Re: [PATCH 3/6] PCI: generic: Quit clobbering our pci_ops.

[Will Deacon <will.deacon@arm.com>]

On Sat, Sep 12, 2015 at 12:21:56AM +0100, David Daney wrote:
> From: David Daney <david.daney@cavium.com>
> 
> The pci-host-generic driver keeps a global struct pci_ops which it
> then patches with the .map_bus method appropriate for the bus device.
> A problem arises when the driver is used for two different types of
> bus devices, the .map_bus method for the last device probed clobbers
> the method for all previous devices.  The result, only the last bus
> device probed has the proper .map_bus, and the others fail.
> 
> Move the struct pci_ops into the bus specific structure, and
> initialize it when the bus device is probed.  Keep a copy of the
> gen_pci_cfg_bus_ops structure, instead of a pointer to a global copy,
> to future proof against the addition of bus specific elements to
> struct pci_ops.

This looks ok to me:

  Acked-by: Will Deacon <will.deacon@arm.com>

Will

> Signed-off-by: David Daney <david.daney@cavium.com>
> ---
>  drivers/pci/host/pci-host-generic.c | 31 +++++++++++++++++--------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
> index a0fb241..cd6f898 100644
> --- a/drivers/pci/host/pci-host-generic.c
> +++ b/drivers/pci/host/pci-host-generic.c
> @@ -27,7 +27,7 @@
>  
>  struct gen_pci_cfg_bus_ops {
>  	u32 bus_shift;
> -	void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int);
> +	struct pci_ops ops;
>  };
>  
>  struct gen_pci_cfg_windows {
> @@ -35,7 +35,7 @@ struct gen_pci_cfg_windows {
>  	struct resource				*bus_range;
>  	void __iomem				**win;
>  
> -	const struct gen_pci_cfg_bus_ops	*ops;
> +	struct gen_pci_cfg_bus_ops		ops;
>  };
>  
>  /*
> @@ -65,7 +65,11 @@ static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
>  
>  static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = {
>  	.bus_shift	= 16,
> -	.map_bus	= gen_pci_map_cfg_bus_cam,
> +	.ops		= {
> +		.map_bus	= gen_pci_map_cfg_bus_cam,
> +		.read		= pci_generic_config_read,
> +		.write		= pci_generic_config_write,
> +	}
>  };
>  
>  static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
> @@ -80,12 +84,11 @@ static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
>  
>  static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
>  	.bus_shift	= 20,
> -	.map_bus	= gen_pci_map_cfg_bus_ecam,
> -};
> -
> -static struct pci_ops gen_pci_ops = {
> -	.read	= pci_generic_config_read,
> -	.write	= pci_generic_config_write,
> +	.ops		= {
> +		.map_bus	= gen_pci_map_cfg_bus_ecam,
> +		.read		= pci_generic_config_read,
> +		.write		= pci_generic_config_write,
> +	}
>  };
>  
>  static const struct of_device_id gen_pci_of_match[] = {
> @@ -175,7 +178,7 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
>  
>  	/* Limit the bus-range to fit within reg */
>  	bus_max = pci->cfg.bus_range->start +
> -		  (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
> +		  (resource_size(&pci->cfg.res) >> pci->cfg.ops.bus_shift) - 1;
>  	pci->cfg.bus_range->end = min_t(resource_size_t,
>  					pci->cfg.bus_range->end, bus_max);
>  
> @@ -193,7 +196,7 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
>  	bus_range = pci->cfg.bus_range;
>  	for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
>  		u32 idx = busn - bus_range->start;
> -		u32 sz = 1 << pci->cfg.ops->bus_shift;
> +		u32 sz = 1 << pci->cfg.ops.bus_shift;
>  
>  		pci->cfg.win[idx] = devm_ioremap(dev,
>  						 pci->cfg.res.start + busn * sz,
> @@ -240,8 +243,7 @@ static int gen_pci_probe(struct platform_device *pdev)
>  	}
>  
>  	of_id = of_match_node(gen_pci_of_match, np);
> -	pci->cfg.ops = of_id->data;
> -	gen_pci_ops.map_bus = pci->cfg.ops->map_bus;
> +	pci->cfg.ops = *(struct gen_pci_cfg_bus_ops *)of_id->data;
>  	pci->host.dev.parent = dev;
>  	INIT_LIST_HEAD(&pci->host.windows);
>  	INIT_LIST_HEAD(&pci->resources);
> @@ -262,7 +264,8 @@ static int gen_pci_probe(struct platform_device *pdev)
>  	if (!pci_has_flag(PCI_PROBE_ONLY))
>  		pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS);
>  
> -	bus = pci_scan_root_bus(dev, 0, &gen_pci_ops, pci, &pci->resources);
> +	bus = pci_scan_root_bus(dev, 0,
> +				&pci->cfg.ops.ops, pci, &pci->resources);
>  	if (!bus) {
>  		dev_err(dev, "Scanning rootbus failed");
>  		return -ENODEV;
> -- 
> 1.7.11.7
>