From 3f2546b2ef55b661fd8dd69682b38992225e86f6 Mon Sep 17 00:00:00 2001 From: fishsoupisgood Date: Mon, 29 Apr 2019 01:17:54 +0100 Subject: Initial import of qemu-2.4.1 --- roms/u-boot/doc/SPI/README.ti_qspi_flash | 47 ++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 roms/u-boot/doc/SPI/README.ti_qspi_flash (limited to 'roms/u-boot/doc/SPI/README.ti_qspi_flash') diff --git a/roms/u-boot/doc/SPI/README.ti_qspi_flash b/roms/u-boot/doc/SPI/README.ti_qspi_flash new file mode 100644 index 00000000..1b86d01a --- /dev/null +++ b/roms/u-boot/doc/SPI/README.ti_qspi_flash @@ -0,0 +1,47 @@ +QSPI U-boot support +------------------ + +Host processor is connected to serial flash device via qpsi +interface. QSPI is a kind of spi module that allows single, +dual and quad read access to external spi devices. The module +has a memory mapped interface which provide direct interface +for accessing data form external spi devices. + +The one QSPI in the device is primarily intended for fast booting +from Quad SPI flash devices. + +Usecase +------- + +MLO/u-boot.img will be flashed from SD/MMC to the flash device +using serial flash erase and write commands. Then, switch settings +will be changed to qspi boot. Then, the ROM code will read MLO +from the predefined location in the flash, where it was flashed and +execute it after storing it in SDRAM. Then, the MLO will read +u-boot.img from flash and execute it from SDRAM. + +SPI mode +------- +SPI mode uses mtd spi framework for transfer and reception of data. +Can be used in: +1. Normal mode: use single pin for transfers +2. Dual Mode: use two pins for transfers. +3. Quad mode: use four pin for transfer + +Memory mapped read mode +----------------------- +In this, SPI controller is configured using configuration port and then +controler is switched to memory mapped port for data read. + +Driver +------ +drivers/qspi/ti_qspi.c + - Newly created file which is responsible for configuring the + qspi controller and also for providing the low level api which + is responsible for transferring the datas from host controller + to flash device and vice versa. + +Testing +------- +A seperated file named README.dra_qspi_test has been created which gives all the +details about the commands required to test qspi at u-boot level. -- cgit v1.2.3