4 files changed, 205 insertions, 1 deletions

diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 2e9079df26b3..4190be64917f 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -33,6 +33,19 @@ config UIO_PDRV
 
 	  If you don't know what to do here, say N.
 
+config UIO_PDRV_GENIRQ
+	tristate "Userspace I/O platform driver with generic IRQ handling"
+	help
+	  Platform driver for Userspace I/O devices, including generic
+	  interrupt handling code. Shared interrupts are not supported.
+
+	  This kernel driver requires that the matching userspace driver
+	  handles interrupts in a special way. Userspace is responsible
+	  for acknowledging the hardware device if needed, and re-enabling
+	  interrupts in the interrupt controller using the write() syscall.
+
+	  If you don't know what to do here, say N.
+
 config UIO_SMX
 	tristate "SMX cryptengine UIO interface"
 	default n
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index e00ce0def1a0..8667bbdef904 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_UIO)	+= uio.o
 obj-$(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
diff --git a/drivers/uio/uio_pdrv.c b/drivers/uio/uio_pdrv.c
index 5d0d2e85d982..0b4ef39cd85d 100644
--- a/drivers/uio/uio_pdrv.c
+++ b/drivers/uio/uio_pdrv.c
@@ -88,6 +88,8 @@ static int uio_pdrv_remove(struct platform_device *pdev)
 
 	uio_unregister_device(pdata->uioinfo);
 
+	kfree(pdata);
+
 	return 0;
 }
 
@@ -114,5 +116,5 @@ module_exit(uio_pdrv_exit);
 
 MODULE_AUTHOR("Uwe Kleine-Koenig");
 MODULE_DESCRIPTION("Userspace I/O platform driver");
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:" DRIVER_NAME);
diff --git a/drivers/uio/uio_pdrv_genirq.c b/drivers/uio/uio_pdrv_genirq.c
new file mode 100644
index 000000000000..1f82c83a92ae
--- /dev/null
+++ b/drivers/uio/uio_pdrv_genirq.c
@@ -0,0 +1,188 @@
+/*
+ * drivers/uio/uio_pdrv_genirq.c
+ *
+ * Userspace I/O platform driver with generic IRQ handling code.
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * Based on uio_pdrv.c by Uwe Kleine-Koenig,
+ * Copyright (C) 2008 by Digi International Inc.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/uio_driver.h>
+#include <linux/spinlock.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/stringify.h>
+
+#define DRIVER_NAME "uio_pdrv_genirq"
+
+struct uio_pdrv_genirq_platdata {
+	struct uio_info *uioinfo;
+	spinlock_t lock;
+	unsigned long flags;
+};
+
+static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
+{
+	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
+
+	/* Just disable the interrupt in the interrupt controller, and
+	 * remember the state so we can allow user space to enable it later.
+	 */
+
+	if (!test_and_set_bit(0, &priv->flags))
+		disable_irq_nosync(irq);
+
+	return IRQ_HANDLED;
+}
+
+static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
+{
+	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
+	unsigned long flags;
+
+	/* Allow user space to enable and disable the interrupt
+	 * in the interrupt controller, but keep track of the
+	 * state to prevent per-irq depth damage.
+	 *
+	 * Serialize this operation to support multiple tasks.
+	 */
+
+	spin_lock_irqsave(&priv->lock, flags);
+	if (irq_on) {
+		if (test_and_clear_bit(0, &priv->flags))
+			enable_irq(dev_info->irq);
+	} else {
+		if (!test_and_set_bit(0, &priv->flags))
+			disable_irq(dev_info->irq);
+	}
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int uio_pdrv_genirq_probe(struct platform_device *pdev)
+{
+	struct uio_info *uioinfo = pdev->dev.platform_data;
+	struct uio_pdrv_genirq_platdata *priv;
+	struct uio_mem *uiomem;
+	int ret = -EINVAL;
+	int i;
+
+	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
+		dev_err(&pdev->dev, "missing platform_data\n");
+		goto bad0;
+	}
+
+	if (uioinfo->handler || uioinfo->irqcontrol || uioinfo->irq_flags) {
+		dev_err(&pdev->dev, "interrupt configuration error\n");
+		goto bad0;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		ret = -ENOMEM;
+		dev_err(&pdev->dev, "unable to kmalloc\n");
+		goto bad0;
+	}
+
+	priv->uioinfo = uioinfo;
+	spin_lock_init(&priv->lock);
+	priv->flags = 0; /* interrupt is enabled to begin with */
+
+	uiomem = &uioinfo->mem[0];
+
+	for (i = 0; i < pdev->num_resources; ++i) {
+		struct resource *r = &pdev->resource[i];
+
+		if (r->flags != IORESOURCE_MEM)
+			continue;
+
+		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
+			dev_warn(&pdev->dev, "device has more than "
+					__stringify(MAX_UIO_MAPS)
+					" I/O memory resources.\n");
+			break;
+		}
+
+		uiomem->memtype = UIO_MEM_PHYS;
+		uiomem->addr = r->start;
+		uiomem->size = r->end - r->start + 1;
+		++uiomem;
+	}
+
+	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
+		uiomem->size = 0;
+		++uiomem;
+	}
+
+	/* This driver requires no hardware specific kernel code to handle
+	 * interrupts. Instead, the interrupt handler simply disables the
+	 * interrupt in the interrupt controller. User space is responsible
+	 * for performing hardware specific acknowledge and re-enabling of
+	 * the interrupt in the interrupt controller.
+	 *
+	 * Interrupt sharing is not supported.
+	 */
+
+	uioinfo->irq_flags = IRQF_DISABLED;
+	uioinfo->handler = uio_pdrv_genirq_handler;
+	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
+	uioinfo->priv = priv;
+
+	ret = uio_register_device(&pdev->dev, priv->uioinfo);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register uio device\n");
+		goto bad1;
+	}
+
+	platform_set_drvdata(pdev, priv);
+	return 0;
+ bad1:
+	kfree(priv);
+ bad0:
+	return ret;
+}
+
+static int uio_pdrv_genirq_remove(struct platform_device *pdev)
+{
+	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
+
+	uio_unregister_device(priv->uioinfo);
+	kfree(priv);
+	return 0;
+}
+
+static struct platform_driver uio_pdrv_genirq = {
+	.probe = uio_pdrv_genirq_probe,
+	.remove = uio_pdrv_genirq_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init uio_pdrv_genirq_init(void)
+{
+	return platform_driver_register(&uio_pdrv_genirq);
+}
+
+static void __exit uio_pdrv_genirq_exit(void)
+{
+	platform_driver_unregister(&uio_pdrv_genirq);
+}
+
+module_init(uio_pdrv_genirq_init);
+module_exit(uio_pdrv_genirq_exit);
+
+MODULE_AUTHOR("Magnus Damm");
+MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);