Date: Mon, 16 Mar 2015 14:42:04 -0700 From: Thomas Skibo <thomasskibo@sbcglobal.net> To: =?utf-8?Q?Mat=C3=ADas_Perret_Cantoni?= <perretcantonim@gmail.com> Cc: freebsd-arm@freebsd.org Subject: Re: hexdumping /dev/mem Message-ID: <29227F8C-4A83-4C95-9CD2-BA14E797A882@sbcglobal.net> In-Reply-To: <CADLKG01HXRf9FE0JZ3hDdr6Ap-AbLM0r3TmhfLNOfwAUUqmbdA@mail.gmail.com> References: <CADLKG01HXRf9FE0JZ3hDdr6Ap-AbLM0r3TmhfLNOfwAUUqmbdA@mail.gmail.com>
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> On Mar 16, 2015, at 1:00 PM, Mat=C3=ADas Perret Cantoni = <perretcantonim@gmail.com> wrote: >=20 > Hello! >=20 > I'm trying to read a 32 bit register of the System Level Control > Registers of the ZedBoard (Zynq-7000 SoC) from a running FreeBSD. I > thought that I could simply do it with hexdump(1) to avoid writing a > driver since I only need to read it once. I've tried: >=20 >=20 > #hexdump -s 0xF8000910 -n 4 /dev/mem >=20 >=20 > and I get this message: >=20 > hexdump: /dev/mem: Invalid argument >=20 >=20 > Reading some archives in this mailing list I've found that "the arm > version of /dev/mem is not functionally equivalent to that of amd64 or > i386. Arm disallows access to non-DRAM addresses through /dev/mem=E2=80= =9D. That=E2=80=99s correct. /dev/mem only reads from memory not devices. I always use kdb to peek/dump registers. You have to translate the = device addresses (use =E2=80=9Cshow devmap=E2=80=9D to see the = mappings). But, once you know the kernel virtual addresses of the registers, you = might be able to hexdump them through /dev/kmem. (I don=E2=80=99t have = a Zedboard in front of me to try that.) >=20 > Is there any other way of doing this? Maybe the whole idea of using > hexdump for this isn't really good. >=20 >=20 >=20 > Thanks in advance. > Regards, > Matias. > _______________________________________________ > freebsd-arm@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org" ------- Thomas Skibo thomasskibo@sbcglobal.net
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