linux/drivers/uio/uio_pdrv_genirq.c

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/*
* 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>
#include <linux/pm_runtime.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#define DRIVER_NAME "uio_pdrv_genirq"
struct uio_pdrv_genirq_platdata {
struct uio_info *uioinfo;
spinlock_t lock;
unsigned long flags;
struct platform_device *pdev;
};
static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
{
struct uio_pdrv_genirq_platdata *priv = info->priv;
/* Wait until the Runtime PM code has woken up the device */
pm_runtime_get_sync(&priv->pdev->dev);
return 0;
}
static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode)
{
struct uio_pdrv_genirq_platdata *priv = info->priv;
/* Tell the Runtime PM code that the device has become idle */
pm_runtime_put_sync(&priv->pdev->dev);
return 0;
}
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 & 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;
}
priv->uioinfo = uioinfo;
spin_lock_init(&priv->lock);
priv->flags = 0; /* interrupt is enabled to begin with */
priv->pdev = pdev;
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->handler = uio_pdrv_genirq_handler;
uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
uioinfo->open = uio_pdrv_genirq_open;
uioinfo->release = uio_pdrv_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:
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);
pm_runtime_disable(&pdev->dev);
kfree(priv);
return 0;
}
static int uio_pdrv_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_pdrv_genirq_dev_pm_ops = {
.runtime_suspend = uio_pdrv_genirq_runtime_nop,
.runtime_resume = uio_pdrv_genirq_runtime_nop,
};
static struct platform_driver uio_pdrv_genirq = {
.probe = uio_pdrv_genirq_probe,
.remove = uio_pdrv_genirq_remove,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.pm = &uio_pdrv_genirq_dev_pm_ops,
},
};
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);