1/*
  2 * drm_irq.c IRQ and vblank support
  3 *
  4 * \author Rickard E. (Rik) Faith <faith@valinux.com>
  5 * \author Gareth Hughes <gareth@valinux.com>
  6 *
  7 * Permission is hereby granted, free of charge, to any person obtaining a
  8 * copy of this software and associated documentation files (the "Software"),
  9 * to deal in the Software without restriction, including without limitation
 10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 11 * and/or sell copies of the Software, and to permit persons to whom the
 12 * Software is furnished to do so, subject to the following conditions:
 13 *
 14 * The above copyright notice and this permission notice (including the next
 15 * paragraph) shall be included in all copies or substantial portions of the
 16 * Software.
 17 *
 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 21 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 22 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 24 * OTHER DEALINGS IN THE SOFTWARE.
 25 */
 26
 27/*
 28 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
 29 *
 30 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 31 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 32 * All Rights Reserved.
 33 *
 34 * Permission is hereby granted, free of charge, to any person obtaining a
 35 * copy of this software and associated documentation files (the "Software"),
 36 * to deal in the Software without restriction, including without limitation
 37 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 38 * and/or sell copies of the Software, and to permit persons to whom the
 39 * Software is furnished to do so, subject to the following conditions:
 40 *
 41 * The above copyright notice and this permission notice (including the next
 42 * paragraph) shall be included in all copies or substantial portions of the
 43 * Software.
 44 *
 45 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 46 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 47 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 48 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 49 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 50 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 51 * OTHER DEALINGS IN THE SOFTWARE.
 52 */
 53
 54
 55#include <linux/export.h>
 56#include <linux/interrupt.h>	/* For task queue support */
 57#include <linux/pci.h>
 58#include <linux/vgaarb.h>
 59
 60#include <drm/drm.h>
 61#include <drm/drm_device.h>
 62#include <drm/drm_drv.h>
 63#include <drm/drm_irq.h>
 64#include <drm/drm_print.h>
 65#include <drm/drm_vblank.h>
 66
 67#include "drm_internal.h"
 68
 69/**
 70 * DOC: irq helpers
 71 *
 72 * The DRM core provides very simple support helpers to enable IRQ handling on a
 73 * device through the drm_irq_install() and drm_irq_uninstall() functions. This
 74 * only supports devices with a single interrupt on the main device stored in
 75 * &drm_device.dev and set as the device paramter in drm_dev_alloc().
 76 *
 77 * These IRQ helpers are strictly optional. Drivers which roll their own only
 78 * need to set &drm_device.irq_enabled to signal the DRM core that vblank
 79 * interrupts are working. Since these helpers don't automatically clean up the
 80 * requested interrupt like e.g. devm_request_irq() they're not really
 81 * recommended.
 82 */
 83
 84/**
 85 * drm_irq_install - install IRQ handler
 86 * @dev: DRM device
 87 * @irq: IRQ number to install the handler for
 88 *
 89 * Initializes the IRQ related data. Installs the handler, calling the driver
 90 * &drm_driver.irq_preinstall and &drm_driver.irq_postinstall functions before
 91 * and after the installation.
 92 *
 93 * This is the simplified helper interface provided for drivers with no special
 94 * needs. Drivers which need to install interrupt handlers for multiple
 95 * interrupts must instead set &drm_device.irq_enabled to signal the DRM core
 96 * that vblank interrupts are available.
 97 *
 98 * @irq must match the interrupt number that would be passed to request_irq(),
 99 * if called directly instead of using this helper function.
100 *
101 * &drm_driver.irq_handler is called to handle the registered interrupt.
102 *
103 * Returns:
104 * Zero on success or a negative error code on failure.
