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Diffstat (limited to 'doc/develop/falcon.rst')
| -rw-r--r-- | doc/develop/falcon.rst | 84 |
1 files changed, 7 insertions, 77 deletions
diff --git a/doc/develop/falcon.rst b/doc/develop/falcon.rst index 244b4ccb5c2..5689d5b93a7 100644 --- a/doc/develop/falcon.rst +++ b/doc/develop/falcon.rst @@ -22,7 +22,7 @@ copies U-Boot image into the memory. The Falcon Mode extends this way allowing to start the Linux kernel directly from SPL. A new command is added to U-Boot to prepare the parameters that SPL -must pass to the kernel, using ATAGS or Device Tree. +must pass to the kernel using a Device Tree. In normal mode, these parameters are generated each time before loading the kernel, passing to Linux the address in memory where @@ -117,10 +117,7 @@ spl - SPL configuration Usage:: - spl export <img=atags|fdt> [kernel_addr] [initrd_addr] [fdt_addr ] - -img - "atags" or "fdt" + spl export fdt [kernel_addr] [initrd_addr] [fdt_addr ] kernel_addr kernel is loaded as part of the boot process, but it is not started. @@ -134,11 +131,11 @@ fdt_addr in case of fdt, the address of the device tree. The *spl export* command does not write to a storage media. The user is -responsible to transfer the gathered information (assembled ATAGS list -or prepared FDT) from temporary storage in RAM into persistent storage -after each run of *spl export*. Unfortunately the position of temporary -storage can not be predicted nor provided at command line, it depends -highly on your system setup and your provided data (ATAGS or FDT). +responsible to transfer the gathered information (prepared FDT) from temporary +storage in RAM into persistent storage after each run of *spl export*. +Unfortunately the position of temporary storage can not be predicted nor +provided at command line, it depends highly on your system setup and your +provided device tree. However at the end of an successful *spl export* run it will print the RAM address of temporary storage. The RAM address of FDT will also be set in the environment variable *fdtargsaddr*, the new length of the @@ -152,73 +149,6 @@ to the pre-defined address in persistent storage The following example shows how to prepare the data for Falcon Mode on twister board with ATAGS BLOB. -The *spl export* command is prepared to work with ATAGS and FDT. However, -using FDT is at the moment untested. The ppc port (see a3m071 example -later) prepares the fdt blob with the fdt command instead. - - -Usage on the twister board --------------------------- - -Using mtd names with the following (default) configuration -for mtdparts:: - - device nand0 <omap2-nand.0>, # parts = 9 - #: name size offset mask_flags - 0: MLO 0x00080000 0x00000000 0 - 1: u-boot 0x00100000 0x00080000 0 - 2: env1 0x00040000 0x00180000 0 - 3: env2 0x00040000 0x001c0000 0 - 4: kernel 0x00600000 0x00200000 0 - 5: bootparms 0x00040000 0x00800000 0 - 6: splashimg 0x00200000 0x00840000 0 - 7: mini 0x02800000 0x00a40000 0 - 8: rootfs 0x1cdc0000 0x03240000 0 - -:: - - twister => nand read 82000000 kernel - - NAND read: device 0 offset 0x200000, size 0x600000 - 6291456 bytes read: OK - -Now the kernel is in RAM at address 0x82000000:: - - twister => spl export atags 0x82000000 - ## Booting kernel from Legacy Image at 82000000 ... - Image Name: Linux-3.5.0-rc4-14089-gda0b7f4 - Image Type: ARM Linux Kernel Image (uncompressed) - Data Size: 3654808 Bytes = 3.5 MiB - Load Address: 80008000 - Entry Point: 80008000 - Verifying Checksum ... OK - Loading Kernel Image ... OK - OK - cmdline subcommand not supported - bdt subcommand not supported - Argument image is now in RAM at: 0x80000100 - -The result can be checked at address 0x80000100:: - - twister => md 0x80000100 - 80000100: 00000005 54410001 00000000 00000000 ......AT........ - 80000110: 00000000 00000067 54410009 746f6f72 ....g.....ATroot - 80000120: 65642f3d 666e2f76 77722073 73666e20 =/dev/nfs rw nfs - -The parameters generated with this step can be saved into NAND at the offset -0x800000 (value for twister for CONFIG_CMD_SPL_NAND_OFS):: - - nand erase.part bootparms - nand write 0x80000100 bootparms 0x4000 - -Now the parameters are stored into the NAND flash at the address -CONFIG_CMD_SPL_NAND_OFS (=0x800000). - -Next time, the board can be started into Falcon Mode moving the -setting the GPIO (on twister GPIO 55 is used) to kernel mode. - -The kernel is loaded directly by the SPL without passing through U-Boot. - Example with FDT: a3m071 board ------------------------------ |