From b97ea289cf6aff8d4cbcefe2b707bb9b00a73c73 Mon Sep 17 00:00:00 2001 From: Yijing Wang Date: Mon, 16 Mar 2015 11:18:56 +0800 Subject: PCI: Assign resources before drivers claim devices (pci_scan_root_bus()) Previously, pci_scan_root_bus() created a root PCI bus, enumerated the devices on it, and called pci_bus_add_devices(), which made the devices available for drivers to claim them. Most callers assigned resources to devices after pci_scan_root_bus() returns, which may be after drivers have claimed the devices. This is incorrect; the PCI core should not change device resources while a driver is managing the device. Remove pci_bus_add_devices() from pci_scan_root_bus() and do it after any resource assignment in the callers. Note that ARM's pci_common_init_dev() already called pci_bus_add_devices() after pci_scan_root_bus(), so we only need to remove the first call: pci_common_init_dev pcibios_init_hw pci_scan_root_bus pci_bus_add_devices # first call pci_bus_assign_resources pci_bus_add_devices # second call [bhelgaas: changelog, drop "root_bus" var in alpha common_init_pci(), return failure earlier in mn10300, add "return" in x86 pcibios_scan_root(), return early if xtensa platform_pcibios_fixup() fails] Signed-off-by: Yijing Wang Signed-off-by: Bjorn Helgaas CC: Richard Henderson CC: Ivan Kokshaysky CC: Matt Turner CC: David Howells CC: Tony Luck CC: Michal Simek CC: Ralf Baechle CC: Koichi Yasutake CC: Sebastian Ott CC: "David S. Miller" CC: Chris Metcalf CC: Chris Zankel CC: Max Filippov CC: Thomas Gleixner --- arch/xtensa/kernel/pci.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/xtensa') diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c index 5b3403388d7f..b848cc3dc913 100644 --- a/arch/xtensa/kernel/pci.c +++ b/arch/xtensa/kernel/pci.c @@ -174,7 +174,7 @@ static int __init pcibios_init(void) struct pci_controller *pci_ctrl; struct list_head resources; struct pci_bus *bus; - int next_busno = 0; + int next_busno = 0, ret; printk("PCI: Probing PCI hardware\n"); @@ -185,14 +185,25 @@ static int __init pcibios_init(void) pci_controller_apertures(pci_ctrl, &resources); bus = pci_scan_root_bus(NULL, pci_ctrl->first_busno, pci_ctrl->ops, pci_ctrl, &resources); + if (!bus) + continue; + pci_ctrl->bus = bus; pci_ctrl->last_busno = bus->busn_res.end; if (next_busno <= pci_ctrl->last_busno) next_busno = pci_ctrl->last_busno+1; } pci_bus_count = next_busno; + ret = platform_pcibios_fixup(); + if (ret) + return ret; - return platform_pcibios_fixup(); + for (pci_ctrl = pci_ctrl_head; pci_ctrl; pci_ctrl = pci_ctrl->next) { + if (pci_ctrl->bus) + pci_bus_add_devices(pci_ctrl->bus); + } + + return 0; } subsys_initcall(pcibios_init); -- cgit v1.2.3