From c93a4dfb31f2c023da3ad1238c352452f2cc0e05 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Mon, 23 Aug 2010 11:59:28 +0100 Subject: xen: pvhvm: allow user to request no emulated device unplug this allows the user to disable pvhvm and revert to emulated devices in case of a system misconfiguration (e.g. initramfs with only emulated drivers in it). Signed-off-by: Ian Campbell Acked-by: Jeremy Fitzhardinge Acked-by: Stefano Stabellini --- Documentation/kernel-parameters.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 2c85c0692b01..8bbe83b9d0b2 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2631,6 +2631,7 @@ and is between 256 and 4096 characters. It is defined in the file all -- unplug all emulated devices (NICs and IDE disks) ignore -- continue loading the Xen platform PCI driver even if the version check failed + never -- do not unplug even if version check succeeds xirc2ps_cs= [NET,PCMCIA] Format: -- cgit v1.2.3 From 1dc7ce99b091a11cce0f34456c1ffcb928f17edd Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Mon, 23 Aug 2010 11:59:29 +0100 Subject: xen: pvhvm: rename xen_emul_unplug=ignore to =unnnecessary It is not immediately clear what this option causes to become ignored. The actual meaning is that it is not necessary to unplug the emulated devices to safely use the PV ones, even if the platform does not support the unplug protocol. (pressumably the user will only add this option if they have ensured that their domain configuration is safe). I think xen_emul_unplug=unnecessary better captures this. Signed-off-by: Ian Campbell Acked-by: Jeremy Fitzhardinge Acked-by: Stefano Stabellini --- Documentation/kernel-parameters.txt | 5 +++-- arch/x86/xen/platform-pci-unplug.c | 13 +++++++------ drivers/block/xen-blkfront.c | 2 +- include/xen/platform_pci.h | 2 +- 4 files changed, 12 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8bbe83b9d0b2..f084af0cb8e0 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2629,8 +2629,9 @@ and is between 256 and 4096 characters. It is defined in the file aux-ide-disks -- unplug non-primary-master IDE devices nics -- unplug network devices all -- unplug all emulated devices (NICs and IDE disks) - ignore -- continue loading the Xen platform PCI driver even - if the version check failed + unnecessary -- unplugging emulated devices is + unnecessary even if the host did not respond to + the unplug protocol never -- do not unplug even if version check succeeds xirc2ps_cs= [NET,PCMCIA] diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c index 070dfa0654bd..0f456386cce5 100644 --- a/arch/x86/xen/platform-pci-unplug.c +++ b/arch/x86/xen/platform-pci-unplug.c @@ -78,10 +78,11 @@ void __init xen_unplug_emulated_devices(void) /* check the version of the xen platform PCI device */ r = check_platform_magic(); /* If the version matches enable the Xen platform PCI driver. - * Also enable the Xen platform PCI driver if the version is really old - * and the user told us to ignore it. */ + * Also enable the Xen platform PCI driver if the host does + * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC) + * but the user told us that unplugging is unnecessary. */ if (r && !(r == XEN_PLATFORM_ERR_MAGIC && - (xen_emul_unplug & XEN_UNPLUG_IGNORE))) + (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))) return; /* Set the default value of xen_emul_unplug depending on whether or * not the Xen PV frontends and the Xen platform PCI driver have @@ -102,7 +103,7 @@ void __init xen_unplug_emulated_devices(void) } } /* Now unplug the emulated devices */ - if (!(xen_emul_unplug & XEN_UNPLUG_IGNORE)) + if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)) outw(xen_emul_unplug, XEN_IOPORT_UNPLUG); xen_platform_pci_unplug = xen_emul_unplug; } @@ -128,8 +129,8 @@ static int __init parse_xen_emul_unplug(char *arg) xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS; else if (!strncmp(p, "nics", l)) xen_emul_unplug |= XEN_UNPLUG_ALL_NICS; - else if (!strncmp(p, "ignore", l)) - xen_emul_unplug |= XEN_UNPLUG_IGNORE; + else if (!strncmp(p, "unnecessary", l)) + xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY; else if (!strncmp(p, "never", l)) xen_emul_unplug |= XEN_UNPLUG_NEVER; else diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index ac1b682edecb..ab735a605cf3 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -834,7 +834,7 @@ static int blkfront_probe(struct xenbus_device *dev, char *type; int len; /* no unplug has been done: do not hook devices != xen vbds */ - if (xen_platform_pci_unplug & XEN_UNPLUG_IGNORE) { + if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) { int major; if (!VDEV_IS_EXTENDED(vdevice)) diff --git a/include/xen/platform_pci.h b/include/xen/platform_pci.h index 123b7752fa6a..590ccfd82645 100644 --- a/include/xen/platform_pci.h +++ b/include/xen/platform_pci.h @@ -20,7 +20,7 @@ #define XEN_UNPLUG_ALL_NICS 2 #define XEN_UNPLUG_AUX_IDE_DISKS 4 #define XEN_UNPLUG_ALL 7 -#define XEN_UNPLUG_IGNORE 8 +#define XEN_UNPLUG_UNNECESSARY 8 #define XEN_UNPLUG_NEVER 16 static inline int xen_must_unplug_nics(void) { -- cgit v1.2.3 From 79dd9182db2072d63ccf160bb9a3463b1c952723 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 21 Aug 2010 01:51:44 +0200 Subject: PCI: PCIe: Introduce commad line switch for disabling port services Introduce kernel command line switch pcie_ports= allowing one to disable all of the native PCIe port services, so that PCIe ports are treated like PCI-to-PCI bridges. