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From: "John Zhou" <zjzhou@newrocktech.com>
To: <linuxppc-embedded@lists.linuxppc.org>
Cc: <wd@denx.de>
Subject: This question may be simple for you, but it doesn't let me sleeping.
Date: Wed, 13 Feb 2002 14:32:44 +0800	[thread overview]
Message-ID: <000301c1b458$3f342bf0$9f02a8c0@newrock2> (raw)
In-Reply-To: <20030807213228.A9194C59E4@atlas.denx.de>


Dear all,

This question may be simple for you, but it doesn't let me sleeping.

I have linux2.4.1 from Lineo runing on ppc8250, IMMR = 0xF0000000, in my driver function, I can directly access 0xF00xxxxx( internal memory area on PPC's chip), why? I think , in device driver, we also use logical memory, when accessing physical address, it should first map this address to be accessed by hardware. Is it right?

Another, I write a character driver to operate I2C device. When passing a logical address pointer to BD's address pointer that allocated by function kmalloc().  I can't correctly operate I2C device, But when I used free memory located in IMM ( 0xF00037C0 ~ 0xF00037F0  ) and directly pass this address to BD's buffer pointer, I can correctly operate I2C device. I also try to use function __pa() and virt_to_phys()  to map logical address to physical address, The driver still can't work OK.

Any comments and suggestions are appreciated!

John Zhou

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2002-02-13  6:32 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-08-05 18:37 debugging IBM405GP with abatron bdi 2000 Steven Blakeslee
2003-08-05 19:12 ` Wolfgang Denk
2003-08-06 14:52   ` MPC8250 MCC driver Adam Kaczynski
2002-02-07  3:21     ` kernel memory mapping problem ZhongJun Zhou
2002-02-07  4:24       ` John Zhou
2003-08-07 13:22         ` load_elf_bin problem dong in kang
2003-08-07 15:01       ` kernel memory mapping problem Peter Barada
2003-08-07 15:49         ` ZhongJun Zhou
2003-08-07 21:32           ` Wolfgang Denk
2002-02-13  6:32             ` John Zhou [this message]
2003-08-28  9:53               ` how to use busybox to make a ramdisk? John Zhou
2003-08-29 16:42                 ` Brian Padalino
2003-08-29 14:50                   ` Dan Kegel
2003-08-29 14:52                     ` Wolfgang Denk
2003-08-08 14:09             ` Does Linux kernel use paging or BAT registers before running the first user-level program "/bin/sh"? dong in kang
  -- strict thread matches above, loose matches on Subject: below --
2003-08-13 18:05 This question may be simple for you, but it doesn't let me sleeping Jean-Denis Boyer

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