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![Jan Viktorin](/assets/img/avatar_default.png)
The variable i contains a total number of resources (including
IORESOURCE_IRQ). However, we want the dmem_region_start to point
after the last resource of type IORESOURCE_MEM. The original behaviour
leads (very likely) to skipping several UIO mapping regions and makes
them useless. Fix this by computing dmem_region_start from the uiomem
which points to the last used UIO mapping.
Fixes: 0a0c3b5a24
("Add new uio device for dynamic memory allocation")
Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
356 lines
9.1 KiB
C
356 lines
9.1 KiB
C
/*
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* drivers/uio/uio_dmem_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) 2012 Damian Hobson-Garcia
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*
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* Based on uio_pdrv_genirq.c by Magnus Damm
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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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/platform_data/uio_dmem_genirq.h>
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#include <linux/stringify.h>
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#include <linux/pm_runtime.h>
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#include <linux/dma-mapping.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_dmem_genirq"
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#define DMEM_MAP_ERROR (~0)
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struct uio_dmem_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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unsigned int dmem_region_start;
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unsigned int num_dmem_regions;
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void *dmem_region_vaddr[MAX_UIO_MAPS];
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struct mutex alloc_lock;
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unsigned int refcnt;
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};
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static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
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{
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struct uio_dmem_genirq_platdata *priv = info->priv;
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struct uio_mem *uiomem;
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int ret = 0;
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int dmem_region = priv->dmem_region_start;
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uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
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mutex_lock(&priv->alloc_lock);
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while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
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void *addr;
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if (!uiomem->size)
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break;
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addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
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(dma_addr_t *)&uiomem->addr, GFP_KERNEL);
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if (!addr) {
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uiomem->addr = DMEM_MAP_ERROR;
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}
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priv->dmem_region_vaddr[dmem_region++] = addr;
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++uiomem;
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}
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priv->refcnt++;
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mutex_unlock(&priv->alloc_lock);
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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 ret;
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}
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static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
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{
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struct uio_dmem_genirq_platdata *priv = info->priv;
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struct uio_mem *uiomem;
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int dmem_region = priv->dmem_region_start;
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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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uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
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mutex_lock(&priv->alloc_lock);
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priv->refcnt--;
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while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
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if (!uiomem->size)
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break;
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if (priv->dmem_region_vaddr[dmem_region]) {
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dma_free_coherent(&priv->pdev->dev, uiomem->size,
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priv->dmem_region_vaddr[dmem_region],
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uiomem->addr);
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}
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uiomem->addr = DMEM_MAP_ERROR;
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++dmem_region;
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++uiomem;
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}
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mutex_unlock(&priv->alloc_lock);
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return 0;
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}
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static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
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{
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struct uio_dmem_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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if (!test_and_set_bit(0, &priv->flags))
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disable_irq_nosync(irq);
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return IRQ_HANDLED;
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}
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static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
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{
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struct uio_dmem_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.
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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(0, &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(0, &priv->flags))
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disable_irq(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_dmem_genirq_probe(struct platform_device *pdev)
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{
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struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
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struct uio_info *uioinfo = &pdata->uioinfo;
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struct uio_dmem_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 (pdev->dev.of_node) {
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int irq;
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/* alloc uioinfo for one device */
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uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
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if (!uioinfo) {
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ret = -ENOMEM;
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dev_err(&pdev->dev, "unable to kmalloc\n");
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goto bad2;
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}
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uioinfo->name = pdev->dev.of_node->name;
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uioinfo->version = "devicetree";
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/* Multiple IRQs are not supported */
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irq = platform_get_irq(pdev, 0);
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if (irq == -ENXIO)
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uioinfo->irq = UIO_IRQ_NONE;
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else
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uioinfo->irq = irq;
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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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goto bad0;
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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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goto bad0;
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}
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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dev_err(&pdev->dev, "unable to kmalloc\n");
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goto bad0;
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}
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dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
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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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mutex_init(&priv->alloc_lock);
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if (!uioinfo->irq) {
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ret = platform_get_irq(pdev, 0);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to get IRQ\n");
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goto bad1;
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}
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uioinfo->irq = ret;
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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;
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}
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priv->dmem_region_start = uiomem - &uioinfo->mem[0];
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priv->num_dmem_regions = pdata->num_dynamic_regions;
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for (i = 0; i < pdata->num_dynamic_regions; ++i) {
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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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" dynamic and fixed memory regions.\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 = DMEM_MAP_ERROR;
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uiomem->size = pdata->dynamic_region_sizes[i];
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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_dmem_genirq_handler;
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uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
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uioinfo->open = uio_dmem_genirq_open;
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uioinfo->release = uio_dmem_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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goto bad1;
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}
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platform_set_drvdata(pdev, priv);
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return 0;
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bad1:
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kfree(priv);
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bad0:
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/* kfree uioinfo for OF */
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if (pdev->dev.of_node)
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kfree(uioinfo);
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bad2:
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return ret;
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}
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static int uio_dmem_genirq_remove(struct platform_device *pdev)
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{
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struct uio_dmem_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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/* kfree uioinfo for OF */
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if (pdev->dev.of_node)
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kfree(priv->uioinfo);
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kfree(priv);
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return 0;
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}
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static int uio_dmem_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_dmem_genirq_dev_pm_ops = {
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.runtime_suspend = uio_dmem_genirq_runtime_nop,
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.runtime_resume = uio_dmem_genirq_runtime_nop,
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};
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#ifdef CONFIG_OF
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static const struct of_device_id uio_of_genirq_match[] = {
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{ /* empty for now */ },
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};
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MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
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#endif
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static struct platform_driver uio_dmem_genirq = {
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.probe = uio_dmem_genirq_probe,
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.remove = uio_dmem_genirq_remove,
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.driver = {
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.name = DRIVER_NAME,
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.pm = &uio_dmem_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_dmem_genirq);
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MODULE_AUTHOR("Damian Hobson-Garcia");
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MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:" DRIVER_NAME);
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