Re: [PATCH v2] alpha: fix nautilus PCI setup

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Mar 18, 2020 at 12:50:29AM +0000, Ivan Kokshaysky wrote:
> Example (hopefully reasonable) of the new "size_windows" flag usage.
> 
> Fixes accidental breakage caused by commit f75b99d5a77d (PCI: Enforce
> bus address limits in resource allocation),
> 
> Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>

Applied both of these to pci/resource for v5.7, thanks!

  086946bd47ba ("PCI: Add support for root bus sizing")
  a2b7f8c8d882 ("alpha: Fix nautilus PCI setup")

> ---
>  arch/alpha/kernel/sys_nautilus.c | 52 ++++++++++++++++------------------------
>  1 file changed, 20 insertions(+), 32 deletions(-)
> 
> diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c
> index cd9a112d67ff..32850e45834b 100644
> --- a/arch/alpha/kernel/sys_nautilus.c
> +++ b/arch/alpha/kernel/sys_nautilus.c
> @@ -187,10 +187,6 @@ nautilus_machine_check(unsigned long vector, unsigned long la_ptr)
>  
>  extern void pcibios_claim_one_bus(struct pci_bus *);
>  
> -static struct resource irongate_io = {
> -	.name	= "Irongate PCI IO",
> -	.flags	= IORESOURCE_IO,
> -};
>  static struct resource irongate_mem = {
>  	.name	= "Irongate PCI MEM",
>  	.flags	= IORESOURCE_MEM,
> @@ -208,17 +204,19 @@ nautilus_init_pci(void)
>  	struct pci_controller *hose = hose_head;
>  	struct pci_host_bridge *bridge;
>  	struct pci_bus *bus;
> -	struct pci_dev *irongate;
>  	unsigned long bus_align, bus_size, pci_mem;
>  	unsigned long memtop = max_low_pfn << PAGE_SHIFT;
> -	int ret;
>  
>  	bridge = pci_alloc_host_bridge(0);
>  	if (!bridge)
>  		return;
>  
> +	/* Use default IO. */
>  	pci_add_resource(&bridge->windows, &ioport_resource);
> -	pci_add_resource(&bridge->windows, &iomem_resource);
> +	/* Irongate PCI memory aperture, calculate requred size before
> +	   setting it up. */
> +	pci_add_resource(&bridge->windows, &irongate_mem);
> +
>  	pci_add_resource(&bridge->windows, &busn_resource);
>  	bridge->dev.parent = NULL;
>  	bridge->sysdata = hose;
> @@ -226,59 +224,49 @@ nautilus_init_pci(void)
>  	bridge->ops = alpha_mv.pci_ops;
>  	bridge->swizzle_irq = alpha_mv.pci_swizzle;
>  	bridge->map_irq = alpha_mv.pci_map_irq;
> +	bridge->size_windows = 1;
>  
>  	/* Scan our single hose.  */
> -	ret = pci_scan_root_bus_bridge(bridge);
> -	if (ret) {
> +	if (pci_scan_root_bus_bridge(bridge)) {
>  		pci_free_host_bridge(bridge);
>  		return;
>  	}
> -
>  	bus = hose->bus = bridge->bus;
>  	pcibios_claim_one_bus(bus);
>  
> -	irongate = pci_get_domain_bus_and_slot(pci_domain_nr(bus), 0, 0);
> -	bus->self = irongate;
> -	bus->resource[0] = &irongate_io;
> -	bus->resource[1] = &irongate_mem;
> -
>  	pci_bus_size_bridges(bus);
>  
> -	/* IO port range. */
> -	bus->resource[0]->start = 0;
> -	bus->resource[0]->end = 0xffff;
> -
> -	/* Set up PCI memory range - limit is hardwired to 0xffffffff,
> -	   base must be at aligned to 16Mb. */
> -	bus_align = bus->resource[1]->start;
> -	bus_size = bus->resource[1]->end + 1 - bus_align;
> +	/* Now we've got the size and alignment of PCI memory resources
> +	   stored in irongate_mem. Set up the PCI memory range: limit is
> +	   hardwired to 0xffffffff, base must be aligned to 16Mb. */
> +	bus_align = irongate_mem.start;
> +	bus_size = irongate_mem.end + 1 - bus_align;
>  	if (bus_align < 0x1000000UL)
>  		bus_align = 0x1000000UL;
>  
>  	pci_mem = (0x100000000UL - bus_size) & -bus_align;
> +	irongate_mem.start = pci_mem;
> +	irongate_mem.end = 0xffffffffUL;
>  
> -	bus->resource[1]->start = pci_mem;
> -	bus->resource[1]->end = 0xffffffffUL;
> -	if (request_resource(&iomem_resource, bus->resource[1]) < 0)
> +	/* Register our newly calculated PCI memory window in the resource
> +	   tree. */
> +	if (request_resource(&iomem_resource, &irongate_mem) < 0)
>  		printk(KERN_ERR "Failed to request MEM on hose 0\n");
>  
> +	printk(KERN_INFO "Irongate pci_mem %pR\n", &irongate_mem);
> +
>  	if (pci_mem < memtop)
>  		memtop = pci_mem;
>  	if (memtop > alpha_mv.min_mem_address) {
>  		free_reserved_area(__va(alpha_mv.min_mem_address),
>  				   __va(memtop), -1, NULL);
> -		printk("nautilus_init_pci: %ldk freed\n",
> +		printk(KERN_INFO "nautilus_init_pci: %ldk freed\n",
>  			(memtop - alpha_mv.min_mem_address) >> 10);
>  	}
> -
>  	if ((IRONGATE0->dev_vendor >> 16) > 0x7006)	/* Albacore? */
>  		IRONGATE0->pci_mem = pci_mem;
>  
>  	pci_bus_assign_resources(bus);
> -
> -	/* pci_common_swizzle() relies on bus->self being NULL
> -	   for the root bus, so just clear it. */
> -	bus->self = NULL;
>  	pci_bus_add_devices(bus);
>  }
>