[U-Boot] About convert to LIVE DT

[Dr. Philipp Tomsich <philipp.tomsich@theobroma-systems.com>]

Kever,

> On 13 Feb 2018, at 09:04, Kever Yang <kever.yang@rock-chips.com> wrote:
> 
> Simon,
> 
> 
> On 02/12/2018 10:35 PM, Simon Glass wrote:
>> Hi Kever,
>> 
>> On 4 February 2018 at 18:00, Kever Yang <kever.yang@rock-chips.com> wrote:
>>> 
>>> On 02/04/2018 09:40 PM, Simon Glass wrote:
>>>> Hi Kever,
>>>> 
>>>> On 4 February 2018 at 00:44, Kever Yang <kever.yang@rock-chips.com> wrote:
>>>>> Hi Simon, Philipp,
>>>>> 
>>>>>    When I try to convert to live dt, I fount there are many APIs work
>>>>> in fdt are missing in live dt,
>>>>> 
>>>>> do you have any suggestion to add these APIs in live dt quickly? I need:
>>>>> 
>>>>> fdtdec_get_addr_size_auto_noparent
>>>> dev_read_addr_size() - not having a parent doesn't happen with livetree
>>>> 
>>>>> fdt_alloc_phandle
>>>> We don't support changing the live tree yet.
>>>> 
>>>>> fdt_device_is_available
>>>> dev_read_enabled()
>>>> 
>>>>> fdt_for_each_subnode
>>>> dev_for_each_subnode()
>>>> 
>>>>> fdt_getprop
>>>> dev_read_prop()
>>>> 
>>>>> fdt_getprop_u32_default_node
>>>> This is an odd function. Can you first check that the property exists,
>>>> and then use a dev_read_...() function to read it?
>>>> 
>>>>> fdt_get_named_resource
>>>> dev_read_resource_byname()
>>>> 
>>>>> fdt_get_name
>>>> dev_read_name() - although I see that the comment is wrong
>>>> 
>>>>> fdt_get_path
>>>> Not available but you can add it
>>>> 
>>>>> fdt_get_phandle
>>>> Why do you need this?
>>> Most of the APIs are used in this file or other files in this folder,
>>> https://github.com/rockchip-linux/u-boot/blob/release/drivers/video/drm/rockchip_display.c
>>> It needs to handle quite complicated dts node for display system in
>>> rockchip drm display driver(not upstream yet):
>>> https://github.com/rockchip-linux/u-boot/blob/release/arch/arm/dts/rk3128.dtsi#L421
>>> https://github.com/rockchip-linux/u-boot/blob/release/arch/arm/dts/rk3126-bnd-d708.dts#L114
>> One difference I see with Linux is that U-Boot creates devices for all
>> nodes automatically, provided that they have a compatible string and
>> matching driver. This should simplify things in U-Boot.
>> 
>> The supernode-at-depth function looks like it just takes the parent of
>> the parent when an argument of -2 is used.
>> 
>> The existing rockchip driver in U-Boot handles a similar binding,
>> doesn't it? It has phandles and multiple nodes and subnodes.
> 
> Yes, but it does not able to migrate to support both live dt and fdt,
> because there is no same api in live dt, and here is what I do locally
> for live dt:
> 823                 phandle = ofnode_read_u32_default(node, "connect",
> -1);        
> 824                 if (phandle < 0)
> {                                             
> 825                         printf("Warn: can't find connect node's
> handle\n");    
> 826                        
> continue;                                              
> 827                
> }                                                              
> 828                 ep_node =
> of_find_node_by_phandle(phandle);                    
> 829                 if (!ofnode_valid(np_to_ofnode(ep_node)))
> {                    
> 830                         printf("Warn: can't find endpoint node from
> phandle\n");
> 831                        
> continue;                                              
> 832                
> }                                                              
> 833                 port_node =
> of_get_parent(ep_node);                            
> 834                 if (!ofnode_valid(np_to_ofnode(port_node)))
> {                  
> 835                         printf("Warn: can't find port node from
> phandle\n");   
> 836                        
> continue;                                              
> 837                
> }                                                              
> 838                 vop_node =
> of_get_parent(port_node);                           
> 839                 if (!ofnode_valid(np_to_ofnode(vop_node)))
> {                   
> 840                         printf("Warn: can't find crtc node from
> phandle\n");   
> 841                        
> continue;                                              
> 842                
> }                                                              
> 843                 ret =
> uclass_get_device_by_ofnode(UCLASS_VIDEO_CRTC,           
> 844                                                  
> np_to_ofnode(vop_node),      
> 845                                                   &crtc_dev);
> 
> In usb phy, we have similar requirement, but only need find "-1" depth
> parent.

Can you use dev_get_parent() to get the parent and then use dev_read_*()
on the parent?

> Thanks,
> - Kever
>> 
>>> Thanks,
>>> - Kever
>>>>> fdt_node_depth
>>>>> fdt_node_offset_by_phandle
>>>>> fdt_node_offset_by_phandle_node
>>>> uclass_get_device_by_phandle() or similar?
>>>> 
>>>>> fdt_path_offset
>>>> ofnode_path() although it does not return a device. Best avoided.
>>>> 
>>>>> fdt_set_phandle
>>>> You can't change the livtree at present.
>>>> 
>>>>> fdt_stringlist_get
>>>> dev_read_string_index()
>>>> 
>>>>> fdt_stringlist_search
>>>> dev_read_stringlist_search()
>>>> 
>>>>> fdt_subnode_offset
>>>> Why do you want that?
>>>> 
>>>>> fdt_supernode_atdepth_offset
>>>> This should be found by scanning, generally using separate drivers for
>>>> each DT node.
>>>> 
>>>> If you like you could send a patch with the info above, to
>>>> doc/driver-model/livetree.txt to help others.
>> Regards,
>> Simon