[U-Boot] [PATCH 4/6] dma: ti: add driver to K3 UDMA

[Vignesh R]

Tom,

On 23/01/19 4:05 PM, Peter Ujfalusi wrote:
> Tom,
> 
> On 22/01/2019 20.56, Tom Rini wrote:
>> On Tue, Jan 22, 2019 at 08:33:57PM +0530, Vignesh R wrote:
>>
>>> The UDMA-P is intended to perform similar (but significantly upgraded) functions
>>> as the packet-oriented DMA used on previous SoC devices. The UDMA-P module
>>> supports the transmission and reception of various packet types.
>>> The UDMA-P also supports acting as both a UTC and UDMA-C for its internal
>>> channels. Channels in the UDMA-P can be configured to be either Packet-Based or
>>> Third-Party channels on a channel by channel basis.
>>>
>>> The initial driver supports:
>>> - MEM_TO_MEM (TR mode)
>>> - DEV_TO_MEM (Packet mode)
>>> - MEM_TO_DEV (Packet mode)
>>>
>>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
>>> Signed-off-by: Grygorii Strashko <grygorii.strashko at ti.com>
>>> Signed-off-by: Vignesh R <vigneshr at ti.com>
>>
>> Reviewed-by: Tom Rini <trini at konsulko.com>
>>
>> And the DT binding is common to Linux, and been reviewed there?  Or?

As Peter pointed out DT bindings are not yet frozen and may change.
Hence, I have added the nodes in -u-boot.dtsi. As and when DT bindings
are accepted, these would be moved to base dtsi.

UDMA support in kernel is currently blocked due to on going discussions
on how UDMA/ring interrupts needs to be modeled and supported (not a so
important for U-Boot UDMA support). But, I submitted patches for U-Boot
as UDMA is support is required to support networking on AM654 which is
essential for ease of booting the platform with U-Boot.

> 
> The binding is the same for Linux but unfortunately it has not went
> through a proper review yet due to the fact that I need to wait for the
> interrupt support to arrive to mainline.
> 
> However I have sent an earlier version as RFC:
> https://www.spinics.net/lists/dmaengine/msg16661.html
> 
> As for the bindings (and code):
> The linux bindings are different:
> 
> - there is no ti,psi-proxy anymore.

Will drop this as U-Boot driver does not use them either.

> - ringacc uses tisci to get GP ring range and we need
>   ti,sci-rm-range-gp-rings property in DT for it
> - UDMA also uses tisci to get resource ranges and needs:
>   ti,sci-rm-range-tchan, ti,sci-rm-range-rchan, ti,sci-rm-range-rflow in DT
> - UDMA does not have/need dma-channels property

I plan to align above bindings with Linux as when bindings are accepted
into kernel and then port it to U-Boot along with relevant TI-SCI driver
code.

Meanwhile would it be acceptable to add these nodes in -u-boot.dtsi to
get closer to enable tftp?


-- 
Regards
Vignesh