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-rw-r--r--drivers/pci/pci-driver.c4
-rw-r--r--drivers/pci/pci-sysfs.c33
-rw-r--r--drivers/pci/pci.c40
-rw-r--r--drivers/pci/pci.h1
4 files changed, 57 insertions, 21 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);