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b0297622a9
When probed via DT, the uio_pdrv_genirq driver currently uses the name of the node and exposes that as name of the UIO device to userspace. This doesn't work for systems where multiple nodes with the same name (but different unit addresses) are present, or for systems where the node names are auto-generated by a third-party tool. This patch adds the possibility to read the UIO name from the optional "linux,uio-name" property. Signed-off-by: Daniel Mack <daniel@zonque.org> Link: https://lore.kernel.org/r/20190815212807.25058-1-daniel@zonque.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
286 lines
7.5 KiB
C
286 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* drivers/uio/uio_pdrv_genirq.c
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*
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* Userspace I/O platform driver with generic IRQ handling code.
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*
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* Copyright (C) 2008 Magnus Damm
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*
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* Based on uio_pdrv.c by Uwe Kleine-Koenig,
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* Copyright (C) 2008 by Digi International Inc.
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* All rights reserved.
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*/
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#include <linux/platform_device.h>
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#include <linux/uio_driver.h>
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#include <linux/spinlock.h>
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#include <linux/bitops.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/stringify.h>
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#include <linux/pm_runtime.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/of_address.h>
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#define DRIVER_NAME "uio_pdrv_genirq"
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struct uio_pdrv_genirq_platdata {
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struct uio_info *uioinfo;
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spinlock_t lock;
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unsigned long flags;
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struct platform_device *pdev;
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};
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/* Bits in uio_pdrv_genirq_platdata.flags */
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enum {
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UIO_IRQ_DISABLED = 0,
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};
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static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
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{
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struct uio_pdrv_genirq_platdata *priv = info->priv;
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/* Wait until the Runtime PM code has woken up the device */
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pm_runtime_get_sync(&priv->pdev->dev);
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return 0;
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}
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static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode)
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{
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struct uio_pdrv_genirq_platdata *priv = info->priv;
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/* Tell the Runtime PM code that the device has become idle */
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pm_runtime_put_sync(&priv->pdev->dev);
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return 0;
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}
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static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
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{
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struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
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/* Just disable the interrupt in the interrupt controller, and
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* remember the state so we can allow user space to enable it later.
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*/
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spin_lock(&priv->lock);
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if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
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disable_irq_nosync(irq);
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spin_unlock(&priv->lock);
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return IRQ_HANDLED;
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}
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static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
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{
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struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
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unsigned long flags;
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/* Allow user space to enable and disable the interrupt
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* in the interrupt controller, but keep track of the
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* state to prevent per-irq depth damage.
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*
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* Serialize this operation to support multiple tasks and concurrency
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* with irq handler on SMP systems.
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*/
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spin_lock_irqsave(&priv->lock, flags);
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if (irq_on) {
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if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
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enable_irq(dev_info->irq);
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} else {
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if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
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disable_irq_nosync(dev_info->irq);
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}
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spin_unlock_irqrestore(&priv->lock, flags);
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return 0;
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}
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static int uio_pdrv_genirq_probe(struct platform_device *pdev)
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{
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struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
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struct device_node *node = pdev->dev.of_node;
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struct uio_pdrv_genirq_platdata *priv;
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struct uio_mem *uiomem;
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int ret = -EINVAL;
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int i;
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if (node) {
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const char *name;
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/* alloc uioinfo for one device */
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uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
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GFP_KERNEL);
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if (!uioinfo) {
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dev_err(&pdev->dev, "unable to kmalloc\n");
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return -ENOMEM;
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}
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if (!of_property_read_string(node, "linux,uio-name", &name))
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uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
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else
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uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
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"%pOFn", node);
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uioinfo->version = "devicetree";
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/* Multiple IRQs are not supported */
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}
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if (!uioinfo || !uioinfo->name || !uioinfo->version) {
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dev_err(&pdev->dev, "missing platform_data\n");
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return ret;
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}
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if (uioinfo->handler || uioinfo->irqcontrol ||
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uioinfo->irq_flags & IRQF_SHARED) {
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dev_err(&pdev->dev, "interrupt configuration error\n");
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return ret;
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}
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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dev_err(&pdev->dev, "unable to kmalloc\n");
