On Wed, Apr 06, 2022 at 01:01:06PM +0200, Felix Fietkau wrote: > > On 06.04.22 10:20, Krzysztof Kozlowski wrote: > > On 05/04/2022 21:57, Felix Fietkau wrote: > > > From: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> > > > > > > This patch adds the pcie mirror document bindings for MT7622 SoC. > > > The feature is used for intercepting PCIe MMIO access for the WED core > > > Add related info in mediatek-net bindings. > > > > > > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> > > > Signed-off-by: Felix Fietkau <nbd@xxxxxxxx> > > > --- > > > .../mediatek/mediatek,mt7622-pcie-mirror.yaml | 42 +++++++++++++++++++ > > > > Eh, I wanted to ask to not put it inside arm/, but judging by your usage > > - you did not create drivers for both of these (WED and PCIe mirror). > > > > You only need them to expose address spaces via syscon. > > > > This actually looks hacky. Either WED and PCIe mirror are part of > > network driver, then add the address spaces via "reg". If they are not, > > but instead they are separate blocks, why you don't have drivers for them? > The code that uses the WED block is built into the Ethernet driver, but not > all SoCs that use this ethernet core have it. Also, there are two WED > blocks, and I'm not sure if future SoCs might have a different number of > them at some point. > The WED code also needs to access registers of the ethernet MAC. > One reason for having a separate device is this: > As long as WED is not in use, ethernet supports coherent DMA for increased > performance. When the first wireless device attaches to WED, IO coherency > gets disabled and the ethernet DMA rings are cleaned up and allocated again, > this time with the struct device of WED (which doesn't have the dma-coherent > property). I'm pretty sure there are assumptions in the driver core that coherency is not changing on the fly. In any case, if it is, using 'dma-coherent' is not appropriate. You obviously have another method to determine whether you are coherent or not. Rob
