[PATCH] arm: kirkwood: register DT devices earlier

[PATCH] arm: kirkwood: register DT devices earlier

[Thomas Petazzoni]

The board-dt.c initialization functions calls the per-board legacy
init functions (to probe devices that have not yet been converted to
the Device Tree) before probing the devices declared in the Device
Tree.

This unfortunately causes a boot crash on Topkick, because the
board-specific initialization function sets a GPIO to some
value. Unfortunately, since the devices declared in the Device Tree
haven't been probed, the GPIO controllers haven't been probed, and the
gpio_set_value() call causes the following crash:

Unable to handle kernel NULL pointer dereference at virtual address 00000040
pgd = c0004000
[00000040] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.7.0-rc7-01461-g2ef9d7a-dirty #91)
PC is at __gpio_set_value+0x20/0xb4
LR is at usi_topkick_init+0x18/0x2c

Therefore, we invert the order of initialization: we first probe
Device Tree devices, and then allow per-board initialization functions
to do add more devices if they wish.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 arch/arm/mach-kirkwood/board-dt.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
index ff4150a..d8a0275 100644
--- a/arch/arm/mach-kirkwood/board-dt.c
+++ b/arch/arm/mach-kirkwood/board-dt.c
@@ -97,6 +97,7 @@ static void __init kirkwood_dt_init(void)
 #ifdef CONFIG_KEXEC
 	kexec_reinit = kirkwood_enable_pcie;
 #endif
+	of_platform_populate(NULL, kirkwood_dt_match_table, NULL, NULL);
 
 	if (of_machine_is_compatible("globalscale,dreamplug"))
 		dreamplug_init();
@@ -146,8 +147,6 @@ static void __init kirkwood_dt_init(void)
 
 	if (of_machine_is_compatible("zyxel,nsa310"))
 		nsa310_init();
-
-	of_platform_populate(NULL, kirkwood_dt_match_table, NULL, NULL);
 }
 
 static const char * const kirkwood_dt_board_compat[] = {
-- 
1.7.9.5

[PATCH] arm: kirkwood: register DT devices earlier

[Andrew Lunn]

On Tue, Dec 18, 2012 at 03:07:47PM +0100, Thomas Petazzoni wrote:
> The board-dt.c initialization functions calls the per-board legacy
> init functions (to probe devices that have not yet been converted to
> the Device Tree) before probing the devices declared in the Device
> Tree.
> 
> This unfortunately causes a boot crash on Topkick, because the
> board-specific initialization function sets a GPIO to some
> value. Unfortunately, since the devices declared in the Device Tree
> haven't been probed, the GPIO controllers haven't been probed, and the
> gpio_set_value() call causes the following crash:

Hi Thomas

I have a different fix for this.

The gpio is being used to supply power to SATA. So i turn it into a
fixed-regulator, using DT.

I will send the patch tonight.

  Andrew

[PATCH] arm: kirkwood: register DT devices earlier

[Thomas Petazzoni]

Dear Andrew Lunn,

On Tue, 18 Dec 2012 15:19:02 +0100, Andrew Lunn wrote:

> I have a different fix for this.
> 
> The gpio is being used to supply power to SATA. So i turn it into a
> fixed-regulator, using DT.
> 
> I will send the patch tonight.

Indeed sounds a much better fix than mine. My patch posting was mainly
to raise the issue, and ensure we get some fix for it, I was quite sure
there was a better way of fixing this.

Thanks,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com