1 files changed, 354 insertions, 0 deletions
diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c
new file mode 100644
index 0000000..4d4dd00
--- /dev/null
+++ b/drivers/uio/uio_dmem_genirq.c
@@ -0,0 +1,354 @@
+/*
+ * drivers/uio/uio_dmem_genirq.c
+ *
+ * Userspace I/O platform driver with generic IRQ handling code.
+ *
+ * Copyright (C) 2012 Damian Hobson-Garcia
+ *
+ * Based on uio_pdrv_genirq.c by Magnus Damm
+ *
+ * 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/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_data/uio_dmem_genirq.h>
+#include <linux/stringify.h>
+#include <linux/pm_runtime.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+
+#define DRIVER_NAME "uio_dmem_genirq"
+
+struct uio_dmem_genirq_platdata {
+	struct uio_info *uioinfo;
+	spinlock_t lock;
+	unsigned long flags;
+	struct platform_device *pdev;
+	unsigned int dmem_region_start;
+	unsigned int num_dmem_regions;
+	struct mutex alloc_lock;
+	unsigned int refcnt;
+};
+
+static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
+{
+	struct uio_dmem_genirq_platdata *priv = info->priv;
+	struct uio_mem *uiomem;
+	int ret = 0;
+
+	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
+
+	mutex_lock(&priv->alloc_lock);
+	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
+		void *addr;
+		if (!uiomem->size)
+			break;
+
+		addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
+				(dma_addr_t *)&uiomem->addr, GFP_KERNEL);
+		if (!addr) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		uiomem->internal_addr = addr;
+		++uiomem;
+	}
+	priv->refcnt++;
+
+	mutex_unlock(&priv->alloc_lock);
+	/* Wait until the Runtime PM code has woken up the device */
+	pm_runtime_get_sync(&priv->pdev->dev);
+	return ret;
+}
+
+static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
+{
+	struct uio_dmem_genirq_platdata *priv = info->priv;
+	struct uio_mem *uiomem;
+
+	/* Tell the Runtime PM code that the device has become idle */
+	pm_runtime_put_sync(&priv->pdev->dev);
+
+	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
+
+	mutex_lock(&priv->alloc_lock);
+
+	priv->refcnt--;
+	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
+		if (!uiomem->size)
+			break;
+
+		dma_free_coherent(&priv->pdev->dev, uiomem->size,
+				uiomem->internal_addr, uiomem->addr);
+		uiomem->addr = DMA_ERROR_CODE;
+		++uiomem;
+	}
+
+	mutex_unlock(&priv->alloc_lock);
+	return 0;
+}
+
+static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
+{
+	struct uio_dmem_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_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
+{
+	struct uio_dmem_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_dmem_genirq_probe(struct platform_device *pdev)
+{
+	struct uio_dmem_genirq_pdata *pdata = pdev->dev.platform_data;
+	struct uio_info *uioinfo = &pdata->uioinfo;
+	struct uio_dmem_genirq_platdata *priv;
+	struct uio_mem *uiomem;
+	int ret = -EINVAL;
+	int i;
+
+	if (!uioinfo) {
+		int irq;
+
+		/* alloc uioinfo for one device */
+		uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
+		if (!uioinfo) {
+			ret = -ENOMEM;
+			dev_err(&pdev->dev, "unable to kmalloc\n");
+			goto bad2;
+		}
+		uioinfo->name = pdev->dev.of_node->name;
+		uioinfo->version = "devicetree";
+
+		/* Multiple IRQs are not supported */
+		irq = platform_get_irq(pdev, 0);
+		if (irq == -ENXIO)
+			uioinfo->irq = UIO_IRQ_NONE;
+		else
+			uioinfo->irq = irq;
+	}
+
+	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
+		dev_err(&pdev->dev, "missing platform_data\n");
+		goto bad0;
+	}
+
+	if (uioinfo->handler || uioinfo->irqcontrol ||
