[U-Boot] [PATCH v7 00/15] SiFive FU540 Support

[Palmer Dabbelt]

On Mon, 11 Mar 2019 07:33:25 PDT (-0700), bmeng.cn at gmail.com wrote:
> On Thu, Feb 14, 2019 at 7:58 AM Kevin Hilman <khilman at baylibre.com> wrote:
>>
>> Kevin Hilman <khilman at baylibre.com> writes:
>>
>> > Hi Anup,
>> >
>> > Anup Patel <Anup.Patel at wdc.com> writes:
>> >
>> >> This patchset adds SiFive Freedom Unleashed (FU540) support
>> >> to RISC-V U-Boot.
>> >>
>> >> The patches are based upon latest U-Boot source tree
>> >> (git://git.denx.de/u-boot.git) at commit id
>> >> dbe70c7d4e3d5c705a98d82952e05a591efd0683
>> >>
>> >> All drivers namely: SiFive PRCI, SiFive Serial, and Cadance
>> >> MACB Ethernet work fine on actual SiFive Unleashed board and
>> >> QEMU sifive_u machine.
>> >
>> > I tested u-boot networking (DHCP, TFTP) on my desk with a gigE switch
>> > and it worked fine.  Then, I moved it to a lab with a 100Mb switch,
>> > and DHCP doesn't work anymore.
>>
>> And to be clear, neither does TFTP if setting static
>> ipaddr/netmask/gatewayip etc.
>
> Sound to me a bug of the GEM driver on SiFive FU540 board.

It looks to me like u-boot is missing a driver for the GEM clockmux in the 
FU540.  This is necessary to switch between the clock for 1G operation and 100M 
operation.  Without this you'll just get whatever clock was set up by the 
previous boot stage (or even worse, reset).