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- Documentation/kernel-parameters.txt | 4 ++++ drivers/pci/pcie/portdrv.h | 2 ++ drivers/pci/pcie/portdrv_core.c | 3 +++ drivers/pci/pcie/portdrv_pci.c | 15 +++++++++++++++ 4 files changed, 24 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 873b68090098..b9008fc3a53d 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2042,6 +2042,10 @@ and is between 256 and 4096 characters. It is defined in the file force Enable ASPM even on devices that claim not to support it. WARNING: Forcing ASPM on may cause system lockups. + pcie_ports= [PCIE] PCIe ports handling: + compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe + ports driver. + pcie_pme= [PCIE,PM] Native PCIe PME signaling options: Format: {auto|force}[,nomsi] auto Use native PCIe PME signaling if the BIOS allows the diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 813a5c3427b6..966f6e9761c8 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -20,6 +20,8 @@ #define get_descriptor_id(type, service) (((type - 4) << 4) | service) +extern bool pcie_ports_disabled; + extern struct bus_type pcie_port_bus_type; extern int pcie_port_device_register(struct pci_dev *dev); #ifdef CONFIG_PM diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index e73effbe402c..2bf2fe510e15 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -494,6 +494,9 @@ static void pcie_port_shutdown_service(struct device *dev) {} */ int pcie_port_service_register(struct pcie_port_service_driver *new) { + if (pcie_ports_disabled) + return -ENODEV; + new->driver.name = (char *)new->name; new->driver.bus = &pcie_port_bus_type; new->driver.probe = pcie_port_probe_service; diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 3debed25e46b..a04392da6ce1 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -29,6 +29,18 @@ MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL"); +/* If this switch is set, PCIe port native services should not be enabled. */ +bool pcie_ports_disabled; + +static int __init pcie_port_setup(char *str) +{ + if (!strncmp(str, "compat", 6)) + pcie_ports_disabled = true; + + return 1; +} +__setup("pcie_ports=", pcie_port_setup); + /* global data */ static int pcie_portdrv_restore_config(struct pci_dev *dev) @@ -301,6 +313,9 @@ static int __init pcie_portdrv_init(void) { int retval; + if (pcie_ports_disabled) + return -EACCES; + dmi_check_system(pcie_portdrv_dmi_table); retval = pcie_port_bus_register(); -- cgit v1.2.3 From 28eb5f274a305bf3a13b2c80c4804d4515d05c64 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 21 Aug 2010 22:02:38 +0200 Subject: PCI: PCIe: Ask BIOS for control of all native services at once After commit 852972acff8f10f3a15679be2059bb94916cba5d (ACPI: Disable ASPM if the platform won't provide _OSC control for PCIe) control of the PCIe Capability Structure is unconditionally requested by acpi_pci_root_add(), which in principle may cause problems to happen in two ways. First, the BIOS may refuse to give control of the PCIe Capability Structure if it is not asked for any of the _OSC features depending on it at the same time. Second, the BIOS may assume that control of the _OSC features depending on the PCIe Capability Structure will be requested in the future and may behave incorrectly if that doesn't happen. For this reason, control of the PCIe Capability Structure should always be requested along with control of any other _OSC features that may depend on it (ie. PCIe native PME, PCIe native hot-plug, PCIe AER). Rework the PCIe port driver so that (1) it checks which native PCIe port services can be enabled, according to the BIOS, and (2) it requests control of all these services simultaneously. In particular, this causes pcie_portdrv_probe() to fail if the BIOS refuses to grant control of the PCIe Capability Structure, which means that no native PCIe port services can be enabled for the PCIe Root Complex the given port belongs to. If that happens, ASPM is disabled to avoid problems with mishandling it by the part of the PCIe hierarchy for which control of the PCIe Capability Structure has not been received. Make it possible to override this behavior using 'pcie_ports=native' (use the PCIe native services regardless of the BIOS response to the control request), or 'pcie_ports=compat' (do not use the PCIe native services at all). Accordingly, rework the existing PCIe port service drivers so that they don't request control of the services directly. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- Documentation/kernel-parameters.txt | 13 +++--- drivers/acpi/pci_root.c | 9 ----- drivers/pci/hotplug/acpi_pcihp.c | 4 +- drivers/pci/hotplug/pciehp.h | 12 ------ drivers/pci/hotplug/pciehp_acpi.c | 4 +- drivers/pci/hotplug/pciehp_core.c | 4 +- drivers/pci/pcie/Makefile | 1 + drivers/pci/pcie/aer/aerdrv_acpi.c | 36 ----------------- drivers/pci/pcie/aer/aerdrv_core.c | 14 +------ drivers/pci/pcie/pme/Makefile | 5 +-- drivers/pci/pcie/pme/pcie_pme.c | 64 +++--------------------------- drivers/pci/pcie/pme/pcie_pme.h | 28 ------------- drivers/pci/pcie/pme/pcie_pme_acpi.c | 56 -------------------------- drivers/pci/pcie/portdrv.h | 20 ++++++++++ drivers/pci/pcie/portdrv_acpi.c | 77 ++++++++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv_core.c | 25 ++++++++++-- drivers/pci/pcie/portdrv_pci.c | 20 +++++++++- 17 files changed, 155 insertions(+), 237 deletions(-) delete mode 100644 drivers/pci/pcie/pme/pcie_pme.h delete mode 100644 drivers/pci/pcie/pme/pcie_pme_acpi.c create mode 