--- /dev/null
+What: /sys/bus/platform/devices/INTC1092:00/intc_reg
+Date: August 2021
+KernelVersion: 5.15
+Contact: Shravan S <s.shravan@intel.com>,
+ An Sudhakar <sudhakar.an@intel.com>
+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@intel.com>,
+ An Sudhakar <sudhakar.an@intel.com>
+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.
--- /dev/null
+// 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@intel.com>");
--- /dev/null
+/* 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 */
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