On Tue, Jan 23, 2024 at 10:46:39PM +0100, Krzysztof Kozlowski wrote: > On 23/01/2024 20:22, Frank Li wrote: > > On Tue, Jan 23, 2024 at 06:42:27PM +0000, Conor Dooley wrote: > >> On Tue, Jan 23, 2024 at 01:02:21PM -0500, Frank Li wrote: > >>> On Tue, Jan 23, 2024 at 05:51:48PM +0000, Conor Dooley wrote: > >>>> On Tue, Jan 23, 2024 at 12:49:27PM -0500, Frank Li wrote: > >>>>> On Tue, Jan 23, 2024 at 05:27:13PM +0000, Conor Dooley wrote: > >>>>>> On Tue, Jan 23, 2024 at 12:02:05PM -0500, Frank Li wrote: > >>>>>>> Add device tree binding allow platform overwrite default value of *REQIN in > >>>>>>> GSBUSCFG0. > >>>>>> > >>>>>> Why might a platform actually want to do this? Why does this need to be > >>>>>> set at the board level and being aware of which SoC is in use is not > >>>>>> sufficient for the driver to set the correct values? > >>>>> > >>>>> In snps,dwc3.yaml, there are already similary proptery, such as > >>>>> snps,incr-burst-type-adjustment. Use this method can keep whole dwc3 usb > >>>>> driver keep consistent. And not all platform try enable hardware > >>>>> dma_cohenrence. It is configable for difference platform. > >>>> > >>>> When you say "platform", what do you mean? I understand that term to > >>>> mean a combination of board, soc and firmware. > >>> > >>> In my company's environment, "platform" is "board". I will use "board" in > >>> future. Is it big difference here? > >> > >> Nah, that's close enough that it makes no difference here. > >> > >> I'd still like an explanation for why a platform would need to actually > >> set these properties though, and why information about coherency cannot > >> be determined from whether or not the boss the usb controller is on is > >> communicated to be dma coherent via the existing devicetree properties > >> for that purpose. > > > > Actually, I am not very clear about reason. I guest maybe treat off power > > consumption and performance. > > > > What's your judgement about proptery, which should be in dts. Such as > > reg, clk, reset, dma and irq, which is tighted with SOC. It is the fixed > > value for every SOC. The board dts never change these. > > Then it can be deduced from the compatible and there is no need for new > properties. Okay, I think "*reqinfo" match this. When new Soc(using compatible dwc usb controller) appear regardless dma-cohorence or not, connect by AXI3 or AXI4, needn't add new propterties. Frank > > Best regards, > Krzysztof >
