Re: [PATCH 4/5] PCI: aardvark: Implement driver 'remove' function and allow to build it as module

From: Rob Herring
Date: Wed Jul 29 2020 - 14:48:15 EST


On Wed, Jul 15, 2020 at 04:25:56PM +0200, Marek Behún wrote:
> From: Pali Rohár <pali@xxxxxxxxxx>
>
> Providing driver's 'remove' function allows kernel to bind and unbind devices
> from aardvark driver. It also allows to build aardvark driver as a module.
>
> Compiling aardvark as a module simplifies development and debugging of
> this driver as it can be reloaded at runtime without the need to reboot
> to new kernel.
>
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> Reviewed-by: Marek Behún <marek.behun@xxxxxx>
> ---
> drivers/pci/controller/Kconfig | 2 +-
> drivers/pci/controller/pci-aardvark.c | 25 ++++++++++++++++++++++---
> 2 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> index adddf21fa381..f9da5ff2c517 100644
> --- a/drivers/pci/controller/Kconfig
> +++ b/drivers/pci/controller/Kconfig
> @@ -12,7 +12,7 @@ config PCI_MVEBU
> select PCI_BRIDGE_EMUL
>
> config PCI_AARDVARK
> - bool "Aardvark PCIe controller"
> + tristate "Aardvark PCIe controller"
> depends on (ARCH_MVEBU && ARM64) || COMPILE_TEST
> depends on OF
> depends on PCI_MSI_IRQ_DOMAIN
> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index d5f58684d962..0a5aa6d77f5d 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -14,6 +14,7 @@
> #include <linux/irq.h>
> #include <linux/irqdomain.h>
> #include <linux/kernel.h>
> +#include <linux/module.h>
> #include <linux/pci.h>
> #include <linux/init.h>
> #include <linux/phy/phy.h>
> @@ -1114,6 +1115,7 @@ static int advk_pcie_probe(struct platform_device *pdev)
>
> pcie = pci_host_bridge_priv(bridge);
> pcie->pdev = pdev;
> + platform_set_drvdata(pdev, pcie);
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> pcie->base = devm_ioremap_resource(dev, res);
> @@ -1204,18 +1206,35 @@ static int advk_pcie_probe(struct platform_device *pdev)
> return 0;
> }
>
> +static int advk_pcie_remove(struct platform_device *pdev)
> +{
> + struct advk_pcie *pcie = platform_get_drvdata(pdev);
> + struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
> +
> + pci_stop_root_bus(bridge->bus);
> + pci_remove_root_bus(bridge->bus);

Based on pci_host_common_remove() implementation, doesn't this need a
lock around it (pci_lock_rescan_remove)?

We should probably have a common function (say pci_bridge_remove) to
implement this. You could use pci_host_common_remove(), but you'd have
to adjust drvdata.

> +
> + advk_pcie_remove_msi_irq_domain(pcie);
> + advk_pcie_remove_irq_domain(pcie);
> +
> + return 0;
> +}
> +
> static const struct of_device_id advk_pcie_of_match_table[] = {
> { .compatible = "marvell,armada-3700-pcie", },
> {},
> };
> +MODULE_DEVICE_TABLE(of, advk_pcie_of_match_table);
>
> static struct platform_driver advk_pcie_driver = {
> .driver = {
> .name = "advk-pcie",
> .of_match_table = advk_pcie_of_match_table,
> - /* Driver unloading/unbinding currently not supported */
> - .suppress_bind_attrs = true,
> },
> .probe = advk_pcie_probe,
> + .remove = advk_pcie_remove,
> };
> -builtin_platform_driver(advk_pcie_driver);
> +module_platform_driver(advk_pcie_driver);
> +
> +MODULE_DESCRIPTION("Aardvark PCIe controller");
> +MODULE_LICENSE("GPL v2");
> --
> 2.26.2
>