Message ID | 20240527161450.326615-1-herve.codina@bootlin.com (mailing list archive) |
---|---|
Headers | show |
Series | Add support for the LAN966x PCI device using a DT overlay | expand |
On Mon, 27 May 2024 18:14:27 +0200 Herve Codina wrote:
> - Patches 6 and 7 to be taken by network driver maintainers
Could you repost these two separately and address the nit from
Krzysztof? Easier for us to apply that way.
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