From: Subbaraya Sundeep <sbha...@marvell.com> As per the spec, "Enhanced Allocation (EA) for Memory and I/O Resources" ECN, approved 23 October 2014, sec 6.9.1.2, fixed bus numbers of a bridge can be zero when no function that uses EA is located behind it. Hence assign bus numbers sequentially when fixed bus numbers are zero.
Fixes: 2dbce590117981196fe355efc0569bc6f949ae9b Signed-off-by: Subbaraya Sundeep <sbha...@marvell.com> --- drivers/pci/probe.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index a3c7338..c06ca4c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1095,27 +1095,28 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, * @sub: updated with subordinate bus number from EA * * If @dev is a bridge with EA capability, update @sec and @sub with - * fixed bus numbers from the capability and return true. Otherwise, - * return false. + * fixed bus numbers from the capability. Otherwise @sec and @sub + * will be zeroed. */ -static bool pci_ea_fixed_busnrs(struct pci_dev *dev, u8 *sec, u8 *sub) +static void pci_ea_fixed_busnrs(struct pci_dev *dev, u8 *sec, u8 *sub) { int ea, offset; u32 dw; + *sec = *sub = 0; + if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) - return false; + return; /* find PCI EA capability in list */ ea = pci_find_capability(dev, PCI_CAP_ID_EA); if (!ea) - return false; + return; offset = ea + PCI_EA_FIRST_ENT; pci_read_config_dword(dev, offset, &dw); *sec = dw & PCI_EA_SEC_BUS_MASK; *sub = (dw & PCI_EA_SUB_BUS_MASK) >> PCI_EA_SUB_BUS_SHIFT; - return true; } /* @@ -1151,7 +1152,6 @@ static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev, u16 bctl; u8 primary, secondary, subordinate; int broken = 0; - bool fixed_buses; u8 fixed_sec, fixed_sub; int next_busnr; @@ -1254,11 +1254,12 @@ static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev, pci_write_config_word(dev, PCI_STATUS, 0xffff); /* Read bus numbers from EA Capability (if present) */ - fixed_buses = pci_ea_fixed_busnrs(dev, &fixed_sec, &fixed_sub); - if (fixed_buses) + pci_ea_fixed_busnrs(dev, &fixed_sec, &fixed_sub); + + next_busnr = max + 1; + /* Use secondary bus number in EA */ + if (fixed_sec) next_busnr = fixed_sec; - else - next_busnr = max + 1; /* * Prevent assigning a bus number that already exists. @@ -1336,7 +1337,7 @@ static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev, * If fixed subordinate bus number exists from EA * capability then use it. */ - if (fixed_buses) + if (fixed_sub) max = fixed_sub; pci_bus_update_busn_res_end(child, max); pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max); -- 2.7.4