100644 drivers/pci/pcie/portdrv_acpi.c (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b9008fc3a53d..8f126e878dbe 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2043,18 +2043,17 @@ and is between 256 and 4096 characters. It is defined in the file WARNING: Forcing ASPM on may cause system lockups. pcie_ports= [PCIE] PCIe ports handling: + auto Ask the BIOS whether or not to use native PCIe services + associated with PCIe ports (PME, hot-plug, AER). Use + them only if that is allowed by the BIOS. + native Use native PCIe services associated with PCIe ports + unconditionally. compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe ports driver. pcie_pme= [PCIE,PM] Native PCIe PME signaling options: - Format: {auto|force}[,nomsi] - auto Use native PCIe PME signaling if the BIOS allows the - kernel to control PCIe config registers of root ports. - force Use native PCIe PME signaling even if the BIOS refuses - to allow the kernel to control the relevant PCIe config - registers. nomsi Do not use MSI for native PCIe PME signaling (this makes - all PCIe root ports use INTx for everything). + all PCIe root ports use INTx for all services). pcmv= [HW,PCMCIA] BadgePAD 4 diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index c34713112520..3ba8d1f44a73 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -33,7 +33,6 @@ #include #include #include -#include #include #include #include @@ -568,14 +567,6 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) if (flags != base_flags) acpi_pci_osc_support(root, flags); - flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL; - status = acpi_pci_osc_control_set(root->device->handle, &flags, flags); - - if (ACPI_FAILURE(status)) { - printk(KERN_INFO "Unable to assume PCIe control: Disabling ASPM\n"); - pcie_no_aspm(); - } - pci_acpi_add_bus_pm_notifier(device, root->bus); if (device->wakeup.flags.run_wake) device_set_run_wake(root->bus->bridge, true); diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c index 3d93d529a7bd..3bc72d18b121 100644 --- a/drivers/pci/hotplug/acpi_pcihp.c +++ b/drivers/pci/hotplug/acpi_pcihp.c @@ -338,9 +338,7 @@ int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev, u32 flags) acpi_handle chandle, handle; struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL }; - flags &= (OSC_PCI_EXPRESS_NATIVE_HP_CONTROL | - OSC_SHPC_NATIVE_HP_CONTROL | - OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL); + flags &= OSC_SHPC_NATIVE_HP_CONTROL; if (!flags) { err("Invalid flags %u specified!\n", flags); return -EINVAL; diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 4ed76b47b6dc..653de6ff8ac6 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -176,19 +176,7 @@ static inline void pciehp_firmware_init(void) { pciehp_acpi_slot_detection_init(); } - -static inline int pciehp_get_hp_hw_control_from_firmware(struct pci_dev *dev) -{ - int retval; - u32 flags = (OSC_PCI_EXPRESS_NATIVE_HP_CONTROL | - OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL); - retval = acpi_get_hp_hw_control_from_firmware(dev, flags); - if (retval) - return retval; - return pciehp_acpi_slot_detection_check(dev); -} #else #define pciehp_firmware_init() do {} while (0) -#define pciehp_get_hp_hw_control_from_firmware(dev) 0 #endif /* CONFIG_ACPI */ #endif /* _PCIEHP_H */ diff --git a/drivers/pci/hotplug/pciehp_acpi.c b/drivers/pci/hotplug/pciehp_acpi.c index 1f4000a5a108..2574700db461 100644 --- a/drivers/pci/hotplug/pciehp_acpi.c +++ b/drivers/pci/hotplug/pciehp_acpi.c @@ -85,9 +85,7 @@ static int __init dummy_probe(struct pcie_device *dev) acpi_handle handle; struct dummy_slot *slot, *tmp; struct pci_dev *pdev = dev->port; - /* Note: pciehp_detect_mode != PCIEHP_DETECT_ACPI here */ - if (pciehp_get_hp_hw_control_from_firmware(pdev)) - return -ENODEV; + pos = pci_pcie_cap(pdev); if (!pos) return -ENODEV; diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c index 3588ea61b0dd..aa5f3ff629ff 100644 --- a/drivers/pci/hotplug/pciehp_core.c +++ b/drivers/pci/hotplug/pciehp_core.c @@ -59,7 +59,7 @@ module_param(pciehp_force, bool, 0644); MODULE_PARM_DESC(pciehp_debug, "Debugging mode enabled or not"); MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not"); MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds"); -MODULE_PARM_DESC(pciehp_force, "Force pciehp, even if _OSC and OSHP are missing"); +MODULE_PARM_DESC(pciehp_force, "Force pciehp, even if OSHP is missing"); #define PCIE_MODULE_NAME "pciehp" @@ -235,7 +235,7 @@ static int pciehp_probe(struct pcie_device *dev) dev_info(&dev->device, "Bypassing BIOS check for pciehp use on %s\n", pci_name(dev->port)); - else if (pciehp_get_hp_hw_control_from_firmware(dev->port)) + else if (pciehp_acpi_slot_detection_check(dev->port)) goto err_out_none; ctrl = pcie_init(dev); diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile index ea654545e7c4..4d2b18704c47 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_PCIEASPM) += aspm.o pcieportdrv-y := portdrv_core.o portdrv_pci.o portdrv_bus.o +pcieportdrv-$(CONFIG_ACPI) += portdrv_acpi.o obj-$(CONFIG_PCIEPORTBUS) += pcieportdrv.o diff --git a/drivers/pci/pcie/aer/aerdrv_acpi.c b/drivers/pci/pcie/aer/aerdrv_acpi.c index 3a276a0cea93..2bb9b8972211 100644 --- a/drivers/pci/pcie/aer/aerdrv_acpi.c +++ b/drivers/pci/pcie/aer/aerdrv_acpi.c @@ -19,42 +19,6 @@ #include #include "aerdrv.h" -/** - * aer_osc_setup - run ACPI _OSC method - * @pciedev: pcie_device which AER is being enabled on - * - * @return: Zero on success. Nonzero