Hi Scott,
On Tue, 24 Feb 2015 18:17:59 -0600 Scott Wood <scottw...@freescale.com> wrote: > On Tue, 2015-02-24 at 16:20 +0900, Masahiro Yamada wrote: > > Hi Scott, > > > > > > On Mon, 23 Feb 2015 19:22:51 -0600 > > Scott Wood <scottw...@freescale.com> wrote: > > > > > On Fri, 2015-02-20 at 14:24 +0900, Masahiro Yamada wrote: > > > > When Kconfig for U-boot was examined, one of the biggest issues was > > > > how to support multiple images (Normal, SPL, TPL). There were > > > > actually two options, "single .config" and "multiple .config". > > > > After some discussions and thought experiments, I chose the latter, > > > > i.e. to create ".config", "spl/.config", "tpl/.config" for Normal, > > > > SPL, TPL, respectively. > > > > > > > > It is true that the "multiple .config" strategy provided us the > > > > maximum flexibility and helped to avoid duplicating CONFIGs among > > > > Normal, SPL, TPL, but I have noticed some fatal problems: > > > > > > > > [1] It is impossible to share CONFIG options across the images. > > > > If you change the configuration of Main image, you often have to > > > > adjust some SPL configurations correspondingly. Currently, we > > > > cannot handle the dependencies between them. It means one of the > > > > biggest advantages of Kconfig is lost. > > > > > > Sharing can happen in the defconfig with "+S:"... > > > > Yes, it can as for "make *_defconfig". > > > > If we modify some options in .config for example by "make menuconfig", > > we also modify some in spl/.config correspondingly. > > > > Users are responsible for configure .config and spl/.config in sync > > in the sane combination. > > > > > > > > > What sort of dependencies are people wanting? Would it be possible to > > > modify kconfig to import SPL .config into the main config (or vice > > > versa?) with a name prefix so that dependencies could happen, without > > > sacrificing the ability to set symbols independently? > > > > To have independent symboles coexist in a single .config, > > I can only suggest to duplicate options like > > CONFIG_FOO=0x100 > > CONFIG_SPL_FOO=0x200 > > CONFIG_TPL_FOO=0x300 > > What I meant was a way to keep the configs separate, but automatically > import the CONFIG_FOO from the SPL .config as CONFIG_SPL_FOO (or some > other prefix that doesn't conflict with SPL-specific options). What is the benefit of doing this? > > > Or as Ian suggested, have only the main config be user-editable, but > > > still let select/depends turn certain things on/off for the > > > auto-generated SPL config. > > > > I guess it is possible for boolean options, > > but impossible to set hex/int options independently. > > How many hex/int options are there, that need to be different in SPL > versus the main U-Boot? Having a few CONFIG_SPL_xxx for those is better > than having a bunch. OK. But, I do not think we need to tweak the Kconfig just for saving boolean options. > > BTW, Ian's idea had been already achieved by include/config_uncmd_spl.h > > So, the answer is to avoid kconfig and go back to using the preprocessor > for configuration? :-( I am not saying I prefer the preprocessor. Indeed, include/config_uncmd_spl.h is ugly, so I'd like to propose a better solution. If we introduce CONFIG_SPL_DM, for example, the ifdef conditional in source files will be like this: #if (!defined(CONFIG_SPL_BUILD) && defined(CONFIG_DM)) || \ (defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_DM)) [Driver Model Code] #else [Non Driver Model Code] #endif This is too ugly to be written in each conditional. So, I want to describe like this: #if IS_ENABLED_CONFIG(DM) [Driver Model Code] #else [Non Driver Model Code] #endif I will post some patches later on. > > > > [2] It is too painful to change both ".config" and "spl/.config". > > > > Sunxi