Hi John, On 11/11/2014 18:15, John Tobias wrote:
>>>> You add a new entry point here (spl_board_mmc_init), but why cannot you >>>> do this in the functions already supplied by SPL ? Why not in board_init_f >>>> ? >>> >>> When the spl_mmc_load_image function being called, it call >>> mmc_initialize. By default, the mmc_initialize >>> call board_mmc_init. By looking the said function, it initialize all mmc >>> ports. >>> >>> While, in spl_board_mmc_init, only initialize the current mmc port. >> >> ok - but which is the issue by initializing all ports ? I mean, if >> board_mmc_init initialize all ports including what you need in SPL, >> which is the reason to exclude the other ones ? >> > > When board_mmc_init initialize all ports, we can issue a command > at uboot console to switch to different port. > e.g: > > mmc dev 0 (e.g. SD4) > mmc dev 1 (e.g. SD2) > mmc dev 2 (e.g. SD3) > > We can also re-map which is index 0, 1 and 2 by re-arranging the contents of > > struct fsl_esdhc_cfg usdhc_cfg[3] = { > {USDHC4_BASE_ADDR}, > {USDHC2_BASE_ADDR}, > {USDHC3_BASE_ADDR}, > }; > > Assuming the bootstrap is configured to port 3 (USDHC3). The SPL image will > call spl_mmc_load_image to load the uboot image. In order to do that, > it will call > the find_mmc_device(0), based on example above the index 0 is port 4, index 1 > is port 2 and index 2 is port 3. The find_mmc_device will return with errors > because it couldn't initialize the said port. > > So by default, the user should switch back the bootstrap to port 4 in > order to load the > uboot correctly. Then, if the user really want to use the different > ports, they have > to change the arrangement of the contents of usdhc_cfg and compile the > u-boot again. > > In spl_board_mmc_init function, it will read the bootstrap and configure it. > The > settings are passed to fsl_esdhc_initialize which is to be stored in > index 0. So, > find_mmc_device(0) could get a correct information. > > Then, switching to different bootstrap doesn't require to re-compile the > image. This is not enough for adding a new exported weak function, that reamins undocumented, and does not avoid using #ifdef, only moved into drivers/mmc/mmc.c. We have other cases where the behavior is different between SPL and U-Boot, and this is handled in board file using the same #ifdef CONFIG_SPL_BUILD. The question is: why do you need to change the API (as I said, it remains undocumented) instead of doing : int board_mmc_init(bd_t *bis) { #ifdef CONFIG_SPL_BUILD <initialization single port based on bootstrap> #else <instantiate all ports as usual> #endif Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot