dev_info(&wdev->dev, "Slim Bootloader signaling driver attached\n"); |
|
return 0; |
|
} |
|
|
|
static int intel_wmi_sbl_fw_update_remove(struct wmi_device *wdev) |
|
{ |
|
dev_info(&wdev->dev, "Slim Bootloader signaling driver removed\n"); |
|
return 0; |
|
} |
|
|
|
static const struct wmi_device_id intel_wmi_sbl_id_table[] = { |
|
{ .guid_string = INTEL_WMI_SBL_GUID }, |
|
{} |
|
}; |
|
MODULE_DEVICE_TABLE(wmi, intel_wmi_sbl_id_table); |
|
|
|
static struct wmi_driver intel_wmi_sbl_fw_update_driver = { |
|
.driver = { |
|
.name = "intel-wmi-sbl-fw-update", |
|
.dev_groups = firmware_update_groups, |
|
}, |
|
.probe = intel_wmi_sbl_fw_update_probe, |
|
.remove = intel_wmi_sbl_fw_update_remove, |
|
.id_table = intel_wmi_sbl_id_table, |
|
}; |
|
module_wmi_driver(intel_wmi_sbl_fw_update_driver); |
|
|
|
MODULE_AUTHOR("Jithu Joseph <[email protected]>"); |
|
MODULE_DESCRIPTION("Slim Bootloader firmware update signaling driver"); |
|
MODULE_LICENSE("GPL v2");
|
|
|