Subject: Re: [PATCH v6 39/42] drivers/of: Allow to specify root node in of_fdt_unflatten_tree()

From: Gavin Shan <[email-masked]>
Date: Tue, 11 Aug 2015 10:52:43 +1000

On Mon, Aug 10, 2015 at 03:42:13PM -0700, Frank Rowand wrote:
>On 8/5/2015 9:11 PM, Gavin Shan wrote:
>> This introduces one more argument to of_fdt_unflatten_tree()
>> to specify the root node for the FDT blob, which is going to be
>> unflattened. In the result, the function can be used to unflatten
>> FDT blob, which represents device sub-tree in PowerNV hotplug
>> driver.
>> 
>> Signed-off-by: Gavin Shan <[email-masked]>
>> ---
>>  drivers/of/fdt.c       | 13 ++++++++-----
>>  drivers/of/unittest.c  |  2 +-
>>  include/linux/of_fdt.h |  1 +
>>  3 files changed, 10 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
>> index a18a2ce..074870a 100644
>> --- a/drivers/of/fdt.c
>> +++ b/drivers/of/fdt.c
>> @@ -388,10 +388,11 @@ static void *unflatten_dt_node(const void *blob,
>>  			       struct device_node **nodepp,
>>  			       bool dryrun)
>>  {
>> +	unsigned long fpsize = dad ? strlen(of_node_full_name(dad)) : 0;
>>  	int depth = 1;
>>  
>>  	return __unflatten_dt_node(blob, mem, poffset,
>> -				   dad, nodepp, 0,
>> +				   dad, nodepp, fpsize,
>>  				   dryrun, &depth);
>>  }
>>  
>> @@ -408,6 +409,7 @@ static void *unflatten_dt_node(const void *blob,
>>   * for the resulting tree
>>   */
>>  static void __unflatten_device_tree(const void *blob,
>> +			     struct device_node *dad,
>>  			     struct device_node **mynodes,
>>  			     void * (*dt_alloc)(u64 size, u64 align))
>>  {
>
>Please add @dad to the documentation header for the function.
>

Yes, it will be included in next revision.

>> @@ -435,7 +437,7 @@ static void __unflatten_device_tree(const void *blob,
>>  	/* First pass, scan for size */
>>  	start = 0;
>>  	size = (unsigned long)unflatten_dt_node(blob, NULL, &start,
>> -						NULL, NULL, true);
>> +						dad, NULL, true);
>>  	size = ALIGN(size, 4);
>>  
>>  	pr_debug("  size is %lx, allocating...\n", size);
>> @@ -450,7 +452,7 @@ static void __unflatten_device_tree(const void *blob,
>>  
>>  	/* Second pass, do actual unflattening */
>>  	start = 0;
>> -	unflatten_dt_node(blob, mem, &start, NULL, mynodes, false);
>> +	unflatten_dt_node(blob, mem, &start, dad, mynodes, false);
>>  	if (be32_to_cpup(mem + size) != 0xdeadbeef)
>>  		pr_warning("End of tree marker overwritten: %08x\n",
>>  			   be32_to_cpup(mem + size));
>> @@ -472,9 +474,10 @@ static void *kernel_tree_alloc(u64 size, u64 align)
>>   * can be used.
>>   */
>>  void of_fdt_unflatten_tree(const unsigned long *blob,
>> +			struct device_node *dad,
>>  			struct device_node **mynodes)
>>  {
>> -	__unflatten_device_tree(blob, mynodes, &kernel_tree_alloc);
>> +	__unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc);
>>  }
>>  EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
>>  
>> @@ -1125,7 +1128,7 @@ bool __init early_init_dt_scan(void *params)
>>   */
>>  void __init unflatten_device_tree(void)
>>  {
>> -	__unflatten_device_tree(initial_boot_params, &of_root,
>> +	__unflatten_device_tree(initial_boot_params, NULL, &of_root,
>>  				early_init_dt_alloc_memory_arch);
>>  
>>  	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
>> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
>> index 1801634..2270830 100644
>> --- a/drivers/of/unittest.c
>> +++ b/drivers/of/unittest.c
>> @@ -907,7 +907,7 @@ static int __init unittest_data_add(void)
>>  			"not running tests\n", __func__);
>>  		return -ENOMEM;
>>  	}
>> -	of_fdt_unflatten_tree(unittest_data, &unittest_data_node);
>> +	of_fdt_unflatten_tree(unittest_data, NULL, &unittest_data_node);
>>  	if (!unittest_data_node) {
>>  		pr_warn("%s: No tree to attach; not running tests\n", __func__);
>>  		return -ENODATA;
>> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
>> index df9ef38..3644960 100644
>> --- a/include/linux/of_fdt.h
>> +++ b/include/linux/of_fdt.h
>> @@ -38,6 +38,7 @@ extern bool of_fdt_is_big_endian(const void *blob,
>>  extern int of_fdt_match(const void *blob, unsigned long node,
>>  			const char *const *compat);
>>  extern void of_fdt_unflatten_tree(const unsigned long *blob,
>> +			       struct device_node *dad,
>>  			       struct device_node **mynodes);
>>  
>>  /* TBD: Temporary export of fdt globals - remove when code fully merged */
>> 

Thanks,
Gavin