From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Wed, 3 Apr 2019 16:01:59 +0200 Subject: [U-Boot] [PATCH] pinctrl: renesas: Fix linker error when PINCTRL_PFC=n In-Reply-To: References: <20190402131823.15841-1-erosca@de.adit-jv.com> <1a61e450-6c59-56b2-2efa-ff2bce58d369@gmail.com> <47a77b99-711a-fde1-220f-057bdb08ca6a@gmail.com> <2e9e3d57-2690-4c64-f4cf-c0832f3e74b4@gmail.com> <20190402154020.GA21698@vmlxhi-102.adit-jv.com> <22ce7959-7615-012b-73dd-b3aee3d21220@gmail.com> <20190402170207.GA23017@vmlxhi-102.adit-jv.com> Message-ID: <5e965baf-c7f6-1ea1-2117-a18964a464e0@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: u-boot@lists.denx.de On 4/3/19 2:30 PM, Dirk Behme wrote: > On 03.04.2019 14:11, Marek Vasut wrote: >> On 4/2/19 7:02 PM, Eugeniu Rosca wrote: >>> On Tue, Apr 02, 2019 at 06:02:46PM +0200, Marek Vasut wrote: >>>> On 4/2/19 5:40 PM, Eugeniu Rosca wrote: >>>>> On Tue, Apr 02, 2019 at 05:28:43PM +0200, Marek Vasut wrote: >>>>>> On 4/2/19 5:17 PM, Dirk Behme wrote: >>>>>>> On 02.04.19 15:34, Marek Vasut wrote: >>>>>>>> On 4/2/19 3:18 PM, Eugeniu Rosca wrote: >>>>>>>>> With CONFIG_PINCTRL_PFC=n, aarch64-linux-gnu-ld reports: >>>>>>>>> >>>>>>>>> -----8<----- >>>>>>>>>     LD      u-boot >>>>>>>>> drivers/gpio/built-in.o: In function `rcar_gpio_request': >>>>>>>>> drivers/gpio/gpio-rcar.c:128: undefined reference to >>>>>>>>> `sh_pfc_config_mux_for_gpio' >>>>>>>>> -----8<----- >>> [..] >>>>>>>> Does CONFIG_PINCTRL_PFC=n produce a bootable binary ? >>>>>>> >>>>>>> Why not? Main memory, boot device and UART are configured before >>>>>>> U-Boot, >>>>>>> no? >>>>>> >>>>>> It depends on what is running before U-Boot, so not necessarily. >>>>>> >>>>>> And speaking of boot device, consider the case where the system runs >>>>>> from eMMC and uses the HS200/HS400 modes, which need to switch bus >>>>>> mode >>>>>> using the pinmux driver. >>>>>> >>>>>> Is there a real-world use case where you would want to disable the >>>>>> pinmux driver ? And what is the benefit of that, except that it would >>>>>> cause all kinds of weird problems. >>>>> >>>>> My H3ULCB-KF boots just fine [1] with CONFIG_PINCTRL_PFC=n, but I >>>>> personally don't have any use-case which I need to fulfill on a >>>>> Renesas reference design by disabling PFC. >>>> >>>> And the eMMC and SDHI both work fine too in HS400/SDR104 modes ? >>>> They cannot, since you cannot switch the pinmux properties of the bus. >>>> What about the errors in the log below, they don't look quite fine. >>>> >>>>> Rather, the motivation here is to ensure U-Boot builds fine with as >>>>> many randconfig results as possible, which is a standard practice in >>>>> Linux. I personally favor my solution, but I am also open minded if >>>>> the linker error is avoided by introducing a direct/reverse dependency >>>>> between PFC and another relevant R-Car3 Kconfig symbol. >>>> >>>> I am fine with fixing randconfig build errors. My question here is >>>> whether it makes sense to allow U-Boot build without PFC support, >>>> since that would cause all kinds of problems. I am banking toward >>>> playing it safe and not allowing such an option at all. Thoughts ? >>> >>> It looks like in Linux, PINCTRL is a fundamental feature selected >>> (i.e. *cannot* be disabled by users) by ARCH_RENESAS since v4.5 commit >>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=26a7e06dfee9 >>> >>> ("arm64: renesas: r8a7795: Add Renesas R8A7795 SoC support"). >>> >>> So, demanding a PFC-free U-Boot doesn't look reasonable to me. >> >> That's sensible. >> >>> Should PINCTRL be selected by CONFIG_RCAR_GEN3 as it is done in Linux? >>> One caveat is that PINCTRL currently depends on DM, so R-Car3 U-Boot >>> would become dependent on DM too, i.e. users won't have the option of >>> a legacy U-Boot anymore. >> >> Non-DM operation is not supported anyway, the direction is toward DM/DT >> support. Ultimately, it should be possible to have a single U-Boot >> binary and just exchange the DT to support different boards. >> >> My concern is with the size of the PFC tables, they are massive, sparse >> and keep growing, but that's a different topic. >> >> That said, what about making the GPIO driver depend on PFC driver and >> then have Gen3 select PFC by default in Kconfig ? > > > Of course, you can add such a dependency in Kconfig. But that's not the > question here and won't fix the issue: What is the question then ? > It won't fix the issue that we have code encapsulated with a CONFIG_* > option and a caller which is not encapsulated with this. > > To fix this with your proposal, you need to merge CONFIG_PINCTRL_PFC and > CONFIG_RCAR_GPIO to *one* CONFIG_RCAR_PINCTRL_PFC_GPIO (or whatever) to > ensure that both, the function definition *and* the caller are > encapsulated by the *same* CONFIG switch. But this sounds somehow quite > strange to me ... I don't think I understand this part. If the GPIO driver depends on the PFC driver in Kconfig, then you can either have - both compiled in - neither PFC nor GPIO driver - only the PFC driver and all three options provide working result. Did I miss something ? We can add this patch too, but I'd like to see the Kconfig fix alongside it. Note that the patch should use #if CONFIG_IS_ENABLED(PINCTRL_PFC) . -- Best regards, Marek Vasut