BIOS SAR (Specific Absorption Rate) driver for RF power regulation on Intel M.2 Modem.
Limits the exposure of human body to RF frequencies.
Uses ACPI to communicate to BIOS to retrieve SAR information data.
Uses Sysfs to communicate this data to userspace via read and notify.
Userspace will further use MBIM interface to enable data communication to modem.
Signed-off-by: Shravan S <s.shravan@xxxxxxxxx>
---
V3 :
* Changes to the remove netlink and introduce sysfs to communicate to Userspace via notify
* Handled review comments by changing ioctl calls to sysfs
* "sar" name change for platform_device_id to "intc1092"
* sar_init and sar_exit is modified as per review to minimal initialization
* logging reduction and cleanup based on reviews.
---
.../networking/device_drivers/wwan/index.rst | 9 +-
.../device_drivers/wwan/intc_sar.rst | 60 ++++
drivers/platform/x86/Kconfig | 12 +
drivers/platform/x86/Makefile | 1 +
drivers/platform/x86/intel-sar.c | 326 ++++++++++++++++++
include/linux/platform_data/x86/intel-sar.h | 89 +++++
6 files changed, 493 insertions(+), 4 deletions(-)
create mode 100644 Documentation/networking/device_drivers/wwan/intc_sar.rst
create mode 100644 drivers/platform/x86/intel-sar.c
create mode 100644 include/linux/platform_data/x86/intel-sar.h
diff --git a/Documentation/networking/device_drivers/wwan/index.rst b/Documentation/networking/device_drivers/wwan/index.rst
index 1cb8c7371401..93dfd89f76e8 100644
--- a/Documentation/networking/device_drivers/wwan/index.rst
+++ b/Documentation/networking/device_drivers/wwan/index.rst
@@ -1,14 +1,15 @@
-.. SPDX-License-Identifier: GPL-2.0-only
+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
-WWAN Device Drivers
-===================
+Classic WAN Device Drivers
+==========================
Contents:
.. toctree::
:maxdepth: 2
- iosm
+ z8530book
+ intc_sar
.. only:: subproject and html
diff --git a/Documentation/networking/device_drivers/wwan/intc_sar.rst b/Documentation/networking/device_drivers/wwan/intc_sar.rst
new file mode 100644
index 000000000000..7319d6e593ed
--- /dev/null
+++ b/Documentation/networking/device_drivers/wwan/intc_sar.rst
@@ -0,0 +1,60 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+.. Copyright (C) 2020-21 Intel Corporation
+
+.. _INTEL_SAR_driver_doc:
+
+===========================================
+BIOS Dynamic SAR driver for Intel M.2 Modem
+===========================================
+SAR (Specific Absorption Rate) driver is a host driver implemented for Linux
+or chrome platform to limit the exposure of human body to RF frequency by
+informing the Intel M.2 modem to regulate the RF power based on SAR data
+obtained from the sensors captured in the BIOS.
+
+Basic usage
+===========
+ACPI interface exposes this data from the BIOS to SAR driver. The front end
+application in userspace ( eg: Modem Manager) will interact with SAR driver
+to obtain information like the device mode (Example: tablets, laptops, etx),
+Antenna index, baseband index, SAR table index and use available communication
+like MBIM interface to enable data communication to modem for power regulation.
+
+Applications to carry out below required actions for establishing connection
+with driver for data communication with the SAR driver:
+- open the sysfs file for communication
+- read the data to get the information
+- get notification from sysfs if data is changed
+- write into sysfs to change regulatory mode.
+
+Management application development
+==================================
+The driver and userspace interfaces are described below.
+
+sysfs channel for communication to userspace
+--------------------------------------------
+
+/sys/bus/platform/devices/INTC1092:00/intc_reg
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes an sysfs entry in the kernel which is used for sending and
+receiving regulatory information. The regulatory modes are depending on network.
+FCC(0), CE(1), ISED(2)
+
+/sys/bus/platform/devices/INTC1092:00/intc_reg write()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The regulatory modes should not exceed the allowed reguulatory worldwide.
