Date: Sat, 6 Aug 2016 22:07:03 -0400 From: Thomas Skibo <ThomasSkibo@yahoo.com> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: Zynq/Zybo USB bug: ubldr "fixes" my device tree Message-ID: <5C8C3F8B-A487-4239-A2ED-C24D7AE3AB57@yahoo.com> In-Reply-To: <CAJ-VmokhEeqyTpdhmZ7g-CPwe8M-0cHC9Q6ExAczAO1bS7CXrg@mail.gmail.com> References: <7C4D45AC-3DDB-46FE-85AB-5F692E5C1283@yahoo.com> <CAJ-VmokhEeqyTpdhmZ7g-CPwe8M-0cHC9Q6ExAczAO1bS7CXrg@mail.gmail.com>
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Done and patch committed! Sent from my iPhone > On Aug 6, 2016, at 9:54 PM, Adrian Chadd <adrian.chadd@gmail.com> wrote: >=20 > hi! >=20 > Cool! can you create a PR for that? >=20 >=20 > -adrian >=20 >=20 > On 31 July 2016 at 10:55, Thomas Skibo via freebsd-arm > <freebsd-arm@freebsd.org> wrote: >>=20 >> Hello. >>=20 >> I finally tracked down a bug that kept me from being able to use a USB dr= ive as root on a Zybo (or Zedboard). Mounting USB drives has worked fine be= fore but using one as root would fail. >>=20 >> The first megabyte of memory space on Zynq has several caveats including a= hole between 256K-512K that is inaccessible by bus masters. My solution wa= s to simply ignore the first megabyte by starting memory at 0x100000 in my D= TS file(s). But, I discovered that the first megabyte was being allocated a= nd the ehci device hung trying to DMA to the hole. It turns out that ubldr,= after loading the board.dtb file, proceeded to =E2=80=9Cfix up=E2=80=9D the= device tree from memory range information it got in a sysinfo call to u-boo= t=E2=80=99s API. The memory range started at 0. >>=20 >> The simplest work-around seems to be to add a =E2=80=9Cmemreserve=E2=80=9D= property to the DTS. Also, It turns out that only the first half megabyte n= eeds to be ignored. Patch attached. >>=20 >> =E2=80=94 >> Thomas Skibo >> thomasskibo@yahoo.com >>=20 >>=20 >>=20 >> _______________________________________________ >> freebsd-arm@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-arm >> To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"
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