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Commit 2502dbdf authored by Jan Kiszka's avatar Jan Kiszka Committed by Jesse Barnes
Browse files

uio: Convert uio_generic_pci to new intx masking API 



The new PCI API provides both generic probing for 2.3 masking support
and check&mask in the interrupt handler.

Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent a2e27787

drivers/uio/uio_pci_generic.c

+7 −72
Original line number Original line Diff line number Diff line
@@ -45,78 +45,12 @@ to_uio_pci_generic_dev(struct uio_info *info) 
static irqreturn_t irqhandler(int irq, struct uio_info *info)

static irqreturn_t irqhandler(int irq, struct uio_info *info)

{

{

	struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);

	struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);

	struct pci_dev *pdev = gdev->pdev;

	irqreturn_t ret = IRQ_NONE;

	u32 cmd_status_dword;

	u16 origcmd, newcmd, status;



	/* We do a single dword read to retrieve both command and status.

	 * Document assumptions that make this possible. */

	BUILD_BUG_ON(PCI_COMMAND % 4);

	BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS);



	if (!pci_cfg_access_trylock(pdev))

		goto error;



	/* Read both command and status registers in a single 32-bit operation.

	 * Note: we could cache the value for command and move the status read

	 * out of the lock if there was a way to get notified of user changes

	 * to command register through sysfs. Should be good for shared irqs. */

	pci_read_config_dword(pdev, PCI_COMMAND, &cmd_status_dword);

	origcmd = cmd_status_dword;

	status = cmd_status_dword >> 16;



	/* Check interrupt status register to see whether our device

	 * triggered the interrupt. */

	if (!(status & PCI_STATUS_INTERRUPT))

		goto done;



	/* We triggered the interrupt, disable it. */

	newcmd = origcmd | PCI_COMMAND_INTX_DISABLE;

	if (newcmd != origcmd)

		pci_write_config_word(pdev, PCI_COMMAND, newcmd);





	/* UIO core will signal the user process. */

	if (!pci_check_and_mask_intx(gdev->pdev))

	ret = IRQ_HANDLED;

		return IRQ_NONE;

done:



	pci_cfg_access_lock(pdev);

	return ret;

}





/* Verify that the device supports Interrupt Disable bit in command register,

	/* UIO core will signal the user process. */

 * per PCI 2.3, by flipping this bit and reading it back: this bit was readonly

	return IRQ_HANDLED;

 * in PCI 2.2. */

static int __devinit verify_pci_2_3(struct pci_dev *pdev)

{

	u16 orig, new;

	int err = 0;



	pci_cfg_access_lock(pdev);

	pci_read_config_word(pdev, PCI_COMMAND, &orig);

	pci_write_config_word(pdev, PCI_COMMAND,

			      orig ^ PCI_COMMAND_INTX_DISABLE);

	pci_read_config_word(pdev, PCI_COMMAND, &new);

	/* There's no way to protect against

	 * hardware bugs or detect them reliably, but as long as we know

	 * what the value should be, let's go ahead and check it. */

	if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE) {

		err = -EBUSY;

		dev_err(&pdev->dev, "Command changed from 0x%x to 0x%x: "

			"driver or HW bug?\n", orig, new);

		goto err;

	}

	if (!((new ^ orig) & PCI_COMMAND_INTX_DISABLE)) {

		dev_warn(&pdev->dev, "Device does not support "

			 "disabling interrupts: unable to bind.\n");

		err = -ENODEV;

		goto err;

	}

	/* Now restore the original value. */

	pci_write_config_word(pdev, PCI_COMMAND, orig);

err:

	pci_cfg_access_unlock(pdev);

	return err;

}

}





static int __devinit probe(struct pci_dev *pdev,

static int __devinit probe(struct pci_dev *pdev,
@@ -139,9 +73,10 @@ static int __devinit probe(struct pci_dev *pdev, 
		return -ENODEV;

		return -ENODEV;

	}

	}





	err = verify_pci_2_3(pdev);

	if (!pci_intx_mask_supported(pdev)) {

	if (err)

		err = -ENODEV;

		goto err_verify;

		goto err_verify;

	}





	gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);

	gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);

	if (!gdev) {

	if (!gdev) {