Re: [PATCH v2] PCI: mvebu: Fix use of for_each_of_range() iterator

[Bjorn Helgaas <helgaas@kernel.org>]

On Sun, Sep 07, 2025 at 12:21:46PM +0200, Klaus Kudielka wrote:
> The blamed commit simplifies code, by using the for_each_of_range()
> iterator. But it results in no pci devices being detected anymore on
> Turris Omnia (and probably other mvebu targets).
> 
> Issue #1:
> 
> To determine range.flags, of_pci_range_parser_one() uses bus->get_flags(),
> which resolves to of_bus_pci_get_flags(). That function already returns an
> IORESOURCE bit field, and NOT the original flags from the "ranges"
> resource.
> 
> Then mvebu_get_tgt_attr() attempts the very same conversion again.
> But this is a misinterpretation of range.flags.
> 
> Remove the misinterpretation of range.flags in mvebu_get_tgt_attr(),
> to restore the intended behavior.
> 
> Issue #2:
> 
> The driver needs target and attributes, which are encoded in the raw
> address values of the "/soc/pcie/ranges" resource. According to
> of_pci_range_parser_one(), the raw values are stored in range.bus_addr
> and range.parent_bus_addr, respectively. range.cpu_addr is a translated
> version of range.parent_bus_addr, and not relevant here.
> 
> Use the correct range structure member, to extract target and attributes.
> This restores the intended behavior.
> 
> Signed-off-by: Klaus Kudielka <klaus.kudielka@gmail.com>
> Fixes: 5da3d94a23c6 ("PCI: mvebu: Use for_each_of_range() iterator for parsing "ranges"")
> Reported-by: Bjorn Helgaas <helgaas@kernel.org>
> Closes: https://lore.kernel.org/r/20250820184603.GA633069@bhelgaas/
> Reported-by: Jan Palus <jpalus@fastmail.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220479

Applied to for-linus for v6.17, thanks!

> ---
> v2: Fix issue #2, as well.
> 
>  drivers/pci/controller/pci-mvebu.c | 21 ++++-----------------
>  1 file changed, 4 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
> index 755651f338..a72aa57591 100644
> --- a/drivers/pci/controller/pci-mvebu.c
> +++ b/drivers/pci/controller/pci-mvebu.c
> @@ -1168,12 +1168,6 @@ static void __iomem *mvebu_pcie_map_registers(struct platform_device *pdev,
>  	return devm_ioremap_resource(&pdev->dev, &port->regs);
>  }
>  
> -#define DT_FLAGS_TO_TYPE(flags)       (((flags) >> 24) & 0x03)
> -#define    DT_TYPE_IO                 0x1
> -#define    DT_TYPE_MEM32              0x2
> -#define DT_CPUADDR_TO_TARGET(cpuaddr) (((cpuaddr) >> 56) & 0xFF)
> -#define DT_CPUADDR_TO_ATTR(cpuaddr)   (((cpuaddr) >> 48) & 0xFF)
> -
>  static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
>  			      unsigned long type,
>  			      unsigned int *tgt,
> @@ -1189,19 +1183,12 @@ static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
>  		return -EINVAL;
>  
>  	for_each_of_range(&parser, &range) {
> -		unsigned long rtype;
>  		u32 slot = upper_32_bits(range.bus_addr);
>  
> -		if (DT_FLAGS_TO_TYPE(range.flags) == DT_TYPE_IO)
> -			rtype = IORESOURCE_IO;
> -		else if (DT_FLAGS_TO_TYPE(range.flags) == DT_TYPE_MEM32)
> -			rtype = IORESOURCE_MEM;
> -		else
> -			continue;
> -
> -		if (slot == PCI_SLOT(devfn) && type == rtype) {
> -			*tgt = DT_CPUADDR_TO_TARGET(range.cpu_addr);
> -			*attr = DT_CPUADDR_TO_ATTR(range.cpu_addr);
> +		if (slot == PCI_SLOT(devfn) &&
> +		    type == (range.flags & IORESOURCE_TYPE_BITS)) {
> +			*tgt = (range.parent_bus_addr >> 56) & 0xFF;
> +			*attr = (range.parent_bus_addr >> 48) & 0xFF;
>  			return 0;
>  		}
>  	}
> -- 
> 2.50.1
>