On Tue, 16 May 2023 17:53:38 -0600 Sam Edwards <cfswo...@gmail.com> wrote:
Hi Sam, > On 5/16/23 15:08, Andre Przywara wrote: > > This whole memory map is somewhat of a legacy. Apart from a few > > addresses for the SPL needs we shouldn't have those defines at all. > > Some symbols are needed because there are other macros using them, > > although these then are eventually unused. > > I have some patches to remove most of the symbols, and patch 14/17 > > demonstrates some idea how to pin this down to what's really needed. > > > > For this particular case: this was copied from the H6 memory map, some > > addresses are just plain wrong for the D1 family. I will try to remove > > them as much as possible, leaving only the ones needed in. > > I see - the only "tangible" concern I had was the access to > prcm->res_cal_ctrl done in > arch/arm/mach-sunxi/clock_sun50i_h6.c:clock_init_safe > > This doesn't appear to upset the silicon but also doesn't seem necessary > either -- and with how tight of a memory footprint SPL has to fit into, What's the particular concern here? Compared to the A64 we are pretty cool: it's Thumb2 code and we are at around 27KB, at least with my toolchain. And I haven't tried, but I am pretty sure the BROM loads more than 32K, as it does on the H6 and H616 already. The U-Boot build system and the code already supports this - we rely on this for the H616 - so we can lift the limit anytime, if really needed. > I wanted to check whether this was just something undocumented or dead > code that needed to be removed. It sounds like it's mostly the latter. I haven't checked if the vendor boot0 does this. I am pretty sure there is a PRCM block, it's just regularly not mentioned in the manuals. > > So where did you see problems? If you would (wrongly) reference > > PortL somewhere in SPL GPIO code, it would use a wrong pointer, but at > > least the code would still compile fine, wouldn't it? > > The specific patch I had to apply (to arch/arm/mach-sunxi/board.c) was: > /* Update PIO power bias configuration by copy hardware > detected value */ > val = readl(SUNXI_PIO_BASE + SUN50I_H6_GPIO_POW_MOD_VAL); > writel(val, SUNXI_PIO_BASE + SUN50I_H6_GPIO_POW_MOD_SEL); > - val = readl(SUNXI_R_PIO_BASE + SUN50I_H6_GPIO_POW_MOD_VAL); > - writel(val, SUNXI_R_PIO_BASE + SUN50I_H6_GPIO_POW_MOD_SEL); > + if (SUNXI_R_PIO_BASE) { > + val = readl(SUNXI_R_PIO_BASE + SUN50I_H6_GPIO_POW_MOD_VAL); > + writel(val, SUNXI_R_PIO_BASE + SUN50I_H6_GPIO_POW_MOD_SEL); > + } Ah, I see, I indeed missed that. We seem to define all symbols anyway, so we can even lose the #ifdef and use proper if's here. Will incorporate that in the next drop. > With SUNXI_R_PIO_BASE being 0, this was actually attempting to write to > BROM. This might also be something that doesn't really upset the > silicon, though: my debug environment is a concolic emulator I quickly > hacked up to trace MMIO accesses, and it flagged the write to BROM as an > error. It was easier to patch the SPL than to have the emulator ignore > the error (and verify that the T113 was cool with it). Ah yeah, the Allwinner interconnect is pretty relaxed about those things: accesses to addresses with no device behind them are usually ignored (RAZ/WI), where other platform might throw an external abort. Writes to ROM areas are ignored as well. > Since this kind of extraneous/erroneous init code tends to remain > undetected when the symbols they need are dummied-out like this, I > figured I'd give a nudge in the direction of instead *removing* the > symbols where appropriate and fixing whatever breaks -- especially since > we really need to be thrifty about SPL size. But that might also be > something that happens in a later cleanup pass when the patchset is > being prepared for upstream inclusion. :) > > > P.S. Could you try the github post? Then compiled and booted fine for > > me, and includes the DRAM code as well now: > > https://github.com/apritzel/u-boot/commits/t113s-mq-r-WIP > > Ooh, more up-to-date code, thanks for the link! I'll switch to using > this instead going forward. My pulls from that branch might be > relatively infrequent Don't worry, I won't push to this anymore. > since I'm also working on some patches for better > Clang compatibility concurrent with the efforts here. Is this email > thread a good venue for feedback against that branch or would you prefer > that I use GitHub issues instead? Please use this thread here, if you find something still wrong in the branch. I just pushed it to github since someone asked for a fixed and complete version, and I didn't have time to prepare a proper post again. I will hopefully post a proper version for upstreaming in the next days. > Warm regards, > Sam > > P.S. My target is the BMC on the Turing Pi 2 board. Ah, interesting, didn't know that this is now a BMC - for a SoC from Allwinner's arch nemesis Rockchip ;-) > They have the same > SoC and (apparently) UART console configuration, but the differences end > there: in particular, my target supports boot from either/both > microSD+SPI-NAND. I might have to start pushing for room for SPI drivers > in the SPL soon. :) We already have SPI(-NOR) booting support, check arch/arm/mach-sunxi/spl_spi_sunxi.c. This code is very small, and just needs to be updated to cover the D1/T113 SPI controller, which is slightly different. See https://lore.kernel.org/linux-arm-kernel/20230507150345.1971083-1-biguncle...@gmail.com/ for the Linux SPI bits. Regarding SPI-*NAND*: there is https://patchwork.ozlabs.org/user/todo/uboot/?series=322733 which is supposed to allow loading U-Boot proper from SPI-NAND. I haven't tested it yet, and wasn't overly happy with the refactoring, but would appreciate any kind of review or test. Cheers, Andre