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author | Sascha Hauer <s.hauer@pengutronix.de> | 2015-06-09 09:26:43 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2015-06-09 09:26:43 +0200 |
commit | 780c5c84e9b321323ad57738f188ee13fe2ed2ec (patch) | |
tree | 1469d336f2ea64a4308b19d2dcfebb5e0389afee /Documentation | |
parent | 327106c52b771d30ec8ff77ba3ca99cb7ac6abae (diff) | |
parent | 7f9b96cd96332b7a569e21612d3b905b7691c637 (diff) | |
download | barebox-780c5c84e9b321323ad57738f188ee13fe2ed2ec.tar.gz barebox-780c5c84e9b321323ad57738f188ee13fe2ed2ec.tar.xz |
Merge branch 'for-next/imx'
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/boards/imx.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/boards/imx.rst b/Documentation/boards/imx.rst index 466f69c5ba..ef1a6a507e 100644 --- a/Documentation/boards/imx.rst +++ b/Documentation/boards/imx.rst @@ -46,6 +46,33 @@ The images can also always be started second stage:: bootm /mnt/tftp/barebox-freescale-imx51-babbage.img +Internal Boot Mode Through Internal RAM(IRAM) +--------------------------------------- + +The Internal Boot Mode Through Internal RAM is supported on: + +* i.MX51 + +As can be easily deduced from its name, the Internal Boot Mode Through +Internal RAM is just a variant of Internal Boot Mode so all of the +stated above still applies in this case. What it differs in is the following: + +* Boot process is done in two stages(First stage binary can be + produced with ``imx_v7-xload_defconfig``) +* DCD of the first stage image is set such that the image is fetched + into an unoccupied area or IRAM +* First stage image once uncompressed and set up will look for a + second stage bootloader on the same media it booted from and start + it(see mach-imx/xload.c for more details) +* Second stage images are just regular i.MX boot images + +Since on a typical i.MX SoC unused IRAM area is not enough to run +anything but a PBL this mode, due to its very limited usability, +serves only one purpose -- allow for a portion of a bootloader to be +executed without depending on DRAM to be functional. This peculiarity +of the mode can be used to implement various memory testing +scenarious. + USB Boot ^^^^^^^^ |