diff options
| -rw-r--r-- | drivers/pci/pci-driver.c | 4 | ||||
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 33 | ||||
| -rw-r--r-- | drivers/pci/pci.c | 40 | ||||
| -rw-r--r-- | drivers/pci/pci.h | 1 | ||||
| -rw-r--r-- | include/linux/pci.h | 3 |
5 files changed, 59 insertions, 22 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 84ec9c8f6703..e5ae3a0c13bb 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -329,8 +329,8 @@ static int pci_default_resume(struct pci_dev *pci_dev) /* restore the PCI config space */ pci_restore_state(pci_dev); /* if the device was enabled before suspend, reenable */ - if (pci_dev->is_enabled) - retval = pci_enable_device(pci_dev); + if (atomic_read(&pci_dev->enable_cnt)) + retval = __pci_enable_device(pci_dev); /* if the device was busmaster before the suspend, make it busmaster again */ if (pci_dev->is_busmaster) pci_set_master(pci_dev); diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index f952bfea48a6..7a94076752d0 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -42,7 +42,6 @@ pci_config_attr(subsystem_vendor, "0x%04x\n"); pci_config_attr(subsystem_device, "0x%04x\n"); pci_config_attr(class, "0x%06x\n"); pci_config_attr(irq, "%u\n"); -pci_config_attr(is_enabled, "%u\n"); static ssize_t broken_parity_status_show(struct device *dev, struct device_attribute *attr, @@ -112,26 +111,36 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, (u8)(pci_dev->class >> 16), (u8)(pci_dev->class >> 8), (u8)(pci_dev->class)); } -static ssize_t -is_enabled_store(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) + +static ssize_t is_enabled_store(struct device *dev, + struct device_attribute *attr, const char *buf, + size_t count) { + ssize_t result = -EINVAL; struct pci_dev *pdev = to_pci_dev(dev); - int retval = 0; /* this can crash the machine when done on the "wrong" device */ if (!capable(CAP_SYS_ADMIN)) return count; - if (*buf == '0') - pci_disable_device(pdev); + if (*buf == '0') { + if (atomic_read(&pdev->enable_cnt) != 0) + pci_disable_device(pdev); + else + result = -EIO; + } else if (*buf == '1') + result = pci_enable_device(pdev); + + return result < 0 ? result : count; +} - if (*buf == '1') - retval = pci_enable_device(pdev); +static ssize_t is_enabled_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pdev; - if (retval) - return retval; - return count; + pdev = to_pci_dev (dev); + return sprintf (buf, "%u\n", atomic_read(&pdev->enable_cnt)); } static ssize_t diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 427991741cf3..5a14b73cf3a1 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -612,30 +612,51 @@ pci_enable_device_bars(struct pci_dev *dev, int bars) } /** - * pci_enable_device - Initialize device before it's used by a driver. + * __pci_enable_device - Initialize device before it's used by a driver. * @dev: PCI device to be initialized * * Initialize device before it's used by a driver. Ask low-level code * to enable I/O and memory. Wake up the device if it was suspended. * Beware, this function can fail. + * + * Note this function is a backend and is not supposed to be called by + * normal code, use pci_enable_device() instead. */ int -pci_enable_device(struct pci_dev *dev) +__pci_enable_device(struct pci_dev *dev) { int err; - if (dev->is_enabled) - return 0; - err = pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1); if (err) return err; pci_fixup_device(pci_fixup_enable, dev); - dev->is_enabled = 1; return 0; } /** + * pci_enable_device - Initialize device before it's used by a driver. + * @dev: PCI device to be initialized + * + * Initialize device before it's used by a driver. Ask low-level code + * to enable I/O and memory. Wake up the device if it was suspended. + * Beware, this function can fail. + * + * Note we don't actually enable the device many times if we call + * this function repeatedly (we just increment the count). + */ +int pci_enable_device(struct pci_dev *dev) +{ + int result; + if (atomic_add_return(1, &dev->enable_cnt) > 1) + return 0; /* already enabled */ + result = __pci_enable_device(dev); + if (result < 0) + atomic_dec(&dev->enable_cnt); + return result; +} + +/** * pcibios_disable_device - disable arch specific PCI resources for device dev * @dev: the PCI device to disable * @@ -651,12 +672,18 @@ void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {} * * Signal to the system that the PCI device is not in use by the system * anymore. This only involves disabling PCI bus-mastering, if active. + * + * Note we don't actually disable the device until all callers of + * pci_device_enable() have called pci_device_disable(). */ void pci_disable_device(struct pci_dev *dev) { u16 pci_command; + if (atomic_sub_return(1, &dev->enable_cnt) != 0) + return; + if (dev->msi_enabled) disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI), PCI_CAP_ID_MSI); @@ -672,7 +699,6 @@ pci_disable_device(struct pci_dev *dev) dev->is_busmaster = 0; pcibios_disable_device(dev); - dev->is_enabled = 0; } /** diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 6bf327db5c5e..398852f526a6 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -1,5 +1,6 @@ /* Functions internal to the PCI core code */ +extern int __must_check __pci_enable_device(struct pci_dev *); extern int pci_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size); extern int pci_create_sysfs_dev_files(struct pci_dev *pdev); diff --git a/include/linux/pci.h b/include/linux/pci.h index 09be0f81b27b..01c707261f9c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -51,6 +51,7 @@ #include <linux/list.h> #include <linux/compiler.h> #include <linux/errno.h> +#include <asm/atomic.h> #include <linux/device.h> /* File state for mmap()s on /proc/bus/pci/X/Y */ @@ -159,7 +160,6 @@ struct pci_dev { unsigned int transparent:1; /* Transparent PCI bridge */ unsigned int multifunction:1;/* Part of multi-function device */ /* keep track of device state */ - unsigned int is_enabled:1; /* pci_enable_device has been called */ unsigned int is_busmaster:1; /* device is busmaster */ unsigned int no_msi:1; /* device may not use msi */ unsigned int no_d1d2:1; /* only allow d0 or d3 */ @@ -167,6 +167,7 @@ struct pci_dev { unsigned int broken_parity_status:1; /* Device generates false positive parity */ unsigned int msi_enabled:1; unsigned int msix_enabled:1; + atomic_t enable_cnt; /* pci_enable_device has been called */ u32 saved_config_space[16]; /* config space saved at suspend time */ struct hlist_head saved_cap_space; |