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226 lines
6.1 KiB
226 lines
6.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* sercos3: UIO driver for the Automata Sercos III PCI card |
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Copyright (C) 2008 Linutronix GmbH |
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Author: John Ogness <[email protected]> |
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This is a straight-forward UIO driver, where interrupts are disabled |
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by the interrupt handler and re-enabled via a write to the UIO device |
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by the userspace-part. |
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The only part that may seem odd is the use of a logical OR when |
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storing and restoring enabled interrupts. This is done because the |
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userspace-part could directly modify the Interrupt Enable Register |
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at any time. To reduce possible conflicts, the kernel driver uses |
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a logical OR to make more controlled changes (rather than blindly |
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overwriting previous values). |
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Race conditions exist if the userspace-part directly modifies the |
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Interrupt Enable Register while in operation. The consequences are |
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that certain interrupts would fail to be enabled or disabled. For |
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this reason, the userspace-part should only directly modify the |
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Interrupt Enable Register at the beginning (to get things going). |
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The userspace-part can safely disable interrupts at any time using |
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a write to the UIO device. |
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*/ |
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#include <linux/device.h> |
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#include <linux/module.h> |
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#include <linux/pci.h> |
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#include <linux/uio_driver.h> |
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#include <linux/io.h> |
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#include <linux/slab.h> |
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/* ID's for SERCOS III PCI card (PLX 9030) */ |
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#define SERCOS_SUB_VENDOR_ID 0x1971 |
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#define SERCOS_SUB_SYSID_3530 0x3530 |
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#define SERCOS_SUB_SYSID_3535 0x3535 |
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#define SERCOS_SUB_SYSID_3780 0x3780 |
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/* Interrupt Enable Register */ |
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#define IER0_OFFSET 0x08 |
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/* Interrupt Status Register */ |
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#define ISR0_OFFSET 0x18 |
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struct sercos3_priv { |
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u32 ier0_cache; |
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spinlock_t ier0_cache_lock; |
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}; |
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/* this function assumes ier0_cache_lock is locked! */ |
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static void sercos3_disable_interrupts(struct uio_info *info, |
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struct sercos3_priv *priv) |
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{ |
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void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; |
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/* add enabled interrupts to cache */ |
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priv->ier0_cache |= ioread32(ier0); |
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/* disable interrupts */ |
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iowrite32(0, ier0); |
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} |
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/* this function assumes ier0_cache_lock is locked! */ |
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static void sercos3_enable_interrupts(struct uio_info *info, |
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struct sercos3_priv *priv) |
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{ |
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void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; |
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/* restore previously enabled interrupts */ |
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iowrite32(ioread32(ier0) | priv->ier0_cache, ier0); |
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priv->ier0_cache = 0; |
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} |
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static irqreturn_t sercos3_handler(int irq, struct uio_info *info) |
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{ |
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struct sercos3_priv *priv = info->priv; |
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void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET; |
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void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; |
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if (!(ioread32(isr0) & ioread32(ier0))) |
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return IRQ_NONE; |
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spin_lock(&priv->ier0_cache_lock); |
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sercos3_disable_interrupts(info, priv); |
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spin_unlock(&priv->ier0_cache_lock); |
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return IRQ_HANDLED; |
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} |
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static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on) |
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{ |
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struct sercos3_priv *priv = info->priv; |
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spin_lock_irq(&priv->ier0_cache_lock); |
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if (irq_on) |
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sercos3_enable_interrupts(info, priv); |
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else |
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sercos3_disable_interrupts(info, priv); |
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spin_unlock_irq(&priv->ier0_cache_lock); |
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return 0; |
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} |
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static int sercos3_setup_iomem(struct pci_dev *dev, struct uio_info *info, |
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int n, int pci_bar) |
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{ |
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info->mem[n].addr = pci_resource_start(dev, pci_bar); |
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if (!info->mem[n].addr) |
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return -1; |
