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From: Richard Retanubun <RichardRetanubun@RuggedCom.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] Cleanup the comment for m68k linux boot argument passing.
Date: Fri, 20 Feb 2009 11:34:06 -0500	[thread overview]
Message-ID: <499EDB7E.6050501@RuggedCom.com> (raw)
In-Reply-To: <a90206390902181607n3e9bd07awfcaa988102513fbf@mail.gmail.com>

 From e2e085f8b8e638762c59b0bc5376b241b0046132 Mon Sep 17 00:00:00 2001
From: Richard Retanubun <RichardRetanubun@RuggedCom.com>
Date: Fri, 20 Feb 2009 11:06:36 -0500
Subject: [PATCH] Cleanup the comment for m68k linux boot argument passing.


Signed-off-by: Richard Retanubun <RichardRetanubun@RuggedCom.com>
---
Hi Tsi-Chung,

Thanks for the response, I found the solution after using a hw debugger to
step through the code. The one gotcha here is that the assembly instruction
that the compiler uses to jump to the kernel is 'jsr' which puts the next
instruction after the jsr into the stack pointer so there is an 'off-by-one'
effect from the stack pointer.

This patch cleans up the comment to clarify the boot arg passing.
I'll try to push a patch for the kernel as well.

Thanks for your time

  lib_m68k/bootm.c |   11 ++++++-----
  1 files changed, 6 insertions(+), 5 deletions(-)
  mode change 100644 => 100755 lib_m68k/bootm.c

diff --git a/lib_m68k/bootm.c b/lib_m68k/bootm.c
old mode 100644
new mode 100755
index 0798e07..958c5ce
--- a/lib_m68k/bootm.c
+++ b/lib_m68k/bootm.c
@@ -111,11 +111,12 @@ int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)

  	/*
  	 * Linux Kernel Parameters (passing board info data):
-	 *   r3: ptr to board info data
-	 *   r4: initrd_start or 0 if no initrd
-	 *   r5: initrd_end - unused if r4 is 0
-	 *   r6: Start of command line string
-	 *   r7: End   of command line string
+	 *   sp+00: Ignore, side effect of using jsr to jump to kernel
+	 *   sp+04: ptr to board info data
+	 *   sp+08: initrd_start or 0 if no initrd
+	 *   sp+12: initrd_end - unused if initrd_start is 0
+	 *   sp+16: Start of command line string
+	 *   sp+20: End   of command line string
  	 */
  	(*kernel) (kbd, initrd_start, initrd_end, cmd_start, cmd_end);
  	/* does not return */
-- 
1.5.6.5

  reply	other threads:[~2009-02-20 16:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-13 16:57 [U-Boot] Coldfire: bootm: How does bootm pass bootargs to linux? Richard Retanubun
2009-02-19  0:07 ` TC Liew
2009-02-20 16:34   ` Richard Retanubun [this message]
2009-02-20 17:02     ` [U-Boot] [PATCH] Cleanup the comment for m68k linux boot argument passing Mike Frysinger
2009-02-20 17:15       ` Richard Retanubun
2009-02-20 17:22         ` [U-Boot] [PATCH V2] " Richard Retanubun
2009-02-20 17:41           ` Mike Frysinger
2009-02-20 18:01             ` Richard Retanubun
2009-02-21 22:50               ` Wolfgang Denk

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