+
+/sys/bus/platform/devices/INTC1092:00/intc_reg read()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The application can read the current regulatory mode that is set in the
+driver.
+
+/sys/bus/platform/devices/INTC1092:00/intc_data
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes an sysfs entry in the kernel which is used for receiving
+information sent by BIOS.
+
+/sys/bus/platform/devices/INTC1092:00/intc_data read()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The SAR index, Band index and Antenna index along with the device modes are
+obtained from this sysfs.
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 7d385c3b2239..f3abf935a976 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1306,6 +1306,18 @@ config INTEL_TELEMETRY
directly via debugfs files. Various tools may use
this interface for SoC state monitoring.
+config INTEL_SAR
+ tristate "Intel Specific Absorption Rate Driver"
+ depends on ACPI
+ help
+ This driver limit the exposure of human body to RF frequency by informing
+ 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.
+
endif # X86_PLATFORM_DEVICES
config PMC_ATOM
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 7ee369aab10d..3610ab7a12df 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -123,6 +123,7 @@ obj-$(CONFIG_INTEL_SMARTCONNECT) += intel-smartconnect.o
obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += intel_speed_select_if/
obj-$(CONFIG_INTEL_TURBO_MAX_3) += intel_turbo_max_3.o
obj-$(CONFIG_INTEL_UNCORE_FREQ_CONTROL) += intel-uncore-frequency.o
+obj-$(CONFIG_INTEL_SAR) += intel-sar.o
# Intel PMIC / PMC / P-Unit devices
obj-$(CONFIG_INTEL_BXTWC_PMIC_TMU) += intel_bxtwc_tmu.o
diff --git a/drivers/platform/x86/intel-sar.c b/drivers/platform/x86/intel-sar.c
new file mode 100644
index 000000000000..9906eb4d79a7
--- /dev/null
+++ b/drivers/platform/x86/intel-sar.c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Corporation - ACPI for Specific Absorption Rate
+ * Copyright (c) 2021, Intel Corporation.
+ */
+
+#include <asm/errno.h>
+#include <linux/acpi.h>
+#include <linux/kobject.h>
+#include <linux/platform_data/x86/intel-sar.h>
+#include <linux/platform_device.h>
+#include <linux/sysfs.h>
+
+/**
+ * get_int_value - Retrieve Integer values from ACPI Object
+ * Value of the integer from the object of ACPI is obtained.
+ * @obj: acpi_object pointer which has the integer value
+ * @out: output pointer will get integer value
+ * returns 0 on success
+ */
+static int get_int_value(union acpi_object *obj, int *out)
+{
+ if (obj && obj->type == ACPI_TYPE_INTEGER) {
+ *out = (int)obj->integer.value;
+ return 0;
+ } else {
+ return -EFAULT;
+ }
+}
+
+/**
+ * update_sar_data - sar data is updated based on reg_value
+ * sar_data is updated based on regulatory value
+ * context->reg_value will never exceed MAX_REGULATORY
+ * @context: context pointer used for data
+ */
+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 package for SAR
+ * @context: context pointer used for data
+ * @item : acpi_object ptr
+ * returns if success or error
+ */
+static acpi_status parse_package(struct wwan_sar_context *context, union acpi_object *item)
+{
+ int value = 0, itr = 0, reg = 0;
+ union acpi_object *num;
+ struct wwan_device_mode_configuration *data;
+
+ num = &item->package.elements[0];
+ if (get_int_value(num, &value) == 0) {
+ if (value >= 0 && value < MAX_REGULATORY)
+ reg = value;
+ else
+ return AE_ERROR;
+ }
+ data = &context->config_data[reg];
+ if (data->total_dev_mode > MAX_DEV_MODES)
