mirror of
https://github.com/AsahiLinux/u-boot
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README.altera_spi | ||
README.ftssp010_spi_test | ||
README.sandbox-spi | ||
README.sh_qspi_test | ||
README.ti_qspi_am43x_test | ||
README.ti_qspi_dra_test | ||
README.ti_qspi_flash | ||
status.txt |
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 controller 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.