archive mirror
 help / color / mirror / Atom feed
From: Shravan S <>
Subject: [PATCH V5 0/1] platform/x86: BIOS SAR driver for Intel M.2 Modem
Date: Wed, 11 Aug 2021 18:06:06 +0530	[thread overview]
Message-ID: <> (raw)

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. 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 RF power regulation.

The BIOS gets notified about device mode changes through Sensor Driver. This information is given to a (newly created) WWAN ACPI function driver when there is a device mode change. 
The driver then uses a _DSM method to retrieve the required information from BIOS. 
This information is then forwarded to the User-space using the sysfs_notify interface.
A lookup table is maintained inside the BIOS which suggests the SAR Table index and Antenna Tuner Table Index values for individual device modes.

The SAR parameters to be used on the Modem differs for each Regulatory Mode like FCC, CE and ISED.
Hence, the SAR parameters are stored separately in the SMBIOS table in the OEM BIOS, for each of the Regulatory mode. Regulatory modes will be different based on the region and network available in that region.

Hence the entire SAR functionality handling is divided into 2 parts:

•	A ACPI function driver implemented that uses a dedicated ACPI node for WWAN device.
	Sends notifications whenever there is change in Device Mode. (each OEM has different mechanism
	of updating this DEVICE Mode info). This is notified to User-space applications using
	the sysfs_notify interface.
•	WWAN Device Service listens for sysfs_notify messages and reads the sysfs data and routes them
	to Modem using MBIM.

Shravan S (1):
  platform/x86: BIOS SAR driver for Intel M.2 Modem

 .../ABI/testing/sysfs-driver-intc_sar         |  57 ++++
 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    | 319 ++++++++++++++++++
 .../platform/x86/intel/int1092/intel_sar.h    |  86 +++++
 8 files changed, 486 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

base-commit: 761c6d7ec820f123b931e7b8ef7ec7c8564e450f

             reply	other threads:[~2021-08-11 12:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 12:36 Shravan S [this message]
2021-08-11 12:36 ` [PATCH V5 1/1] platform/x86: BIOS SAR driver for Intel M.2 Modem Shravan S

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).