alistair23-linux/drivers/gpu/drm/drm_irq.c

/*
 * drm_irq.c IRQ and vblank support
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */


#include <linux/export.h>
#include <linux/interrupt.h>	/* For task queue support */
#include <linux/pci.h>
#include <linux/vgaarb.h>

#include <drm/drm.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
#include <drm/drm_irq.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>

#include "drm_internal.h"

/**
 * DOC: irq helpers
 *
 * The DRM core provides very simple support helpers to enable IRQ handling on a
 * device through the drm_irq_install() and drm_irq_uninstall() functions. This
 * only supports devices with a single interrupt on the main device stored in
 * &drm_device.dev and set as the device paramter in drm_dev_alloc().
 *
 * These IRQ helpers are strictly optional. Drivers which roll their own only
 * need to set &drm_device.irq_enabled to signal the DRM core that vblank
 * interrupts are working. Since these helpers don't automatically clean up the
 * requested interrupt like e.g. devm_request_irq() they're not really
 * recommended.
 */

/**
 * drm_irq_install - install IRQ handler
 * @dev: DRM device
 * @irq: IRQ number to install the handler for
 *
 * Initializes the IRQ related data. Installs the handler, calling the driver
 * &drm_driver.irq_preinstall and &drm_driver.irq_postinstall functions before
 * and after the installation.
 *
 * This is the simplified helper interface provided for drivers with no special
 * needs. Drivers which need to install interrupt handlers for multiple
 * interrupts must instead set &drm_device.irq_enabled to signal the DRM core
 * that vblank interrupts are available.
 *
 * @irq must match the interrupt number that would be passed to request_irq(),
 * if called directly instead of using this helper function.
 *
 * &drm_driver.irq_handler is called to handle the registered interrupt.
 *
 * Returns:
 * Zero on success or a negative error code on failure.
 */
int drm_irq_install(struct drm_device *dev, int irq)
{
	int ret;
	unsigned long sh_flags = 0;

	if (irq == 0)
		return -EINVAL;

	/* Driver must have been initialized */
	if (!dev->dev_private)
		return -EINVAL;

	if (dev->irq_enabled)
		return -EBUSY;
	dev->irq_enabled = true;

	DRM_DEBUG("irq=%d\n", irq);

	/* Before installing handler */
	if (dev->driver->irq_preinstall)
		dev->driver->irq_preinstall(dev);

	/* PCI devices require shared interrupts. */
	if (dev->pdev)
		sh_flags = IRQF_SHARED;

	ret = request_irq(irq, dev->driver->irq_handler,
			  sh_flags, dev->driver->name, dev);

	if (ret < 0) {
		dev->irq_enabled = false;
		return ret;
	}

	/* After installing handler */
	if (dev->driver->irq_postinstall)
		ret = dev->driver->irq_postinstall(dev);

	if (ret < 0) {
		dev->irq_enabled = false;
		if (drm_core_check_feature(dev, DRIVER_LEGACY))
			vga_client_register(dev->pdev, NULL, NULL, NULL);
		free_irq(irq, dev);
	} else {
		dev->irq = irq;
	}

	return ret;
}
EXPORT_SYMBOL(drm_irq_install);

/**
 * drm_irq_uninstall - uninstall the IRQ handler
 * @dev: DRM device
 *
 * Calls the driver's &drm_driver.irq_uninstall function and unregisters the IRQ
 * handler.  This should only be called by drivers which used drm_irq_install()
 * to set up their interrupt handler. Other drivers must only reset
 * &drm_device.irq_enabled to false.
 *
 * Note that for kernel modesetting drivers it is a bug if this function fails.
 * The sanity checks are only to catch buggy user modesetting drivers which call
 * the same function through an ioctl.
 *
 * Returns:
 * Zero on success or a negative error code on failure.
 */
int drm_irq_uninstall(struct drm_device *dev)
{
	unsigned long irqflags;
	bool irq_enabled;
	int i;

	irq_enabled = dev->irq_enabled;
	dev->irq_enabled = false;

	/*
	 * Wake up any waiters so they don't hang. This is just to paper over
	 * issues for UMS drivers which aren't in full control of their
	 * vblank/irq handling. KMS drivers must ensure that vblanks are all
	 * disabled when uninstalling the irq handler.
	 */
	if (dev->num_crtcs) {
		spin_lock_irqsave(&dev->vbl_lock, irqflags);
		for (i = 0; i < dev->num_crtcs; i++) {
			struct drm_vblank_crtc *vblank = &dev->vblank[i];

			if (!vblank->enabled)
				continue;

			WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));

			drm_vblank_disable_and_save(dev, i);
			wake_up(&vblank->queue);
		}
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
	}

	if (!irq_enabled)
		return -EINVAL;

	DRM_DEBUG("irq=%d\n", dev->irq);

	if (drm_core_check_feature(dev, DRIVER_LEGACY))
		vga_client_register(dev->pdev, NULL, NULL, NULL);

	if (dev->driver->irq_uninstall)
		dev->driver->irq_uninstall(dev);

	free_irq(dev->irq, dev);

	return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);

#if IS_ENABLED(CONFIG_DRM_LEGACY)
int drm_legacy_irq_control(struct drm_device *dev, void *data,
			   struct drm_file *file_priv)
{
	struct drm_control *ctl = data;
	int ret = 0, irq;

	/* if we haven't irq we fallback for compatibility reasons -
	 * this used to be a separate function in drm_dma.h
	 */

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return 0;
	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
		return 0;
	/* UMS was only ever supported on pci devices. */
	if (WARN_ON(!dev->pdev))
		return -EINVAL;

	switch (ctl->func) {
	case DRM_INST_HANDLER:
		irq = dev->pdev->irq;

		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
		    ctl->irq != irq)
			return -EINVAL;
		mutex_lock(&dev->struct_mutex);
		ret = drm_irq_install(dev, irq);
		mutex_unlock(&dev->struct_mutex);

		return ret;
	case DRM_UNINST_HANDLER:
		mutex_lock(&dev->struct_mutex);
		ret = drm_irq_uninstall(dev);
		mutex_unlock(&dev->struct_mutex);

		return ret;
	default:
		return -EINVAL;
	}
}
#endif