1*2f24223aSPoddar, SouravQSPI U-boot support 2*2f24223aSPoddar, Sourav------------------ 3*2f24223aSPoddar, Sourav 4*2f24223aSPoddar, SouravHost processor is connected to serial flash device via qpsi 5*2f24223aSPoddar, Souravinterface. QSPI is a kind of spi module that allows single, 6*2f24223aSPoddar, Souravdual and quad read access to external spi devices. The module 7*2f24223aSPoddar, Souravhas a memory mapped interface which provide direct interface 8*2f24223aSPoddar, Souravfor accessing data form external spi devices. 9*2f24223aSPoddar, Sourav 10*2f24223aSPoddar, SouravThe one QSPI in the device is primarily intended for fast booting 11*2f24223aSPoddar, Souravfrom Quad SPI flash devices. 12*2f24223aSPoddar, Sourav 13*2f24223aSPoddar, SouravUsecase 14*2f24223aSPoddar, Sourav------- 15*2f24223aSPoddar, Sourav 16*2f24223aSPoddar, SouravMLO/u-boot.img will be flashed from SD/MMC to the flash device 17*2f24223aSPoddar, Souravusing serial flash erase and write commands. Then, switch settings 18*2f24223aSPoddar, Souravwill be changed to qspi boot. Then, the ROM code will read MLO 19*2f24223aSPoddar, Souravfrom the predefined location in the flash, where it was flashed and 20*2f24223aSPoddar, Souravexecute it after storing it in SDRAM. Then, the MLO will read 21*2f24223aSPoddar, Souravu-boot.img from flash and execute it from SDRAM. 22*2f24223aSPoddar, Sourav 23*2f24223aSPoddar, SouravSPI mode 24*2f24223aSPoddar, Sourav------- 25*2f24223aSPoddar, SouravSPI mode uses mtd spi framework for transfer and reception of data. 26*2f24223aSPoddar, SouravCan be used in: 27*2f24223aSPoddar, Sourav1. Normal mode: use single pin for transfers 28*2f24223aSPoddar, Sourav2. Dual Mode: use two pins for transfers. 29*2f24223aSPoddar, Sourav3. Quad mode: use four pin for transfer 30*2f24223aSPoddar, Sourav 31*2f24223aSPoddar, SouravMemory mapped read mode 32*2f24223aSPoddar, Sourav----------------------- 33*2f24223aSPoddar, SouravIn this, SPI controller is configured using configuration port and then 34*2f24223aSPoddar, Souravcontroler is switched to memory mapped port for data read. 35*2f24223aSPoddar, Sourav 36*2f24223aSPoddar, SouravDriver 37*2f24223aSPoddar, Sourav------ 38*2f24223aSPoddar, Souravdrivers/qspi/ti_qspi.c 39*2f24223aSPoddar, Sourav - Newly created file which is responsible for configuring the 40*2f24223aSPoddar, Sourav qspi controller and also for providing the low level api which 41*2f24223aSPoddar, Sourav is responsible for transferring the datas from host controller 42*2f24223aSPoddar, Sourav to flash device and vice versa. 43*2f24223aSPoddar, Sourav 44*2f24223aSPoddar, SouravTesting 45*2f24223aSPoddar, Sourav------- 46*2f24223aSPoddar, SouravA seperated file named README.dra_qspi_test has been created which gives all the 47*2f24223aSPoddar, Souravdetails about the commands required to test qspi at u-boot level. 48