[PATCH v3 4/4] PCI: j721e: Add support to build as a loadable module

[Siddharth Vadapalli]

On Thu, Apr 10, 2025 at 04:14:26PM +0530, Siddharth Vadapalli wrote:
> The 'pci-j721e.c' driver is the application/glue/wrapper driver for the
> Cadence PCIe Controllers on TI SoCs. Implement support for building it as a
> loadable module.
> 
> Signed-off-by: Siddharth Vadapalli <s-vadapalli at ti.com>
> ---
> 
> v2 of this patch is at:
> https://lore.kernel.org/r/20250330083914.529222-5-s-vadapalli@ti.com/
> Change since v2:
> - Dropped a delay before PERST assertion in the driver's remove callback
>   based on Mani's feedback at:
>   https://lore.kernel.org/r/zsxnx7biwogov5dw5yiafkgk6tsrtspac75bjbrca5uevweaim@ly67hwfyk7qh/
> 
>  drivers/pci/controller/cadence/Kconfig     |  6 ++---
>  drivers/pci/controller/cadence/pci-j721e.c | 31 +++++++++++++++++++++-
>  2 files changed, 33 insertions(+), 4 deletions(-)
> 

[...]

> diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
> index ef1cfdae33bb..51b09f70000c 100644
> --- a/drivers/pci/controller/cadence/pci-j721e.c
> +++ b/drivers/pci/controller/cadence/pci-j721e.c
> @@ -15,6 +15,7 @@
>  #include <linux/irqchip/chained_irq.h>
>  #include <linux/irqdomain.h>
>  #include <linux/mfd/syscon.h>
> +#include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/pci.h>
>  #include <linux/platform_device.h>
> @@ -27,6 +28,7 @@
>  #define cdns_pcie_to_rc(p) container_of(p, struct cdns_pcie_rc, pcie)
>  
>  #define ENABLE_REG_SYS_2	0x108
> +#define ENABLE_CLR_REG_SYS_2	0x308
>  #define STATUS_REG_SYS_2	0x508
>  #define STATUS_CLR_REG_SYS_2	0x708
>  #define LINK_DOWN		BIT(1)
> @@ -116,6 +118,15 @@ static irqreturn_t j721e_pcie_link_irq_handler(int irq, void *priv)
>  	return IRQ_HANDLED;
>  }
>  
> +static void j721e_pcie_disable_link_irq(struct j721e_pcie *pcie)
> +{
> +	u32 reg;
> +
> +	reg = j721e_pcie_intd_readl(pcie, ENABLE_CLR_REG_SYS_2);
> +	reg |= pcie->linkdown_irq_regfield;
> +	j721e_pcie_intd_writel(pcie, ENABLE_CLR_REG_SYS_2, reg);
> +}
> +
>  static void j721e_pcie_config_link_irq(struct j721e_pcie *pcie)
>  {
>  	u32 reg;
> @@ -633,9 +644,23 @@ static void j721e_pcie_remove(struct platform_device *pdev)
>  	struct j721e_pcie *pcie = platform_get_drvdata(pdev);
>  	struct cdns_pcie *cdns_pcie = pcie->cdns_pcie;
>  	struct device *dev = &pdev->dev;
> +	struct cdns_pcie_ep *ep;
> +	struct cdns_pcie_rc *rc;
> +
> +	if (pcie->mode == PCI_MODE_RC) {
> +		rc = container_of(cdns_pcie, struct cdns_pcie_rc, pcie);
> +		cdns_pcie_host_disable(rc);
> +	} else {
> +		ep = container_of(cdns_pcie, struct cdns_pcie_ep, pcie);
> +		cdns_pcie_ep_disable(ep);
> +	}
> +
> +	if (pcie->reset_gpio)
> +		gpiod_set_value_cansleep(pcie->reset_gpio, 1);

As Mani pointed out in the v2 series at:
https://lore.kernel.org/r/6bi5gul3sqvycmkf6cwokkvownjffaf2tkonjlefo2d7cautwx@uhfexzgz3okp/
for PERST# assert in the .remove callback, it should have been a 0
instead of a 1. I will fix this in the v4 series.

Regards,
Siddharth.