Date:	Thu, 13 Oct 2011 22:30:24 -0700
From:	Yinghai Lu <yinghai.lu@...cle.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
CC:	linux-pci@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Jesse Barnes <jbarnes@...tuousgeek.org>
Subject: Re: [PATCH v2 06/29] x86/PCI: convert to pci_create_root_bus() and
 pci_scan_root_bus()

On 10/13/2011 09:27 PM, Bjorn Helgaas wrote:

> x86 has two kinds of PCI root bus scanning:
> 
> (1) ACPI-based, using _CRS resources.  This used pci_create_bus() because
>     ACPI hotplug needed to split the pci_bus_add_devices() into a separate
>     .start() method.
> 
>     This patch parses the _CRS resources earlier, so we can build a list of
>     resources and pass it to pci_create_root_bus().
> 
>     Note that as before, we parse the _CRS even if we aren't going to use
>     it so we can print it for debugging purposes.
> 
> (2) All other, which used either default resources (ioport_resource and
>     iomem_resource) or information read from the hardware via amd_bus.c or
>     similar.  This used pci_scan_bus().
> 
>     This patch converts x86_pci_root_bus_res_quirks() (previously called
>     from pcibios_fixup_bus()) to x86_pci_root_bus_resources(), which builds
>     a list of resources before we call pci_scan_root_bus().
> 
>     We also use x86_pci_root_bus_resources() if we have ACPI but are
>     ignoring _CRS.
> 
> CC: Yinghai Lu <yinghai.lu@...cle.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> ---
>  arch/x86/include/asm/topology.h |    2 +-
>  arch/x86/pci/acpi.c             |   31 +++++++++++++++++--------------
>  arch/x86/pci/bus_numa.c         |   31 ++++++++++++++++++-------------
>  arch/x86/pci/common.c           |   21 ++++++++++++++-------
>  4 files changed, 50 insertions(+), 35 deletions(-)
> 
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index c006924..5f83b13 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -174,7 +174,7 @@ static inline void arch_fix_phys_package_id(int num, u32 slot)
>  }
>  
>  struct pci_bus;
> -void x86_pci_root_bus_res_quirks(struct pci_bus *b);
> +void x86_pci_root_bus_resources(int bus, struct list_head *resources);
>  
>  #ifdef CONFIG_SMP
>  #define mc_capable()	((boot_cpu_data.x86_max_cores > 1) && \
> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
> index 039d913..77bb332 100644
> --- a/arch/x86/pci/acpi.c
> +++ b/arch/x86/pci/acpi.c
> @@ -12,7 +12,7 @@ struct pci_root_info {
>  	char *name;
>  	unsigned int res_num;
>  	struct resource *res;
> -	struct pci_bus *bus;
> +	struct list_head *resources;
>  	int busnum;
>  };
>  
> @@ -250,23 +250,20 @@ static void add_resources(struct pci_root_info *info)
>  				 "ignoring host bridge window %pR (conflicts with %s %pR)\n",
>  				 res, conflict->name, conflict);
>  		else
> -			pci_bus_add_resource(info->bus, res, 0);
> +			pci_add_resource(info->resources, res);
>  	}
>  }
>  
>  static void
>  get_current_resources(struct acpi_device *device, int busnum,
> -			int domain, struct pci_bus *bus)
> +		      int domain, struct list_head *resources)
>  {
>  	struct pci_root_info info;
>  	size_t size;
>  
> -	if (pci_use_crs)
> -		pci_bus_remove_resources(bus);
> -
>  	info.bridge = device;
> -	info.bus = bus;
>  	info.res_num = 0;
> +	info.resources = resources;
>  	acpi_walk_resources(device->handle, METHOD_NAME__CRS, count_resource,
>  				&info);
>  	if (!info.res_num)
> @@ -275,7 +272,7 @@ get_current_resources(struct acpi_device *device, int busnum,
>  	size = sizeof(*info.res) * info.res_num;
>  	info.res = kmalloc(size, GFP_KERNEL);
>  	if (!info.res)
> -		goto res_alloc_fail;
> +		return;
>  
>  	info.name = kasprintf(GFP_KERNEL, "PCI Bus %04x:%02x", domain, busnum);
>  	if (!info.name)
> @@ -290,8 +287,6 @@ get_current_resources(struct acpi_device *device, int busnum,
>  
>  name_alloc_fail:
>  	kfree(info.res);
> -res_alloc_fail:
> -	return;
>  }
>  
>  struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
> @@ -299,6 +294,7 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
>  	struct acpi_device *device = root->device;
>  	int domain = root->segment;
>  	int busnum = root->secondary.start;
> +	struct list_head resources;
>  	struct pci_bus *bus;
>  	struct pci_sysdata *sd;
>  	int node;
> @@ -353,11 +349,18 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
>  		memcpy(bus->sysdata, sd, sizeof(*sd));
>  		kfree(sd);
>  	} else {
> -		bus = pci_create_bus(NULL, busnum, &pci_root_ops, sd);
> -		if (bus) {
> -			get_current_resources(device, busnum, domain, bus);
> -			bus->subordinate = pci_scan_child_bus(bus);
> +		INIT_LIST_HEAD(&resources);
> +		get_current_resources(device, busnum, domain, &resources);
> +		if (!pci_use_crs) {
> +			pci_free_resource_list(&resources);
> +			x86_pci_root_bus_resources(busnum, &resources);
>  		}


You may need to update get_current_resources() to return status about handling _CRS...
and check that status insteaf of !pci_use_crs.

