On 13/09/2019 12:08, Stefan Wahren wrote: > Am 13.09.19 um 11:25 schrieb Matthias Brugger: >> >> On 13/09/2019 10:50, Stefan Wahren wrote: >>> Am 13.09.19 um 10:09 schrieb Matthias Brugger: >>>> On 12/09/2019 21:32, Stefan Wahren wrote: >>>>> Am 12.09.19 um 19:18 schrieb Matthias Brugger: >>>>>> On 10/09/2019 11:27, Matthias Brugger wrote: >>>>>>> On 09/09/2019 21:33, Stefan Wahren wrote: >>>>>>>> Hi Nicolas, >>>>>>>> >>>>>>>> Am 09.09.19 um 11:58 schrieb Nicolas Saenz Julienne: >>>>>>>>> Hi all, >>>>>>>>> this series attempts to address some issues we found while bringing up >>>>>>>>> the new Raspberry Pi 4 in arm64 and it's intended to serve as a follow >>>>>>>>> up of these discussions: >>>>>>>>> v4: https://lkml.org/lkml/2019/9/6/352 >>>>>>>>> v3: https://lkml.org/lkml/2019/9/2/589 >>>>>>>>> v2: https://lkml.org/lkml/2019/8/20/767 >>>>>>>>> v1: https://lkml.org/lkml/2019/7/31/922 >>>>>>>>> RFC: https://lkml.org/lkml/2019/7/17/476 >>>>>>>>> >>>>>>>>> The new Raspberry Pi 4 has up to 4GB of memory but most peripherals can >>>>>>>>> only address the first GB: their DMA address range is >>>>>>>>> 0xc0000000-0xfc000000 which is aliased to the first GB of physical >>>>>>>>> memory 0x00000000-0x3c000000. Note that only some peripherals have these >>>>>>>>> limitations: the PCIe, V3D, GENET, and 40-bit DMA channels have a wider >>>>>>>>> view of the address space by virtue of being hooked up trough a second >>>>>>>>> interconnect. >>>>>>>>> >>>>>>>>> Part of this is solved on arm32 by setting up the machine specific >>>>>>>>> '.dma_zone_size = SZ_1G', which takes care of reserving the coherent >>>>>>>>> memory area at the right spot. That said no buffer bouncing (needed for >>>>>>>>> dma streaming) is available at the moment, but that's a story for >>>>>>>>> another series. >>>>>>>>> >>>>>>>>> Unfortunately there is no such thing as 'dma_zone_size' in arm64. Only >>>>>>>>> ZONE_DMA32 is created which is interpreted by dma-direct and the arm64 >>>>>>>>> arch code as if all peripherals where be able to address the first 4GB >>>>>>>>> of memory. >>>>>>>>> >>>>>>>>> In the light of this, the series implements the following changes: >>>>>>>>> >>>>>>>>> - Create both DMA zones in arm64, ZONE_DMA will contain the first 1G >>>>>>>>> area and ZONE_DMA32 the rest of the 32 bit addressable memory. So far >>>>>>>>> the RPi4 is the only arm64 device with such DMA addressing limitations >>>>>>>>> so this hardcoded solution was deemed preferable. >>>>>>>>> >>>>>>>>> - Properly set ARCH_ZONE_DMA_BITS. >>>>>>>>> >>>>>>>>> - Reserve the CMA area in a place suitable for all peripherals. >>>>>>>>> >>>>>>>>> This series has been tested on multiple devices both by checking the >>>>>>>>> zones setup matches the expectations and by double-checking physical >>>>>>>>> addresses on pages allocated on the three relevant areas GFP_DMA, >>>>>>>>> GFP_DMA32, GFP_KERNEL: >>>>>>>>> >>>>>>>>> - On an RPi4 with variations on the ram memory size. But also forcing >>>>>>>>> the situation where all three memory zones are nonempty by setting a 3G >>>>>>>>> ZONE_DMA32 ceiling on a 4G setup. Both with and without NUMA support. >>>>>>>>> >>>>>>>> i like to test this series on Raspberry Pi 4 and i have some questions >>>>>>>> to get arm64 running: >>>>>>>> >>>>>>>> Do you use U-Boot? Which tree? >>>>>>> If you want to use U-Boot, try v2019.10-rc4, it should have everything you need >>>>>>> to boot your kernel. >>>>>>> >>>>>> Ok, here is a thing. In the linux kernel we now use bcm2711 as SoC name, but the >>>>>> RPi4 devicetree provided by the FW uses mostly bcm2838. >>>>> Do you mean the DTB provided at runtime? >>>>> >>>>> You mean the merged U-Boot changes, doesn't work with my Raspberry Pi >>>>> series? >>>>> >>>>>> U-Boot in its default >>>>>> config uses the devicetree provided by the FW, mostly because this way you don't >>>>>> have to do anything to find out how many RAM you really have. Secondly because >>>>>> this will allow us, in the near future, to have one U-boot binary for both RPi3 >>>>>> and