Patchwork [U-Boot,02/16] arch/arm/lib/bootm.c: Optionally use existing atags

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Submitter Pali Rohár
Date Dec. 17, 2011, 5:03 p.m.
Message ID <1324141398-14859-2-git-send-email-pali.rohar@gmail.com>
Download mbox | patch
Permalink /patch/132003/
State Changes Requested
Headers show

Comments

Pali Rohár - Dec. 17, 2011, 5:03 p.m.
This patch adapts the bootm command so that it can use an existing atags command
set up by a previous bootloader. If the environment variable "atagaddr" is unset,
bootm behaves as normal. If "atagaddr" is set, bootm will use atags address from
environment variable and also append new boot args (if specified in u-boot). For
example, if a previous boot loader already set up the atags struct at 0x80000100:

setenv atagaddr 0x80000100; bootm 0x80008000

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
---
 README               |    2 ++
 arch/arm/lib/bootm.c |   27 +++++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)
Mike Frysinger - Dec. 18, 2011, 6:54 p.m.
On Saturday 17 December 2011 12:03:04 Pali Rohár wrote:
> +	s = getenv ("atagaddr");

no space before the "("

>  #if defined (CONFIG_SETUP_MEMORY_TAGS) || \
>      defined (CONFIG_CMDLINE_TAG) || \
>      defined (CONFIG_INITRD_TAG) || \
>      defined (CONFIG_SERIAL_TAG) || \
>      defined (CONFIG_REVISION_TAG)
> ...
> +#if defined (CONFIG_SETUP_MEMORY_TAGS) || \
> +    defined (CONFIG_CMDLINE_TAG) || \
> +    defined (CONFIG_INITRD_TAG) || \
> +    defined (CONFIG_SERIAL_TAG) || \
> +    defined (CONFIG_REVISION_TAG)

rather than duplicating the same list in multiple places, why not setup a 
local define in this file and then use that everywhere else.
-mike
Pali Rohár - Dec. 18, 2011, 8:12 p.m.
On Sunday 18 December 2011 13:54:21 Mike Frysinger wrote:
> On Saturday 17 December 2011 12:03:04 Pali Rohár wrote:
> > +	s = getenv ("atagaddr");
> 
> no space before the "("
> 
> >  #if defined (CONFIG_SETUP_MEMORY_TAGS) || \
> >  
> >      defined (CONFIG_CMDLINE_TAG) || \
> >      defined (CONFIG_INITRD_TAG) || \
> >      defined (CONFIG_SERIAL_TAG) || \
> >      defined (CONFIG_REVISION_TAG)
> > 
> > ...
> > +#if defined (CONFIG_SETUP_MEMORY_TAGS) || \
> > +    defined (CONFIG_CMDLINE_TAG) || \
> > +    defined (CONFIG_INITRD_TAG) || \
> > +    defined (CONFIG_SERIAL_TAG) || \
> > +    defined (CONFIG_REVISION_TAG)
> 
> rather than duplicating the same list in multiple places, why not setup a
> local define in this file and then use that everywhere else.
> -mike

I will add local define CONFIG_ANY_TAG to bootm.c

+#if defined (CONFIG_SETUP_MEMORY_TAGS) || \
+    defined (CONFIG_CMDLINE_TAG) || \
+    defined (CONFIG_INITRD_TAG) || \
+    defined (CONFIG_SERIAL_TAG) || \
+    defined (CONFIG_REVISION_TAG)
+#define CONFIG_ANY_TAG
+#endif

Patch

diff --git a/README b/README
index ff72e47..3dd5a97 100644
--- a/README
+++ b/README
@@ -3564,6 +3564,8 @@  Some configuration options can be set using Environment Variables.
 
 List of environment variables (most likely not complete):
 
+  atagaddr	- bootm will use ATAGs struct from specified address (arm only)
+
   baudrate	- see CONFIG_BAUDRATE
 
   bootdelay	- see CONFIG_BOOTDELAY
diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index 802e833..4a3c423 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -125,12 +125,24 @@  int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
 	debug ("## Transferring control to Linux (at address %08lx) ...\n",
 	       (ulong) kernel_entry);
 
+	s = getenv ("atagaddr");
+	if (s) {
+		bd->bi_boot_params = simple_strtoul(s, NULL, 16);
+		printf("Using existing atags at %#x\n", bd->bi_boot_params);
+
+		params = (struct tag *) bd->bi_boot_params;
+		while (params->hdr.size > 0)
+			params = tag_next (params);
+	} else {
 #if defined (CONFIG_SETUP_MEMORY_TAGS) || \
     defined (CONFIG_CMDLINE_TAG) || \
     defined (CONFIG_INITRD_TAG) || \
     defined (CONFIG_SERIAL_TAG) || \
     defined (CONFIG_REVISION_TAG)
-	setup_start_tag (bd);
+		setup_start_tag (bd);
+	}
+#endif
+
 #ifdef CONFIG_SERIAL_TAG
 	setup_serial_tag (&params);
 #endif
@@ -147,8 +159,19 @@  int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
 	if (images->rd_start && images->rd_end)
 		setup_initrd_tag (bd, images->rd_start, images->rd_end);
 #endif
-	setup_end_tag(bd);
+
+	if (s) {
+		if (params->hdr.size > 0)
+			setup_end_tag(bd);
+	} else {
+#if defined (CONFIG_SETUP_MEMORY_TAGS) || \
+    defined (CONFIG_CMDLINE_TAG) || \
+    defined (CONFIG_INITRD_TAG) || \
+    defined (CONFIG_SERIAL_TAG) || \
+    defined (CONFIG_REVISION_TAG)
+		setup_end_tag(bd);
 #endif
+	}
 
 	announce_and_cleanup();