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Date: Fri, 4 Nov 2011 09:46:01 +0100
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Jesse Barnes <jbarnes@...tuousgeek.org>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: "Hans J. Koch" <hjk@...sjkoch.de>,
Greg Kroah-Hartman <gregkh@...e.de>,
"Michael S. Tsirkin" <mst@...hat.com>, kvm@...r.kernel.org
Subject: [PATCH v2 3/3] 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: Michael S. Tsirkin <mst@...hat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
---
drivers/uio/uio_pci_generic.c | 77 +++-------------------------------------
1 files changed, 6 insertions(+), 71 deletions(-)
diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
index 56d00c62..0bd08ef 100644
--- a/drivers/uio/uio_pci_generic.c
+++ b/drivers/uio/uio_pci_generic.c
@@ -45,78 +45,12 @@ to_uio_pci_generic_dev(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 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. */
- ret = IRQ_HANDLED;
-done:
-
- pci_cfg_access_lock(pdev);
- return ret;
-}
+ if (!pci_check_and_mask_intx(gdev->pdev))
+ return IRQ_NONE;
-/* Verify that the device supports Interrupt Disable bit in command register,
- * per PCI 2.3, by flipping this bit and reading it back: this bit was readonly
- * 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;
+ /* UIO core will signal the user process. */
+ return IRQ_HANDLED;
}
static int __devinit probe(struct pci_dev *pdev,
@@ -139,9 +73,10 @@ static int __devinit probe(struct pci_dev *pdev,
return -ENODEV;
}
- err = verify_pci_2_3(pdev);
- if (err)
+ if (!pci_intx_mask_supported(pdev)) {
+ err = -ENODEV;
goto err_verify;
+ }
gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
if (!gdev) {
--
1.7.3.4
--
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