PCI: cleanup Function Level Reset

This patch enhances the FLR functions:
  1) remove disable_irq() so the shared IRQ won't be disabled.
  2) replace the 1s wait with 100, 200 and 400ms wait intervals
     for the Pending Transaction.
  3) replace mdelay() with msleep().
  4) add might_sleep().
  5) lock the device to prevent PM suspend from accessing the CSRs
     during the reset.
  6) coding style fixes.

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index e87fe95..03c7706 100644 (file)
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -110,7 +110,7 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset)
        }
 
        if (reset)
-               pci_execute_reset_function(virtfn);
+               __pci_reset_function(virtfn);
 
        pci_device_add(virtfn, virtfn->bus);
        mutex_unlock(&iov->dev->sriov->lock);
@@ -164,7 +164,7 @@ static void virtfn_remove(struct pci_dev *dev, int id, int reset)
 
        if (reset) {
                device_release_driver(&virtfn->dev);
-               pci_execute_reset_function(virtfn);
+               __pci_reset_function(virtfn);
        }
 
        sprintf(buf, "virtfn%u", id);

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8ea911e..6a052ad 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2055,111 +2055,112 @@ int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask)
 EXPORT_SYMBOL(pci_set_dma_seg_boundary);
 #endif
 
-static int __pcie_flr(struct pci_dev *dev, int probe)
+static int pcie_flr(struct pci_dev *dev, int probe)
 {
-       u16 status;
+       int i;
+       int pos;
        u32 cap;
-       int exppos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+       u16 status;
 
-       if (!exppos)
+       pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+       if (!pos)
                return -ENOTTY;
-       pci_read_config_dword(dev, exppos + PCI_EXP_DEVCAP, &cap);
+
+       pci_read_config_dword(dev, pos + PCI_EXP_DEVCAP, &cap);
        if (!(cap & PCI_EXP_DEVCAP_FLR))
                return -ENOTTY;
 
        if (probe)
                return 0;
 
-       pci_block_user_cfg_access(dev);
-
        /* Wait for Transaction Pending bit clean */
-       pci_read_config_word(dev, exppos + PCI_EXP_DEVSTA, &status);
-       if (!(status & PCI_EXP_DEVSTA_TRPND))
-               goto transaction_done;
+       for (i = 0; i < 4; i++) {
+               if (i)
+                       msleep((1 << (i - 1)) * 100);
 
-       msleep(100);
-       pci_read_config_word(dev, exppos + PCI_EXP_DEVSTA, &status);
-       if (!(status & PCI_EXP_DEVSTA_TRPND))
-               goto transaction_done;
-
-       dev_info(&dev->dev, "Busy after 100ms while trying to reset; "
-                       "sleeping for 1 second\n");
-       ssleep(1);
-       pci_read_config_word(dev, exppos + PCI_EXP_DEVSTA, &status);
-       if (status & PCI_EXP_DEVSTA_TRPND)
-               dev_info(&dev->dev, "Still busy after 1s; "
-                               "proceeding with reset anyway\n");
-
-transaction_done:
-       pci_write_config_word(dev, exppos + PCI_EXP_DEVCTL,
+               pci_read_config_word(dev, pos + PCI_EXP_DEVSTA, &status);
+               if (!(status & PCI_EXP_DEVSTA_TRPND))
+                       goto clear;
+       }
+
+       dev_err(&dev->dev, "transaction is not cleared; "
+                       "proceeding with reset anyway\n");
+
+clear:
+       pci_write_config_word(dev, pos + PCI_EXP_DEVCTL,
                                PCI_EXP_DEVCTL_BCR_FLR);
-       mdelay(100);
+       msleep(100);
 
-       pci_unblock_user_cfg_access(dev);
        return 0;
 }
 
-static int __pci_af_flr(struct pci_dev *dev, int probe)
+static int pci_af_flr(struct pci_dev *dev, int probe)
 {
-       int cappos = pci_find_capability(dev, PCI_CAP_ID_AF);
-       u8 status;
+       int i;
+       int pos;
        u8 cap;
+       u8 status;
 
-       if (!cappos)
+       pos = pci_find_capability(dev, PCI_CAP_ID_AF);
+       if (!pos)
                return -ENOTTY;
-       pci_read_config_byte(dev, cappos + PCI_AF_CAP, &cap);
+
+       pci_read_config_byte(dev, pos + PCI_AF_CAP, &cap);
        if (!(cap & PCI_AF_CAP_TP) || !(cap & PCI_AF_CAP_FLR))
                return -ENOTTY;
 
        if (probe)
                return 0;
 
-       pci_block_user_cfg_access(dev);
-
        /* Wait for Transaction Pending bit clean */
-       pci_read_config_byte(dev, cappos + PCI_AF_STATUS, &status);
-       if (!(status & PCI_AF_STATUS_TP))
-               goto transaction_done;
+       for (i = 0; i < 4; i++) {
+               if (i)
+                       msleep((1 << (i - 1)) * 100);
+
+               pci_read_config_byte(dev, pos + PCI_AF_STATUS, &status);
+               if (!(status & PCI_AF_STATUS_TP))
+                       goto clear;
+       }
+
+       dev_err(&dev->dev, "transaction is not cleared; "
+                       "proceeding with reset anyway\n");
 