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info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar), |
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pci_resource_len(dev, pci_bar)); |
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if (!info->mem[n].internal_addr) |
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return -1; |
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info->mem[n].size = pci_resource_len(dev, pci_bar); |
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info->mem[n].memtype = UIO_MEM_PHYS; |
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return 0; |
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} |
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static int sercos3_pci_probe(struct pci_dev *dev, |
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const struct pci_device_id *id) |
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{ |
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struct uio_info *info; |
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struct sercos3_priv *priv; |
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int i; |
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info = devm_kzalloc(&dev->dev, sizeof(struct uio_info), GFP_KERNEL); |
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if (!info) |
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return -ENOMEM; |
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priv = devm_kzalloc(&dev->dev, sizeof(struct sercos3_priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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if (pci_enable_device(dev)) |
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return -ENODEV; |
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if (pci_request_regions(dev, "sercos3")) |
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goto out_disable; |
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/* we only need PCI BAR's 0, 2, 3, 4, 5 */ |
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if (sercos3_setup_iomem(dev, info, 0, 0)) |
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goto out_unmap; |
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if (sercos3_setup_iomem(dev, info, 1, 2)) |
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goto out_unmap; |
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if (sercos3_setup_iomem(dev, info, 2, 3)) |
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goto out_unmap; |
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if (sercos3_setup_iomem(dev, info, 3, 4)) |
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goto out_unmap; |
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if (sercos3_setup_iomem(dev, info, 4, 5)) |
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goto out_unmap; |
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spin_lock_init(&priv->ier0_cache_lock); |
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info->priv = priv; |
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info->name = "Sercos_III_PCI"; |
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info->version = "0.0.1"; |
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info->irq = dev->irq; |
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info->irq_flags = IRQF_SHARED; |
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info->handler = sercos3_handler; |
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info->irqcontrol = sercos3_irqcontrol; |
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pci_set_drvdata(dev, info); |
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if (uio_register_device(&dev->dev, info)) |
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goto out_unmap; |
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return 0; |
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out_unmap: |
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for (i = 0; i < 5; i++) { |
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if (info->mem[i].internal_addr) |
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iounmap(info->mem[i].internal_addr); |
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} |
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pci_release_regions(dev); |
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out_disable: |
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pci_disable_device(dev); |
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return -ENODEV; |
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} |
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static void sercos3_pci_remove(struct pci_dev *dev) |
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{ |
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struct uio_info *info = pci_get_drvdata(dev); |
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int i; |
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uio_unregister_device(info); |
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pci_release_regions(dev); |
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pci_disable_device(dev); |
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for (i = 0; i < 5; i++) { |
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if (info->mem[i].internal_addr) |
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iounmap(info->mem[i].internal_addr); |
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} |
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} |
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static struct pci_device_id sercos3_pci_ids[] = { |
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{ |
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.vendor = PCI_VENDOR_ID_PLX, |
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.device = PCI_DEVICE_ID_PLX_9030, |
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.subvendor = SERCOS_SUB_VENDOR_ID, |
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.subdevice = SERCOS_SUB_SYSID_3530, |
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}, |
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{ |
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.vendor = PCI_VENDOR_ID_PLX, |
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.device = PCI_DEVICE_ID_PLX_9030, |
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.subvendor = SERCOS_SUB_VENDOR_ID, |
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.subdevice = SERCOS_SUB_SYSID_3535, |
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}, |
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{ |
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.vendor = PCI_VENDOR_ID_PLX, |
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.device = PCI_DEVICE_ID_PLX_9030, |
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.subvendor = SERCOS_SUB_VENDOR_ID, |
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.subdevice = SERCOS_SUB_SYSID_3780, |
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}, |
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{ 0, } |
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}; |
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static struct pci_driver sercos3_pci_driver = { |
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.name = "sercos3", |
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.id_table = sercos3_pci_ids, |
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.probe = sercos3_pci_probe, |
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.remove = sercos3_pci_remove, |
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}; |
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module_pci_driver(sercos3_pci_driver); |
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MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card"); |
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MODULE_AUTHOR("John Ogness <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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