On Wednesday 29 July 2020 12:48:09 Rob Herring wrote:
> On Wed, Jul 15, 2020 at 04:25:56PM +0200, Marek Behún wrote:
> > From: Pali Rohár <p...@kernel.org>
> >
> > 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 <p...@kernel.org>
> > Reviewed-by: Marek Behún <marek.be...@nic.cz>
> > ---
> > 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)?
Well, I'm not sure. I looked into other pci drivers and none of
following drivers pci-tegra.c, pcie-altera.c, pcie-brcmstb.c,
pcie-iproc.c, pcie-mediatek.c, pcie-rockchip-host.c calls
pci_lock_rescan_remove() and pci_unlock_rescan_remove().
Only pci-host-common.c and pci-hyperv.c protect pci_stop_root_bus() and
pci_remove_root_bus() by locks.
> 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.
Ok, I agree that some common function could be useful as the same code
(pci_stop_root_bus(); pci_remove_root_bus();) is called in more pci
drivers.
But first we need to know if locks are required or not.
> > +
> > + 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
> >
