From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: Grant Likely <grant.likely@secretlab•ca>
Cc: linuxppc-dev@ozlabs•org, Paul Mackerras <paulus@samba•org>,
John Linn <john.linn@xilinx•com>
Subject: Re: [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart 16550.
Date: Mon, 24 Mar 2008 19:15:55 +0300 [thread overview]
Message-ID: <47E7D3BB.1050403@ru.mvista.com> (raw)
In-Reply-To: <fa686aa40803240727p14c7e8c0r8575f7d5feb776dd@mail.gmail.com>
Grant Likely wrote:
>> >> > Personally, I'm not fond of this approach. There is already some
>> >> > traction to using the reg-shift property to specify spacing, and I
>> >> > think it would be appropriate to also define a reg-offset property to
>> >> > handle the +3 offset and then let the xilinx 16550 nodes use those.
>> >> Why do we need a reg-offset property when we can just add the offset
>> >> to the appropriate word(s) in the reg property?
>
>> > Primarily because the device creates 32 byte registers starting at 0;
>> > but they are also big-endian byte accessible so a byte read at offset
>> > 8 also works.
>> Probably I misunderstood you: does it give the same result as offset 11?
> er; typo; oops. A 32 bit read add offset 0 is the same as a byte read
> at offset *3*.
Oh, well... unfortunately, we can't use UPIO_MEM32 "register model" in
8250.c anyway since that makes use of readl()/writel() -- which treat the bus
as bigendian on PPC... anyway, we would need at least a "reg-size" property,
if not new "compatible"...
>> > reg-offset seems to be a better description of the hardware to me.
>> Have you considered using the existing "big-endian" property?
> No I haven't, but that would work too. I'm happy with that if it
> works for you. If the property was defined, then the byte offset to
> the first reg would be adjusted by 1^(reg-shift) - 1
You don't mean "xor" by ^, do you? :-O
In fact, it should be <<...
> Cheers,
> g.
WBR, Sergei
next prev parent reply other threads:[~2008-03-24 16:14 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <12060242324116-git-send-email-john.linn@xilinx.com>
2008-03-20 14:43 ` [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart 16550 John Linn
2008-03-21 0:19 ` Grant Likely
2008-03-21 9:21 ` Paul Mackerras
2008-03-21 11:39 ` Segher Boessenkool
2008-03-21 16:08 ` [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart16550 Stephen Neuendorffer
2008-03-21 16:48 ` Segher Boessenkool
2008-03-22 14:50 ` [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart 16550 Grant Likely
2008-03-22 16:06 ` Sergei Shtylyov
2008-03-24 14:09 ` Sergei Shtylyov
2008-03-24 14:27 ` Grant Likely
2008-03-24 16:15 ` Sergei Shtylyov [this message]
2008-03-24 16:48 ` Grant Likely
2008-03-24 17:03 ` Sergei Shtylyov
2008-03-25 22:48 ` John Linn
2008-03-21 13:00 ` Sergei Shtylyov
2008-03-21 15:37 ` Segher Boessenkool
2008-03-21 15:54 ` Sergei Shtylyov
2008-03-21 16:45 ` Segher Boessenkool
2008-03-21 16:50 ` [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart16550 Stephen Neuendorffer
2008-03-21 17:01 ` [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart 16550 Sergei Shtylyov
2008-03-22 15:06 ` Grant Likely
2008-03-22 16:40 ` Sergei Shtylyov
2008-03-21 16:14 ` [PATCH 2/3] [POWERPC] Xilinx: of_serial support for Xilinx uart16550 Stephen Neuendorffer
[not found] ` <1206024232655-git-send-email-john.linn@xilinx.com>
2008-03-20 14:43 ` [PATCH 3/3] [POWERPC] Xilinx: boot support for Xilinx uart 16550 John Linn
2008-03-20 14:54 ` Grant Likely
2008-03-20 16:15 ` John Linn
2008-03-20 21:18 ` Grant Likely
[not found] ` <20080320175601.5D86217C8055@mail127-sin.bigfish.com>
2008-03-20 21:07 ` Grant Likely
2008-03-20 22:04 ` Grant Likely
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=47E7D3BB.1050403@ru.mvista.com \
--to=sshtylyov@ru$(echo .)mvista.com \
--cc=grant.likely@secretlab$(echo .)ca \
--cc=john.linn@xilinx$(echo .)com \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=paulus@samba$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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