Re: [PATCH v2 4/5] PCI: designware: Add disable IO support

[Kumar Gala <galak@codeaurora.org>]

On Mar 16, 2015, at 9:20 AM, Gabriel FERNANDEZ <gabriel.fernandez@st.com> wrote:

> ST sti SoCs PCIe IPs are built around DesignWare IP Core.
> But in these SoCs PCIe IP doesn't support IO.
> 
> This patch adds the possibility to disable it through
> a DT property, by creating an empty IO window and by
> removing PCI_COMMAND_IO from the setup register.
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
> Signed-off-by: Gabriel Fernandez <gabriel.fernandez@linaro.org>
> ---
> .../devicetree/bindings/pci/designware-pcie.txt    |  2 ++
> drivers/pci/host/pcie-designware.c                 | 24 ++++++++++++++++++++--
> drivers/pci/host/pcie-designware.h                 |  1 +
> 3 files changed, 25 insertions(+), 2 deletions(-)

Why not just update the code such that if the ranges doesn’t have an IO space rather than introducing a new DT property?

- k

> 
> diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> index 9f4faa8..40544d4 100644
> --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> @@ -26,3 +26,5 @@ Optional properties:
> - bus-range: PCI bus numbers covered (it is recommended for new devicetrees to
>   specify this property, to keep backwards compatibility a range of 0x00-0xff
>   is assumed if not present)
> +- disable_io_support: set this property for PCIe host controller without IO
> +  port access
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index 1f4ea6f..f9d70f5 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -471,6 +471,9 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
> 		return -EINVAL;
> 	}
> 
> +	pp->disable_io_support = of_property_read_bool(np,
> +			"disable_io_support");
> +
> 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> 		if (!pp->ops->msi_host_init) {
> 			pp->irq_domain = irq_domain_add_linear(pp->dev->of_node,
> @@ -704,6 +707,7 @@ static struct pci_ops dw_pcie_ops = {
> static int dw_pcie_setup(int nr, struct pci_sys_data *sys)
> {
> 	struct pcie_port *pp;
> +	struct resource *res;
> 
> 	pp = sys_to_pcie(sys);
> 
> @@ -719,6 +723,18 @@ static int dw_pcie_setup(int nr, struct pci_sys_data *sys)
> 	pci_add_resource_offset(&sys->resources, &pp->mem, sys->mem_offset);
> 	pci_add_resource(&sys->resources, &pp->busn);
> 
> +	if (pp->disable_io_support) {
> +		/* This PCIe controller does not support IO, set an empty one */
> +		res = devm_kzalloc(pp->dev, sizeof(*res), GFP_KERNEL);
> +		if (res) {
> +			res->start = 0;
> +			res->end = 0;
> +			res->name = "PCIe empty IO space";
> +			res->flags = IORESOURCE_IO;
> +			pci_add_resource(&sys->resources, res);

Do we really need an empty resource?  What happens if we just dont have one?

> +		}
> +	}
> +
> 	return 1;
> }
> 
> @@ -822,8 +838,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
> 	/* setup command register */
> 	dw_pcie_readl_rc(pp, PCI_COMMAND, &val);
> 	val &= 0xffff0000;
> -	val |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
> -		PCI_COMMAND_MASTER | PCI_COMMAND_SERR;
> +
> +	if (!pp->disable_io_support)
> +		val |= PCI_COMMAND_IO;
> +
> +	val |= PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER | PCI_COMMAND_SERR;
> +
> 	dw_pcie_writel_rc(pp, val, PCI_COMMAND);
> }
> 
> diff --git a/drivers/pci/host/pcie-designware.h b/drivers/pci/host/pcie-designware.h
> index d0bbd27..027045d 100644
> --- a/drivers/pci/host/pcie-designware.h
> +++ b/drivers/pci/host/pcie-designware.h
> @@ -52,6 +52,7 @@ struct pcie_port {
> 	int			msi_irq;
> 	struct irq_domain	*irq_domain;
> 	unsigned long		msi_data;
> +	bool			disable_io_support;
> 	DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
> };
> 
> -- 
> 1.9.1
> 

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