Re: [PATCH v9 19/30] powerpc/pci: Use pci_scan_host_bridge() for simplicity

Yijing Wang
2015-04-07T02:52:26Z

On 2015/4/7 7:35, Daniel Axtens wrote:
> I've been looking at this patch series for a while now, and I now
> believe it's ready on the PowerPC side.
>
> I was originally concerned that it would break odd corner cases,
> particularly where similar code appears (namely kernel/pci_hotplug.c and
> kernel/pci_of_scan.c). However, upon further examination, talking with
> Yijing, and some testing, I'm now convinced that it is indeed restricted
> to the generic code, and doesn't change behaviour.
>
> This is both a plus and a minus: because it's currently restricted to
> generic code, I'm confident it works, but the down side is that it
> doesn't yet simplify our arch-specific complexity. We'll need to do some
> more work on our side to reap the full benefits.
>
> I tested this entire series on a PowerNV machine, including doing EEH
> injection to trigger PCI hotplug:
> Tested-by: Daniel Axtens <dja@axtens.net>
> For completeness, it would be good to test it on Cell, as they are the
> only remaining user of pci_of_scan.c
>
> In conclusion, this patch is
> Reviewed-by: Daniel Axtens <dja@axtens.net>
>

Thanks very much for your test and review.

Thanks!
Yijing.

>
>
> On Fri, 2015-04-03 at 17:25 +0800, Yijing Wang wrote:
>> Now we could use pci_scan_host_bridge() to scan
>> pci buses, provide powerpc specific pci_host_bridge_ops.
>>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> CC: linuxppc-dev@lists.ozlabs.org
>> ---
>> arch/powerpc/kernel/pci-common.c | 62 +++++++++++++++++++++++--------------
>> 1 files changed, 38 insertions(+), 24 deletions(-)
>>
>> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
>> index 2c58200..50b32f6 100644
>> --- a/arch/powerpc/kernel/pci-common.c
>> +++ b/arch/powerpc/kernel/pci-common.c
>> @@ -773,6 +773,29 @@ void pcibios_set_root_bus_speed(struct pci_host_bridge *bridge)
>> return ppc_md.pcibios_set_root_bus_speed(bridge);
>> }
>>
>> +static int pci_host_scan_bus(struct pci_host_bridge *host)
>> +{
>> + int mode = PCI_PROBE_NORMAL;
>> + struct pci_bus *bus = host->bus;
>> + struct pci_controller *hose = dev_get_drvdata(&host->dev);
>> +
>> + /* Get probe mode and perform scan */
>> + if (hose->dn && ppc_md.pci_probe_mode)
>> + mode = ppc_md.pci_probe_mode(bus);
>> +
>> + pr_debug(" probe mode: %d\n", mode);
>> + if (mode == PCI_PROBE_DEVTREE)
>> + of_scan_bus(hose->dn, bus);
>> +
>> + if (mode == PCI_PROBE_NORMAL) {
>> + pci_bus_update_busn_res_end(bus, 255);
>> + hose->last_busno = pci_scan_child_bus(bus);
>> + pci_bus_update_busn_res_end(bus, hose->last_busno);
>> + }
>> +
>> + return pci_bus_child_max_busnr(bus);
>> +}
>> +
>> /* This header fixup will do the resource fixup for all devices as they are
>> * probed, but not for bridge ranges
>> */
>> @@ -1585,6 +1608,11 @@ struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus)
>> return of_node_get(hose->dn);
>> }
>>
>> +static struct pci_host_bridge_ops pci_host_ops = {
>> + .set_root_bus_speed = pcibios_set_root_bus_speed,
>> + .scan_bus = pci_host_scan_bus,
>> +};
>> +
>> /**
>> * pci_scan_phb - Given a pci_controller, setup and scan the PCI bus
>> * @hose: Pointer to the PCI host controller instance structure
>> @@ -1592,9 +1620,8 @@ struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus)
>> void pcibios_scan_phb(struct pci_controller *hose)
>> {
>> LIST_HEAD(resources);
>> - struct pci_bus *bus;
>> + struct pci_host_bridge *host;
>> struct device_node *node = hose->dn;
>> - int mode;
>>
>> pr_debug("PCI: Scanning PHB %s\n", of_node_full_name(node));
>>
>> @@ -1609,30 +1636,17 @@ void pcibios_scan_phb(struct pci_controller *hose)
>> hose->busn.flags = IORESOURCE_BUS;
>> pci_add_resource(&resources, &hose->busn);
>>
>> + pci_host_ops.pci_ops = hose->ops;
>> /* Create an empty bus for the toplevel */
>> - bus = pci_create_root_bus(hose->parent, hose->global_number,
>> - hose->first_busno, hose->ops, hose, &resources);
>> - if (bus == NULL) {
>> - pr_err("Failed to create bus for PCI domain %04x\n",
>> - hose->global_number);
>> + host = pci_scan_host_bridge(hose->parent, hose->global_number,
>> + hose->first_busno, hose, &resources, &pci_host_ops);
>> + if (host == NULL) {
>> + pr_err("Failed to create host bridge for pci%04x:%02x\n",
>> + hose->global_number, hose->first_busno);
>> pci_free_resource_list(&resources);
>> return;
>> }
>> - hose->bus = bus;
>> -
>> - /* Get probe mode and perform scan */
>> - mode = PCI_PROBE_NORMAL;
>> - if (node && ppc_md.pci_probe_mode)
>> - mode = ppc_md.pci_probe_mode(bus);
>> - pr_debug(" probe mode: %d\n", mode);
>> - if (mode == PCI_PROBE_DEVTREE)
>> - of_scan_bus(node, bus);
>> -
>> - if (mode == PCI_PROBE_NORMAL) {
>> - pci_bus_update_busn_res_end(bus, 255);
>> - hose->last_busno = pci_scan_child_bus(bus);
>> - pci_bus_update_busn_res_end(bus, hose->last_busno);
>> - }
>> + hose->bus = host->bus;
>>
>> /* Platform gets a chance to do some global fixups before
>> * we proceed to resource allocation
>> @@ -1641,9 +1655,9 @@ void pcibios_scan_phb(struct pci_controller *hose)
>> ppc_md.pcibios_fixup_phb(hose);
>>
>> /* Configure PCI Express settings */
>> - if (bus && !pci_has_flag(PCI_PROBE_ONLY)) {
>> + if (host->bus && !pci_has_flag(PCI_PROBE_ONLY)) {
>> struct pci_bus *child;
>> - list_for_each_entry(child, &bus->children, node)
>> + list_for_each_entry(child, &host->bus->children, node)
>> pcie_bus_configure_settings(child);
>> }
>> }
>

--
Thanks!
Yijing