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    Subject[PATCH 3/3] uio: Convert uio_generic_pci to new intx masking API
    Date
    The new PCI API provides both generic probing for 2.3 masking support
    and check&mask in the interrupt handler.

    Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
    ---
    drivers/uio/uio_pci_generic.c | 84 +++-------------------------------------
    1 files changed, 7 insertions(+), 77 deletions(-)

    diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
    index 67535f9..33f7dfb 100644
    --- a/drivers/uio/uio_pci_generic.c
    +++ b/drivers/uio/uio_pci_generic.c
    @@ -33,7 +33,6 @@
    struct uio_pci_generic_dev {
    struct uio_info info;
    struct pci_dev *pdev;
    - spinlock_t lock; /* guards command register accesses */
    };

    static inline struct uio_pci_generic_dev *
    @@ -47,81 +46,12 @@ 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);
    -
    - spin_lock_irq(&gdev->lock);
    - 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);
    -error:
    - spin_unlock_irq(&gdev->lock);
    - 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,
    @@ -144,9 +74,10 @@ 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) {
    @@ -160,7 +91,6 @@ static int __devinit probe(struct pci_dev *pdev,
    gdev->info.irq_flags = IRQF_SHARED;
    gdev->info.handler = irqhandler;
    gdev->pdev = pdev;
    - spin_lock_init(&gdev->lock);

    if (uio_register_device(&pdev->dev, &gdev->info))
    goto err_register;
    --
    1.7.3.4


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