[PATCH RFC v4 15/21] PCI: Allow the failed resources to be reassigned later

[Bjorn Helgaas]

On Mon, Mar 11, 2019 at 04:31:16PM +0300, Sergey Miroshnichenko wrote:
> Don't lose the size of the requested EP's BAR if it can't be fit
> in a current trial, so this can be retried.

s/EP/device/, since this applies equally to conventional PCI.

> But a failed bridge window must be dropped and recalculated in the
> next trial.
> 
> Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko at yadro.com>
> ---
>  drivers/pci/setup-bus.c |  3 ++-
>  drivers/pci/setup-res.c | 12 ++++++++++++
>  2 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index f9d605cd1725..c1559a4a8564 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -309,7 +309,8 @@ static void assign_requested_resources_sorted(struct list_head *head,
>  						    0 /* don't care */,
>  						    0 /* don't care */);
>  			}
> -			reset_resource(res);
> +			if (!pci_movable_bars_enabled())
> +				reset_resource(res);
>  		}
>  	}
>  }
> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
> index d8ca40a97693..732d18f60f1b 100644
> --- a/drivers/pci/setup-res.c
> +++ b/drivers/pci/setup-res.c
> @@ -298,6 +298,18 @@ static int _pci_assign_resource(struct pci_dev *dev, int resno,
>  
>  	bus = dev->bus;
>  	while ((ret = __pci_assign_resource(bus, dev, resno, size, min_align))) {
> +		if (pci_movable_bars_enabled()) {
> +			if (resno >= PCI_BRIDGE_RESOURCES &&
> +			    resno <= PCI_BRIDGE_RESOURCE_END) {
> +				struct resource *res = dev->resource + resno;
> +
> +				res->start = 0;
> +				res->end = 0;
> +				res->flags = 0;
> +			}
> +			break;
> +		}
> +
>  		if (!bus->parent || !bus->self->transparent)
>  			break;
>  		bus = bus->parent;
> -- 
> 2.20.1
>