On Mon, May 27, 2024 at 06:14:27PM +0200, Herve Codina wrote: > Hi, > > This series adds support for the LAN966x chip when used as a PCI > device. > > For reference, the LAN996x chip is a System-on-chip that integrates an > Ethernet switch and a number of other traditional hardware blocks such > as a GPIO controller, I2C controllers, SPI controllers, etc. The > LAN996x can be used in two different modes: > > - With Linux running on its Linux built-in ARM cores. > This mode is already supported by the upstream Linux kernel, with the > LAN996x described as a standard ARM Device Tree in > arch/arm/boot/dts/microchip/lan966x.dtsi. Thanks to this support, > all hardware blocks in the LAN996x already have drivers in the > upstream Linux kernel. > > - As a PCI device, thanks to its built-in PCI endpoint controller. > In this case, the LAN996x ARM cores are not used, but all peripherals > of the LAN996x can be accessed by the PCI host using memory-mapped > I/O through the PCI BARs. > > This series aims at supporting this second use-case. As all peripherals > of the LAN996x already have drivers in the Linux kernel, our goal is to > re-use them as-is to support this second use-case. > > Therefore, this patch series introduces a PCI driver that binds on the > LAN996x PCI VID/PID, and when probed, instantiates all devices that are > accessible through the PCI BAR. As the list and characteristics of such > devices are non-discoverable, this PCI driver loads a Device Tree > overlay that allows to teach the kernel about which devices are > available, and allows to probe the relevant drivers in kernel, re-using > all existing drivers with no change. > > This patch series for now adds a Device Tree overlay that describes an > initial subset of the devices available over PCI in the LAN996x, and > follow-up patch series will add support for more once this initial > support has landed. > > In order to add this PCI driver, a number of preparation changes are > needed: > > - Patches 1 to 5 allow the reset driver used for the LAN996x to be > built as a module. Indeed, in the case where Linux runs on the ARM > cores, it is common to have the reset driver built-in. However, when > the LAN996x is used as a PCI device, it makes sense that all its > drivers can be loaded as modules. > > - Patches 6 and 7 improve the MDIO controller driver to properly > handle its reset signal. > > - Patches 8 to 12 introduce the internal interrupt controller used in > the LAN996x. It is one of the few peripherals in the LAN996x that > are only relevant when the LAN996x is used as a PCI device, which is > why this interrupt controller did not have a driver so far. > > - Patches 13 to 16 make some small additions to the OF core and > PCI/OF core to consider the PCI device as an interrupt controller. > This topic was previously mentioned in [1] to avoid the need of > phandle interrupt parents which are not available at some points. > > - Patches 17 and 18 introduce the LAN996x PCI driver itself, together > with its DT bindings. > > We believe all items from the above list can be merged separately, with > no build dependencies. We expect: > > - Patches 1 to 5 to be taken by reset maintainers > > - Patches 6 and 7 to be taken by network driver maintainers > > - Patches 8 to 12 to be taken by irqchip maintainers > > - Patch 13 to 17 to be taken by DT/PCI maintainers I've applied patches 13-17. Rob