105 */
106int drm_irq_install(struct drm_device *dev, int irq)
107{
108	int ret;
109	unsigned long sh_flags = 0;
110
111	if (irq == 0)
112		return -EINVAL;
113
114	if (dev->irq_enabled)
115		return -EBUSY;
116	dev->irq_enabled = true;
117
118	DRM_DEBUG("irq=%d\n", irq);
119
120	/* Before installing handler */
121	if (dev->driver->irq_preinstall)
122		dev->driver->irq_preinstall(dev);
123
124	/* PCI devices require shared interrupts. */
125	if (dev->pdev)
126		sh_flags = IRQF_SHARED;
127
128	ret = request_irq(irq, dev->driver->irq_handler,
129			  sh_flags, dev->driver->name, dev);
130
131	if (ret < 0) {
132		dev->irq_enabled = false;
133		return ret;
134	}
135
136	/* After installing handler */
137	if (dev->driver->irq_postinstall)
138		ret = dev->driver->irq_postinstall(dev);
139
140	if (ret < 0) {
141		dev->irq_enabled = false;
142		if (drm_core_check_feature(dev, DRIVER_LEGACY))
143			vga_client_register(dev->pdev, NULL, NULL, NULL);
144		free_irq(irq, dev);
145	} else {
146		dev->irq = irq;
147	}
148
149	return ret;
150}
151EXPORT_SYMBOL(drm_irq_install);
152
153/**
154 * drm_irq_uninstall - uninstall the IRQ handler
155 * @dev: DRM device
156 *
157 * Calls the driver's &drm_driver.irq_uninstall function and unregisters the IRQ
158 * handler.  This should only be called by drivers which used drm_irq_install()
159 * to set up their interrupt handler. Other drivers must only reset
160 * &drm_device.irq_enabled to false.
161 *
162 * Note that for kernel modesetting drivers it is a bug if this function fails.
163 * The sanity checks are only to catch buggy user modesetting drivers which call
164 * the same function through an ioctl.
165 *
166 * Returns:
167 * Zero on success or a negative error code on failure.
168 */
169int drm_irq_uninstall(struct drm_device *dev)
170{
171	unsigned long irqflags;
172	bool irq_enabled;
173	int i;
174
175	irq_enabled = dev->irq_enabled;
176	dev->irq_enabled = false;
177
178	/*
179	 * Wake up any waiters so they don't hang. This is just to paper over
180	 * issues for UMS drivers which aren't in full control of their
181	 * vblank/irq handling. KMS drivers must ensure that vblanks are all
182	 * disabled when uninstalling the irq handler.
183	 */
184	if (drm_dev_has_vblank(dev)) {
185		spin_lock_irqsave(&dev->vbl_lock, irqflags);
186		for (i = 0; i < dev->num_crtcs; i++) {
187			struct drm_vblank_crtc *vblank = &dev->vblank[i];
188
189			if (!vblank->enabled)
190				continue;
191
192			WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
193
194			drm_vblank_disable_and_save(dev, i);
195			wake_up(&vblank->queue);
196		}
197		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
198	}
199
200	if (!irq_enabled)
201		return -EINVAL;
202
203	DRM_DEBUG("irq=%d\n", dev->irq);
204
205	if (drm_core_check_feature(dev, DRIVER_LEGACY))
206		vga_client_register(dev->pdev, NULL, NULL, NULL);
207
208	if (dev->driver->irq_uninstall)
209		dev->driver->irq_uninstall(dev);
210
211	free_irq(dev->irq, dev);
212
213	return 0;
214}
215EXPORT_SYMBOL(drm_irq_uninstall);
216
217#if IS_ENABLED(CONFIG_DRM_LEGACY)
218int drm_legacy_irq_control(struct drm_device *dev, void *data,
219			   struct drm_file *file_priv)
220{
221	struct drm_control *ctl = data;
222	int ret = 0, irq;
223
224	/* if we haven't irq we fallback for compatibility reasons -
225	 * this used to be a separate function in drm_dma.h
226	 */
227
228	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
229		return 0;
230	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
231		return 0;
232	/* UMS was only ever supported on pci devices. */
233	if (WARN_ON(!dev->pdev))
234		return -EINVAL;
235
236	switch (ctl->func) {
237	case DRM_INST_HANDLER:
238		irq = dev->pdev->irq;
239
240		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
241		    ctl->irq != irq)
242			return -EINVAL;
243		mutex_lock(&dev->struct_mutex);
244		ret = drm_irq_install(dev, irq);
245		mutex_unlock(&dev->struct_mutex);
246
247		return ret;
248	case DRM_UNINST_HANDLER:
249		mutex_lock(&dev->struct_mutex);
250		ret = drm_irq_uninstall(dev);
251		mutex_unlock(&dev->struct_mutex);
252
253		return ret;
254	default:
255		return -EINVAL;
256	}
257}
258#endif