227 lines
6.1 KiB
C
227 lines
6.1 KiB
C
// 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 <john.ogness@linutronix.de>
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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 <john.ogness@linutronix.de>");
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MODULE_LICENSE("GPL v2");
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