Subject: [PATCH v3 3/5] ARM: vexpress: Add DT support in v2m

From: [email-masked] (Dave Martin)
Date: Wed, 30 Nov 2011 15:58:00 +0000

On Tue, Nov 29, 2011 at 03:11:11PM +0000, Pawel Moll wrote:
> This patch provides hooks for DT-based tile machine implementations
> and adds Device Tree description for the motherboard.

[...]

> +config ARCH_VEXPRESS_DT
> +	bool
> +	select OF
> +	help
> +	  VE platform *requiring* Flattened Device Tree to boot.
> +

Now that a person may fail to boot on a supported board simply due to
failing to supply a device tree, it may be a good idea to have a more
helpful panic message for that situation, perhaps something like the
following.

If you don't think this fits in this series, I can always follow up 
later.

Cheers
---Dave

diff --git a/arch/arm/mach-vexpress/v2m.c b/arch/arm/mach-vexpress/v2m.c
index 6965f64..9dda482 100644
--- a/arch/arm/mach-vexpress/v2m.c
+++ b/arch/arm/mach-vexpress/v2m.c
@@ -434,8 +434,11 @@ static void __init v2m_populate_ct_desc(void)
 			ct_desc = ct_descs[i];
 
 	if (!ct_desc)
-		panic("vexpress: failed to populate core tile description "
-		      "for tile ID 0x%8x\n", current_tile_id);
+		panic("vexpress: this kernel does not support core tile ID "
+		      "0x%08x when booting via ATAGs.\n"
+		      "You may need a device tree blob or a different kernel "
+		      "to boot on this board.\n",
+		      current_tile_id);
 }
 
 static void __init v2m_map_io(void)