From: Scott Wood <scottwood@freescale.com>
To: Shawn Jin <shawnxjin@gmail.com>
Cc: ppcdev <linuxppc-dev@ozlabs.org>
Subject: Re: cpm_uart_console_write() stuck in waiting for transmitter fifo ready
Date: Mon, 19 Jul 2010 10:36:22 -0500 [thread overview]
Message-ID: <20100719103622.54158697@schlenkerla.am.freescale.net> (raw)
In-Reply-To: <AANLkTikyHvocHW6YzBPtxDrC9M5mih4ZpSoqo0mg6M1E@mail.gmail.com>
On Fri, 16 Jul 2010 17:30:01 -0700
Shawn Jin <shawnxjin@gmail.com> wrote:
> >> > My RCCR=3D0x1, meaning the first 512B is for microcode. So the data =
and
> >> > the TxBD should really be starting at 0xfa202200? Then my muram data=
's
> >> > reg should be <0x200 ?>? What size shall I specify?
> >>
> >> After the muram data's reg is changed to <0x200 0x1a00>, the cpm_uart
> >> driver works properly and the kernel messages are printed on the
> >> serial port.
> >
> > The muram node is supposed to show the portions of DPRAM that are
> > usable by the OS. =A0If some portion has been taken up by microcode (or
> > anything else not under the OS's control) before the OS has started,
> > then it must be excluded from the muram node.
>=20
> It would be nicer that the initialization code could query the RCCR
> value and adjust the base address.
Is that the only thing that could possibly conflict with OS usage of
DPRAM? It seemed simpler to just specify the usable chunks.
Before the kernel supported allocating CPM2 SMC parameter RAM, that was
another thing that firmware allocated that had to be kept out of the
muram node.
> It took me quite a while to understand the design.
Sorry...
This constraint is described in the MURAM section of
Documentation/powerpc/dts-bindings/fsl/cpm_qe/cpm.txt, though.
-Scott
prev parent reply other threads:[~2010-07-19 15:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-14 9:05 cpm_uart_console_write() stuck in waiting for transmitter fifo ready Shawn Jin
2010-07-15 22:33 ` Shawn Jin
2010-07-16 7:12 ` Shawn Jin
2010-07-16 18:13 ` Scott Wood
2010-07-17 0:30 ` Shawn Jin
2010-07-19 15:36 ` Scott Wood [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100719103622.54158697@schlenkerla.am.freescale.net \
--to=scottwood@freescale.com \
--cc=linuxppc-dev@ozlabs.org \
--cc=shawnxjin@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).