From b7a4706f66e5dfbb981c4f669e5b3fa92ad80fe1 Mon Sep 17 00:00:00 2001 From: Armin Wolf Date: Thu, 23 Nov 2023 01:48:18 +0100 Subject: hwmon: (dell-smm) Add support for WMI SMM interface MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some Dell machines like the Dell Optiplex 7000 do not support the legacy SMM interface, but instead expect all SMM calls to be issued over a special WMI interface. Add support for this interface so users can control the fans on those machines. Tested-by: Reviewed-by: Hans de Goede Reviewed-by: Pali Rohár Signed-off-by: Armin Wolf Link: https://lore.kernel.org/r/20231123004820.50635-8-W_Armin@gmx.de Signed-off-by: Guenter Roeck --- drivers/hwmon/dell-smm-hwmon.c | 199 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 180 insertions(+), 19 deletions(-) (limited to 'drivers/hwmon/dell-smm-hwmon.c') diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c index a377cd08355f..95330437c5af 100644 --- a/drivers/hwmon/dell-smm-hwmon.c +++ b/drivers/hwmon/dell-smm-hwmon.c @@ -12,6 +12,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include #include @@ -34,8 +35,10 @@ #include #include #include +#include #include +#include #define I8K_SMM_FN_STATUS 0x0025 #define I8K_SMM_POWER_STATUS 0x0069 @@ -66,6 +69,9 @@ #define I8K_POWER_AC 0x05 #define I8K_POWER_BATTERY 0x01 +#define DELL_SMM_WMI_GUID "F1DDEE52-063C-4784-A11E-8A06684B9B01" +#define DELL_SMM_LEGACY_EXECUTE 0x1 + #define DELL_SMM_NO_TEMP 10 #define DELL_SMM_NO_FANS 3 @@ -219,6 +225,103 @@ static const struct dell_smm_ops i8k_smm_ops = { .smm_call = i8k_smm_call, }; +/* + * Call the System Management Mode BIOS over WMI. + */ +static ssize_t wmi_parse_register(u8 *buffer, u32 length, unsigned int *reg) +{ + __le32 value; + u32 reg_size; + + if (length <= sizeof(reg_size)) + return -ENODATA; + + reg_size = get_unaligned_le32(buffer); + if (!reg_size || reg_size > sizeof(value)) + return -ENOMSG; + + if (length < sizeof(reg_size) + reg_size) + return -ENODATA; + + memcpy_and_pad(&value, sizeof(value), buffer + sizeof(reg_size), reg_size, 0); + *reg = le32_to_cpu(value); + + return reg_size + sizeof(reg_size); +} + +static int wmi_parse_response(u8 *buffer, u32 length, struct smm_regs *regs) +{ + unsigned int *registers[] = { + ®s->eax, + ®s->ebx, + ®s->ecx, + ®s->edx + }; + u32 offset = 0; + ssize_t ret; + int i; + + for (i = 0; i < ARRAY_SIZE(registers); i++) { + if (offset >= length) + return -ENODATA; + + ret = wmi_parse_register(buffer + offset, length - offset, registers[i]); + if (ret < 0) + return ret; + + offset += ret; + } + + if (offset != length) + return -ENOMSG; + + return 0; +} + +static int wmi_smm_call(struct device *dev, struct smm_regs *regs) +{ + struct wmi_device *wdev = container_of(dev, struct wmi_device, dev); + struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL }; + u32 wmi_payload[] = { + sizeof(regs->eax), + regs->eax, + sizeof(regs->ebx), + regs->ebx, + sizeof(regs->ecx), + regs->ecx, + sizeof(regs->edx), + regs->edx + }; + const struct acpi_buffer in = { + .length = sizeof(wmi_payload), + .pointer = &wmi_payload, + }; + union acpi_object *obj; + acpi_status status; + int ret; + + status = wmidev_evaluate_method(wdev, 0x0, DELL_SMM_LEGACY_EXECUTE, &in, &out); + if (ACPI_FAILURE(status)) + return -EIO; + + obj = out.pointer; + if (!obj) + return -ENODATA; + + if (obj->type != ACPI_TYPE_BUFFER) { + ret = -ENOMSG; + + goto err_free; + } + + ret = wmi_parse_response(obj->buffer.pointer, obj->buffer.length, regs); + +err_free: + kfree(obj); + + return ret; +} + static int dell_smm_call(const struct dell_smm_ops *ops, struct smm_regs *regs) { unsigned int eax = regs->eax; @@ -306,7 +409,7 @@ static int i8k_get_fan_type(struct dell_smm_data *data, u8 fan) /* * Read the fan nominal rpm for specific fan speed. */ -static int __init i8k_get_fan_nominal_speed(const struct dell_smm_data *data, u8 fan, int speed) +static int i8k_get_fan_nominal_speed(const struct dell_smm_data *data, u8 fan, int speed) { struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, @@ -349,7 +452,7 @@ static int i8k_set_fan(const struct dell_smm_data *data, u8 fan, int speed) return dell_smm_call(data->ops, ®s); } -static int __init i8k_get_temp_type(const struct dell_smm_data *data, u8 sensor) +static int i8k_get_temp_type(const struct dell_smm_data *data, u8 sensor) { struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, @@ -401,7 +504,7 @@ static int i8k_get_temp(const struct dell_smm_data *data, u8 sensor) return temp; } -static int __init dell_smm_get_signature(const struct dell_smm_ops *ops, int req_fn) +static int dell_smm_get_signature(const struct dell_smm_ops *ops, int req_fn) { struct smm_regs regs = { .eax = req_fn, }; int rc; @@ -986,7 +1089,7 @@ static const struct hwmon_chip_info dell_smm_chip_info = { .info = dell_smm_info, }; -static int __init dell_smm_init_cdev(struct device *dev, u8 fan_num) +static int dell_smm_init_cdev(struct device *dev, u8 fan_num) { struct dell_smm_data *data = dev_get_drvdata(dev); struct thermal_cooling_device *cdev; @@ -1017,7 +1120,7 @@ static int __init dell_smm_init_cdev(struct device *dev, u8 fan_num) return ret; } -static int __init dell_smm_init_hwmon(struct device *dev) +static int dell_smm_init_hwmon(struct device *dev) { struct dell_smm_data *data = dev_get_drvdata(dev); struct device *dell_smm_hwmon_dev; @@ -1083,7 +1186,7 @@ static int __init dell_smm_init_hwmon(struct device *dev) return PTR_ERR_OR_ZERO(dell_smm_hwmon_dev); } -static int __init dell_smm_init_data(struct device *dev, const struct dell_smm_ops *ops) +static int dell_smm_init_data(struct device *dev, const struct dell_smm_ops *ops) { struct dell_smm_data *data; @@ -1409,6 +1512,9 @@ static const struct dmi_system_id i8k_whitelist_fan_control[] __initconst = { { } }; +/* + * Legacy SMM backend driver. + */ static int __init dell_smm_probe(struct platform_device *pdev) { int ret; @@ -1434,6 +1540,47 @@ static struct platform_driver dell_smm_driver = { static struct platform_device *dell_smm_device; +/* + * WMI SMM backend driver. + */ +static int dell_smm_wmi_probe(struct wmi_device *wdev, const void *context) +{ + struct dell_smm_ops *ops; + int ret; + + ops = devm_kzalloc(&wdev->dev, sizeof(*ops), GFP_KERNEL); + if (!ops) + return -ENOMEM; + + ops->smm_call = wmi_smm_call; + ops->smm_dev = &wdev->dev; + + if (dell_smm_get_signature(ops, I8K_SMM_GET_DELL_SIG1) && + dell_smm_get_signature(ops, I8K_SMM_GET_DELL_SIG2)) + return -ENODEV; + + ret = dell_smm_init_data(&wdev->dev, ops); + if (ret < 0) + return ret; + + return dell_smm_init_hwmon(&wdev->dev); +} + +static const struct wmi_device_id dell_smm_wmi_id_table[] = { + { DELL_SMM_WMI_GUID, NULL }, + { } +}; +MODULE_DEVICE_TABLE(wmi, dell_smm_wmi_id_table); + +static struct wmi_driver dell_smm_wmi_driver = { + .driver = { + .name = KBUILD_MODNAME, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, + .id_table = dell_smm_wmi_id_table, + .probe = dell_smm_wmi_probe, +}; + /* * Probe for the presence of a supported laptop. */ @@ -1485,33 +1632,43 @@ static void __init dell_smm_init_dmi(void) } } -static int __init i8k_init(void) +static int __init dell_smm_legacy_check(void) { - /* - * Get DMI information - */ if (!dmi_check_system(i8k_dmi_table)) { if (!ignore_dmi && !force) return -ENODEV; - pr_info("not running on a supported Dell system.\n"); + pr_info("Probing for legacy SMM handler on unsupported machine\n"); pr_info("vendor=%s, model=%s, version=%s\n", i8k_get_dmi_data(DMI_SYS_VENDOR), i8k_get_dmi_data(DMI_PRODUCT_NAME), i8k_get_dmi_data(DMI_BIOS_VERSION)); } - dell_smm_init_dmi(); - - /* - * Get SMM Dell signature - */ if (dell_smm_get_signature(&i8k_smm_ops, I8K_SMM_GET_DELL_SIG1) && dell_smm_get_signature(&i8k_smm_ops, I8K_SMM_GET_DELL_SIG2)) { if (!force) return -ENODEV; - pr_err("Unable to get Dell SMM signature\n"); + pr_warn("Forcing legacy SMM calls on a possibly incompatible machine\n"); + } + + return 0; +} + +static int __init i8k_init(void) +{ + int ret; + + dell_smm_init_dmi(); + + ret = dell_smm_legacy_check(); + if (ret < 0) { + /* + * On modern machines, SMM communication happens over WMI, meaning + * the SMM handler might not react to legacy SMM calls. + */ + return wmi_driver_register(&dell_smm_wmi_driver); } dell_smm_device = platform_create_bundle(&dell_smm_driver, dell_smm_probe, NULL, 0, NULL, @@ -1522,8 +1679,12 @@ static int __init i8k_init(void) static void __exit i8k_exit(void) { - platform_device_unregister(dell_smm_device); - platform_driver_unregister(&dell_smm_driver); + if (dell_smm_device) { + platform_device_unregister(dell_smm_device); + platform_driver_unregister(&dell_smm_driver); + } else { + wmi_driver_unregister(&dell_smm_wmi_driver); + } } module_init(i8k_init); -- cgit v1.2.3