guys started to work around this problem by creating a new > > > > configuration target. Commit cbdd9a9737cc (sunxi: kconfig: Add > > > > %_felconfig rule to enable FEL build of sunxi platforms.) added > > > > "make *_felconfig" to enable CONFIG_SPL_FEL on both images. > > > > Changing the configuration of multiple images in one command is a > > > > generic demand. The current implementation cannot propose any > > > > good solution about this. > > > > > > How about defconfig fragments? Instead of having script infrastructure > > > specifically for CONFIG_SPL_FEL, merge a fragment containing > > > "+S:CONFIG_SPL_FEL". > > > > Do you mean something like this? > > U-boot proper : common/.config + .config > > SPL : common/.config + spl/.config > > TPL : common/.config + tpl/.config > > No, I meant having a fragment containing only "+S:CONFIG_SPL_FEL" that > could be merged into any other config. So, the fragment is something like the _common_ .config, right? > > > > [3] Kconfig files are getting ugly and difficult to understand. > > > > Commit b724bd7d6349 (dm: Kconfig: Move CONFIG_SYS_MALLOC_F_LEN to > > > > Kconfig) has sprinkled "if !SPL_BUILD" over the Kconfig files. > > > > > > It seems like the root cause of this sprinkling is wanting to use > > > default y to avoid touching a bunch of defconfig files, but not wanting > > > to do the default y at the toplevel Kconfig. Maybe better tooling for > > > bulk defconfig updates would help. > > > > Yes. If we could move the default settings into defconfig files > > (and defconfig is just for that purpose), this problem would go away. > > But, in the duscussion with Simon and Alexey, we understood > > maintaining many defconfigs in sync is a pain. > > I think that's a problem that needs to be solved regardless of SPL. Agree. I think we can live the defaults in Kconfig, but I am still searching for a different solution. > > > In any case, couldn't you do > > > CONFIG_SPL_DM currently, by making DM depend on "!SPL_BUILD || SPL_DM", > > > without fundamentally changing the SPL kconfig infrastructure? > > > > As for the Driver Model options, the dependency descriptions will get ugly, > > but we won't carry them so long. > > In a long run, all the boards will be converted and eventually CONFIG_DM > > will bocome the default. > > ...so it's not a very good example of why the current situation must > change. Right, but we still have many other options that can be enabled on SPL. > > > Why do symbols like LOCALVERSION and CC_OPTIMIZE_FOR_SIZE depend on ! > > > SPL_BUILD? > > > > These two options are used by the top-level Makefile > > and it is automatically propagated to spl/*. > > > > It is harmless to define them again in spl/.config, but meaningless. > > ...so not all of the existing !SPL_BUILD instances in Kconfig need to be > there. > > > > > [4] The build system got more complicated than it should be. > > > > To adjust Linux-originated Kconfig to U-Boot, the helper script > > > > "scripts/multiconfig.sh" was introduced. Writing a complicated > > > > text processor is a shell script sometimes caused problems. > > > > > > > > Now I believe the "single .config" will serve us better. With it, > > > > all the problems above would go away. Instead, we will have to add > > > > some CONFIG_SPL_* (and CONFIG_TPL_*) options such as CONFIG_SPL_DM, > > > > but we will not have much. Anyway, this is what we do now in > > > > scripts/Makefile.spl. > > > > > > I had been hoping that the split configs would let us get rid of many of > > > the CONFIG_SPL_* options that we already have. > > > > > > How will TPL be handled? Are you going to duplicate all the SPL > > > symbols? Or just avoid ever kconfigizing them? > > > > Not all, but I expect some duplicated CONFIG_TPL_* such