Thanks


> +		bus = pci_create_root_bus(NULL, busnum, &pci_root_ops, sd,
> +					  &resources);
> +		if (bus)
> +			bus->subordinate = pci_scan_child_bus(bus);
> +		else
> +			pci_free_resource_list(&resources);
>  	}

>  

>  	/* After the PCI-E bus has been walked and all devices discovered,
> diff --git a/arch/x86/pci/bus_numa.c b/arch/x86/pci/bus_numa.c
> index 64a1228..fd3f655 100644
> --- a/arch/x86/pci/bus_numa.c
> +++ b/arch/x86/pci/bus_numa.c
> @@ -7,45 +7,50 @@
>  int pci_root_num;
>  struct pci_root_info pci_root_info[PCI_ROOT_NR];
>  
> -void x86_pci_root_bus_res_quirks(struct pci_bus *b)
> +void x86_pci_root_bus_resources(int bus, struct list_head *resources)
>  {
>  	int i;
>  	int j;
>  	struct pci_root_info *info;
>  
> -	/* don't go for it if _CRS is used already */
> -	if (b->resource[0] != &ioport_resource ||
> -	    b->resource[1] != &iomem_resource)
> -		return;
> -
>  	if (!pci_root_num)
> -		return;
> +		goto default_resources;
>  
>  	for (i = 0; i < pci_root_num; i++) {
> -		if (pci_root_info[i].bus_min == b->number)
> +		if (pci_root_info[i].bus_min == bus)
>  			break;
>  	}
>  
>  	if (i == pci_root_num)
> -		return;
> +		goto default_resources;
>  
> -	printk(KERN_DEBUG "PCI: peer root bus %02x res updated from pci conf\n",
> -			b->number);
> +	printk(KERN_DEBUG "PCI: root bus %02x: hardware-probed resources\n",
> +	       bus);
>  
> -	pci_bus_remove_resources(b);
>  	info = &pci_root_info[i];
>  	for (j = 0; j < info->res_num; j++) {
>  		struct resource *res;
>  		struct resource *root;
>  
>  		res = &info->res[j];
> -		pci_bus_add_resource(b, res, 0);
> +		pci_add_resource(resources, res);
>  		if (res->flags & IORESOURCE_IO)
>  			root = &ioport_resource;
>  		else
>  			root = &iomem_resource;
>  		insert_resource(root, res);
>  	}
> +	return;
> +
> +default_resources:
> +	/*
> +	 * We don't have any host bridge aperture information from the
> +	 * "native host bridge drivers," e.g., amd_bus or broadcom_bus,
> +	 * so fall back to the defaults historically used by pci_create_bus().
> +	 */
> +	printk(KERN_DEBUG "PCI: root bus %02x: using default resources\n", bus);
> +	pci_add_resource(resources, &ioport_resource);
> +	pci_add_resource(resources, &iomem_resource);
>  }
>  
>  void __devinit update_res(struct pci_root_info *info, resource_size_t start,
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index b389a2d..7f595cc 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -164,9 +164,6 @@ void __devinit pcibios_fixup_bus(struct pci_bus *b)
>  {
>  	struct pci_dev *dev;
>  
> -	/* root bus? */
> -	if (!b->parent)
> -		x86_pci_root_bus_res_quirks(b);
>  	pci_read_bridge_bases(b);
>  	list_for_each_entry(dev, &b->devices, bus_list)
>  		pcibios_fixup_device_resources(dev);
> @@ -433,6 +430,7 @@ void __init dmi_check_pciprobe(void)
>  
>  struct pci_bus * __devinit pcibios_scan_root(int busnum)
>  {
> +	struct list_head resources;
>  	struct pci_bus *bus = NULL;
>  	struct pci_sysdata *sd;
>  
> @@ -456,9 +454,13 @@ struct pci_bus * __devinit pcibios_scan_root(int busnum)
>  	sd->node = get_mp_bus_to_node(busnum);
>  
>  	printk(KERN_DEBUG "PCI: Probing PCI hardware (bus %02x)\n", busnum);
> -	bus = pci_scan_bus(busnum, &pci_root_ops, sd);
> -	if (!bus)
> +	INIT_LIST_HEAD(&resources);
> +	x86_pci_root_bus_resources(busnum, &resources);
> +	bus = pci_scan_root_bus(NULL, busnum, &pci_root_ops, sd, &resources);
> +	if (!bus) {
> +		pci_free_resource_list(&resources);
>  		kfree(sd);
> +	}
>  
>  	return bus;
>  }
> @@ -639,6 +641,7 @@ int pci_ext_cfg_avail(struct pci_dev *dev)
>  
>  struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops, int node)
>  {
> +	struct list_head resources;
>  	struct pci_bus *bus = NULL;
>  	struct pci_sysdata *sd;
>  
> @@ -653,9 +656,13 @@ struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops,
>  		return NULL;
>  	}
>  	sd->node = node;
> -	bus = pci_scan_bus(busno, ops, sd);
> -	if (!bus)
> +	INIT_LIST_HEAD(&resources);
> +	x86_pci_root_bus_resources(busno, &resources);
> +	bus = pci_scan_root_bus(NULL, busno, ops, sd, &resources);
> +	if (!bus) {
> +		pci_free_resource_list(&resources);
>  		kfree(sd);
> +	}
>  
>  	return bus;
>  }
> 


well, that will break 
arch/x86/pci/broadcom_bus.c

it is using

DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_LE,
                        cnb20le_res);


to fill pci_root_info...

need to update it to fill that array early.


amd_bus.c is using 
postcore_initcall(amd_postcore_init);

and my local intel_bus.c is using

/*
 * need to call it just after pci_arch_init
 * so we can have mmconf ready
 */
int __init intel_postarch_init(void)
{
        if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
                return 0;

        if (!pci_ext_cfg_avail(NULL))
                return 0;

        postarch_check_pci_devs();

        return 0;
}

so they are ok.

Thanks

Yinghai Lu
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