otherwise. - * - * Invoked when PCIe bus loads AER service driver. To avoid conflict with - * BIOS AER support requires BIOS to yield AER control to OS native driver. - **/ -int aer_osc_setup(struct pcie_device *pciedev) -{ - acpi_status status = AE_NOT_FOUND; - struct pci_dev *pdev = pciedev->port; - acpi_handle handle = NULL; - - if (acpi_pci_disabled) - return -1; - - handle = acpi_find_root_bridge_handle(pdev); - if (handle) { - u32 flags = OSC_PCI_EXPRESS_AER_CONTROL | - OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL; - status = acpi_pci_osc_control_set(handle, &flags, flags); - } - - if (ACPI_FAILURE(status)) { - dev_printk(KERN_DEBUG, &pciedev->device, "AER service couldn't " - "init device: %s\n", - (status == AE_SUPPORT || status == AE_NOT_FOUND) ? - "no _OSC support" : "_OSC failed"); - return -1; - } - - return 0; -} - #ifdef CONFIG_ACPI_APEI static inline int hest_match_pci(struct acpi_hest_aer_common *p, struct pci_dev *pci) diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c index fc0b5a93e1de..29e268fadf14 100644 --- a/drivers/pci/pcie/aer/aerdrv_core.c +++ b/drivers/pci/pcie/aer/aerdrv_core.c @@ -772,22 +772,10 @@ void aer_isr(struct work_struct *work) */ int aer_init(struct pcie_device *dev) { - if (pcie_aer_get_firmware_first(dev->port)) { - dev_printk(KERN_DEBUG, &dev->device, - "PCIe errors handled by platform firmware.\n"); - goto out; - } - - if (aer_osc_setup(dev)) - goto out; - - return 0; -out: if (forceload) { dev_printk(KERN_DEBUG, &dev->device, "aerdrv forceload requested.\n"); pcie_aer_force_firmware_first(dev->port, 0); - return 0; } - return -ENXIO; + return 0; } diff --git a/drivers/pci/pcie/pme/Makefile b/drivers/pci/pcie/pme/Makefile index 8b9238053080..3c67bf4d26cf 100644 --- a/drivers/pci/pcie/pme/Makefile +++ b/drivers/pci/pcie/pme/Makefile @@ -2,7 +2,4 @@ # Makefile for PCI-Express Root Port PME signaling driver # -obj-$(CONFIG_PCIE_PME) += pmedriver.o - -pmedriver-objs := pcie_pme.o -pmedriver-$(CONFIG_ACPI) += pcie_pme_acpi.o +obj-$(CONFIG_PCIE_PME) += pcie_pme.o diff --git a/drivers/pci/pcie/pme/pcie_pme.c b/drivers/pci/pcie/pme/pcie_pme.c index bbdea18693d9..9d1361e1a776 100644 --- a/drivers/pci/pcie/pme/pcie_pme.c +++ b/drivers/pci/pcie/pme/pcie_pme.c @@ -24,36 +24,11 @@ #include #include "../../pci.h" -#include "pcie_pme.h" +#include "../portdrv.h" #define PCI_EXP_RTSTA_PME 0x10000 /* PME status */ #define PCI_EXP_RTSTA_PENDING 0x20000 /* PME pending */ -/* - * If set, this switch will prevent the PCIe root port PME service driver from - * being registered. Consequently, the interrupt-based PCIe PME signaling will - * not be used by any PCIe root ports in that case. - */ -static bool pcie_pme_disabled = true; - -/* - * The PCI Express Base Specification 2.0, Section 6.1.8, states the following: - * "In order to maintain compatibility with non-PCI Express-aware system - * software, system power management logic must be configured by firmware to use - * the legacy mechanism of signaling PME by default. PCI Express-aware system - * software must notify the firmware prior to enabling native, interrupt-based - * PME signaling." However, if the platform doesn't provide us with a suitable - * notification mechanism or the notification fails, it is not clear whether or - * not we are supposed to use the interrupt-based PCIe PME signaling. The - * switch below can be used to indicate the desired behaviour. When set, it - * will make the kernel use the interrupt-based PCIe PME signaling regardless of - * the platform notification status, although the kernel will attempt to notify - * the platform anyway. When unset, it will prevent the kernel from using the - * the interrupt-based PCIe PME signaling if the platform notification fails, - * which is the default. - */ -static bool pcie_pme_force_enable; - /* * If this switch is set, MSI will not be used for PCIe PME signaling. This * causes the PCIe port driver to use INTx interrupts only, but it turns out @@ -64,38 +39,13 @@ bool pcie_pme_msi_disabled; static int __init pcie_pme_setup(char *str) { - if (!strncmp(str, "auto", 4)) - pcie_pme_disabled = false; - else if (!strncmp(str, "force", 5)) - pcie_pme_force_enable = true; - - str = strchr(str, ','); - if (str) { - str++; - str += strspn(str, " \t"); - if (*str && !strcmp(str, "nomsi")) - pcie_pme_msi_disabled = true; - } + if (!strncmp(str, "nomsi", 5)) + pcie_pme_msi_disabled = true; return 1; } __setup("pcie_pme=", pcie_pme_setup); -/** - * pcie_pme_platform_setup - Ensure that the kernel controls the PCIe PME. - * @srv: PCIe PME root port service to use for carrying out the check. - * - * Notify the platform that the native PCIe PME is going to be used and return - * 'true' if the control of the PCIe PME registers has been acquired from the - * platform. - */ -static bool pcie_pme_platform_setup(struct pcie_device *srv) -{ - if (!pcie_pme_platform_notify(srv)) - return true; - return pcie_pme_force_enable; -} - struct pcie_pme_service_data { spinlock_t lock; struct pcie_device *srv; @@ -108,7 +58,7 @@ struct pcie_pme_service_data { * @dev: PCIe root port or event collector. * @enable: Enable or disable the interrupt. */ -static void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable) +void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable) { int rtctl_pos; u16 rtctl; @@ -417,9 +367,6 @@ static int pcie_pme_probe(struct pcie_device *srv) struct pcie_pme_service_data *data; int ret; - if (!pcie_pme_platform_setup(srv)) - return -EACCES; - data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; @@ -509,8 +456,7 @@ static struct pcie_port_service_driver pcie_pme_driver = { */ static int __init pcie_pme_service_init(void) { - return pcie_pme_disabled ? - -ENODEV : pcie_port_service_register(&pcie_pme_driver); + return pcie_port_service_register(&pcie_pme_driver); } module_init(pcie_pme_service_init); diff --git a/drivers/pci/pcie/pme/pcie_pme.h b/drivers/pci/pcie/pme/pcie_pme.h deleted file mode 100644 index b30d2b7c9775..000000000000 --- a/drivers/pci/pcie/pme/pcie_pme.h +++ /dev/null @@ -1,28 +0,0 @@ -/* - * drivers/pci/pcie/pme/pcie_pme.h - * - * PCI Express Root Port PME signaling support - * - * Copyright (C) 2009 Rafael J. Wysocki , Novell Inc. - */ - -#ifndef _PCIE_PME_H_ -#define _PCIE_PME_H_ - -struct pcie_device; - -#ifdef CONFIG_ACPI -extern int pcie_pme_acpi_setup(struct pcie_device *srv); - -static inline int pcie_pme_platform_notify(struct pcie_device *srv) -{ - return pcie_pme_acpi_setup(srv); -} -#else /* !CONFIG_ACPI */ -static inline int pcie_pme_platform_notify(struct pcie_device *srv) -{ - return 0; -} -#endif /* !CONFIG_ACPI */ - -#endif diff --git a/drivers/pci/pcie/pme/pcie_pme_acpi.c b/drivers/pci/pcie/pme/pcie_pme_acpi.c deleted file mode 100644 index be20222b12d3..000000000000 --- a/drivers/pci/pcie/pme/pcie_pme_acpi.c +++ /dev/null @@ -1,56 +0,0 @@ -/* - * PCIe Native PME support, ACPI-related part - * - * Copyright (C) 2009 Rafael J. Wysocki , Novell Inc. - * - * This file is subject to the terms and conditions of the GNU General Public - * License V2. See the file "COPYING" in the main directory of this archive - * for more details. - */ - -#include -#include -#include -#include -#include -#include - -/** - * pcie_pme_acpi_setup - Request the ACPI BIOS to release control over PCIe PME. - * @srv - PCIe PME service for a root port or event collector. - * - * Invoked when the PCIe bus type loads PCIe PME service driver. To avoid - * conflict with the BIOS PCIe support requires the BIOS to yield PCIe PME - * control to the kernel. - */ -int pcie_pme_acpi_setup(struct pcie_device *srv) -{ - acpi_status status = AE_NOT_FOUND; - struct pci_dev *port = srv->port; - acpi_handle handle; - u32 flags; - int error = 0; - - if (acpi_pci_disabled) - return -ENOSYS; - - dev_info(&port->dev, "Requesting control of PCIe PME from ACPI BIOS\n"); - - handle = acpi_find_root_bridge_handle(port); - if (!handle) - return -EINVAL; - - flags = OSC_PCI_EXPRESS_PME_CONTROL | - OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL; - - status = acpi_pci_osc_control_set(handle, &flags, flags); - if (ACPI_FAILURE(status)) { - dev_info(&port->dev, - "Failed to receive control of PCIe PME service: %s\n", - (status == AE_SUPPORT || status == AE_NOT_FOUND) ? - "no _OSC support" : "ACPI _OSC failed"); - error = -ENODEV; - } - - return error; -} diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 966f6e9761c8..7b5aba0a3291 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -21,6 +21,7 @@ #define get_descriptor_id(type, service) (((type - 4) << 4) | service) extern bool pcie_ports_disabled; +extern bool pcie_ports_auto; extern struct bus_type pcie_port_bus_type; extern int pcie_port_device_register(struct pci_dev *dev); @@ -32,6 +33,8 @@ extern void pcie_port_device_remove(struct pci_dev *dev); extern int __must_check pcie_port_bus_register(void); extern void pcie_port_bus_unregister(void); +struct pci_dev; + #ifdef CONFIG_PCIE_PME extern bool pcie_pme_msi_disabled; @@ -44,9 +47,26 @@ static inline bool pcie_pme_no_msi(void) { return pcie_pme_msi_disabled; } + +extern void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable); #else /* !CONFIG_PCIE_PME */ static inline void pcie_pme_disable_msi(void) {} static inline bool pcie_pme_no_msi(void) { return false; } +static inline void pcie_pme_interrupt_enable(struct pci_dev *dev, bool en) {} #endif /* !CONFIG_PCIE_PME */ +#ifdef CONFIG_ACPI +extern int pcie_port_acpi_setup(struct pci_dev *port, int *mask); + +static inline int pcie_port_platform_notify(struct pci_dev *port, int *mask) +{ + return pcie_port_acpi_setup(port, mask); +} +#else /* !CONFIG_ACPI */ +static inline int pcie_port_platform_notify(struct pci_dev *port, int *mask) +{ + return 0; +} +#endif /* !CONFIG_ACPI */ + #endif /* _PORTDRV_H_ */ diff --git a/drivers/pci/pcie/portdrv_acpi.c b/drivers/pci/pcie/portdrv_acpi.c new file mode 100644 index 000000000000..b7c4cb1ccb23 --- /dev/null +++ b/drivers/pci/pcie/portdrv_acpi.c @@ -0,0 +1,77 @@ +/* + * PCIe Port Native Services Support, ACPI-Related Part + * + * Copyright (C) 2010 Rafael J. Wysocki , Novell Inc. + * + * This file is subject to the terms and conditions of the GNU General Public + * License V2. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include +#include +#include +#include +#include +#include + +#include "aer/aerdrv.h" +#include "../pci.h" + +/** + * pcie_port_acpi_setup - Request the BIOS to release control of PCIe services. + * @port: PCIe Port service for a root port or event collector. + * @srv_mask: Bit mask of services that can be enabled for @port. + * + * Invoked when @port is identified as a PCIe port device. To avoid conflicts + * with the BIOS PCIe port native services support requires the BIOS to yield + * control of these services to the kernel. The mask of services that the BIOS + * allows to be enabled for @port is written to @srv_mask. + * + * NOTE: It turns out that we cannot do that for individual port services + * separately, because that would make some systems work incorrectly. + */ +int pcie_port_acpi_setup(struct pci_dev *port, int *srv_mask) +{ + acpi_status status; + acpi_handle handle; + u32 flags; + + if (acpi_pci_disabled) + return 0; + + handle = acpi_find_root_bridge_handle(port); + if (!handle) + return -EINVAL; + + flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL + | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL + | OSC_PCI_EXPRESS_PME_CONTROL; + + if (pci_aer_available()) { + if (pcie_aer_get_firmware_first(port)) + dev_dbg(&port->dev, "PCIe errors handled by BIOS.