Hi, On 7/23/21 11:14 PM, Shravan S wrote: > Dynamic BIOS SAR driver exposing dynamic SAR information from BIOS > > The Dynamic SAR (Specific Absorption Rate) driver uses ACPI DSM > (Device Specific Method) to communicate with BIOS and retrieve > dynamic SAR information and change notifications. The driver uses > sysfs to expose this data to userspace via read and notify. > > Sysfs interface is documented in detail under: > Documentation/ABI/testing/sysfs-driver-intc_sar > > Signed-off-by: Shravan S <s.shravan@xxxxxxxxx> > --- > V7 : > * Review comment fixes > * Document modification > * Code changes to handle errors Thank you for the new verson, this looks good now. I've applied this patch to my review-hans branch: https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans Once I've run some tests on this branch the patches there will be added to the platform-drivers-x86/for-next branch and eventually will be included in the pdx86 pull-request to Linus for the next merge-window. Regards, Hans > > --- > .../ABI/testing/sysfs-driver-intc_sar | 54 +++ > MAINTAINERS | 7 + > drivers/platform/x86/intel/Kconfig | 1 + > drivers/platform/x86/intel/Makefile | 1 + > drivers/platform/x86/intel/int1092/Kconfig | 14 + > drivers/platform/x86/intel/int1092/Makefile | 1 + > .../platform/x86/intel/int1092/intel_sar.c | 316 ++++++++++++++++++ > .../platform/x86/intel/int1092/intel_sar.h | 86 +++++ > 8 files changed, 480 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-driver-intc_sar > create mode 100644 drivers/platform/x86/intel/int1092/Kconfig > create mode 100644 drivers/platform/x86/intel/int1092/Makefile > create mode 100644 drivers/platform/x86/intel/int1092/intel_sar.c > create mode 100644 drivers/platform/x86/intel/int1092/intel_sar.h > > diff --git a/Documentation/ABI/testing/sysfs-driver-intc_sar b/Documentation/ABI/testing/sysfs-driver-intc_sar > new file mode 100644 > index 000000000000..ec334b0e5ed9 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-driver-intc_sar > @@ -0,0 +1,54 @@ > +What: /sys/bus/platform/devices/INTC1092:00/intc_reg > +Date: August 2021 > +KernelVersion: 5.15 > +Contact: Shravan S <s.shravan@xxxxxxxxx>, > + An Sudhakar <sudhakar.an@xxxxxxxxx> > +Description: > + Specific Absorption Rate (SAR) regulatory mode is typically > + derived based on information like mcc (Mobile Country Code) and > + mnc (Mobile Network Code) that is available for the currently > + attached LTE network. A userspace application is required to set > + the current SAR regulatory mode on the Dynamic SAR driver using > + this sysfs node. Such an application can also read back using > + this sysfs node, the currently configured regulatory mode value > + from the Dynamic SAR driver. > + > + Acceptable regulatory modes are: > + == ==== > + 0 FCC > + 1 CE > + 2 ISED > + == ==== > + > + - The regulatory mode value has one of the above values. > + - The default regulatory mode used in the driver is 0. > + > +What: /sys/bus/platform/devices/INTC1092:00/intc_data > +Date: August 2021 > +KernelVersion: 5.15 > +Contact: Shravan S <s.shravan@xxxxxxxxx>, > + An Sudhakar <sudhakar.an@xxxxxxxxx> > +Description: > + This sysfs entry is used to retrieve Dynamic SAR information > + emitted/maintained by a BIOS that supports Dynamic SAR. > + > + The retrieved information is in the order given below: > + - device_mode > + - bandtable_index > + - antennatable_index > + - sartable_index > + > + The above information is sent as integer values separated > + by a single space. This information can then be pushed to a > + WWAN modem that uses this to control the transmit signal > + level using the Band/Antenna/SAR table index information. > + These parameters are derived/decided by aggregating > + device-mode like laptop/tablet/clamshell etc. and the > + proximity-sensor data available to the embedded controller on > + given host. The regulatory mode configured on Dynamic SAR > + driver also influences these values. > + > + The userspace applications can poll for changes to this file > + using POLLPRI event on file-descriptor (fd) obtained by opening > + this sysfs entry. Application can then read this information from > + the sysfs node and consume the given information. > diff --git a/MAINTAINERS b/MAINTAINERS > index 279af7e9a281..b731988a4452 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9220,6 +9220,13 @@ L: platform-driver-x86@xxxxxxxxxxxxxxx > S: Maintained > F: drivers/platform/x86/intel_atomisp2_led.c > > +INTEL BIOS SAR INT1092 DRIVER > +M: Shravan S <s.shravan@xxxxxxxxx> > +M: Intel Corporation <linuxwwan@xxxxxxxxx> > +L: platform-driver-x86@xxxxxxxxxxxxxxx > +S: Maintained > +F: drivers/platform/x86/intel/int1092/ > + > INTEL BROXTON PMC DRIVER > M: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > M: Zha Qipeng <qipeng.zha@xxxxxxxxx> > diff --git a/drivers/platform/x86/intel/Kconfig b/drivers/platform/x86/intel/Kconfig > index 6eec084d9bf9..4dd1fd4450ad 100644 > --- a/drivers/platform/x86/intel/Kconfig > +++ b/drivers/platform/x86/intel/Kconfig > @@ -16,6 +16,7 @@ menuconfig X86_PLATFORM_DRIVERS_INTEL > > if X86_PLATFORM_DRIVERS_INTEL > > +source "drivers/platform/x86/intel/int1092/Kconfig" > source "drivers/platform/x86/intel/int33fe/Kconfig" > source "drivers/platform/x86/intel/int3472/Kconfig" > source "drivers/platform/x86/intel/pmt/Kconfig" > diff --git a/drivers/platform/x86/intel/Makefile b/drivers/platform/x86/intel/Makefile > index ca0ec2c85b05..dc6baf420808 100644 > --- a/drivers/platform/x86/intel/Makefile > +++ b/drivers/platform/x86/intel/Makefile > @@ -4,6 +4,7 @@ > # Intel x86 Platform-Specific Drivers > # > > +obj-$(CONFIG_INTEL_SAR_INT1092) += int1092/ > obj-$(CONFIG_INTEL_CHT_INT33FE) += int33fe/ > obj-$(CONFIG_INTEL_SKL_INT3472) += int3472/ > obj-$(CONFIG_INTEL_PMT_CLASS) += pmt/ > diff --git a/drivers/platform/x86/intel/int1092/Kconfig b/drivers/platform/x86/intel/int1092/Kconfig > new file mode 100644 > index 000000000000..2e9a177241aa > --- /dev/null > +++ b/drivers/platform/x86/intel/int1092/Kconfig > @@ -0,0 +1,14 @@ > +config INTEL_SAR_INT1092 > + tristate "Intel Specific Absorption Rate Driver" > + depends on ACPI > + help > + This driver helps to limit the exposure of human body to RF frequency by > + providing information to userspace application that will inform the Intel > + M.2 modem to regulate the RF power based on SAR data obtained from the > + sensors captured in the BIOS. ACPI interface exposes this data from the BIOS > + to SAR driver. The front end application in userspace will interact with SAR > + driver to obtain information like the device mode, Antenna index, baseband index, > + SAR table index and use available communication like MBIM interface to enable > + data communication to modem for RF power regulation. Enable this config when > + given platform needs to support "Dynamic SAR" configuration for a modem available > + on the platform. > diff --git a/drivers/platform/x86/intel/int1092/Makefile b/drivers/platform/x86/intel/int1092/Makefile > new file mode 100644 > index 000000000000..4ab94e541de3 > --- /dev/null > +++ b/drivers/platform/x86/intel/int1092/Makefile > @@ -0,0 +1 @@ > +obj-$(CONFIG_INTEL_SAR_INT1092) += intel_sar.o > diff --git a/drivers/platform/x86/intel/int1092/intel_sar.c b/drivers/platform/x86/intel/int1092/intel_sar.c > new file mode 100644 > index 000000000000..379560fe5df9 > --- /dev/null > +++ b/drivers/platform/x86/intel/int1092/intel_sar.c > @@ -0,0 +1,316 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2021, Intel Corporation. > + */ > + > +#include <linux/acpi.h> > +#include <linux/kobject.h> > +#include <linux/platform_device.h> > +#include <linux/sysfs.h> > +#include "intel_sar.h" > + > +/** > + * get_int_value: Retrieve integer values from ACPI Object > + * @obj: acpi_object pointer which has the integer value > + * @out: output pointer will get integer value > + * > + * Function is used to retrieve integer value from acpi object. > + * > + * Return: > + * * 0 on success > + * * -EIO if there is an issue in acpi_object passed. > + */ > +static int get_int_value(union acpi_object *obj, int *out) > +{ > + if (!obj || obj->type != ACPI_TYPE_INTEGER) > + return -EIO; > + *out = (int)obj->integer.value; > + return 0; > +} > + > +/** > + * update_sar_data: sar data is updated based on regulatory mode > + * @context: pointer to driver context structure > + * > + * sar_data is updated based on regulatory value > + * context->reg_value will never exceed MAX_REGULATORY > + */ > +static void update_sar_data(struct wwan_sar_context *context) > +{ > + struct wwan_device_mode_configuration *config = > + &context->config_data[context->reg_value]; > + > + if (config->device_mode_info && > + context->sar_data.device_mode < config->total_dev_mode) { > + struct wwan_device_mode_info *dev_mode = > + &config->device_mode_info[context->sar_data.device_mode]; > + > + context->sar_data.antennatable_index = dev_mode->antennatable_index; > + context->sar_data.bandtable_index = dev_mode->bandtable_index; > + context->sar_data.sartable_index = dev_mode->sartable_index; > + } > +} > + > +/** > + * parse_package: parse acpi package for retrieving SAR information > + * @context: pointer to driver context structure > + * @item : acpi_object pointer > + * > + * Given acpi_object is iterated to retrieve information for each device mode. > + * If a given package corresponding to a specific device mode is faulty, it is > + * skipped and the specific entry in context structure will have the default value > + * of zero. Decoding of subsequent device modes is realized by having "continue" > + * statements in the for loop on encountering error in parsing given device mode. > + * > + * Return: > + * AE_OK if success > + * AE_ERROR on error > + */ > +static acpi_status parse_package(struct wwan_sar_context *context, union acpi_object *item) > +{ > + struct wwan_device_mode_configuration *data; > + int value, itr, reg; > + union acpi_object *num; > + > + num = &item->package.elements[0]; > + if (get_int_value(num, &value) || value < 0 || value >= MAX_REGULATORY) > + return AE_ERROR; > + > + reg = value; > + > + data = &context->config_data[reg]; > + if (data->total_dev_mode > MAX_DEV_MODES || data->total_dev_mode == 0 || > + item->package.count <= data->total_dev_mode) > + return AE_ERROR; > + > + data->device_mode_info = kmalloc_array(data->total_dev_mode, > + sizeof(struct wwan_device_mode_info), GFP_KERNEL); > + if (!data->device_mode_info) > + return AE_ERROR; > + > + for (itr = 0; itr < data->total_dev_mode; itr++) { > + struct wwan_device_mode_info temp = { 0 }; > + > + num = &item->package.elements[itr + 1]; > + if (num->type != ACPI_TYPE_PACKAGE || num->package.count < TOTAL_DATA) > + continue; > + if (get_int_value(&num->package.elements[0], &temp.device_mode)) > + continue; > + if (get_int_value(&num->package.elements[1], &temp.bandtable_index)) > + continue; > + if (get_int_value(&num->package.elements[2], &temp.antennatable_index)) > + continue; > + if (get_int_value(&num->package.elements[3], &temp.sartable_index)) > + continue; > + data->device_mode_info[itr] = temp; > + } > + return AE_OK; > +} > + > +/** > + * sar_get_device_mode: Extraction of information from BIOS via DSM calls > + * @device: ACPI device for which to retrieve the data > + * > + * Retrieve the current device mode information from the BIOS. > + * > + * Return: > + * AE_OK on success > + * AE_ERROR on error > + */ > +static acpi_status sar_get_device_mode(struct platform_device *device) > +{ > + struct wwan_sar_context *context = dev_get_drvdata(&device->dev); > + acpi_status status = AE_OK; > + union acpi_object *out; > + u32 rev = 0; > + int value; > + > + out = acpi_evaluate_dsm(context->handle, &context->guid, rev, > + COMMAND_ID_DEV_MODE, NULL); > + if (get_int_value(out, &value)) { > + dev_err(&device->dev, "DSM cmd:%d Failed to retrieve value\n", COMMAND_ID_DEV_MODE); > + status = AE_ERROR; > + goto dev_mode_error; > + } > + context->sar_data.device_mode = value; > + update_sar_data(context); > + sysfs_notify(&device->dev.kobj, NULL, SYSFS_DATANAME); > + > +dev_mode_error: > + ACPI_FREE(out); > + return status; > +} > + > +static const struct acpi_device_id