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301 lines
8.0 KiB
301 lines
8.0 KiB
// 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/irq.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 void uio_pdrv_genirq_cleanup(void *data) |
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{ |
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struct device *dev = data; |
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pm_runtime_disable(dev); |
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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_optional(pdev, 0); |
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uioinfo->irq = ret; |
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if (ret == -ENXIO) |
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uioinfo->irq = UIO_IRQ_NONE; |
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else if (ret == -EPROBE_DEFER) |
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return ret; |
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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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if (uioinfo->irq) { |
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struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq); |
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/* |
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* If a level interrupt, dont do lazy disable. Otherwise the |
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* irq will fire again since clearing of the actual cause, on |
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* device level, is done in userspace |
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* irqd_is_level_type() isn't used since isn't valid until |
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* irq is configured. |
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*/ |
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if (irq_data && |
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irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) { |
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dev_dbg(&pdev->dev, "disable lazy unmask\n"); |
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irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY); |
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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 & PAGE_MASK; |
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uiomem->offs = r->start & ~PAGE_MASK; |
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uiomem->size = (uiomem->offs + resource_size(r) |
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+ PAGE_SIZE - 1) & PAGE_MASK; |
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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 = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup, |
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&pdev->dev); |
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if (ret) |
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return ret; |
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ret = devm_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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return ret; |
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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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.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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