Re: [PATCH 00/28] Early flattened DT init consolidation

[James Hogan]

On 17/09/13 00:08, Rob Herring wrote:
> From: Rob Herring <rob.herring@xxxxxxxxxxx>
> 
> This is the first of 2 series to do some consolidation of per
> architecture Device Tree code. We now have 12 architectures with DT
> support. As new architectures have been added, much of the DT related
> code for the early flattened DT scanning has been duplicated. Yet little
> of this code is architecture specific. This series has 4 main parts:
> 
> - Create a common function to copy built-in dtb's out of init section
> - Create a single, common function to scan the FDT
> - Removal of early_init_dt_setup_initrd_arch
> - Create common functions for machine matching with DT
> 
> The entire series is available here:
> git://sources.calxeda.com/kernel/linux.git dt-cleanup

Hi Rob,

I gave this branch a try on metag.

The following patches break the build:
e09b397e of: only include prom.h on sparc
740de19c of: remove empty arch prom.h headers

because metag's prom.h has a setup_machine_fdt function declaration
which is used in arch/metag/kernel/setup.c (and defined in
arch/metag/kernel/devtree.c). Please move that declaration elsewhere
(asm/setup.h would seem appropriate) if you're going to remove prom.h.


Also I appear to hit the BUG_ON at
drivers/of/fdt.c:511/of_get_flat_dt_root().

This is because on metag we try interpreting the command line argument
as a device tree and only use the built-in DT if that fails. Previously
we relied on the be32_to_cpu(devtree->magic) != OF_DT_HEADER check in
setup_machine_fdt. The following seems to fix it:

diff --git a/arch/metag/kernel/devtree.c b/arch/metag/kernel/devtree.c
index abe607e..550dd91 100644
--- a/arch/metag/kernel/devtree.c
+++ b/arch/metag/kernel/devtree.c
@@ -52,7 +52,10 @@ struct machine_desc * __init setup_machine_fdt(void *dt)
 {
 	struct machine_desc *mdesc;

-	early_init_dt_scan(dt);
+	/* check device tree validity */
+	if (!early_init_dt_scan(dt))
+		return NULL;
+
 	mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
 	if (!mdesc)
 		dump_machine_table(); /* does not return */

Cheers
James

> 
> Compiled on arm, arm64, microblaze, mips, openrisc, powerpc, sparc,
> xtensa.
> 
> Rob
> 
> Rob Herring (28):
>   c6x: use boot_command_line instead of private c6x_command_line
>   openrisc: use boot_command_line instead of private cmd_line
>   of: create unflatten_and_copy_device_tree
>   arc: use unflatten_and_copy_device_tree
>   openrisc: use unflatten_and_copy_device_tree
>   x86: use unflatten_and_copy_device_tree
>   xtensa: use unflatten_and_copy_device_tree
>   metag: use unflatten_and_copy_device_tree
>   of: Introduce common early_init_dt_scan
>   arc: use early_init_dt_scan
>   arm: use early_init_dt_scan
>   arm64: use early_init_dt_scan
>   c6x: use early_init_dt_scan
>   microblaze: use early_init_dt_scan
>   mips: use early_init_dt_scan
>   openrisc: use early_init_dt_scan
>   xtensa: use early_init_dt_scan
>   of: create default early_init_dt_add_memory_arch
>   arm: set initrd_start/initrd_end for fdt scan
>   arm64: set initrd_start/initrd_end for fdt scan
>   of: remove early_init_dt_setup_initrd_arch
>   openrisc: remove unnecessary prom.c includes
>   of: introduce common FDT machine related functions
>   arc: use common of_flat_dt_match_machine
>   arm: use common of_flat_dt_match_machine
>   arm64: use common of_flat_dt_get_machine_name
>   metag: use common of_flat_dt_match_machine
>   mips: use common of_flat_dt_get_machine_name
> 
>  arch/arc/include/asm/mach_desc.h |   1 -
>  arch/arc/kernel/devtree.c        |  94 +++++++--------------------------
>  arch/arc/kernel/setup.c          |   3 +-
>  arch/arc/mm/init.c               |   7 ---
>  arch/arm/kernel/devtree.c        |  57 ++++++++------------
>  arch/arm/mm/init.c               |  13 ++---
>  arch/arm64/kernel/setup.c        |  60 ++-------------------
>  arch/arm64/mm/init.c             |  24 +++------
>  arch/c6x/include/asm/setup.h     |   2 -
>  arch/c6x/kernel/devicetree.c     |  29 ----------
>  arch/c6x/kernel/setup.c          |  13 +----
>  arch/metag/kernel/devtree.c      |  87 ++++++------------------------
>  arch/metag/kernel/setup.c        |   4 +-
>  arch/metag/mm/init.c             |   9 ----
>  arch/microblaze/kernel/prom.c    |  31 ++---------
>  arch/microblaze/kernel/setup.c   |   2 +-
>  arch/mips/include/asm/prom.h     |   3 --
>  arch/mips/kernel/prom.c          |  60 +--------------------
>  arch/openrisc/kernel/prom.c      |  70 +-----------------------
>  arch/openrisc/kernel/setup.c     |   6 +--
>  arch/powerpc/kernel/prom.c       |   9 ----
>  arch/x86/kernel/devicetree.c     |  42 +++------------
>  arch/xtensa/kernel/setup.c       |  55 +++++--------------
>  drivers/of/fdt.c                 | 111 +++++++++++++++++++++++++++++++++++++--
>  include/linux/of_fdt.h           |  18 +++----
>  25 files changed, 223 insertions(+), 587 deletions(-)
>

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