From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Mon, 14 Jan 2019 21:01:32 +0100 Subject: [U-Boot] [PATCH v1 1/4] arm: socfpga: imply SPL config instead of select In-Reply-To: References: <20190107211423.10151-1-simon.k.r.goldschmidt@gmail.com> <20190107211423.10151-2-simon.k.r.goldschmidt@gmail.com> <033b301a-612d-3b80-7ecc-04530851c1ec@denx.de> <1dd165cd-2cad-013b-877c-78fe5780f9cf@gmail.com> <00f186a1-7aea-8d46-770d-b5e08f1f92c2@denx.de> <8d7142cb-5674-57d2-dce2-a4595b8a5538@gmail.com> <9bcf5990-df16-b10f-4f61-4f40bdcd5eb0@kernel.org> <28940ce1-aba0-6fcc-7dcb-8d6f4bc34ea1@gmail.com> <1c639b12-e963-f5b4-9136-83ebe0cd1a9b@denx.de> <60997006-4808-2931-0612-5a32a0db601c@gmail.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 1/14/19 8:43 PM, Simon Goldschmidt wrote: > Am 14.01.2019 um 20:33 schrieb Marek Vasut: >> On 1/14/19 7:58 PM, Simon Goldschmidt wrote: >>> Am 14.01.2019 um 19:31 schrieb Marek Vasut: >>>> On 1/14/19 5:05 PM, Simon Goldschmidt wrote: >>>>> Hi Dinh, >>>> >>>> Hi, >>>> >>>>> Am 14.01.2019 um 16:58 schrieb Dinh Nguyen: >>>>>> Hi Simon, >>>>>> >>>>>> On 1/14/19 9:50 AM, Simon Goldschmidt wrote: >>>>>>> Am 11.01.2019 um 23:02 schrieb Marek Vasut: >>>>>>>> On 1/11/19 9:39 PM, Simon Goldschmidt wrote: >>>>>>>>> Am 07.01.2019 um 23:53 schrieb Marek Vasut: >>>>>>>>>> On 1/7/19 10:14 PM, Simon Goldschmidt wrote: >>>>>>>>>>> In order to build a smaller SPL, let's imply SPL_DM_RESET and >>>>>>>>>>> SPL_WATCHDOG_SUPPORT instead of selecting them, so they can be >>>>>>>>>>> disabled >>>>>>>>>>> via defconfig. >>>>>>>>>>> >>>>>>>>>>> This also seems to be required to use OF_PLATDATA, as the reset >>>>>>>>>>> drivers >>>>>>>>>>> don't seem to work with it. >>>>>>>>>> >>>>>>>>>> How do you un-reset IP blocks if you disable the reset >>>>>>>>>> controller ? >>>>>>>>> >>>>>>>>> I found that out just now: there's the function >>>>>>>>> 'reset_deassert_peripherals_handoff()' in spl_gen5.c that should >>>>>>>>> "De-assert reset for peripherals and bridges based on handoff". >>>>>>>>> However, >>>>>>>>> at least for Gen5, it just writes a 0 to rstmgr->permodrst. By >>>>>>>>> doing >>>>>>>>> that, it enables *ALL* peripherals on the SoC (except for some DMA >>>>>>>>> channels that aren't really used) :-) >>>>>>>>> >>>>>>>>> I guess that needs some cleaning up as well ;-) >>>>>>>> >>>>>>>> Yes >>>>>>>> >>>>>>>>> I think the proper thing to do here would be to remove this >>>>>>>>> function and >>>>>>>>> convert all drivers to provide appropriate 'resets' properties in >>>>>>>>> the >>>>>>>>> dts? >>>>>>>> >>>>>>>> Indeed >>>>>>> >>>>>>> So I just did that and it works nice for SPL and U-Boot: By adding >>>>>>> some >>>>>>> "resets" properties the the main dtsi and adding reset bulk code to >>>>>>> the >>>>>>> cadence_qspi, denali_dt nand and drivers, I can nearly remove the >>>>>>> reset >>>>>>> code from arch/mach_socfpga. >>>>>>> >>>>>>> The problem would be that now Linux cannot use peripherals that >>>>>>> aren't >>>>>>> enabled by U-Boot because it relies on them being enabled. How are >>>>>>> such >>>>>>> dependencies solved? Because even if I would add reset support in >>>>>>> the >>>>>>> corresponding Linux drivers, we probably could not bootolder Kernels >>>>>>> (e.g. the Debian 9 kernel - v4.9.x) with a new U-Boot... >>>>>>> >>>>>> >>>>>> I added an early reset driver for SoCFPGA that should take care of >>>>>> this. >>>>>> The patch is in v5.0-rc2[1]. >>>>> >>>>> OK, it's good to know that this work is already done, I haven't >>>>> monitored this close enough. >>>> >>>> We had the same problem with A10, indeed. >>>> >>>>> But am I correct that my above problem remains even in v5.0 as not all >>>>> peripherals in socfpga.dtsi have a "resets" property set (e.g. mmc and >>>>> qspi) and would thuse not be taken out of reset by Linux? >>>>> >>>>> Plus: should U-Boot work with older Linux kernels? Because if so, we >>>>> need fallback code in U-Boot to unreset peripherals when running >>>>> with an >>>>> older kernel... >>>> >>>> Yes, it'd break old broken kernels . The real question is, do we care ? >>> >>> Ok, so that at leat shows me I'm going into the right direction :-) >>> >>> There are some problems though: >>> - I do care (we're running 4.9 currently) *g* >>> - people running an RT kernel will care for a while (until the next >>> stable RT after fixing this will be released) >>> - we would currently be breaking *all* kernels, since no kernel should >>> yet be able to deassert reset for mmc and qspi (unless this is already >>> done by U-Boot)... >>> >>> So would it be OK to add a Kconfig option to U-Boot to keep the current >>> behaviour (for old broken kernels like you said) until that code is >>> spread widely enough? Or is that a no-go? >> >> Would be nice to be able to tweak the reset driver behavior at runtime, >> to unreset things before booting the kernel if the user desires so. > > Instead of tweaking the reset driver, we could just add a command that > does that 'rstmgr->permodrst = 0;' thing my patch would remove. I don't want a new custom command. > Since noone has complained so far, I think writing 0 should be OK here. > I don't think it would make too much sense to use the reset handoff > defines from Quartus output for such a command. I think the way Quartus > does this is strange anyway... > > The question is if defconfigs should be able to use this to > automatically build a U-Boot config for older kernels. If so, we'd still > need a Kconfig option? I'd much rather have this runtime configurable. > Thinking further about cleanup: I guess the clock driver is not that > hard to implement, either. The only thing that's driving me mad is > pinmux. Is there any chance to get more info from Intel to write this > properly so we can get rid of that iocsr scanchain defines? Clock driver should be easy, yes. Pinmux, I don't know, maybe project chibi has some information (the cyclone I documentation project). -- Best regards, Marek Vasut