+ 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) {
+ pr_err("Cannot allocate memory in kernel\n");
+ return AE_ERROR;
+ }
+ for (itr = 0; itr < data->total_dev_mode; itr++) {
+ if (itr + 1 == item->package.count)
+ break;
+ num = &item->package.elements[itr + 1];
+ if (num->type != ACPI_TYPE_PACKAGE)
+ continue;
+ if (num->package.count < TOTAL_DATA)
+ break;
+ if (get_int_value(&num->package.elements[0], &value) == 0)
+ data->device_mode_info[itr].device_mode = value;
+ if (get_int_value(&num->package.elements[1], &value) == 0)
+ data->device_mode_info[itr].bandtable_index = value;
+ if (get_int_value(&num->package.elements[2], &value) == 0)
+ data->device_mode_info[itr].antennatable_index = value;
+ if (get_int_value(&num->package.elements[3], &value) == 0)
+ data->device_mode_info[itr].sartable_index = value;
+ }
+ return AE_OK;
+}
+
+/**
+ * sar_module_probe - Extraction of information from BIOS via DSM calls
+ * Retrieve all values related to device mode, SAR Table index,
+ * Antenna Table index, Band Table index
+ * @device: ACPI device for which to retrieve the data
+ * Returns AE_OK on success
+ */
+static acpi_status sar_module_probe(struct platform_device *device)
+{
+ acpi_status status = AE_OK;
+ union acpi_object *out;
+ u32 rev = 0;
+ int value = 0;
+ struct wwan_sar_context *context = dev_get_drvdata(&device->dev);
+
+ pr_alert("%s Triggered\n", __func__);
+ out = acpi_evaluate_dsm(context->handle, &context->guid, rev,
+ COMMAND_ID_DEV_MODE, NULL);
+ if (get_int_value(out, &value) == 0) {
+ context->sar_data.device_mode = value;
+ } else {
+ pr_err("%s: Cmd:%d Failed\n", __func__, COMMAND_ID_DEV_MODE);
+ ACPI_FREE(out);
+ return AE_ERROR;
+ }
+ ACPI_FREE(out);
+ dev_set_drvdata(&device->dev, context);
+ sysfs_notify(context->sar_kobject, NULL, SYSFS_DATANAME);
+ return status;
+}
+
+static const struct acpi_device_id sar_device_ids[] = {
+ { "INTC1092", 0},
+ { "", 0},
+};
+
+MODULE_DEVICE_TABLE(acpi, sar_device_ids);
+
+static const struct platform_device_id sar_device_table[] = {
+ {"intc1092", 0},
+ {},
+};
+
+static ssize_t intc_data_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ unsigned long ret = 0;
+ struct wwan_sar_context *context = dev_get_drvdata(dev);
+
+ ret = sprintf(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);
+ return ret;
+}
+
+static ssize_t intc_reg_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ unsigned long ret = 0;
+ struct wwan_sar_context *context = dev_get_drvdata(dev);
+
+ ret = sprintf(buf, "%d\n", context->reg_value);
+ return ret;
+}
+
+static ssize_t intc_reg_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int value = 0, read = 0;
+ struct wwan_sar_context *context = dev_get_drvdata(dev);
+
+ if (!count) {
+ pr_err("%s count = %d", __func__, (int)count);
+ return -EFAULT;
+ }
+ read = sscanf(buf, "%u", &value);
+ if (read <= 0) {
+ pr_alert("%s Not a integer", __func__);
+ return -EFAULT;
+ }
+ if (value >= 0 && value < MAX_REGULATORY) {
+ context->reg_value = value;
+ update_sar_data(context);
+ dev_set_drvdata(dev, context);
+ sysfs_notify(context->sar_kobject, NULL, SYSFS_DATANAME);
+ }
+ return count;
+}
+
+static DEVICE_ATTR_RO(intc_data);
+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_module_probe(device) != AE_OK)
+ pr_err("sar_module_probe error");
+ }
+}
+
+static int sar_probe(struct platform_device *device)
+{
+ int result = 0;
+ struct wwan_sar_context *context;
+ union acpi_object *out, *item, req;
+ acpi_status status = AE_OK;
+ u32 rev = 0, reg = 0;
+ int value = 0;
+