sar_device_ids[] = { > + { "INTC1092", 0}, > + {} > +}; > +MODULE_DEVICE_TABLE(acpi, sar_device_ids); > + > +static ssize_t intc_data_show(struct device *dev, struct device_attribute *attr, char *buf) > +{ > + struct wwan_sar_context *context = dev_get_drvdata(dev); > + > + return sysfs_emit(buf, "%d %d %d %d\n", context->sar_data.device_mode, > + context->sar_data.bandtable_index, > + context->sar_data.antennatable_index, > + context->sar_data.sartable_index); > +} > +static DEVICE_ATTR_RO(intc_data); > + > +static ssize_t intc_reg_show(struct device *dev, struct device_attribute *attr, char *buf) > +{ > + struct wwan_sar_context *context = dev_get_drvdata(dev); > + > + return sysfs_emit(buf, "%d\n", context->reg_value); > +} > + > +static ssize_t intc_reg_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct wwan_sar_context *context = dev_get_drvdata(dev); > + unsigned int value; > + int read; > + > + if (!count) > + return -EINVAL; > + read = kstrtouint(buf, 10, &value); > + if (read < 0) > + return read; > + if (value >= MAX_REGULATORY) > + return -EOVERFLOW; > + context->reg_value = value; > + update_sar_data(context); > + sysfs_notify(&dev->kobj, NULL, SYSFS_DATANAME); > + return count; > +} > +static DEVICE_ATTR_RW(intc_reg); > + > +static struct attribute *intcsar_attrs[] = { > + &dev_attr_intc_data.attr, > + &dev_attr_intc_reg.attr, > + NULL > +}; > + > +static struct attribute_group intcsar_group = { > + .attrs = intcsar_attrs, > +}; > + > +static void sar_notify(acpi_handle handle, u32 event, void *data) > +{ > + struct platform_device *device = data; > + > + if (event == SAR_EVENT) { > + if (sar_get_device_mode(device) != AE_OK) > + dev_err(&device->dev, "sar_get_device_mode error"); > + } > +} > + > +static void sar_get_data(int reg, struct wwan_sar_context *context) > +{ > + union acpi_object *out, req; > + u32 rev = 0; > + > + req.type = ACPI_TYPE_INTEGER; > + req.integer.value = reg; > + out = acpi_evaluate_dsm(context->handle, &context->guid, rev, > + COMMAND_ID_CONFIG_TABLE, &req); > + if (!out) > + return; > + if (out->type == ACPI_TYPE_PACKAGE && out->package.count >= 3 && > + out->package.elements[0].type == ACPI_TYPE_INTEGER && > + out->package.elements[1].type == ACPI_TYPE_INTEGER && > + out->package.elements[2].type == ACPI_TYPE_PACKAGE && > + out->package.elements[2].package.count > 0) { > + context->config_data[reg].version = out->package.elements[0].integer.value; > + context->config_data[reg].total_dev_mode = > + out->package.elements[1].integer.value; > + if (context->config_data[reg].total_dev_mode <= 0 || > + context->config_data[reg].total_dev_mode > MAX_DEV_MODES) { > + ACPI_FREE(out); > + return; > + } > + parse_package(context, &out->package.elements[2]); > + } > + ACPI_FREE(out); > +} > + > +static int sar_probe(struct platform_device *device) > +{ > + struct wwan_sar_context *context; > + int reg; > + int result; > + > + context = kzalloc(sizeof(*context), GFP_KERNEL); > + if (!context) > + return -ENOMEM; > + > + context->sar_device = device; > + context->handle = ACPI_HANDLE(&device->dev); > + dev_set_drvdata(&device->dev, context); > + > + result = guid_parse(SAR_DSM_UUID, &context->guid); > + if (result) { > + dev_err(&device->dev, "SAR UUID parse error: %d\n", result); > + goto r_free; > + } > + > + for (reg = 0; reg < MAX_REGULATORY; reg++) > + sar_get_data(reg, context); > + > + if (sar_get_device_mode(device) != AE_OK) { > + dev_err(&device->dev, "Failed to get device mode\n"); > + result = -EIO; > + goto r_free; > + } > + > + result = sysfs_create_group(&device->dev.kobj, &intcsar_group); > + if (result) { > + dev_err(&device->dev, "sysfs creation failed\n"); > + goto r_free; > + } > + > + if (acpi_install_notify_handler(ACPI_HANDLE(&device->dev), ACPI_DEVICE_NOTIFY, > + sar_notify, (void *)device) != AE_OK) { > + dev_err(&device->dev, "Failed acpi_install_notify_handler\n"); > + result = -EIO; > + goto r_sys; > + } > + return 0; > + > +r_sys: > + sysfs_remove_group(&device->dev.kobj, &intcsar_group); > +r_free: > + kfree(context); > + return