Commit 8c1c699f authored by Yu Zhao's avatar Yu Zhao Committed by Jesse Barnes
Browse files

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: default avatarKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: default avatarYu Zhao <yu.zhao@intel.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent c465def6

drivers/pci/iov.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

drivers/pci/pci.c

+84 −82
Original line number Diff line number Diff line
@@ -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);

		pci_read_config_word(dev, pos + 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; "

			goto clear;

	}



	dev_err(&dev->dev, "transaction is not cleared; "

			"proceeding with reset anyway\n");



transaction_done:

	pci_write_config_word(dev, exppos + PCI_EXP_DEVCTL,

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);



	msleep(100);

	pci_read_config_byte(dev, cappos + PCI_AF_STATUS, &status);

		pci_read_config_byte(dev, pos + 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; "

			goto clear;

	}



	dev_err(&dev->dev, "transaction is not cleared; "

			"proceeding with reset anyway\n");



transaction_done:

	pci_write_config_byte(dev, cappos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);

	mdelay(100);

clear:

	pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);

	msleep(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();



	res = __pcie_flr(pdev, probe);

	if (res != -ENOTTY)

		return res;

	if (!probe) {

		pci_block_user_cfg_access(dev);

		/* block PM suspend, driver probe, etc. */

		down(&dev->dev.sem);

	}



	res = __pci_af_flr(pdev, probe);

	if (res != -ENOTTY)

		return res;

	rc = pcie_flr(dev, probe);

	if (rc != -ENOTTY)

		goto done;



	return res;

	rc = pci_af_flr(dev, probe);

done:

	if (!probe) {

		up(&dev->dev.sem);

		pci_unblock_user_cfg_access(dev);

	}



	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);

include/linux/pci.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

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