+ context = kmalloc(sizeof(*context), GFP_KERNEL);
+ if (!context)
+ return -ENOMEM;
+ memset(context, 0, sizeof(struct wwan_sar_context));
+ result = sysfs_create_group(&device->dev.kobj, &intcsar_group);
+ if (result) {
+ pr_err("sysfs creation failed\n");
+ goto r_free;
+ }
+ context->sar_kobject = &device->dev.kobj;
+ context->sar_device = device;
+ dev_set_drvdata(&device->dev, context);
+ if (guid_parse(SAR_DSM_UUID, &context->guid)) {
+ pr_err("%s: UUID error\n", __func__);
+ goto r_sys;
+ }
+ context->handle = ACPI_HANDLE(&device->dev);
+ for (reg = 0; reg < MAX_REGULATORY; reg++) {
+ 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) {
+ pr_err("%s: Cmd:%d Failed\n", __func__, COMMAND_ID_CONFIG_TABLE);
+ continue;
+ }
+ if (out->type == ACPI_TYPE_PACKAGE && out->package.count >= 3) {
+ item = &out->package.elements[0];
+ if (get_int_value(item, &value) == 0)
+ context->config_data[reg].version = value;
+ item = &out->package.elements[1];
+ if (get_int_value(item, &value) == 0)
+ context->config_data[reg].total_dev_mode = value;
+ if (context->config_data[reg].total_dev_mode <= 0 &&
+ context->config_data[reg].total_dev_mode >
+ MAX_DEV_MODES) {
+ pr_err("total_dev_mode is not within range : %d\n",
+ context->config_data[reg].total_dev_mode);
+ ACPI_FREE(out);
+ continue;
+ }
+ item = &out->package.elements[2];
+ if (item->type == ACPI_TYPE_PACKAGE && item->package.count > 0)
+ status = parse_package(context, item);
+ else
+ status = AE_ERROR;
+ if (status != AE_OK) {
+ ACPI_FREE(out);
+ continue;
+ }
+ }
+ ACPI_FREE(out);
+ }
+ update_sar_data(context);
+ if (sar_module_probe(device) != AE_OK) {
+ pr_err("Failed sar_module_probe\n");
+ goto r_sys;
+ }
+ if (acpi_install_notify_handler(ACPI_HANDLE(&device->dev), ACPI_DEVICE_NOTIFY,
+ sar_notify, (void *)device) != AE_OK) {
+ pr_err("Failed acpi_install_notify_handler\n");
+ goto r_sys;
+ }
+ return 0;
+
+r_sys:
+ sysfs_remove_group(&device->dev.kobj, &intcsar_group);
+r_free:
+ kfree(context);
+ return -1;
+}
+
+static int sar_remove(struct platform_device *device)
+{
+ struct wwan_sar_context *context = dev_get_drvdata(&device->dev);
+ int reg = 0;
+
+ 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);
+ context->config_data[reg].device_mode_info = NULL;
+ }
+ kfree(context);
+ return 0;
+}
+
+MODULE_DEVICE_TABLE(platform, sar_device_table);
+
+static struct platform_driver sar_driver = {
+ .probe = sar_probe,
+ .remove = sar_remove,
+ .driver = {
+ .name = DRVNAME,
+ .owner = THIS_MODULE,
+ /* FOR ACPI HANDLING */
+ .acpi_match_table = ACPI_PTR(sar_device_ids),
+ },
+ .id_table = sar_device_table,
+};
+
+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/include/linux/platform_data/x86/intel-sar.h b/include/linux/platform_data/x86/intel-sar.h
new file mode 100644
index 000000000000..6e2ac93a3ebc
--- /dev/null
+++ b/include/linux/platform_data/x86/intel-sar.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Intel Corporation Header File for Specific Absorption Rate
+ * Copyright (c) 2021, Intel Corporation.
+ */
+#ifndef INTEL_SAR_H
+#define INTEL_SAR_H
+
+#define DRVNAME "intc_sar"
+#define SYSFS_DATANAME "intc_data"
+#define SAR_DSM_UUID "82737E72-3A33-4C45-A9C7-57C0411A5F13"
+#define COMMAND_ID_DEV_MODE 1
+#define COMMAND_ID_CONFIG_TABLE 2
+#define COMMAND_TEST_SET 31
+#define MAX_REGULATORY 3
+#define SAR_EVENT 0x80
+#define MAX_DEV_MODES 50
+#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 kobject *sar_kobject;
+ 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 */
--
2.17.1
