Hello Thomas, (sending this e-mail again because previously I sent it to Thomas' old e-mail address at free-electrons) we have enountered an issue with pci-mvebu driver and would like your opinion, since you are the author of commit https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f4ac99011e542d06ea2bda10063502583c6d7991 After upgrading to new version of U-Boot on a Armada XP / 38x device, some WiFi cards stopped working in kernel. Ath10k driver, for example, could not load firmware into the card. We discovered that the issue is caused by U-Boot: - when U-Boot's pci_mvebu driver was converted to driver model API, U-Boot started to configure PCIe registers not only for the newtork adapter, but also for the Marvell Memory Controller (that you are mentioning in your commit). - Since pci-mvebu driver in Linux is ignoring the Marvell Memory Controller device, and U-Boot configures its registers (BARs and what not), after kernel boots, the registers of this device are incompatible with kernel, or something, and this causes problems for the real PCIe device. - Stefan Roese has temporarily solved this issue with U-Boot commit https://gitlab.denx.de/u-boot/custodians/u-boot-marvell/-/commit/6a2fa284aee2981be2c7661b3757ce112de8d528 which basically just masks the Memory Controller's existence. - in Linux commit f4ac99011e54 ("pci: mvebu: no longer fake the slot location of downstream devices") you mention that: * On slot 0, a "Marvell Memory controller", identical on all PCIe interfaces, and which isn't useful when the Marvell SoC is the PCIe root complex (i.e, the normal case when we run Linux on the Marvell SoC). What we are wondering is: - what does the Marvell Memory controller really do? Can it be used to configure something? It clearly does something, because if it is configured in U-Boot somehow but not in kernel, problems can occur. - is the best solution really just to ignore this device? - should U-Boot also start doing what commit f4ac99011e54 does? I.e. to make sure that the real device is in slot 0, and Marvell Memory Controller in slot 1. - why is Linux ignoring this device? It isn't even listed in lspci output. Thanks, Marek