\n"); + else + flags |= OSC_PCI_EXPRESS_AER_CONTROL; + } + + status = acpi_pci_osc_control_set(handle, &flags, + OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL); + if (ACPI_FAILURE(status)) { + dev_dbg(&port->dev, "ACPI _OSC request failed (code %d)\n", + status); + return -ENODEV; + } + + dev_info(&port->dev, "ACPI _OSC control granted for 0x%02x\n", flags); + + *srv_mask = PCIE_PORT_SERVICE_VC; + if (flags & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL) + *srv_mask |= PCIE_PORT_SERVICE_HP; + if (flags & OSC_PCI_EXPRESS_PME_CONTROL) + *srv_mask |= PCIE_PORT_SERVICE_PME; + if (flags & OSC_PCI_EXPRESS_AER_CONTROL) + *srv_mask |= PCIE_PORT_SERVICE_AER; + + return 0; +} diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 2bf2fe510e15..d0245c83b621 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -14,6 +14,8 @@ #include #include #include +#include +#include #include "../pci.h" #include "portdrv.h" @@ -236,23 +238,40 @@ static int get_port_device_capability(struct pci_dev *dev) int services = 0, pos; u16 reg16; u32 reg32; + int cap_mask; + int err; + + err = pcie_port_platform_notify(dev, &cap_mask); + if (pcie_ports_auto) { + if (err) { + pcie_no_aspm(); + return 0; + } + } else { + cap_mask = PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP + | PCIE_PORT_SERVICE_VC; + if (pci_aer_available()) + cap_mask |= PCIE_PORT_SERVICE_AER; + } pos = pci_pcie_cap(dev); pci_read_config_word(dev, pos + PCI_EXP_FLAGS, ®16); /* Hot-Plug Capable */ - if (reg16 & PCI_EXP_FLAGS_SLOT) { + if ((cap_mask & PCIE_PORT_SERVICE_HP) && (reg16 & PCI_EXP_FLAGS_SLOT)) { pci_read_config_dword(dev, pos + PCI_EXP_SLTCAP, ®32); if (reg32 & PCI_EXP_SLTCAP_HPC) services |= PCIE_PORT_SERVICE_HP; } /* AER capable */ - if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR)) + if ((cap_mask & PCIE_PORT_SERVICE_AER) + && pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR)) services |= PCIE_PORT_SERVICE_AER; /* VC support */ if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VC)) services |= PCIE_PORT_SERVICE_VC; /* Root ports are capable of generating PME too */ - if (dev->pcie_type == PCI_EXP_TYPE_ROOT_PORT) + if ((cap_mask & PCIE_PORT_SERVICE_PME) + && dev->pcie_type == PCI_EXP_TYPE_ROOT_PORT) services |= PCIE_PORT_SERVICE_PME; return services; diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index a04392da6ce1..8f1338d1c53f 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "portdrv.h" #include "aer/aerdrv.h" @@ -32,10 +33,23 @@ MODULE_LICENSE("GPL"); /* If this switch is set, PCIe port native services should not be enabled. */ bool pcie_ports_disabled; +/* + * If this switch is set, ACPI _OSC will be used to determine whether or not to + * enable PCIe port native services. + */ +bool pcie_ports_auto = true; + static int __init pcie_port_setup(char *str) { - if (!strncmp(str, "compat", 6)) + if (!strncmp(str, "compat", 6)) { pcie_ports_disabled = true; + } else if (!strncmp(str, "native", 6)) { + pcie_ports_disabled = false; + pcie_ports_auto = false; + } else if (!strncmp(str, "auto", 4)) { + pcie_ports_disabled = false; + pcie_ports_auto = true; + } return 1; } @@ -313,8 +327,10 @@ static int __init pcie_portdrv_init(void) { int retval; - if (pcie_ports_disabled) + if (pcie_ports_disabled) { + pcie_no_aspm(); return -EACCES; + } dmi_check_system(pcie_portdrv_dmi_table); -- cgit v1.2.3 From f846619e7f875b0efa9853b1c821bbc756656d47 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 27 Aug 2010 08:39:48 -0600 Subject: lguest: clean up warnings in demonstration launcher. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit These days the headers we use are in glibc. If those are too old, you can add the -I lines to get the kernel headers. In file included from ../../include/linux/if_tun.h:19, from lguest.c:33: ../../include/linux/types.h:13:2: warning: #warning "Attempt to use kernel headers from user space, see http://kernelnewbies.org/KernelHeaders" lguest.c: In function ‘setup_tun_net’: lguest.c:1456: warning: dereferencing pointer ‘sin’ does break strict-aliasing rules lguest.c:1457: warning: dereferencing pointer ‘sin’ does break strict-aliasing rules lguest.c:1450: note: initialized from here Signed-off-by: Rusty Russell --- Documentation/lguest/Makefile | 3 ++- Documentation/lguest/lguest.c | 23 ++++++++++++----------- 2 files changed, 14 insertions(+), 12 deletions(-) (limited to 'Documentation') diff --git a/Documentation/lguest/Makefile b/Documentation/lguest/Makefile index 28c8cdfcafd8..bebac6b4f332 100644 --- a/Documentation/lguest/Makefile +++ b/Documentation/lguest/Makefile @@ -1,5 +1,6 @@ # This creates the demonstration utility "lguest" which runs a Linux guest. -CFLAGS:=-m32 -Wall -Wmissing-declarations -Wmissing-prototypes -O3 -I../../include -I../../arch/x86/include -U_FORTIFY_SOURCE +# Missing headers? Add "-I../../include -I../../arch/x86/include" +CFLAGS:=-m32 -Wall -Wmissing-declarations -Wmissing-prototypes -O3 -U_FORTIFY_SOURCE all: lguest diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index e9ce3c554514..8a6a8c6d4980 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -39,14 +39,14 @@ #include #include #include -#include "linux/lguest_launcher.h" -#include "linux/virtio_config.h" -#include "linux/virtio_net.h" -#include "linux/virtio_blk.h" -#include "linux/virtio_console.h" -#include "linux/virtio_rng.h" -#include "linux/virtio_ring.h" -#include "asm/bootparam.h" +#include +#include +#include +#include +#include +#include +#include +#include "../../include/linux/lguest_launcher.h" /*L:110 * We can ignore the 42 include files we need for this program, but I do want * to draw attention to the use of kernel-style types. @@ -1447,14 +1447,15 @@ static void add_to_bridge(int fd, const char *if_name, const char *br_name) static void configure_device(int fd, const char *tapif, u32 ipaddr) { struct ifreq ifr; - struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr; + struct sockaddr_in sin; memset(&ifr, 0, sizeof(ifr)); strcpy(ifr.ifr_name, tapif); /* Don't read these incantations. Just cut & paste them like I did! */ - sin->sin_family = AF_INET; - sin->sin_addr.s_addr = htonl(ipaddr); + sin.sin_family = AF_INET; + sin.sin_addr.s_addr = htonl(ipaddr); + memcpy(&ifr.ifr_addr, &sin, sizeof(sin)); if (ioctl(fd, SIOCSIFADDR, &ifr) != 0) err(1, "Setting %s interface address", tapif); ifr.ifr_flags = IFF_UP; -- cgit v1.2.3 From 7c38875a0d0a9b90eee66be79e36995c86acc70c Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Thu, 26 Aug 2010 10:35:43 -0400 Subject: workqueue: Add a workqueue chapter to the tracepoint docbook Add a workqueue chapter to the traceopint docbook. Current book is at: http://www.kernel.org/doc/htmldocs/tracepoint/ Signed-off-by: Jason Baron Signed-off-by: Tejun Heo --- Documentation/DocBook/tracepoint.tmpl | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation') diff --git a/Documentation/DocBook/tracepoint.tmpl b/Documentation/DocBook/tracepoint.tmpl index e8473eae2a20..b57a9ede3224 100644 --- a/Documentation/DocBook/tracepoint.tmpl +++ b/Documentation/DocBook/tracepoint.tmpl @@ -104,4 +104,9 @@ Block IO !Iinclude/trace/events/block.h + + + Workqueue +!Iinclude/trace/events/workqueue.h + -- cgit v1.2.3 From ef5dc121d5a0bb1fa477c5395277259f07d318a3 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Thu, 2 Sep 2010 15:48:16 -0700 Subject: mutex: Fix annotations to include it in kernel-locking docbook Fix kernel-doc notation in linux/mutex.h and kernel/mutex.c, then add these 2 files to the kernel-locking docbook as the Mutex API reference chapter. Add one API function to mutex-design.txt and correct a typo in that file. Signed-off-by: Randy Dunlap Cc: Rusty Russell LKML-Reference: <20100902154816.6cc2f9ad.randy.dunlap@oracle.com> Signed-off-by: Ingo Molnar --- Documentation/DocBook/kernel-locking.tmpl | 6 ++++++ Documentation/mutex-design.txt | 3 ++- include/linux/mutex.h | 8 ++++++++ kernel/mutex.c | 23 +++++++---------------- 4 files changed, 23 insertions(+), 17 deletions(-) (limited to 'Documentation') diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl index 0b1a3f97f285..a0d479d1e1dd 100644 --- a/Documentation/DocBook/kernel-locking.tmpl +++ b/Documentation/DocBook/kernel-locking.tmpl @@ -1961,6 +1961,12 @@ machines due to caching. + + Mutex API reference +!Iinclude/linux/mutex.h +!Ekernel/mutex.c + + Further reading diff --git a/Documentation/mutex-design.txt b/Documentation/mutex-design.txt index c91ccc0720fa..38c10fd7f411 100644 --- a/Documentation/mutex-design.txt +++ b/Documentation/mutex-design.txt @@ -9,7 +9,7 @@ firstly, there's nothing wrong with semaphores. But if the simpler mutex semantics are sufficient for your code, then there are a couple of advantages of mutexes: - - 'struct mutex' is smaller on most architectures: .e.g on x86, + - 'struct mutex' is smaller on most architectures: E.g. on x86, 'struct semaphore' is 20 bytes, 'struct mutex' is 16 bytes. A smaller structure size means less RAM footprint, and better CPU-cache utilization. @@ -136,3 +136,4 @@ the APIs of 'struct mutex' have been streamlined: void mutex_lock_nested(struct mutex *lock, unsigned int subclass); int mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass); + int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 878cab4f5fcc..f363bc8fdc74 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -78,6 +78,14 @@ struct mutex_waiter { # include #else # define __DEBUG_MUTEX_INITIALIZER(lockname) +/** + * mutex_init - initialize the mutex + * @mutex: the mutex to be initialized + * + * Initialize the mutex to unlocked state. + * + * It is not allowed to initialize an already locked mutex. + */ # define mutex_init(mutex) \ do { \ static struct lock_class_key __key; \ diff --git a/kernel/mutex.c b/kernel/mutex.c index 4c0b7b3e6d2e..200407c1502f 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -36,15 +36,6 @@ # include #endif -/*** - * mutex_init - initialize the mutex - * @lock: the mutex to be initialized - * @key: the lock_class_key for the class; used by mutex lock debugging - * - * Initialize the mutex to unlocked state. - * - * It is not allowed to initialize an already locked mutex. - */ void __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key) { @@ -68,7 +59,7 @@ EXPORT_SYMBOL(__mutex_init); static __used noinline void __sched __mutex_lock_slowpath(atomic_t *lock_count); -/*** +/** * mutex_lock - acquire the mutex * @lock: the mutex to be acquired * @@ -105,7 +96,7 @@ EXPORT_SYMBOL(mutex_lock); static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count); -/*** +/** * mutex_unlock - release the mutex * @lock: the mutex to be released * @@ -364,8 +355,8 @@ __mutex_lock_killable_slowpath(atomic_t *lock_count); static noinline int __sched __mutex_lock_interruptible_slowpath(atomic_t *lock_count); -/*** - * mutex_lock_interruptible - acquire the mutex, interruptable +/** + * mutex_lock_interruptible - acquire the mutex, interruptible * @lock: the mutex to be acquired * * Lock the mutex like mutex_lock(), and return 0 if the mutex has @@ -456,15 +447,15 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count) return prev == 1; } -/*** - * mutex_trylock - try acquire the mutex, without waiting +/** + * mutex_trylock - try to acquire the mutex, without waiting * @lock: the mutex to be acquired * * Try to acquire the mutex atomically. Returns 1 if the mutex * has been acquired successfully, and 0 on contention. * * NOTE: this function follows the spin_trylock() convention, so - * it is negated to the down_trylock() return values! Be careful + * it is negated from the down_trylock() return values! Be careful * about this when converting semaphore users to mutexes. * * This function must not be used in interrupt context. The -- cgit v1.2.3 From c956126c137d97acb6f4d56fa9572d0bcc84e4ed Mon Sep 17 00:00:00 2001 From: David Brownell Date: Thu, 9 Sep 2010 16:38:03 -0700 Subject: gpio: doc updates There's been some recent confusion about error checking GPIO numbers. briefly, it should be handled mostly during setup, when gpio_request() is called, and NEVER by expectig gpio_is_valid to report more than never-usable GPIO numbers. [akpm@linux-foundation.org: terminate unterminated comment] Signed-off-by: David Brownell Cc: Eric Miao" Cc: "Ryan Mallon" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/gpio.txt | 22 ++++++++++++++-------- include/asm-generic/gpio.h | 14 +++++++++++++- 2 files changed, 27 insertions(+), 9 deletions(-) (limited to 'Documentation') diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index d96a6dba5748..9633da01ff46 100644 --- a/Documentation/gpio.txt +++ b/Documentation/gpio.txt @@ -109,17 +109,19 @@ use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders. If you want to initialize a structure with an invalid GPIO number, use some negative number (perhaps "-EINVAL"); that will never be valid. To -test if a number could reference a GPIO, you may use this predicate: +test if such number from such a structure could reference a GPIO, you +may use this predicate: int gpio_is_valid(int number); A number that's not valid will be rejected by calls which may request or free GPIOs (see below). Other numbers may also be rejected; for -example, a number might be valid but unused on a given board. - -Whether a platform supports multiple GPIO controllers is currently a -platform-specific implementation issue. +example, a number might be valid but temporarily unused on a given board. +Whether a platform supports multiple GPIO controllers is a platform-specific +implementation issue, as are whether that support can leave "holes" in the space +of GPIO numbers, and whether new controllers can be added at runtime. Such issues +can affect things including whether adjacent GPIO numbers are both valid. Using GPIOs ----------- @@ -480,12 +482,16 @@ To support this framework, a platform's Kconfig will "select" either ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB and arrange that its includes and defines three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). -They may also want to provide a custom value for ARCH_NR_GPIOS. -ARCH_REQUIRE_GPIOLIB means that the gpio-lib code will always get compiled +It may also provide a custom value for ARCH_NR_GPIOS, so that it better +reflects the number of GPIOs in actual use on that platform, without +wasting static table space. (It should count both built-in/SoC GPIOs and +also ones on GPIO expanders. + +ARCH_REQUIRE_GPIOLIB means that the gpiolib code will always get compiled into the kernel on that architecture. -ARCH_WANT_OPTIONAL_GPIOLIB means the gpio-lib code defaults to off and the user +ARCH_WANT_OPTIONAL_GPIOLIB means the gpiolib code defaults to off and the user can enable it and build it into the kernel optionally. If neither of these options are selected, the platform does not support diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h index c7376bf80b06..8ca18e26d7e3 100644 --- a/include/asm-generic/gpio.h +++ b/include/asm-generic/gpio.h @@ -16,15 +16,27 @@ * While the GPIO programming interface defines valid GPIO numbers * to be in the range 0..MAX_INT, this library restricts them to the * smaller range 0..ARCH_NR_GPIOS-1. + * + * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of + * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is + * actually an estimate of a board-specific value. */ #ifndef ARCH_NR_GPIOS #define ARCH_NR_GPIOS 256 #endif +/* + * "valid" GPIO numbers are nonnegative and may be passed to + * setup routines like gpio_request(). only some valid numbers + * can successfully be requested and used. + * + * Invalid GPIO numbers are useful for indicating no-such-GPIO in + * platform data and other tables. + */ + static inline int gpio_is_valid(int number) { - /* only some non-negative numbers are valid */ return ((unsigned)number) < ARCH_NR_GPIOS; } -- cgit v1.2.3