Re: [PATCH v2 10/10] PCI: keystone: Add support to build as a loadable module

[Siddharth Vadapalli <s-vadapalli@ti.com>]

On Sat, Sep 20, 2025 at 12:10:59AM +0530, Manivannan Sadhasivam wrote:
> On Fri, Sep 12, 2025 at 05:46:21PM +0530, Siddharth Vadapalli wrote:
> > The 'pci-keystone.c' driver is the application/glue/wrapper driver for the
> > Designware PCIe Controllers on TI SoCs. Now that all of the helper APIs
> > that the 'pci-keystone.c' driver depends upon have been exported for use,
> > enable support to build the driver as a loadable module.
> > 
> > Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
> > ---
> > 
> > v1: https://lore.kernel.org/r/20250903124505.365913-12-s-vadapalli@ti.com/
> > Changes since v1:
> > - Based on the feedback from Manivannan Sadhasivam <mani@kernel.org> at:
> >   https://lore.kernel.org/r/2gzqupa7i7qhiscwm4uin2jmdb6qowp55mzk7w4o3f73ob64e7@taf5vjd7lhc5/
> >   builtin_platform_driver() is being retained in the driver due to which
> >   the change made in the v1 patch of replacing builtin_platform_driver()
> >   with module_platform_driver() has been discarded in this patch.
> > 
> >  drivers/pci/controller/dwc/Kconfig        |  6 +++---
> >  drivers/pci/controller/dwc/pci-keystone.c | 22 ++++++++++++++++++++++
> >  2 files changed, 25 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> > index 34abc859c107..46012d6a607e 100644
> > --- a/drivers/pci/controller/dwc/Kconfig
> > +++ b/drivers/pci/controller/dwc/Kconfig
> > @@ -482,10 +482,10 @@ config PCI_DRA7XX_EP
> >  	  This uses the DesignWare core.
> >  
> >  config PCI_KEYSTONE
> > -	bool
> > +	tristate
> >  
> >  config PCI_KEYSTONE_HOST
> > -	bool "TI Keystone PCIe controller (host mode)"
> > +	tristate "TI Keystone PCIe controller (host mode)"
> >  	depends on ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
> >  	depends on PCI_MSI
> >  	select PCIE_DW_HOST
> > @@ -497,7 +497,7 @@ config PCI_KEYSTONE_HOST
> >  	  DesignWare core functions to implement the driver.
> >  
> >  config PCI_KEYSTONE_EP
> > -	bool "TI Keystone PCIe controller (endpoint mode)"
> > +	tristate "TI Keystone PCIe controller (endpoint mode)"
> >  	depends on ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
> >  	depends on PCI_ENDPOINT
> >  	select PCIE_DW_EP
> > diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
> > index e85942b4f6be..661e31b60a48 100644
> > --- a/drivers/pci/controller/dwc/pci-keystone.c
> > +++ b/drivers/pci/controller/dwc/pci-keystone.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/irqchip/chained_irq.h>
> >  #include <linux/irqdomain.h>
> >  #include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> >  #include <linux/msi.h>
> >  #include <linux/of.h>
> >  #include <linux/of_irq.h>
> > @@ -132,6 +133,7 @@ struct keystone_pcie {
> >  	struct			device_node *msi_intc_np;
> >  	struct irq_domain	*intx_irq_domain;
> >  	struct device_node	*np;
> > +	struct gpio_desc	*reset_gpio;
> >  
> >  	/* Application register space */
> >  	void __iomem		*va_app_base;	/* DT 1st resource */
> > @@ -1211,6 +1213,7 @@ static const struct of_device_id ks_pcie_of_match[] = {
> >  	},
> >  	{ },
> >  };
> > +MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
> >  
> >  static int ks_pcie_probe(struct platform_device *pdev)
> >  {
> > @@ -1329,6 +1332,7 @@ static int ks_pcie_probe(struct platform_device *pdev)
> >  			dev_err(dev, "Failed to get reset GPIO\n");
> >  		goto err_link;
> >  	}
> > +	ks_pcie->reset_gpio = gpiod;
> >  
> >  	/* Obtain references to the PHYs */
> >  	for (i = 0; i < num_lanes; i++)
> > @@ -1440,9 +1444,23 @@ static void ks_pcie_remove(struct platform_device *pdev)
> >  {
> >  	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
> >  	struct device_link **link = ks_pcie->link;
> > +	struct dw_pcie *pci = ks_pcie->pci;
> >  	int num_lanes = ks_pcie->num_lanes;
> > +	const struct ks_pcie_of_data *data;
> >  	struct device *dev = &pdev->dev;
> > +	enum dw_pcie_device_mode mode;
> > +
> > +	ks_pcie_disable_error_irq(ks_pcie);
> > +	data = of_device_get_match_data(dev);
> > +	mode = data->mode;
> > +	if (mode == DW_PCIE_RC_TYPE) {
> > +		dw_pcie_host_deinit(&pci->pp);
> > +	} else {
> > +		pci_epc_deinit_notify(pci->ep.epc);
> > +		dw_pcie_ep_deinit(&pci->ep);
> > +	}
> >  
> > +	gpiod_set_value_cansleep(ks_pcie->reset_gpio, 0);
> 
> Can ks_pcie_remove() be called for a builtin_platform_driver?

It cannot be executed but I have added it for the sake of completeness - in
the same manner that the initial implementation didn't simply make the
'ks_pcie_remove()' function a no-op and the code exists as if it could
be executed or if it were to be executed at some point in the future.

Regards,
Siddharth.