linux-kernel - Re: [PATCH v4 01/18] of/platform: Add common method to populate default bus

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Date:	Thu, 26 May 2016 15:43:00 +0800
From:	Kefeng Wang <wangkefeng.wang@...wei.com>
To:	Rob Herring <robh+dt@...nel.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Arnd Bergmann <arnd@...db.de>,
	"Shawn Guo" <shawnguo@...nel.org>,
	Catalin Marinas <catalin.marinas@....com>,
	"Grant Likely" <grant.likely@...aro.org>,
	Olof Johansson <olof@...om.net>,
	"Russell King - ARM Linux" <linux@....linux.org.uk>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Hanjun Guo <guohanjun@...wei.com>,
	"Frank Rowand" <frowand.list@...il.com>
Subject: Re: [PATCH v4 01/18] of/platform: Add common method to populate
 default bus



On 2016/5/25 22:46, Rob Herring wrote:
> On Thu, May 12, 2016 at 7:05 AM, Kefeng Wang <wangkefeng.wang@...wei.com> wrote:
>> The arch code calls of_platform_populate() with default match table
>> when it want to populate default bus.
>>
>> This patch introduce a new of_platform_default_populate_init() and make it
>> arch_initcall_sync(it should be later than some iommu configration, eg,
>> of_iommu_init() and swiotlb_late_init in arm64), then we can finish above
>> job in common method.
>>
>> In order to avoid the default bus being populated twice, simply checking
>> the flag of bus node whether has be set OF_POPULATED_BUS or not.
>>
>> After that, we can safely remove the caller in arch code.
>>
>> Btw, add debug print in of_platform_populate(), and use __func__ to
>> print function's name of of_platform_bus_create().
>>
>> Cc: Rob Herring <robh+dt@...nel.org>
>> Cc: Frank Rowand <frowand.list@...il.com>
>> Cc: Grant Likely <grant.likely@...aro.org>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
>> ---
>>  drivers/of/platform.c | 23 ++++++++++++++++++++++-
>>  1 file changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>> index 8d103e4..f601b30 100644
>> --- a/drivers/of/platform.c
>> +++ b/drivers/of/platform.c
>> @@ -11,6 +11,7 @@
>>   *  2 of the License, or (at your option) any later version.
>>   *
>>   */
>> +#include <linux/acpi.h>
>>  #include <linux/errno.h>
>>  #include <linux/module.h>
>>  #include <linux/amba/bus.h>
>> @@ -345,6 +346,12 @@ static int of_platform_bus_create(struct device_node *bus,
>>                 return 0;
>>         }
>>
>> +       if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
>> +               pr_debug("%s() - skipping %s, already populated\n",
>> +                       __func__, bus->full_name);
>> +               return 0;
>> +       }
>> +
>>         auxdata = of_dev_lookup(lookup, bus);
>>         if (auxdata) {
>>                 bus_id = auxdata->name;
>> @@ -396,7 +403,7 @@ int of_platform_bus_probe(struct device_node *root,
>>         if (!root)
>>                 return -EINVAL;
>>
>> -       pr_debug("of_platform_bus_probe()\n");
>> +       pr_debug("%s()\n", __func__);
>>         pr_debug(" starting at: %s\n", root->full_name);
>>
>>         /* Do a self check of bus type, if there's a match, create children */
>> @@ -448,6 +455,9 @@ int of_platform_populate(struct device_node *root,
>>         if (!root)
>>                 return -EINVAL;
>>
>> +       pr_debug("%s()\n", __func__);
>> +       pr_debug(" starting at: %s\n", root->full_name);
>> +
>>         for_each_child_of_node(root, child) {
>>                 rc = of_platform_bus_create(child, matches, lookup, parent, true);
>>                 if (rc) {
>> @@ -471,6 +481,17 @@ int of_platform_default_populate(struct device_node *root,
>>  }
>>  EXPORT_SYMBOL_GPL(of_platform_default_populate);
>>
>> +static int __init of_platform_default_populate_init(void)
>> +{
>> +       if (of_have_populated_dt())
>> +               of_platform_default_populate(NULL, NULL, NULL);
>> +       else if (acpi_disabled)
> 
> This ACPI dependency needs to go. The error msg is somewhat pointless
> as if both DT and ACPI are not used, the boot will be horribly broken
> and I'm not sure that you would actually see the message given you
> have no information to setup a console.

Fair enough, will update and rebase patches after 4.7-rc1.

Thanks,
Kefeng

> 
> Rob
> 
> .
>