From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from omta09.mta.everyone.net (sitemail2.everyone.net [216.200.145.36]) by ozlabs.org (Postfix) with ESMTP id C3643DDE3F for ; Tue, 22 Jan 2008 06:57:16 +1100 (EST) Message-ID: <4794F19A.30604@lpbroadband.net> Date: Mon, 21 Jan 2008 12:25:14 -0700 From: Frank Bennett MIME-Version: 1.0 To: "Benedict, Michael" Subject: Re: Early driver development resources References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------020107060008070705040403" Cc: linuxppc-embedded@ozlabs.org Reply-To: bennett78@lpbroadband.net List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multi-part message in MIME format. --------------020107060008070705040403 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Benedict, Michael wrote: > Hello, > I wrote a driver for a 4 segment digital display device. I have > a requirement that this device be used as early as possible to report > kernel bootup state. The driver itself is pretty simple, just using > in/out_be32() and udelay(). The problem is that I don't know how to use > hardware resources in the early stages of booting, before I can call > request_mem_region() and friends. > Can anyone recommend a book / documentation / reference code / > anything that demonstrates this, or at least could improve my > understanding enough to accomplish this? > u-boot for embedded (or OpenBios) documentation, source code. Look for splash screen code although you will want to make multiple calls for various boot states. In the ISA days and now PCI there are cards that display a two hex-digit POST progress code which is a single x86, 8bit output instruction to port 0x80. This may still be supported in closed source BIOS distributions. Not sure what they do now with PCIe since it will take more than a single, simple processor instruction. -Frank Bennett > Many thanks, > Michael > > _______________________________________________ > Linuxppc-embedded mailing list > Linuxppc-embedded@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-embedded > -- */Frank Bennett President/* Mathegraphics,LLC 613 Bentley Pl Fort Collins,CO 80526 970-229-9269 (hm) 970-402-9269 (cell) www.mathegraphics.com bennett78@lpbroadband.net "I think there's a world market for about five computers." -- attr. Thomas J. Watson (Chairman of the Board, IBM), 1943 --------------020107060008070705040403 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Benedict, Michael wrote:

Hello,
	I wrote a driver for a 4 segment digital display device.  I have
a requirement that this device be used as early as possible to report
kernel bootup state.  The driver itself is pretty simple, just using
in/out_be32() and udelay().  The problem is that I don't know how to use
hardware resources in the early stages of booting, before I can call
request_mem_region() and friends.
	Can anyone recommend a book / documentation / reference code /
anything that demonstrates this, or at least could improve my
understanding enough to accomplish this?

u-boot for embedded (or OpenBios) documentation, source code.
Look for splash screen code although you will want to make
multiple calls for various boot states. In the ISA days and now
PCI there are cards that display a two hex-digit POST progress
code which is a single x86, 8bit output instruction to port 0x80.
This may still be supported in closed source BIOS distributions.
Not sure what they do now with PCIe since it will take more than
a single, simple processor instruction.

-Frank Bennett

	Many thanks,
		Michael

_______________________________________________
Linuxppc-embedded mailing list
Linuxppc-embedded@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-embedded

--
sig

Frank Bennett
President

Mathegraphics,LLC
613 Bentley Pl
Fort Collins,CO 80526
970-229-9269 (hm) 970-402-9269 (cell)
www.mathegraphics.com
bennett78@lpbroadband.net

"I think there's a world market for about five computers."  
-- attr. Thomas J. Watson (Chairman of the Board, IBM), 1943

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