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Subject[PATCH 45/46] UIO: add automata sercos3 pci card support
Date
From: John Ogness <john.ogness@linutronix.de>

Here is a new version of the patch to support the Automata Sercos III
PCI card driver. I now check that the IRQ is enabled before accepting
the interrupt.

I still use a logical OR to store the enabled interrupts and I've
added a second use of a logical OR when restoring the enabled
interrupts. I added an explanation of why I do this in comments at the
top of the source file.

Since I use a logical OR, I also removed the extra checks if the
Interrupt Enable Register and ier0_cache are 0.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/uio/Kconfig | 13 +++
drivers/uio/Makefile | 1 +
drivers/uio/uio_sercos3.c | 243 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 257 insertions(+), 0 deletions(-)
create mode 100644 drivers/uio/uio_sercos3.c
diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 4190be6..04b954c 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -58,4 +58,17 @@ config UIO_SMX

If you compile this as a module, it will be called uio_smx.

+config UIO_SERCOS3
+ tristate "Automata Sercos III PCI card driver"
+ default n
+ help
+ Userspace I/O interface for the Sercos III PCI card from
+ Automata GmbH. The userspace part of this driver will be
+ available for download from the Automata GmbH web site.
+
+ Automata GmbH: http://www.automataweb.com
+ Sercos III interface: http://www.sercos.com
+
+ If you compile this as a module, it will be called uio_sercos3.
+
endif
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index 8667bbd..e695581 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_UIO_CIF) += uio_cif.o
obj-$(CONFIG_UIO_PDRV) += uio_pdrv.o
obj-$(CONFIG_UIO_PDRV_GENIRQ) += uio_pdrv_genirq.o
obj-$(CONFIG_UIO_SMX) += uio_smx.o
+obj-$(CONFIG_UIO_SERCOS3) += uio_sercos3.o
diff --git a/drivers/uio/uio_sercos3.c b/drivers/uio/uio_sercos3.c
new file mode 100644
index 0000000..a6d1b2b
--- /dev/null
+++ b/drivers/uio/uio_sercos3.c
@@ -0,0 +1,243 @@
+/* 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>
+
+/* 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 __devinit 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_DISABLED | 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);
+ pci_set_drvdata(dev, NULL);
+ 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[] __devinitdata = {
+ {
+ .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,
+};
+
+static int __init sercos3_init_module(void)
+{
+ return pci_register_driver(&sercos3_pci_driver);
+}
+
+static void __exit sercos3_exit_module(void)
+{
+ pci_unregister_driver(&sercos3_pci_driver);
+}
+
+module_init(sercos3_init_module);
+module_exit(sercos3_exit_module);
+
+MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card");
+MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");
+MODULE_LICENSE("GPL v2");
--
1.6.0.2


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