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@redhat.com> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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1 changed files with 6 additions and 71 deletions
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@ -45,78 +45,12 @@ to_uio_pci_generic_dev(struct uio_info *info)
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static irqreturn_t irqhandler(int irq, struct uio_info *info)
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{
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struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
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struct pci_dev *pdev = gdev->pdev;
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irqreturn_t ret = IRQ_NONE;
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u32 cmd_status_dword;
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u16 origcmd, newcmd, status;
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/* We do a single dword read to retrieve both command and status.
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* Document assumptions that make this possible. */
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BUILD_BUG_ON(PCI_COMMAND % 4);
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BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS);
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if (!pci_cfg_access_trylock(pdev))
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goto error;
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/* Read both command and status registers in a single 32-bit operation.
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* Note: we could cache the value for command and move the status read
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* out of the lock if there was a way to get notified of user changes
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* to command register through sysfs. Should be good for shared irqs. */
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pci_read_config_dword(pdev, PCI_COMMAND, &cmd_status_dword);
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origcmd = cmd_status_dword;
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status = cmd_status_dword >> 16;
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/* Check interrupt status register to see whether our device
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* triggered the interrupt. */
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if (!(status & PCI_STATUS_INTERRUPT))
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goto done;
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/* We triggered the interrupt, disable it. */
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newcmd = origcmd | PCI_COMMAND_INTX_DISABLE;
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if (newcmd != origcmd)
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pci_write_config_word(pdev, PCI_COMMAND, newcmd);
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if (!pci_check_and_mask_intx(gdev->pdev))
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return IRQ_NONE;
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/* UIO core will signal the user process. */
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ret = IRQ_HANDLED;
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done:
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pci_cfg_access_lock(pdev);
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return ret;
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}
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/* Verify that the device supports Interrupt Disable bit in command register,
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* per PCI 2.3, by flipping this bit and reading it back: this bit was readonly
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* in PCI 2.2. */
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static int __devinit verify_pci_2_3(struct pci_dev *pdev)
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{
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u16 orig, new;
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int err = 0;
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pci_cfg_access_lock(pdev);
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pci_read_config_word(pdev, PCI_COMMAND, &orig);
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pci_write_config_word(pdev, PCI_COMMAND,
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orig ^ PCI_COMMAND_INTX_DISABLE);
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pci_read_config_word(pdev, PCI_COMMAND, &new);
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/* There's no way to protect against
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* hardware bugs or detect them reliably, but as long as we know
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* what the value should be, let's go ahead and check it. */
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if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE) {
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err = -EBUSY;
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dev_err(&pdev->dev, "Command changed from 0x%x to 0x%x: "
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"driver or HW bug?\n", orig, new);
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goto err;
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}
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if (!((new ^ orig) & PCI_COMMAND_INTX_DISABLE)) {
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dev_warn(&pdev->dev, "Device does not support "
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"disabling interrupts: unable to bind.\n");
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err = -ENODEV;
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goto err;
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}
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/* Now restore the original value. */
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pci_write_config_word(pdev, PCI_COMMAND, orig);
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err:
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pci_cfg_access_unlock(pdev);
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return err;
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return IRQ_HANDLED;
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}
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static int __devinit probe(struct pci_dev *pdev,
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@ -139,9 +73,10 @@ static int __devinit probe(struct pci_dev *pdev,
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return -ENODEV;
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}
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err = verify_pci_2_3(pdev);
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if (err)
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if (!pci_intx_mask_supported(pdev)) {
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err = -ENODEV;
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goto err_verify;
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}
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gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
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if (!gdev) {
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