![]() The addresses mentioned here are used in the subsequent NAND related commands. The NAND part on the EVM has been configured in the following manner. Micron NAND parts (page size 2KB, block size 128KB) are supported on AM335XEVM platforms. It also describe how to store the kernel image, RAMDISK or the UBIFS filesystem to NAND so as to have a network-free boot right from powering on the board to getting the kernel up and running. This section gives an overview of the NAND support in U-Boot. ![]() Refer to EVM Switch Settings section for more info on enabling/disabling different boot devices.*The following sub-sections illustrate the usage of NAND specific commands on AM335X EVM. Host configuration Serial port configurationĬonnect a serial cable from the serial port of the EVM (serial port is next to the power switch) to the COM port on either the Windows machine or Linux host depending on where you'll be running the serial terminal software.įor correct operation the serial terminal software should be configured with the following settings: This will generate two binaries in the am335x directory, MLO and u-boot.img along with other intermediate binaries that may be needed in some cases (see below). $ make O=am335x CROSS_COMPILE=arm-linux-gnueabihf- ARCH=arm am335x_evm AM335x-LINUX-PSP-MM.mm.pp.bb/src/u-boot/u-boot-MM.mm.pp.bbīuilding into a separate object directory with the "O=" parameter to make is strongly recommended.Ĭommands $ & rm -rf. The 1st binary is generated MLO and the 2nd stage is generated as u-boot.img.īelow steps assumes that the release package is extracted inside directory represented as $AM335x-PSP-DIRĬhange to the base of the U-Boot directory. Initial stage initalize only the required boot devices (NAND, MMC, I2C etc) 2nd full stage initall all other devices (ethernet, timers, clocks etc). Since it is not possible to squeeze in all the functionality that is normally expected from U-Boot in < 110KB (after setting aside some space for stack, heap etc) a two stage approach has been adopted. Also, 1 KB at the start (0x402f0000 - 0x402f0400) is secure and it cannot be accessed This places a limit of 109KB on the size of the U-Boot binary which the ROM code can transfer to the internal RAM and use as an initial stack before initialization of DRAM. The size of the internal RAM in AM335X is 128KB out of which 18KB at the end is used by the ROM code. This section gives an overview of the two stage U-Boot approach adopted for AM335X. RBL loads the image to the internal memory address 0x402f0400 and executes it. RBL would copy the image, whose size is given by the length field in the image header, from the device and loads into the internal memory address specified in the load address field of Image header. The image header is of length 8 byte which has the load address(Entry point) and the size of the image to be copied. The ROM code can load the SPL image from any of the following devices It is built concurrently when building U-Boot. SPL is a non-interactive loader and is a specially built version of U-Boot. The binary for the 2nd U-Boot stage is simply referred to as U-Boot. The binary for the 1st U-Boot stage is referred to as the Secondary Program Loader (SPL) or the MLO. The booting is completed in two consecutive stages by U-Boot binaries. In AM335x the ROM code serves as the bootstrap loader, sometimes referred to as the Initial Program Loader (IPL) or the Primary Program Loader (PPL). 2.7.4 Environment Settings for NFS Filesystem.2.7.3 Environment Settings for jffs2 Filesystem. ![]() 2.7.2 Environment Settings for UBIFS Filesystem. ![]() 2.5.2 Flashing in CPSW Ethernet boot mode.2.3.7 Making use pre-existing uEnv on SD card.2.3.6 Setting U-Boot environment using uEnv.txt.2.3.5.2 Flashing U-Boot to NAND in SD boot.2.3.5.1 Flashing SPL to NAND in SD boot.2.3.5 Flashing images to NAND in SD boot.2.3.3 Setting Up Boot Environment on SD Card.2.3.2 Read and execute u-boot from SD card.2.3.1 Read and execute uImage from SD card.2.2.2.2 Flashing U-Boot to NAND in UART boot mode.2.2.2.1 Flashing SPL to NAND in UART boot mode.2.2.2 Flashing images to NAND in UART boot mode. ![]()
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