From a9479f0431d4ab8834669753124b244a9bb689a2 Mon Sep 17 00:00:00 2001 From: Afzal Mohammed Date: Wed, 18 Sep 2013 01:15:24 +0530 Subject: dfu: ram support DFU spec mentions it as a method to upgrade firmware (software stored in writable non-volatile memory). It also says other potential uses of DFU is beyond scope of the spec. Here such a beyond the scope use is being attempted - directly pumping binary images from host via USB to RAM. This facility is a developer centric one in that it gives advantage over upgrading non-volatile memory for testing new images every time during development and/or testing. Directly putting image onto RAM would speed up upgrade process. This and convenience was the initial thoughts that led to doing this, speed improvement over MMC was only 1 second though - 6 sec on RAM as opposed to 7 sec on MMC in beagle bone, perhaps enabling cache and/or optimizing DFU framework to avoid multiple copy for ram (if worth) may help, and on other platforms and other boot media like NAND maybe improvement would be higher. And for a platform that doesn't yet have proper DFU suppport for non-volatile media's, DFU to RAM can be used. Another minor advantage would be to increase life of mmc/nand as it would be less used during development/testing. usage: ram eg. kernel ram 0x81000000 0x1000000 Downloading images to RAM using DFU is not something new, this is acheived in openmoko also. DFU on RAM can be used for extracting RAM contents to host using dfu upload. Perhaps this can be extended to io for squeezing out register dump through usb, if it is worth. Signed-off-by: Afzal Mohammed Cc: Heiko Schocher Cc: Marek Vasut Cc: Lukasz Majewski Cc: Pantelis Antoniou Cc: Gerhard Sittig Acked-by: Marek Vasut Acked-by: Lukasz Majewski Acked-by: Heiko Schocher --- README | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'README') diff --git a/README b/README index 20ba650248..cab649dedd 100644 --- a/README +++ b/README @@ -1409,6 +1409,12 @@ The following options need to be configured: CONFIG_DFU_NAND This enables support for exposing NAND devices via DFU. + CONFIG_DFU_RAM + This enables support for exposing RAM via DFU. + Note: DFU spec refer to non-volatile memory usage, but + allow usages beyond the scope of spec - here RAM usage, + one that would help mostly the developer. + CONFIG_SYS_DFU_DATA_BUF_SIZE Dfu transfer uses a buffer before writing data to the raw storage device. Make the size (in bytes) of this buffer -- cgit v1.2.3