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From: David Jander <david.jander@protonic•nl>
To: linuxppc-dev@ozlabs•org
Cc: David Miller <davem@davemloft•net>, wd@denx•de
Subject: Re: [PATCH 02/12] fs_enet: Add MPC5121 FEC support.
Date: Mon, 11 May 2009 08:56:58 +0200	[thread overview]
Message-ID: <200905110856.59043.david.jander@protonic.nl> (raw)
In-Reply-To: <20090508.005251.14244652.davem@davemloft.net>

On Friday 08 May 2009 09:52:51 David Miller wrote:
> From: John Rigby <jcrigby@gmail•com>
> Date: Thu, 7 May 2009 20:02:53 -0600
>
> > Also don't forget that the register map is the same on 512x, mx and
> > coldfire platforms but not on the other ppc platforms so if you want
> > to one binary to rule them all you will need to have an offest table
> > or some such.
>
> I would suggest using ->read_reg() ->write_reg() methods for abstracting
> this.  That's how we handle all of the different way ESP scsi chips
> have their registers wired up.
>
> I/O register reads take hundreds, if not thousands of CPU cycles so,
> relatively speaking, the indirection costs absolutely nothing.

I fear the memory-mapped I/O of the PowerPC SoC is *slightly* faster, so in 
terms of cycle count, this WILL matter, although depending on how much 
register-I/O the driver does, overall performance impact _may_ still be 
negligible. I suggest testing this (benchmarks) before and after the change.

Best regsards,

-- 
David Jander
Protonic Holland.

  reply	other threads:[~2009-05-11  6:56 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-06 20:15 [PATCH 00/16] Add support for MPC512x Wolfgang Denk
2009-05-06 20:15 ` [PATCH 01/12] fs_enet: Use defines to set driver tunables Wolfgang Denk
2009-05-06 20:35   ` Grant Likely
2009-05-06 22:02     ` Wolfgang Denk
2009-05-06 22:41       ` Grant Likely
2009-05-06 20:15 ` [PATCH 02/12] fs_enet: Add MPC5121 FEC support Wolfgang Denk
2009-05-06 20:33   ` Grant Likely
2009-05-06 21:08     ` Scott Wood
2009-05-06 22:01     ` Wolfgang Denk
2009-05-06 22:29       ` Grant Likely
2009-05-06 22:41         ` Wolfgang Denk
2009-05-07 14:09           ` Grant Likely
2009-05-08  2:02             ` John Rigby
2009-05-08  7:52               ` David Miller
2009-05-11  6:56                 ` David Jander [this message]
2009-05-07  8:14         ` David Jander
2009-05-07 13:05       ` Kumar Gala
2009-05-06 20:40   ` David Miller
2009-05-06 22:06     ` Wolfgang Denk
2009-05-06 20:41   ` Scott Wood
2009-05-06 22:09     ` Wolfgang Denk
2009-05-06 22:39       ` Grant Likely
2009-05-14 12:38         ` Piotr Zięcik
2009-05-14 14:00           ` Grant Likely
2009-05-18 22:17             ` Benjamin Herrenschmidt
2009-05-19 11:26               ` Piotr Zięcik
2009-05-19 21:56                 ` Benjamin Herrenschmidt
2009-05-21  8:34             ` Piotr Zięcik
2009-05-21 15:36               ` Grant Likely
2009-05-06 20:15 ` [PATCH 03/12] fs_enet: Add FEC TX Alignment workaround for MPC5121 Wolfgang Denk
2009-05-06 20:37   ` Grant Likely
2009-05-06 22:12     ` Wolfgang Denk
2009-05-06 22:42       ` Grant Likely
2009-05-08  2:36         ` John Rigby
2009-05-06 20:15 ` [PATCH 04/12] mpc5121: Added reset module registers representation Wolfgang Denk
2009-05-06 20:29   ` Scott Wood
2009-05-06 21:57     ` Wolfgang Denk
2009-05-06 20:39   ` Grant Likely
2009-05-06 22:14     ` Wolfgang Denk
2009-05-06 20:15 ` [PATCH 05/12] mpc5121ads: Added Reset Module node to DTS Wolfgang Denk
2009-05-06 20:40   ` Grant Likely
2009-05-06 22:16     ` Wolfgang Denk
2009-05-06 22:46       ` Grant Likely
2009-05-06 20:15 ` [PATCH 06/12] mpc5121: Added NAND Flash Controller driver Wolfgang Denk
2009-05-06 20:59   ` Grant Likely
2009-05-08  2:22     ` John Rigby
2009-05-08  3:07       ` Grant Likely
2009-05-07  8:08   ` David Jander
2009-05-08  3:30   ` John Rigby
2009-05-13  8:41     ` Piotr Zięcik
2009-05-06 20:15 ` [PATCH 07/12] mpc5121ads: Clean up and fix NAND description in mpc5121ads DTS Wolfgang Denk
2009-05-06 21:00   ` Grant Likely
2009-05-06 20:15 ` [PATCH 08/12] mpc5121: Added I2C support Wolfgang Denk
2009-05-06 21:01   ` Grant Likely
2009-05-06 22:19     ` Wolfgang Denk
2009-05-06 22:51       ` Grant Likely
2009-05-07  2:41         ` Grant Likely
2009-05-07  6:36           ` Wolfgang Grandegger
2009-05-18 13:57             ` Piotr Zięcik
2009-05-18 14:11               ` Grant Likely
2009-05-18 14:29               ` Wolfgang Grandegger
2009-05-19  7:47                 ` Piotr Zięcik
2009-05-19  8:10                   ` Wolfgang Grandegger
2009-05-08  2:12           ` John Rigby
2009-05-08  3:01             ` Grant Likely
2009-05-06 20:15 ` [PATCH 09/12] mpc5121ads: Added I2C RTC node to mpc5121ads DTS Wolfgang Denk
2009-05-06 21:02   ` Grant Likely
2009-05-07  6:45   ` Wolfgang Grandegger
2009-05-06 20:15 ` [PATCH 10/12] mpc5121: Add MPC5121 Real time clock driver Wolfgang Denk
2009-05-06 21:03   ` Grant Likely
2009-05-06 21:06   ` Wolfram Sang
2009-05-06 22:40     ` Grant Likely
2009-05-08  2:41       ` [rtc-linux] " John Rigby
2009-05-08 15:53         ` Grant Likely
2009-05-08 16:09           ` Alessandro Zummo
2009-05-08 19:18             ` Wolfgang Denk
2009-05-08 16:10           ` Alessandro Zummo
2009-05-06 20:15 ` [PATCH 11/12] mpc5121: Added MPC512x DMA driver Wolfgang Denk
2009-05-06 21:07   ` Grant Likely
2009-05-08  2:49     ` John Rigby
2009-05-19  1:37   ` Hongjun Chen
2009-05-19  8:03     ` Piotr Zięcik
2009-05-20  0:39       ` Hongjun Chen
2009-05-06 20:15 ` [PATCH 12/12] mpc5121: Added default config for MPC5121 Wolfgang Denk
2009-05-06 21:08   ` Grant Likely
2009-05-06 22:23     ` Wolfgang Denk
2009-05-06 22:48       ` Grant Likely

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