Re: [PATCH v2] PCI: mvebu: Fix duplicate resource requests

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Fri, Oct 23, 2020 at 09:52:52AM -0500, Rob Herring wrote:
> With commit 669cbc708122 ("PCI: Move DT resource setup into
> devm_pci_alloc_host_bridge()"), the DT 'ranges' is parsed and populated
> into resources when the host bridge is allocated. The resources are
> requested as well, but that happens a 2nd time for the mvebu driver in
> mvebu_pcie_parse_request_resources(). We should only be requesting the
> additional resources added in mvebu_pcie_parse_request_resources().
> These are not added by default because the use custom properties rather
> than standard DT address translation.
> 
> Also, the bus ranges was also populated by default, so we can remove
> it from mvebu_pci_host_probe().
> 
> Fixes: 669cbc708122 ("PCI: Move DT resource setup into devm_pci_alloc_host_bridge()")
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209729
> Reported-by: vtolkm@googlemail.com
> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: linux-pci@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
> v2:
>  - Fix copy-n-paste error with ioport_resource
> ---
>  drivers/pci/controller/pci-mvebu.c | 23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)

Hi Bjorn, strictly speaking, this bug was introduced in v5.9 - it would
be good to fix it in one of the upcoming -rc*:

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
> index c39978b750ec..653c0b3d2912 100644
> --- a/drivers/pci/controller/pci-mvebu.c
> +++ b/drivers/pci/controller/pci-mvebu.c
> @@ -960,25 +960,16 @@ static void mvebu_pcie_powerdown(struct mvebu_pcie_port *port)
>  }
>  
>  /*
> - * We can't use devm_of_pci_get_host_bridge_resources() because we
> - * need to parse our special DT properties encoding the MEM and IO
> - * apertures.
> + * devm_of_pci_get_host_bridge_resources() only sets up translateable resources,
> + * so we need extra resource setup parsing our special DT properties encoding
> + * the MEM and IO apertures.
>   */
>  static int mvebu_pcie_parse_request_resources(struct mvebu_pcie *pcie)
>  {
>  	struct device *dev = &pcie->pdev->dev;
> -	struct device_node *np = dev->of_node;
>  	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
>  	int ret;
>  
> -	/* Get the bus range */
> -	ret = of_pci_parse_bus_range(np, &pcie->busn);
> -	if (ret) {
> -		dev_err(dev, "failed to parse bus-range property: %d\n", ret);
> -		return ret;
> -	}
> -	pci_add_resource(&bridge->windows, &pcie->busn);
> -
>  	/* Get the PCIe memory aperture */
>  	mvebu_mbus_get_pcie_mem_aperture(&pcie->mem);
>  	if (resource_size(&pcie->mem) == 0) {
> @@ -988,6 +979,9 @@ static int mvebu_pcie_parse_request_resources(struct mvebu_pcie *pcie)
>  
>  	pcie->mem.name = "PCI MEM";
>  	pci_add_resource(&bridge->windows, &pcie->mem);
> +	ret = devm_request_resource(dev, &iomem_resource, &pcie->mem);
> +	if (ret)
> +		return ret;
>  
>  	/* Get the PCIe IO aperture */
>  	mvebu_mbus_get_pcie_io_aperture(&pcie->io);
> @@ -1001,9 +995,12 @@ static int mvebu_pcie_parse_request_resources(struct mvebu_pcie *pcie)
>  		pcie->realio.name = "PCI I/O";
>  
>  		pci_add_resource(&bridge->windows, &pcie->realio);
> +		ret = devm_request_resource(dev, &ioport_resource, &pcie->realio);
> +		if (ret)
> +			return ret;
>  	}
>  
> -	return devm_request_pci_bus_resources(dev, &bridge->windows);
> +	return 0;
>  }
>  
>  /*
> -- 
> 2.25.1
>