On Tue, 28 Apr 2015 09:29:56 +0200
, Paul Kocialkowski <contact@xxxxxxxx>
wrote:
> This grabs the serial number shown in cpuinfo from the serial-number devicetree
> property in priority. When booting with ATAGs (and without device-tree), the
> provided number is still shown instead.
>
> Signed-off-by: Paul Kocialkowski <contact@xxxxxxxx>
One comment below, but otherwise:
Acked-by: Grant Likely <grant.likely@xxxxxxxxxx>
> ---
> arch/arm/include/asm/system_info.h | 1 +
> arch/arm/kernel/setup.c | 23 +++++++++++++++++++++--
> 2 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/system_info.h b/arch/arm/include/asm/system_info.h
> index 720ea03..3860cbd40 100644
> --- a/arch/arm/include/asm/system_info.h
> +++ b/arch/arm/include/asm/system_info.h
> @@ -17,6 +17,7 @@
>
> /* information about the system we're running on */
> extern unsigned int system_rev;
> +extern const char *system_serial;
> extern unsigned int system_serial_low;
> extern unsigned int system_serial_high;
> extern unsigned int mem_fclk_21285;
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index 1d60beb..b501754 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -93,6 +93,9 @@ unsigned int __atags_pointer __initdata;
> unsigned int system_rev;
> EXPORT_SYMBOL(system_rev);
>
> +const char *system_serial;
> +EXPORT_SYMBOL(system_serial);
> +
Is there any need to export this symbol? It's only used by built-in
code. Not by modules.
> unsigned int system_serial_low;
> EXPORT_SYMBOL(system_serial_low);
>
> @@ -821,8 +824,25 @@ arch_initcall(customize_machine);
>
> static int __init init_machine_late(void)
> {
> + struct device_node *root;
> + int ret;
> +
> if (machine_desc->init_late)
> machine_desc->init_late();
> +
> + root = of_find_node_by_path("/");
> + if (root) {
> + ret = of_property_read_string(root, "serial-number",
> + &system_serial);
of_property_read_string() will not modify the argument on failure. If
system_serial is initialized to NULL, then the failure path is
unnecessary.
> + if (ret)
> + system_serial = NULL;
> + }
Calls to of_find_node* functions increment the refcount for the node.
Need an of_node_put() here, or just use the of_root pointer directly. It
is safe to call of_property_read_string() with a NULL node pointer too,
it will fail gracefully.
So, the whole thing can safely boil down to:
of_property_read_string(of_root, "serial-number", &system_serial);
if (!system_serial)
system_serial = kasprintf(GFP_KERNEL, "%08x%08x",
system_serial_high, system_serial_low);
g.
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