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return -ENOMEM;
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}
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priv->uioinfo = uioinfo;
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spin_lock_init(&priv->lock);
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priv->flags = 0; /* interrupt is enabled to begin with */
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priv->pdev = pdev;
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if (!uioinfo->irq) {
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ret = platform_get_irq(pdev, 0);
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uioinfo->irq = ret;
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if (ret == -ENXIO && pdev->dev.of_node)
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uioinfo->irq = UIO_IRQ_NONE;
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else if (ret < 0) {
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dev_err(&pdev->dev, "failed to get IRQ\n");
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return ret;
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}
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}
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uiomem = &uioinfo->mem[0];
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for (i = 0; i < pdev->num_resources; ++i) {
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struct resource *r = &pdev->resource[i];
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if (r->flags != IORESOURCE_MEM)
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continue;
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if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
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dev_warn(&pdev->dev, "device has more than "
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__stringify(MAX_UIO_MAPS)
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" I/O memory resources.\n");
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break;
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}
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uiomem->memtype = UIO_MEM_PHYS;
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uiomem->addr = r->start;
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uiomem->size = resource_size(r);
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uiomem->name = r->name;
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++uiomem;
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}
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while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
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uiomem->size = 0;
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++uiomem;
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}
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/* This driver requires no hardware specific kernel code to handle
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* interrupts. Instead, the interrupt handler simply disables the
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* interrupt in the interrupt controller. User space is responsible
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* for performing hardware specific acknowledge and re-enabling of
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* the interrupt in the interrupt controller.
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*
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* Interrupt sharing is not supported.
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*/
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uioinfo->handler = uio_pdrv_genirq_handler;
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uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
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uioinfo->open = uio_pdrv_genirq_open;
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uioinfo->release = uio_pdrv_genirq_release;
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uioinfo->priv = priv;
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/* Enable Runtime PM for this device:
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* The device starts in suspended state to allow the hardware to be
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* turned off by default. The Runtime PM bus code should power on the
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* hardware and enable clocks at open().
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*/
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pm_runtime_enable(&pdev->dev);
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ret = uio_register_device(&pdev->dev, priv->uioinfo);
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if (ret) {
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dev_err(&pdev->dev, "unable to register uio device\n");
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pm_runtime_disable(&pdev->dev);
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return ret;
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}
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platform_set_drvdata(pdev, priv);
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return 0;
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}
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static int uio_pdrv_genirq_remove(struct platform_device *pdev)
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{
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struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
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uio_unregister_device(priv->uioinfo);
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pm_runtime_disable(&pdev->dev);
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priv->uioinfo->handler = NULL;
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priv->uioinfo->irqcontrol = NULL;
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return 0;
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}
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static int uio_pdrv_genirq_runtime_nop(struct device *dev)
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{
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/* Runtime PM callback shared between ->runtime_suspend()
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* and ->runtime_resume(). Simply returns success.
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*
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* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
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* are used at open() and release() time. This allows the
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* Runtime PM code to turn off power to the device while the
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* device is unused, ie before open() and after release().
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*
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* This Runtime PM callback does not need to save or restore
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* any registers since user space is responsbile for hardware
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* register reinitialization after open().
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*/
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return 0;
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}
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static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
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.runtime_suspend = uio_pdrv_genirq_runtime_nop,
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.runtime_resume = uio_pdrv_genirq_runtime_nop,
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};
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#ifdef CONFIG_OF
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static struct of_device_id uio_of_genirq_match[] = {
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{ /* This is filled with module_parm */ },
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{ /* Sentinel */ },
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};
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MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
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module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
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MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
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#endif
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static struct platform_driver uio_pdrv_genirq = {
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.probe = uio_pdrv_genirq_probe,
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.remove = uio_pdrv_genirq_remove,
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.driver = {
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.name = DRIVER_NAME,
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.pm = &uio_pdrv_genirq_dev_pm_ops,
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.of_match_table = of_match_ptr(uio_of_genirq_match),
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},
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};
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module_platform_driver(uio_pdrv_genirq);
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MODULE_AUTHOR("Magnus Damm");
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MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:" DRIVER_NAME);
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