as > > CONFIG_TPL_TEXT_BASE. > > I'm not talking about TEXT_BASE. I'm talking about stuff like this: We have to add some CONFIG_TPL_*, but we will just have 20. > #ifdef CONFIG_TPL_BUILD > #define CONFIG_SPL_NAND_BOOT > #define CONFIG_SPL_FLUSH_IMAGE > #define CONFIG_SPL_ENV_SUPPORT > #define CONFIG_SPL_NAND_INIT > #define CONFIG_SPL_SERIAL_SUPPORT > #define CONFIG_SPL_LIBGENERIC_SUPPORT > #define CONFIG_SPL_LIBCOMMON_SUPPORT > #define CONFIG_SPL_I2C_SUPPORT > #define CONFIG_SPL_NAND_SUPPORT > #define CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT > #define CONFIG_SPL_COMMON_INIT_DDR > #define CONFIG_SPL_MAX_SIZE (128 << 10) > #define CONFIG_SPL_TEXT_BASE 0xf8f81000 > #define CONFIG_SYS_MPC85XX_NO_RESETVEC > #define CONFIG_SYS_NAND_U_BOOT_SIZE (832 << 10) > #define CONFIG_SYS_NAND_U_BOOT_DST (0x11000000) > #define CONFIG_SYS_NAND_U_BOOT_START (0x11000000) > #define CONFIG_SYS_NAND_U_BOOT_OFFS ((128 + 128) << 10) > #elif defined(CONFIG_SPL_BUILD) > #define CONFIG_SPL_INIT_MINIMAL > #define CONFIG_SPL_SERIAL_SUPPORT > #define CONFIG_SPL_NAND_SUPPORT > #define CONFIG_SPL_FLUSH_IMAGE > #define CONFIG_SPL_TEXT_BASE 0xff800000 > #define CONFIG_SPL_MAX_SIZE 4096 > #define CONFIG_SYS_NAND_U_BOOT_SIZE (128 << 10) > #define CONFIG_SYS_NAND_U_BOOT_DST 0xf8f80000 > #define CONFIG_SYS_NAND_U_BOOT_START 0xf8f80000 > #define CONFIG_SYS_NAND_U_BOOT_OFFS (128 << 10) > #endif > > If symbols like CONFIG_SPL_I2C_SUPPORT or CONFIG_SPL_COMMON_INIT_DDR get > kconfigized, how would you handle them being in TPL but not SPL? We can add CONFIG_TPL_* if necessary. As I said, if we swap the order of SPL and TPL, we will be able to save CONFIG_TPL_* defines. > > Currently, U-Boot runs SPL, TPL, and U-Boot proper in this order, but > > in hindsight, it might have been better to run > > TPL, SPL, and U-Boot proper, in this order. > > TPL is just makefile infrastructure for inserting an extra stage. It > doesn't refer to the contents. > > > In 4KB memory footprint, it is impossible to include Driver Model. > > It would be a really ad-hoc implementation. > > "Is", not "would be". And this applies to some SPL targets without TPL > as well. > > > In the former order, we need CONFIG_TPL_DM, > > but in the latter, we can save it. > > > > I know TPL means "Third Program Loader", but > > can we perhaps swap the order > > if we assume TPL is the abbreviation of "Tiny Program Loader" ? > > If you redefine TPL to mean SPL that doesn't use certain code, you'll > end up with targets that have TPL but no SPL. Are you sure this is > simplifying anything? Sorry, I can't get it. What I expect is like follows: CONFIG_TPL still depends on CONFIG_SPL. We have three options for the boot procedure: [1] U-Boot-proper (CONFIG_SPL is not defined) [2] SPL + U-Boot-proper (CONFIG_SPL is defined) [3] TPL + SPL + U-Boot-proper (CONFIG_SPL and CONFIG_TPL are defined) The image size: TPL < SPL < U-Boot-proper Driver Model and some other features are available on SPL if CONFIG_SPL_* is defined. Almost no systematic infrastructure is available on TPL, so we will have very small number of CONFIG_TPL_*. > > > > - Add some entries to include/config_uncmd_spl.h and the new file > > > > scripts/Makefile.uncmd_spl. Some CONFIG options that are not > > > > supported on SPL must be disabled because one .config is shared > > > > between SPL and U-Boot proper going forward. I know this is not > > > > a beautiful solution and I think we can do better, but let's see > > > > how much we will have to describe them. > > > > > > How is uncmd_spl better than "!SPL_BUILD"? > > > > We can use Kconfig as it is in Linux. > > Not after this patch. > Right, I need to do more cleanups for that. Best Regards Masahiro Yamada _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot