Introduction

The SPI Flash controller drivers are designed for users to access SPI NOR/NAND Flash, currently, only user mode has been supported.

Architecture

The software architectures of SPI Flash controller driver for SPI NOR Flash and NAND Flash are shown in two figures below respectively.

../../_images/spi_flash_controller_for_nor_flash_software_arch.svg — SPI Flash controller for NOR Flash software architecture

../../_images/spi_flash_controller_for_nand_flash_software_arch.svg — SPI Flash controller for NAND Flash software architecture

Implementation

The SPI Flash controller drivers are implemented as following files:

File	Description
`<linux>/drivers/rtkdrivers/spic/Kconfig`	SPI Flash controller driver Kconfig
`<linux>/drivers/rtkdrivers/spic/Makefile`	SPI Flash controller driver Makefile
`<linux>/drivers/rtkdrivers/spic/spi-rxi312-nand.c`	SPI Flash controller driver implementation for NAND Flash
`<linux>/drivers/rtkdrivers/spic/spi-rxi312-nor.c`	SPI Flash controller driver implementation for NOR Flash
`<linux>/drivers/rtkdrivers/spic/spi-rxi312-nor.h`	SPI Flash controller driver header file for NOR Flash

Configuration

DTS Configuration

For SPI Flash controller driver for NOR Flash, the DTS node is defined in <dts>/rtl8730e-spi-nor.dtsi:

spic: spi@44000000 {
   compatible = "realtek,rxi312-nor";
   #address-cells = <1>;
   #size-cells = <0>;
   bus_num = <2>;
   reg = <0x44000000 0x200>;
   interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
   spi-max-frequency = <100000000>;
   flash0: flash@0 {
      /* NOR Flash configurations */
   };
};

For SPI Flash controller driver for NAND Flash, the DTS node is defined in <dts>/rtl8730e-spi-nand-128m.dtsi or <dts>/rtl8730e-spi-nand-256m.dtsi:

spic: spi@44000000 {
   compatible = "realtek,rxi312-nand";
   #address-cells = <1>;
   #size-cells = <0>;
   bus_num = <2>;
   reg = <0x44000000 0x200>;
   interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
   spi-max-frequency = <100000000>;
   flash0: flash@0 {
      /* NAND Flash configurations */
   };
};

The configurations are listed in table below.

Property	Description	Configurable?
compatible	ID to match the SPI Flash controller driver with SPI Flash controller device	No
#address-cells	Address cells for Flash node	No
#size-cells	Size cells for Flash node	No
bus_num	SPI bus number	No
reg	Register resource	No
interrupts	SPI interrupt, for interrupt mode of SPI Flash controller driver for NOR Flash, reserved for SPI Flash controller driver for NAND Flash	No
spi-max-frequency	SPI max frequency in Hz, reserved	No

Note

Above DTS files will be auto selected after chip is chosen, do not change the DTS configurations if not necessary.

Build Configuration

Select Device Drivers > Drivers for Realtek > RXI312 SPI controller driver:

Specially for NOR Flash, select Device Drivers > Drivers for Realtek > RXI312 SPI controller driver > RXI mode as required:

Note

The RXI312 mode is only for SPI Flash controller driver for NOR Flash and it will be ignored for SPI Flash controller driver for NAND Flash.

APIs

APIs for User Space

None.

APIs for Kernel Space

The SPI Flash controller driver for NOR Flash provides spi_nor hooks to SPI NOR Flash driver, the prototypes of these hooks are defined in <linux>/include/linux/mtd/spi-nor.h:

API	Description
read_reg	Read data from the SPI NOR Flash register
write_reg	Write data to the SPI NOR Flash register
read	Read data from the SPI NOR Flash
write	Write data to the SPI NOR Flash
erase	Erase a sector of the SPI NOR Flash

The SPI Flash controller driver for NAND Flash provides spi-mem interface for SPI NAND Flash Core in MTD framework, the spi-mem interface is defined in <linux>/include/linux/spi/spi-mem.h:

API	Description
spi_mem_exec_op	Execute a memory operation