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From: cyril@ti•com (Cyril Chemparathy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 02/14] omap: Make uncompress code and DEBUG_LL code generic
Date: Fri, 30 Apr 2010 12:20:35 -0400	[thread overview]
Message-ID: <4BDB0353.5090800@ti.com> (raw)
In-Reply-To: <1272640022.3051.1534.camel@localhost>

Hi,

[...]
> To fix both problems, maybe we should just use a fixed memory location
> to pass this temporary data from uncompress to the kernel.  We've had a
> similar problem on DaVinci recently and a proposal has been made (and
> tested) to use memory just below the page tables[3].)

Essentially both of these approaches (internal scratch register and
fixed address) implement a weird back-channel communication scheme
between the decompresser and the debug macros.

A more elegant solution may be as follows:
    - pass machine_arch_type as an argument into addruart.
    - move the uart base lookup logic to addruart using macros similar
      to DEBUG_LL_*, except that these expand to assembly code this
      time.
    - reuse these debug-macros in uncompress.h and implement putc() and
      flush() using addruart(), senduart(), etc.

This way, both the decompresser and the kernel debug macros end up using
machine_arch_type to get to the right debug uart, without resorting to
underhand back-channel tricks.

Any thoughts?

-- Cyril.

  reply	other threads:[~2010-04-30 16:20 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-26 20:12 [PATCH 00/14] omap DEBUG_LL and multiboot changes for 2.6.34 Tony Lindgren
2010-01-26 20:12 ` [PATCH 01/14] omap: Clean the serial port defines Tony Lindgren
2010-01-26 20:12 ` [PATCH 02/14] omap: Make uncompress code and DEBUG_LL code generic Tony Lindgren
2010-04-29 14:44   ` Kevin Hilman
2010-04-30 15:07   ` Kevin Hilman
2010-04-30 16:20     ` Cyril Chemparathy [this message]
2010-04-30 16:49       ` Tony Lindgren
2010-04-30 17:18       ` Russell King - ARM Linux
2010-04-30 18:47         ` Tony Lindgren
2010-04-30 21:16           ` Kevin Hilman
2010-01-26 20:12 ` [PATCH 03/14] omap: Remove old DEBUG_LL serial port options Tony Lindgren
2010-01-26 20:12 ` [PATCH 04/14] omap2/3: Make get_irqnr_and_base common for mach-omap2 multiboot Tony Lindgren
2010-01-26 20:12 ` [PATCH 05/14] omap2/3: Multiboot compile fixes to compile in omap2 and omap3 Tony Lindgren
2010-01-26 20:12 ` [PATCH 06/14] omap: Fix dmtimer.c for multi-omap boot Tony Lindgren
2010-01-26 20:12 ` [PATCH 07/14] omap2/3/4: Fix omap2_map_common_io for multi-omap Tony Lindgren
2010-01-26 20:12 ` [PATCH 08/14] omap2/3/4: Fix mbox init " Tony Lindgren
2010-01-26 20:12 ` [PATCH 09/14] omap2: Convert ARCH_OMAP24XX to ARCH_OMAP2 Tony Lindgren
2010-01-26 20:12 ` [PATCH 10/14] omap3: Replace ARCH_OMAP34XX with ARCH_OMAP3 Tony Lindgren
2010-01-26 20:13 ` [PATCH 11/14] omap2/3/4: Replace orred CONFIG_ARCH_OMAP2/3/4 with CONFIG_ARCH_OMAP2PLUS Tony Lindgren
2010-01-26 20:13 ` [PATCH 12/14] omap2/3: Fix initcalls for multi-omap Tony Lindgren
     [not found]   ` <20100819090313.GC3003@shisha.kicks-ass.net>
2010-08-19  9:35     ` Tony Lindgren
2010-01-26 20:13 ` [PATCH 13/14] omap2/3: Fix powerdomain init for multiomap Tony Lindgren
2010-01-27  2:26   ` Paul Walmsley
2010-01-27  2:29     ` Tony Lindgren
2010-01-26 20:13 ` [PATCH 14/14] omap2/3: Update omap3_defconfig to build in all the 2420 based boards Tony Lindgren
2010-03-24 11:43 ` [PATCH 00/14] omap DEBUG_LL and multiboot changes for 2.6.34 Gadiyar, Anand
2010-04-01 12:13   ` Tony Lindgren

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