Messages in this thread | | | Subject | Re: [RFC PATCH 2/3] RISC-V: Initial DTS for Microchip ICICLE board | From | Ben Dooks <> | Date | Tue, 3 Nov 2020 18:39:09 +0000 |
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On 03/11/2020 18:36, Atish Patra wrote: > On Tue, Nov 3, 2020 at 10:28 AM Ben Dooks <ben.dooks@codethink.co.uk> wrote: >> >> On 03/11/2020 18:10, Cyril.Jean@microchip.com wrote: >>> On 11/3/20 3:07 PM, Atish Patra wrote: >>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>>> >>>> On Fri, Oct 30, 2020 at 2:20 PM Ben Dooks <ben.dooks@codethink.co.uk> wrote: >> >> ,snip[ >> >>>>>> @Cyril : Can we enable both eMMC & sdcard at the same time ? >>>>> I would put /both/ in but only enable the one in use for the moment. >>>>> Our boards are booting of eMMC as supplied, so this isn't going to work >>>>> as well. The eMMC is 8bit wide, and thus is only delivering 11MB/sec >>>>> instead of 22MB/sec. This performance is still not great, but losing >>>>> half the data-rate is just not good. >>>>> >>>> I am not sure what should be enabled by default. Updating sdcard is much >>>> easier than eMMC card and we use that approach. >>>> >>>> @Cyril: Is there a way that we can enable both ? >>>> >>> Yes, we can enable both but this requires a modification to the FPGA >>> design. One of the guys prototyped this while I was away. We will move >>> this along. This will require reprogramming the FPGA with a new design >>> and HSS version. >>> >>> Regards, >>> >>> Cyril. >> >> I either missed or couldn't find a way of forcing the boot mode to be >> from the SD slot. Have I missed something? At the moment we'd like to >> have more storage available as the ~7G free on the eMMC is not enough. >> > > I use tftpboot to load the kernel & DT from the network. SD card is > enabled in this DT and Linux > kernel uses SD slot instead of eMMC. > > To summarize, eMMC is used for HSS & U-Boot while SD card is used for > Linux which makes > more storage available to Linux. > > IMO, we should enable the sdcard for Linux DT until updated FPGA > design & HSS is available.
Interesting as for me the default is for Linux to use the eMMC as well. I can't see any way for forcing the selection lines in the DT to say eMMC vs SD.
If there is a way of controlling the selection lines then it might be possible to have both cards enabled with a bus selection MUX in software.
-- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius
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