result; > +} > + > +static int sar_remove(struct platform_device *device) > +{ > + struct wwan_sar_context *context = dev_get_drvdata(&device->dev); > + int reg; > + > + acpi_remove_notify_handler(ACPI_HANDLE(&device->dev), > + ACPI_DEVICE_NOTIFY, sar_notify); > + sysfs_remove_group(&device->dev.kobj, &intcsar_group); > + for (reg = 0; reg < MAX_REGULATORY; reg++) > + kfree(context->config_data[reg].device_mode_info); > + > + kfree(context); > + return 0; > +} > + > +static struct platform_driver sar_driver = { > + .probe = sar_probe, > + .remove = sar_remove, > + .driver = { > + .name = DRVNAME, > + .owner = THIS_MODULE, > + .acpi_match_table = ACPI_PTR(sar_device_ids) > + } > +}; > +module_platform_driver(sar_driver); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("Platform device driver for INTEL MODEM BIOS SAR"); > +MODULE_AUTHOR("Shravan S <s.shravan@xxxxxxxxx>"); > diff --git a/drivers/platform/x86/intel/int1092/intel_sar.h b/drivers/platform/x86/intel/int1092/intel_sar.h > new file mode 100644 > index 000000000000..b5310510b84c > --- /dev/null > +++ b/drivers/platform/x86/intel/int1092/intel_sar.h > @@ -0,0 +1,86 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (c) 2021, Intel Corporation. > + */ > +#ifndef INTEL_SAR_H > +#define INTEL_SAR_H > + > +#define COMMAND_ID_DEV_MODE 1 > +#define COMMAND_ID_CONFIG_TABLE 2 > +#define DRVNAME "intc_sar" > +#define MAX_DEV_MODES 50 > +#define MAX_REGULATORY 3 > +#define SAR_DSM_UUID "82737E72-3A33-4C45-A9C7-57C0411A5F13" > +#define SAR_EVENT 0x80 > +#define SYSFS_DATANAME "intc_data" > +#define TOTAL_DATA 4 > + > +/** > + * Structure wwan_device_mode_info - device mode information > + * Holds the data that needs to be passed to userspace. > + * The data is updated from the BIOS sensor information. > + * @device_mode: Specific mode of the device > + * @bandtable_index: Index of RF band > + * @antennatable_index: Index of antenna > + * @sartable_index: Index of SAR > + */ > +struct wwan_device_mode_info { > + int device_mode; > + int bandtable_index; > + int antennatable_index; > + int sartable_index; > +}; > + > +/** > + * Structure wwan_device_mode_configuration - device configuration > + * Holds the data that is configured and obtained on probe event. > + * The data is updated from the BIOS sensor information. > + * @version: Mode configuration version > + * @total_dev_mode: Total number of device modes > + * @device_mode_info: pointer to structure wwan_device_mode_info > + */ > +struct wwan_device_mode_configuration { > + int version; > + int total_dev_mode; > + struct wwan_device_mode_info *device_mode_info; > +}; > + > +/** > + * Structure wwan_supported_info - userspace datastore > + * Holds the data that is obtained from userspace > + * The data is updated from the userspace and send value back in the > + * structure format that is mentioned here. > + * @reg_mode_needed: regulatory mode set by user for tests > + * @bios_table_revision: Version of SAR table > + * @num_supported_modes: Total supported modes based on reg_mode > + */ > +struct wwan_supported_info { > + int reg_mode_needed; > + int bios_table_revision; > + int num_supported_modes; > +}; > + > +/** > + * Structure wwan_sar_context - context of SAR > + * Holds the complete context as long as the driver is in existence > + * The context holds instance of the data used for different cases. > + * @guid: Group id > + * @handle: store acpi handle > + * @reg_value: regulatory value > + * Regulatory 0: FCC, 1: CE, 2: ISED > + * @sar_device: platform_device type > + * @sar_kobject: kobject for sysfs > + * @supported_data: wwan_supported_info struct > + * @sar_data: wwan_device_mode_info struct > + * @config_data: wwan_device_mode_configuration array struct > + */ > +struct wwan_sar_context { > + guid_t guid; > + acpi_handle handle; > + int reg_value; > + struct platform_device *sar_device; > + struct wwan_supported_info supported_data; > + struct wwan_device_mode_info sar_data; > + struct wwan_device_mode_configuration config_data[MAX_REGULATORY]; > +}; > +#endif /* INTEL_SAR_H */ >