RPi4 (and as a side effect one binary for RPi1 and RPi2). >>>>>> >>>>>> Anyway, I found at least, that the following compatibles need to be added: >>>>>> >>>>>> "brcm,bcm2838-cprman" >>>>>> "brcm,bcm2838-gpio" >>>>>> >>>>>> Without at least the cprman driver update, you won't see anything. >>>>>> >>>>>> "brcm,bcm2838-rng200" is also a candidate. >>>>>> >>>>>> I also suppose we will need to add "brcm,bcm2838" to >>>>>> arch/arm/mach-bcm/bcm2711.c, but I haven't verified this. >>>>> How about changing this in the downstream kernel? Which is much easier. >>>> I'm not sure I understand what you want to say. My goal is to use the upstream >>>> kernel with the device tree blob provided by the FW. >>> The device tree blob you are talking is defined in this repository: >>> >>> https://github.com/raspberrypi/linux >>> >>> So the word FW is misleading to me. >>> >> No, it's part of >> https://github.com/raspberrypi/firmware.git >> file boot/bcm2711-rpi-4-b.dtb > The compiled DT blobs incl. the kernel image are stored in this artifact > repository. But the sources for the kernel and the DT are in the Linux > repo. This is necessary to be compliant to the GPL. Got it, thanks for clarifying. >> >>>> If you talk about the >>>> downstream kernel, I suppose you mean we should change this in the FW DT blob >>>> and in the downstream kernel. That would work for me. >>>> >>>> Did I understand you correctly? >>> Yes >>> >>> So i suggest to add the upstream compatibles into the repo mentioned above. >>> >>> Sorry, but in case you decided as a U-Boot developer to be compatible >>> with a unreviewed DT, we also need to make U-Boot compatible with >>> upstream and downstream DT blobs. >>> >> Well RPi3 is working with the DT blob provided by the FW, as I mentioned earlier >> if we can use this DTB we can work towards one binary that can boot both RPi3 >> and RPi4. On the other hand we can rely on the FW to detect the amount of memory >> our RPi4 has. >> >> That said, I agree that we should make sure that U-Boot can boot with both DTBs, >> the upstream one and the downstream. Now the question is how to get to this. I'm >> a bit puzzled that by talking about "unreviewed DT" you insinuate that bcm2711 >> compatible is already reviewed and can't be changed. From what I can see none of >> these compatibles got merged for now, so we are still at time to change them. > > Stephen Boyd was okay with clk changes except of a small nit. So i fixed > this is as he suggested in a separate series. Unfortunately this hasn't > be applied yet [1]. > > The i2c, pinctrl and the sdhci changes has been applied yet. > > In my opinion it isn't the job of the mainline kernel to adapt to a > vendor device tree. It's the vendor device tree which needs to be fixed. > I agree with that. But if we can make this easier by choosing a compatible which fits downstream without violating upstream and it makes sense with the naming scheme of the RPi, I think that's a good argument. > Sorry, but this is my holiday. I will back after the weekend. > Sure, enjoy. I'll be on travel for the next two weeks but will try to keep up with emails. Regards, Matthias > Best regards > Stefan > > [1] - https://www.spinics.net/lists/linux-clk/msg40534.html > >> >> Apart from the point Florian made, to stay consistent with the RPi SoC naming, >> it will save us work, both in the kernel and in U-Boot, as we would need to add >> both compatibles to the code-base. >> >> Regards, >> Matthias >> >>>>>> Regards, >>>>>> Matthias >>>>>> >>>>>>> Regards, >>>>>>> Matthias >>>>>>> >>>>>>>> Are there any config.txt tweaks necessary? >>>>>>>> >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> linux-arm-kernel mailing list >>>>>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >>>>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>>>>>> >>>>>> _______________________________________________ >>>>>> linux-arm-kernel mailing list >>>>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >>>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
