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diff --git a/doc/README.mxsimage b/doc/README.mxsimage new file mode 100644 index 0000000..88a2caf --- /dev/null +++ b/doc/README.mxsimage @@ -0,0 +1,165 @@ +Freescale i.MX233/i.MX28 SB image generator via mkimage +======================================================= + +This tool allows user to produce SB BootStream encrypted with a zero key. +Such a BootStream is then bootable on i.MX23/i.MX28. + +Usage -- producing image: +========================= +The mxsimage tool is targeted to be a simple replacement for the elftosb2 . +To generate an image, write an image configuration file and run: + + mkimage -A arm -O u-boot -T mxsimage -n <path to configuration file> \ + <output bootstream file> + +The output bootstream file is usually using the .sb file extension. Note +that the example configuration files for producing bootable BootStream with +the U-Boot bootloader can be found under arch/arm/boot/cpu/arm926ejs/mxs/ +directory. See the following files: + + mxsimage.mx23.cfg -- This is an example configuration for i.MX23 + mxsimage.mx28.cfg -- This is an example configuration for i.MX28 + +Each configuration file uses very simple instruction semantics and a few +additional rules have to be followed so that a useful image can be produced. +These semantics and rules will be outlined now. + +- Each line of the configuration file contains exactly one instruction. +- Every numeric value must be encoded in hexadecimal and in format 0xabcdef12 . +- The configuration file is a concatenation of blocks called "sections" and + optionally "DCD blocks" (see below). + - Each "section" is started by the "SECTION" instruction. + - The "SECTION" instruction has the following semantics: + + SECTION u32_section_number [BOOTABLE] + - u32_section_number :: User-selected ID of the section + - BOOTABLE :: Sets the section as bootable + + - A bootable section is one from which the BootROM starts executing + subsequent instructions or code. Exactly one section must be selected + as bootable, usually the one containing the instructions and data to + load the bootloader. + + - A "SECTION" must be immediatelly followed by a "TAG" instruction. + - The "TAG" instruction has the following semantics: + + TAG [LAST] + - LAST :: Flag denoting the last section in the file + + - After a "TAG" unstruction, any of the following instructions may follow + in any order and any quantity: + + NOOP + - This instruction does nothing + + LOAD u32_address string_filename + - Instructs the BootROM to load file pointed by "string_filename" onto + address "u32_address". + + LOAD IVT u32_address u32_IVT_entry_point + - Crafts and loads IVT onto address "u32_address" with the entry point + of u32_IVT_entry_point. + - i.MX28-specific instruction! + + LOAD DCD u32_address u32_DCD_block_ID + - Loads the DCD block with ID "u32_DCD_block_ID" onto address + "u32_address" and executes the contents of this DCD block + - i.MX28-specific instruction! + + FILL u32_address u32_pattern u32_length + - Starts to write memory from addres "u32_address" with a pattern + specified by "u32_pattern". Writes exactly "u32_length" bytes of the + pattern. + + JUMP [HAB] u32_address [u32_r0_arg] + - Jumps onto memory address specified by "u32_address" by setting this + address in PT. The BootROM will pass the "u32_r0_arg" value in ARM + register "r0" to the executed code if this option is specified. + Otherwise, ARM register "r0" will default to value 0x00000000. The + optional "HAB" flag is i.MX28-specific flag turning on the HAB boot. + + CALL [HAB] u32_address [u32_r0_arg] + - See JUMP instruction above, as the operation is exactly the same with + one difference. The CALL instruction does allow returning into the + BootROM from the executed code. U-Boot makes use of this in it's SPL + code. + + MODE string_mode + - Restart the CPU and start booting from device specified by the + "string_mode" argument. The "string_mode" differs for each CPU + and can be: + i.MX23, string_mode = USB/I2C/SPI1_FLASH/SPI2_FLASH/NAND_BCH + JTAG/SPI3_EEPROM/SD_SSP0/SD_SSP1 + i.MX28, string_mode = USB/I2C/SPI2_FLASH/SPI3_FLASH/NAND_BCH + JTAG/SPI2_EEPROM/SD_SSP0/SD_SSP1 + + - An optional "DCD" blocks can be added at the begining of the configuration + file. Note that the DCD is only supported on i.MX28. + - The DCD blocks must be inserted before the first "section" in the + configuration file. + - The DCD block has the following semantics: + + DCD u32_DCD_block_ID + - u32_DCD_block_ID :: The ID number of the DCD block, must match + the ID number used by "LOAD DCD" instruction. + + - The DCD block must be followed by one of the following instructions. All + of the instructions operate either on 1, 2 or 4 bytes. This is selected by + the 'n' suffix of the instruction: + + WRITE.n u32_address u32_value + - Write the "u32_value" to the "u32_address" address. + + ORR.n u32_address u32_value + - Read the "u32_address", perform a bitwise-OR with the "u32_value" and + write the result back to "u32_address". + + ANDC.n u32_address u32_value + - Read the "u32_address", perform a bitwise-AND with the complement of + "u32_value" and write the result back to "u32_address". + + EQZ.n u32_address u32_count + - Read the "u32_address" at most "u32_count" times and test if the value + read is zero. If it is, break the loop earlier. + + NEZ.n u32_address u32_count + - Read the "u32_address" at most "u32_count" times and test if the value + read is non-zero. If it is, break the loop earlier. + + EQ.n u32_address u32_mask + - Read the "u32_address" in a loop and test if the result masked with + "u32_mask" equals the "u32_mask". If the values are equal, break the + reading loop. + + NEQ.n u32_address u32_mask + - Read the "u32_address" in a loop and test if the result masked with + "u32_mask" does not equal the "u32_mask". If the values are not equal, + break the reading loop. + + NOOP + - This instruction does nothing. + +- If the verbose output from the BootROM is enabled, the BootROM will produce a + letter on the Debug UART for each instruction it started processing. Here is a + mapping between the above instructions and the BootROM verbose output: + + H -- SB Image header loaded + T -- TAG instruction + N -- NOOP instruction + L -- LOAD instruction + F -- FILL instruction + J -- JUMP instruction + C -- CALL instruction + M -- MODE instruction + +Usage -- verifying image: +========================= + +The mxsimage can also verify and dump contents of an image. Use the following +syntax to verify and dump contents of an image: + + mkimage -l <input bootstream file> + +This will output all the information from the SB image header and all the +instructions contained in the SB image. It will also check if the various +checksums in the SB image are correct. |