diff options
Diffstat (limited to 'drivers/uio/uio_sercos3.c')
| -rw-r--r-- | drivers/uio/uio_sercos3.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/uio/uio_sercos3.c b/drivers/uio/uio_sercos3.c new file mode 100644 index 000000000..9658a0887 --- /dev/null +++ b/drivers/uio/uio_sercos3.c @@ -0,0 +1,232 @@ +// SPDX-License-Identifier: GPL-2.0 +/* sercos3: UIO driver for the Automata Sercos III PCI card + + Copyright (C) 2008 Linutronix GmbH + Author: John Ogness <john.ogness@linutronix.de> + + This is a straight-forward UIO driver, where interrupts are disabled + by the interrupt handler and re-enabled via a write to the UIO device + by the userspace-part. + + The only part that may seem odd is the use of a logical OR when + storing and restoring enabled interrupts. This is done because the + userspace-part could directly modify the Interrupt Enable Register + at any time. To reduce possible conflicts, the kernel driver uses + a logical OR to make more controlled changes (rather than blindly + overwriting previous values). + + Race conditions exist if the userspace-part directly modifies the + Interrupt Enable Register while in operation. The consequences are + that certain interrupts would fail to be enabled or disabled. For + this reason, the userspace-part should only directly modify the + Interrupt Enable Register at the beginning (to get things going). + The userspace-part can safely disable interrupts at any time using + a write to the UIO device. +*/ + +#include <linux/device.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/uio_driver.h> +#include <linux/io.h> +#include <linux/slab.h> + +/* ID's for SERCOS III PCI card (PLX 9030) */ +#define SERCOS_SUB_VENDOR_ID 0x1971 +#define SERCOS_SUB_SYSID_3530 0x3530 +#define SERCOS_SUB_SYSID_3535 0x3535 +#define SERCOS_SUB_SYSID_3780 0x3780 + +/* Interrupt Enable Register */ +#define IER0_OFFSET 0x08 + +/* Interrupt Status Register */ +#define ISR0_OFFSET 0x18 + +struct sercos3_priv { + u32 ier0_cache; + spinlock_t ier0_cache_lock; +}; + +/* this function assumes ier0_cache_lock is locked! */ +static void sercos3_disable_interrupts(struct uio_info *info, + struct sercos3_priv *priv) +{ + void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; + + /* add enabled interrupts to cache */ + priv->ier0_cache |= ioread32(ier0); + + /* disable interrupts */ + iowrite32(0, ier0); +} + +/* this function assumes ier0_cache_lock is locked! */ +static void sercos3_enable_interrupts(struct uio_info *info, + struct sercos3_priv *priv) +{ + void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; + + /* restore previously enabled interrupts */ + iowrite32(ioread32(ier0) | priv->ier0_cache, ier0); + priv->ier0_cache = 0; +} + +static irqreturn_t sercos3_handler(int irq, struct uio_info *info) +{ + struct sercos3_priv *priv = info->priv; + void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET; + void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; + + if (!(ioread32(isr0) & ioread32(ier0))) + return IRQ_NONE; + + spin_lock(&priv->ier0_cache_lock); + sercos3_disable_interrupts(info, priv); + spin_unlock(&priv->ier0_cache_lock); + + return IRQ_HANDLED; +} + +static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on) +{ + struct sercos3_priv *priv = info->priv; + + spin_lock_irq(&priv->ier0_cache_lock); + if (irq_on) + sercos3_enable_interrupts(info, priv); + else + sercos3_disable_interrupts(info, priv); + spin_unlock_irq(&priv->ier0_cache_lock); + + return 0; +} + +static int sercos3_setup_iomem(struct pci_dev *dev, struct uio_info *info, + int n, int pci_bar) +{ + info->mem[n].addr = pci_resource_start(dev, pci_bar); + if (!info->mem[n].addr) + return -1; + info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar), + pci_resource_len(dev, pci_bar)); + if (!info->mem[n].internal_addr) + return -1; + info->mem[n].size = pci_resource_len(dev, pci_bar); + info->mem[n].memtype = UIO_MEM_PHYS; + return 0; +} + +static int sercos3_pci_probe(struct pci_dev *dev, + const struct pci_device_id *id) +{ + struct uio_info *info; + struct sercos3_priv *priv; + int i; + + info = kzalloc(sizeof(struct uio_info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + priv = kzalloc(sizeof(struct sercos3_priv), GFP_KERNEL); + if (!priv) + goto out_free; + + if (pci_enable_device(dev)) + goto out_free_priv; + + if (pci_request_regions(dev, "sercos3")) + goto out_disable; + + /* we only need PCI BAR's 0, 2, 3, 4, 5 */ + if (sercos3_setup_iomem(dev, info, 0, 0)) + goto out_unmap; + if (sercos3_setup_iomem(dev, info, 1, 2)) + goto out_unmap; + if (sercos3_setup_iomem(dev, info, 2, 3)) + goto out_unmap; + if (sercos3_setup_iomem(dev, info, 3, 4)) + goto out_unmap; + if (sercos3_setup_iomem(dev, info, 4, 5)) + goto out_unmap; + + spin_lock_init(&priv->ier0_cache_lock); + info->priv = priv; + info->name = "Sercos_III_PCI"; + info->version = "0.0.1"; + info->irq = dev->irq; + info->irq_flags = IRQF_SHARED; + info->handler = sercos3_handler; + info->irqcontrol = sercos3_irqcontrol; + + pci_set_drvdata(dev, info); + + if (uio_register_device(&dev->dev, info)) + goto out_unmap; + + return 0; + +out_unmap: + for (i = 0; i < 5; i++) { + if (info->mem[i].internal_addr) + iounmap(info->mem[i].internal_addr); + } + pci_release_regions(dev); +out_disable: + pci_disable_device(dev); +out_free_priv: + kfree(priv); +out_free: + kfree(info); + return -ENODEV; +} + +static void sercos3_pci_remove(struct pci_dev *dev) +{ + struct uio_info *info = pci_get_drvdata(dev); + int i; + + uio_unregister_device(info); + pci_release_regions(dev); + pci_disable_device(dev); + for (i = 0; i < 5; i++) { + if (info->mem[i].internal_addr) + iounmap(info->mem[i].internal_addr); + } + kfree(info->priv); + kfree(info); +} + +static struct pci_device_id sercos3_pci_ids[] = { + { + .vendor = PCI_VENDOR_ID_PLX, + .device = PCI_DEVICE_ID_PLX_9030, + .subvendor = SERCOS_SUB_VENDOR_ID, + .subdevice = SERCOS_SUB_SYSID_3530, + }, + { + .vendor = PCI_VENDOR_ID_PLX, + .device = PCI_DEVICE_ID_PLX_9030, + .subvendor = SERCOS_SUB_VENDOR_ID, + .subdevice = SERCOS_SUB_SYSID_3535, + }, + { + .vendor = PCI_VENDOR_ID_PLX, + .device = PCI_DEVICE_ID_PLX_9030, + .subvendor = SERCOS_SUB_VENDOR_ID, + .subdevice = SERCOS_SUB_SYSID_3780, + }, + { 0, } +}; + +static struct pci_driver sercos3_pci_driver = { + .name = "sercos3", + .id_table = sercos3_pci_ids, + .probe = sercos3_pci_probe, + .remove = sercos3_pci_remove, +}; + +module_pci_driver(sercos3_pci_driver); +MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card"); +MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>"); +MODULE_LICENSE("GPL v2"); |