diff --git a/drivers/platform/x86/p2sb.c b/drivers/platform/x86/p2sb.c index fcf1ce8..1cf2471 100644 --- a/drivers/platform/x86/p2sb.c +++ b/drivers/platform/x86/p2sb.c @@ -26,21 +26,6 @@ static const struct x86_cpu_id p2sb_cpu_ids[] = { {} }; -/* - * Cache BAR0 of P2SB device functions 0 to 7. - * TODO: The constant 8 is the number of functions that PCI specification - * defines. Same definitions exist tree-wide. Unify this definition and - * the other definitions then move to include/uapi/linux/pci.h. - */ -#define NR_P2SB_RES_CACHE 8 - -struct p2sb_res_cache { - u32 bus_dev_id; - struct resource res; -}; - -static struct p2sb_res_cache p2sb_resources[NR_P2SB_RES_CACHE]; - static int p2sb_get_devfn(unsigned int *devfn) { unsigned int fn = P2SB_DEVFN_DEFAULT; @@ -54,16 +39,8 @@ static int p2sb_get_devfn(unsigned int *devfn) return 0; } -static bool p2sb_valid_resource(struct resource *res) -{ - if (res->flags) - return true; - - return false; -} - /* Copy resource from the first BAR of the device in question */ -static void p2sb_read_bar0(struct pci_dev *pdev, struct resource *mem) +static int p2sb_read_bar0(struct pci_dev *pdev, struct resource *mem) { struct resource *bar0 = &pdev->resource[0]; @@ -79,64 +56,47 @@ static void p2sb_read_bar0(struct pci_dev *pdev, struct resource *mem) mem->end = bar0->end; mem->flags = bar0->flags; mem->desc = bar0->desc; + + return 0; } -static void p2sb_scan_and_cache_devfn(struct pci_bus *bus, unsigned int devfn) +static int p2sb_scan_and_read(struct pci_bus *bus, unsigned int devfn, struct resource *mem) { - struct p2sb_res_cache *cache = &p2sb_resources[PCI_FUNC(devfn)]; struct pci_dev *pdev; + int ret; pdev = pci_scan_single_device(bus, devfn); if (!pdev) - return; + return -ENODEV; - p2sb_read_bar0(pdev, &cache->res); - cache->bus_dev_id = bus->dev.id; + ret = p2sb_read_bar0(pdev, mem); pci_stop_and_remove_bus_device(pdev); - return; -} - -static int p2sb_scan_and_cache(struct pci_bus *bus, unsigned int devfn) -{ - unsigned int slot, fn; - - if (PCI_FUNC(devfn) == 0) { - /* - * When function number of the P2SB device is zero, scan it and - * other function numbers, and if devices are available, cache - * their BAR0s. - */ - slot = PCI_SLOT(devfn); - for (fn = 0; fn < NR_P2SB_RES_CACHE; fn++) - p2sb_scan_and_cache_devfn(bus, PCI_DEVFN(slot, fn)); - } else { - /* Scan the P2SB device and cache its BAR0 */ - p2sb_scan_and_cache_devfn(bus, devfn); - } - - if (!p2sb_valid_resource(&p2sb_resources[PCI_FUNC(devfn)].res)) - return -ENOENT; - - return 0; -} - -static struct pci_bus *p2sb_get_bus(struct pci_bus *bus) -{ - static struct pci_bus *p2sb_bus; - - bus = bus ?: p2sb_bus; - if (bus) - return bus; - - /* Assume P2SB is on the bus 0 in domain 0 */ - p2sb_bus = pci_find_bus(0, 0); - return p2sb_bus; + return ret; } -static int p2sb_cache_resources(void) +/** + * p2sb_bar - Get Primary to Sideband (P2SB) bridge device BAR + * @bus: PCI bus to communicate with + * @devfn: PCI slot and function to communicate with + * @mem: memory resource to be filled in + * + * The BIOS prevents the P2SB device from being enumerated by the PCI + * subsystem, so we need to unhide and hide it back to lookup the BAR. + * + * if @bus is NULL, the