+	    uioinfo->irq_flags & IRQF_SHARED) {
+		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;
+	}
+
+	dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
+
+	priv->uioinfo = uioinfo;
+	spin_lock_init(&priv->lock);
+	priv->flags = 0; /* interrupt is enabled to begin with */
+	priv->pdev = pdev;
+	mutex_init(&priv->alloc_lock);
+
+	if (!uioinfo->irq) {
+		ret = platform_get_irq(pdev, 0);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to get IRQ\n");
+			goto bad0;
+		}
+		uioinfo->irq = ret;
+	}
+	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 = resource_size(r);
+		++uiomem;
+	}
+
+	priv->dmem_region_start = i;
+	priv->num_dmem_regions = pdata->num_dynamic_regions;
+
+	for (i = 0; i < pdata->num_dynamic_regions; ++i) {
+		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
+			dev_warn(&pdev->dev, "device has more than "
+					__stringify(MAX_UIO_MAPS)
+					" dynamic and fixed memory regions.\n");
+			break;
+		}
+		uiomem->memtype = UIO_MEM_PHYS;
+		uiomem->addr = DMA_ERROR_CODE;
+		uiomem->size = pdata->dynamic_region_sizes[i];
+		++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->handler = uio_dmem_genirq_handler;
+	uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
+	uioinfo->open = uio_dmem_genirq_open;
+	uioinfo->release = uio_dmem_genirq_release;
+	uioinfo->priv = priv;
+
+	/* Enable Runtime PM for this device:
+	 * The device starts in suspended state to allow the hardware to be
+	 * turned off by default. The Runtime PM bus code should power on the
+	 * hardware and enable clocks at open().
+	 */
+	pm_runtime_enable(&pdev->dev);
+
+	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);
+	pm_runtime_disable(&pdev->dev);
+ bad0:
+	/* kfree uioinfo for OF */
+	if (pdev->dev.of_node)
+		kfree(uioinfo);
+ bad2:
+	return ret;
+}
+
+static int uio_dmem_genirq_remove(struct platform_device *pdev)
+{
+	struct uio_dmem_genirq_platdata *priv = platform_get_drvdata(pdev);
+
+	uio_unregister_device(priv->uioinfo);
+	pm_runtime_disable(&pdev->dev);
+
+	priv->uioinfo->handler = NULL;
+	priv->uioinfo->irqcontrol = NULL;
+
+	/* kfree uioinfo for OF */
+	if (pdev->dev.of_node)
+		kfree(priv->uioinfo);
+
+	kfree(priv);
+	return 0;
+}
+
+static int uio_dmem_genirq_runtime_nop(struct device *dev)
+{
+	/* Runtime PM callback shared between ->runtime_suspend()
+	 * and ->runtime_resume(). Simply returns success.
+	 *
+	 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
+	 * are used at open() and release() time. This allows the
+	 * Runtime PM code to turn off power to the device while the
+	 * device is unused, ie before open() and after release().
+	 *
+	 * This Runtime PM callback does not need to save or restore
+	 * any registers since user space is responsbile for hardware
+	 * register reinitialization after open().
+	 */
+	return 0;
+}
+
+static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
+	.runtime_suspend = uio_dmem_genirq_runtime_nop,
+	.runtime_resume = uio_dmem_genirq_runtime_nop,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id uio_of_genirq_match[] = {
+	{ /* empty for now */ },
+};
+MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
+#else
+# define uio_of_genirq_match NULL
+#endif
+
+static struct platform_driver uio_dmem_genirq = {
+	.probe = uio_dmem_genirq_probe,
+	.remove = uio_dmem_genirq_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+		.pm = &uio_dmem_genirq_dev_pm_ops,
+		.of_match_table = uio_of_genirq_match,
+	},
+};
+
+module_platform_driver(uio_dmem_genirq);
+
+MODULE_AUTHOR("Damian Hobson-Garcia");
+MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);