From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Goldschmidt Date: Mon, 14 Jan 2019 17:05:12 +0100 Subject: [U-Boot] [PATCH v1 1/4] arm: socfpga: imply SPL config instead of select In-Reply-To: <9bcf5990-df16-b10f-4f61-4f40bdcd5eb0@kernel.org> 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> Message-ID: <28940ce1-aba0-6fcc-7dcb-8d6f4bc34ea1@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Dinh, 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. 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... Regards, Simon > > Dinh > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/reset?id=b3ca9888f35fa6919569cf27c929dc0ac49e9716 >