[PATCH v3] of: Create asm-generic/of.h and provide default of_node_to_nid()

Grant Likely grant.likely at secretlab.ca
Tue Jul 27 08:42:20 EST 2010


On Mon, Jul 26, 2010 at 4:26 PM, Sam Ravnborg <sam at ravnborg.org> wrote:
> On Mon, Jul 26, 2010 at 04:04:55PM -0600, Grant Likely wrote:
>> of_node_to_nid() is only relevant in a few architectures.  Don't force
>> everyone to implement it anyway.  This patch also adds asm-generic/of.h
>> which will be used to contain other overrideable symbols.
>>
>> Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
>> ---
>>
>> Changes in v3: don't use asm-generic, just keep macros in of.h
>> Changes in v2: address comments from sfr, add asm-generic/of.h
>
> The use of asm-generic makes perfect sense.
> This is how we usually deal with arch specific stuff.
>
> With v3 of your patch we have a different result depending
> on if we do:
> #include <linux/of.h>
>
> or we do:
> #include <asm/prom.h>
>
> This is undesireable.

The patch does maintain consistency.  Including only asm/prom.h may
mean that of_node_to_nid is undefined, but it will never result in a
different definition.  linux/of.h includes asm/prom.h before doing the
#ifdef test.

> I suggest to go back to v2 of your patch where you use asm-generic/of.h.

Stephen suggested dropping asm-generic/of.h.  I'm happy to do it either way.

> linux/of.h shall include asm/of.h
> Then all archs shall have a of.h that may
> include the asm-generic variant.
>
>
> One patch to introduce of.h all over.
> And a second patch to do the of_node_to_nid stuff would be appropriate.
>
>
>> diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
>> index da7dd63..dca25a5 100644
>> --- a/arch/powerpc/include/asm/prom.h
>> +++ b/arch/powerpc/include/asm/prom.h
>> @@ -103,6 +103,11 @@ struct device_node *of_find_next_cache_node(struct device_node *np);
>>  /* Get the MAC address */
>>  extern const void *of_get_mac_address(struct device_node *np);
>>
>
> This shall go in asm/of.h
>> +#ifdef CONFIG_NUMA
>> +extern int of_node_to_nid(struct device_node *device);
>> +#define of_node_to_nid of_node_to_nid
>
> This define is used to tell asm-generic/of.h that the arch has
> a local definition - OK.
>
>> +#endif
>> +
>>  /**
>>   * of_irq_map_pci - Resolve the interrupt for a PCI device
>>   * @pdev:    the device whose interrupt is to be resolved
>
>> diff --git a/include/linux/of.h b/include/linux/of.h
>> index b0756f3..cc936ca 100644
>> --- a/include/linux/of.h
>> +++ b/include/linux/of.h
>> @@ -146,6 +146,11 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
>>
>>  #define OF_BAD_ADDR  ((u64)-1)
>>
>> +#ifndef of_node_to_nid
>> +static inline int of_node_to_nid(struct device_node *np) { return 0; }
>> +#define of_node_to_nid of_node_to_nid
>
> But I fail to see the purpose of this define.

It protects against some later include file doing a #define
of_node_to_nid and thus resulting in an inconsistent definition.  If
some code tries to do this then the preprocessor will complain.  This
is the pattern that Stephen suggested.

g.


More information about the Linuxppc-dev mailing list