From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Wed, 3 Apr 2019 14:11:02 +0200 Subject: [U-Boot] [PATCH] pinctrl: renesas: Fix linker error when PINCTRL_PFC=n In-Reply-To: <20190402170207.GA23017@vmlxhi-102.adit-jv.com> 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: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: u-boot@lists.denx.de On 4/2/19 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 ? >>> [1] U-Boot 2019.04-rc4-00100-g03ece61db8 (Apr 02 2019 - 17:23:57 +0200) > [..] > > Best regards, > Eugeniu. > -- Best regards, Marek Vasut