bus 0 in domain 0 will be used. + * If @devfn is 0, it will be replaced by devfn of the P2SB device. + * + * Caller must provide a valid pointer to @mem. + * + * Locking is handled by pci_rescan_remove_lock mutex. + * + * Return: + * 0 on success or appropriate errno value on error. + */ +int p2sb_bar(struct pci_bus *bus, unsigned int devfn, struct resource *mem) { - struct pci_bus *bus; + struct pci_dev *pdev_p2sb; unsigned int devfn_p2sb; u32 value = P2SBC_HIDE; int ret; @@ -146,9 +106,8 @@ static int p2sb_cache_resources(void) if (ret) return ret; - bus = p2sb_get_bus(NULL); - if (!bus) - return -ENODEV; + /* if @bus is NULL, use bus 0 in domain 0 */ + bus = bus ?: pci_find_bus(0, 0); /* * Prevent concurrent PCI bus scan from seeing the P2SB device and @@ -156,16 +115,17 @@ static int p2sb_cache_resources(void) */ pci_lock_rescan_remove(); - /* - * The BIOS prevents the P2SB device from being enumerated by the PCI - * subsystem, so we need to unhide and hide it back to lookup the BAR. - * Unhide the P2SB device here, if needed. - */ + /* Unhide the P2SB device, if needed */ pci_bus_read_config_dword(bus, devfn_p2sb, P2SBC, &value); if (value & P2SBC_HIDE) pci_bus_write_config_dword(bus, devfn_p2sb, P2SBC, 0); - ret = p2sb_scan_and_cache(bus, devfn_p2sb); + pdev_p2sb = pci_scan_single_device(bus, devfn_p2sb); + if (devfn) + ret = p2sb_scan_and_read(bus, devfn, mem); + else + ret = p2sb_read_bar0(pdev_p2sb, mem); + pci_stop_and_remove_bus_device(pdev_p2sb); /* Hide the P2SB device, if it was hidden */ if (value & P2SBC_HIDE) @@ -173,62 +133,12 @@ static int p2sb_cache_resources(void) pci_unlock_rescan_remove(); - return ret; -} - -/** - * p2sb_bar - Get Primary to Sideband (P2SB) bridge device BAR - * @bus: PCI bus to communicate with - * @devfn: PCI slot and function to communicate with - * @mem: memory resource to be filled in - * - * If @bus is NULL, the bus 0 in domain 0 will be used. - * If @devfn is 0, it will be replaced by devfn of the P2SB device. - * - * Caller must provide a valid pointer to @mem. - * - * Return: - * 0 on success or appropriate errno value on error. - */ -int p2sb_bar(struct pci_bus *bus, unsigned int devfn, struct resource *mem) -{ - struct p2sb_res_cache *cache; - int ret; - - bus = p2sb_get_bus(bus); - if (!bus) - return -ENODEV; - - if (!devfn) { - ret = p2sb_get_devfn(&devfn); - if (ret) - return ret; - } + if (ret) + return ret; - cache = &p2sb_resources[PCI_FUNC(devfn)]; - if (cache->bus_dev_id != bus->dev.id) + if (mem->flags == 0) return -ENODEV; - if (!p2sb_valid_resource(&cache->res)) - return -ENOENT; - - memcpy(mem, &cache->res, sizeof(*mem)); return 0; } EXPORT_SYMBOL_GPL(p2sb_bar); - -static int __init p2sb_fs_init(void) -{ - p2sb_cache_resources(); - return 0; -} - -/* - * pci_rescan_remove_lock to avoid access to unhidden P2SB devices can - * not be locked in sysfs pci bus rescan path because of deadlock. To - * avoid the deadlock, access to P2SB devices with the lock at an early - * step in kernel initialization and cache required resources. This - * should happen after subsys_initcall which initializes PCI subsystem - * and before device_initcall which requires P2SB resources. - */ -fs_initcall(p2sb_fs_init);