+clear:
+       pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
        msleep(100);
-       pci_read_config_byte(dev, cappos + PCI_AF_STATUS, &status);
-       if (!(status & PCI_AF_STATUS_TP))
-               goto transaction_done;
-
-       dev_info(&dev->dev, "Busy after 100ms while trying to"
-                       " reset; sleeping for 1 second\n");
-       ssleep(1);
-       pci_read_config_byte(dev, cappos + PCI_AF_STATUS, &status);
-       if (status & PCI_AF_STATUS_TP)
-               dev_info(&dev->dev, "Still busy after 1s; "
-                               "proceeding with reset anyway\n");
-
-transaction_done:
-       pci_write_config_byte(dev, cappos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
-       mdelay(100);
-
-       pci_unblock_user_cfg_access(dev);
+
        return 0;
 }
 
-static int __pci_reset_function(struct pci_dev *pdev, int probe)
+static int pci_dev_reset(struct pci_dev *dev, int probe)
 {
-       int res;
+       int rc;
+
+       might_sleep();
+
+       if (!probe) {
+               pci_block_user_cfg_access(dev);
+               /* block PM suspend, driver probe, etc. */
+               down(&dev->dev.sem);
+       }
 
-       res = __pcie_flr(pdev, probe);
-       if (res != -ENOTTY)
-               return res;
+       rc = pcie_flr(dev, probe);
+       if (rc != -ENOTTY)
+               goto done;
 
-       res = __pci_af_flr(pdev, probe);
-       if (res != -ENOTTY)
-               return res;
+       rc = pci_af_flr(dev, probe);
+done:
+       if (!probe) {
+               up(&dev->dev.sem);
+               pci_unblock_user_cfg_access(dev);
+       }
 
-       return res;
+       return rc;
 }
 
 /**
- * pci_execute_reset_function() - Reset a PCI device function
- * @dev: Device function to reset
+ * __pci_reset_function - reset a PCI device function
+ * @dev: PCI device to reset
  *
  * Some devices allow an individual function to be reset without affecting
  * other functions in the same device.  The PCI device must be responsive
@@ -2171,18 +2172,18 @@ static int __pci_reset_function(struct pci_dev *pdev, int probe)
  * device including MSI, bus mastering, BARs, decoding IO and memory spaces,
  * etc.
  *
- * Returns 0 if the device function was successfully reset or -ENOTTY if the
+ * Returns 0 if the device function was successfully reset or negative if the
  * device doesn't support resetting a single function.
  */
-int pci_execute_reset_function(struct pci_dev *dev)
+int __pci_reset_function(struct pci_dev *dev)
 {
-       return __pci_reset_function(dev, 0);
+       return pci_dev_reset(dev, 0);
 }
-EXPORT_SYMBOL_GPL(pci_execute_reset_function);
+EXPORT_SYMBOL_GPL(__pci_reset_function);
 
 /**
- * pci_reset_function() - quiesce and reset a PCI device function
- * @dev: Device function to reset
+ * pci_reset_function - quiesce and reset a PCI device function
+ * @dev: PCI device to reset
  *
  * Some devices allow an individual function to be reset without affecting
  * other functions in the same device.  The PCI device must be responsive
@@ -2190,32 +2191,33 @@ EXPORT_SYMBOL_GPL(pci_execute_reset_function);
  *
  * This function does not just reset the PCI portion of a device, but
  * clears all the state associated with the device.  This function differs
- * from pci_execute_reset_function in that it saves and restores device state
+ * from __pci_reset_function in that it saves and restores device state
  * over the reset.
  *
- * Returns 0 if the device function was successfully reset or -ENOTTY if the
+ * Returns 0 if the device function was successfully reset or negative if the
  * device doesn't support resetting a single function.
  */
 int pci_reset_function(struct pci_dev *dev)
 {
-       int r = __pci_reset_function(dev, 1);
+       int rc;
 
-       if (r < 0)
-               return r;
+       rc = pci_dev_reset(dev, 1);
+       if (rc)
+               return rc;
 
-       if (!dev->msi_enabled && !dev->msix_enabled && dev->irq != 0)
-               disable_irq(dev->irq);
        pci_save_state(dev);
 
+       /*
+        * both INTx and MSI are disabled after the Interrupt Disable bit
+        * is set and the Bus Master bit is cleared.
+        */
        pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
 
-       r = pci_execute_reset_function(dev);
+       rc = pci_dev_reset(dev, 0);
 
        pci_restore_state(dev);
-       if (!dev->msi_enabled && !dev->msix_enabled && dev->irq != 0)
-               enable_irq(dev->irq);
 
-       return r;
+       return rc;
 }
 EXPORT_SYMBOL_GPL(pci_reset_function);
 

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 61d9b79..91b06be 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -702,8 +702,8 @@ int pcix_get_mmrbc(struct pci_dev *dev);
 int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc);
 int pcie_get_readrq(struct pci_dev *dev);
 int pcie_set_readrq(struct pci_dev *dev, int rq);
+int __pci_reset_function(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
-int pci_execute_reset_function(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
 int __must_check pci_assign_resource(struct pci_dev *dev, int i);
 int pci_select_bars(struct pci_dev *dev, unsigned long flags);