doc: peripherals: Add doc for UFSHC peripheral

Add documentation for the UFS Host Controller (UFSHC) driver, which
provides a generic interface for interacting with UFS host controller
devices. It is used by the UFS subsystem to manage UFS-based storage
devices.

The documentation covers key aspects of the UFSHC, including
initialization, transfer request handling, query requests, and
configuration options, helping developers understand how to integrate
and work with the UFS subsystem effectively.

Signed-off-by: Ajay Neeli <[email protected]>

Author: Ajay Neeli

doc/hardware/peripherals/index.rst

@@ -58,6 +58,7 @@ Peripherals
    stepper.rst
    smbus.rst
    uart.rst
+   ufshc.rst
    usbc_vbus.rst
    tcpc.rst
    tgpio.rst

doc/hardware/peripherals/ufshc.rst

@@ -0,0 +1,61 @@
+.. _ufs_api:
+
+Universal Flash Storage (UFS)
+#############################
+
+The UFS Host Controller driver api offers a generic interface for interacting
+with a UFS host controller device. It is used by the UFS subsystem, and is
+not intended to be directly used by the application.
+
+UFS Host Controller (UFSHC) Overview
+************************************
+
+The UFS host controller driver is based on SCSI Framework. UFSHC is a low
+level device driver for UFS subsystem. The UFS subsystem acts as an interface
+between SCSI and UFS Host controllers.
+
+The current UFS subsystem implementation supports the following functionality:
+
+UFS controller initialization
+=============================
+
+Prepares the UFS Host Controller to transfer commands/responses between UFSHC
+and UFS device.
+
+.. _ufs-init-api:
+
+Transfer requests
+=================
+
+It handles SCSI commands from SCSI subsystem, form UPIUs and issues UPIUs to
+the UFS Host controller.
+
+.. _ufs-scsi-api:
+
+Query Request
+=============
+
+It handles query requests which are used to modify and retrieve configuration
+information of the device.
+
+.. _ufs-query-api:
+
+Configuration Options
+*********************
+
+Related configuration options:
+
+* :kconfig:option:`CONFIG_UFSHC`
+* :kconfig:option:`CONFIG_UFS_STACK`
+* :kconfig:option:`CONFIG_SCSI`
+
+API Reference
+*************
+
+UFS subsystem APIs are provided by ufs.h
+
+.. doxygengroup:: ufs_interface
+
+UFS Host Controller (UFSHC) APIs are provided by ufshc.h
+
+.. doxygengroup:: ufshc_interface