On Wed, Mar 19, 2025 at 05:31:01PM +0800, Peter Chen wrote: > On 25-03-19 14:25:34, Siddharth Vadapalli wrote: > > > > > > > > Hello, > > > > > > > > This series enables support to build the PCIe Cadence Controller drivers > > > > and the PCI J721E Application/Wrapper/Glue driver as Loadable Kernel > > > > Modules. The motivation for this series is that PCIe is not a necessity > > > > for booting the SoC, due to which it doesn't have to be a built-in > > > > module. Additionally, the defconfig doesn't enable the PCIe Cadence > > > > Controller drivers and the PCI J721E driver, due to which PCIe is not > > > > supported by default. Enabling the configs as of now (i.e. without this > > > > series) will result in built-in drivers i.e. a bloated Linux Image for > > > > everyone who doesn't have the PCIe Controller. > > > > > > If the user doesn't enable PCIe controller device through DTS/ACPI, > > > that's doesn't matter. > > > > The Linux Image for arm64 systems built using: > > arch/arm64/configs/defconfig > > will not have support for the Cadence PCIe Controller and the PCIe J721e > > driver, because these configs aren't enabled. > > > > > > > > > @@ -209,6 +209,12 @@ CONFIG_NFC=m > > > > CONFIG_NFC_NCI=m > > > > CONFIG_NFC_S3FWRN5_I2C=m > > > > CONFIG_PCI=y > > > > +CONFIG_PCI_J721E=m > > > > +CONFIG_PCI_J721E_HOST=m > > > > +CONFIG_PCI_J721E_EP=m > > > > +CONFIG_PCIE_CADENCE=m > > > > +CONFIG_PCIE_CADENCE_HOST=m > > > > +CONFIG_PCIE_CADENCE_EP=m > > > > > > The common Cadence configuration will be select if the glue layer's > > > configuration is select according to Kconfig. > > > > > > Please do not set common configuration as module, some user may need > > > it as build-in like dw's. Considering the situation, the rootfs is at > > > NVMe. > > > > The common configuration at the moment is "DISABLED" i.e. no support for > > the Cadence Controller at all. Which "user" are you referring to? This > > series was introduced since having the drivers built-in was pushed back at: > > We are using Cadence controller, and prepare upstream radxa-o6 board > whose rootfs is at PCIe NVMe. > It doesn't matter. Only criteria AFAIK to build the driver as built-in in defconfig is that it should be a depedency for console. For some time, storage was also a dependency, but for sure PCIe is not. Moreover, CONFIG_BLK_DEV_NVME is built as a module in ARM64 defconfig. So it doesn't matter if you build PCIe controller driver as a built-in or not. You need to load the NVMe driver somehow. So please use initramfs. > You could build driver as module for TI glue layer, but don't force > other vendors using module as well, see dwc as an example please. > DWC is a bad example here. Only reason the DWC drivers are not loadable is due to the in-built MSI controller implementation as irqchip. People tend to build the irqchip controllers as always built-in for some known issues. Even then some driver developers prefer to built them as loadable module but suppress unbind to avoid rmmoding the module. - Mani -- மணிவண்ணன் சதாசிவம்
