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      1 /* mga_irq.c -- IRQ handling for radeon -*- linux-c -*-
      2  */
      3 /*
      4  * Copyright (C) The Weather Channel, Inc.  2002.  All Rights Reserved.
      5  *
      6  * The Weather Channel (TM) funded Tungsten Graphics to develop the
      7  * initial release of the Radeon 8500 driver under the XFree86 license.
      8  * This notice must be preserved.
      9  *
     10  * Permission is hereby granted, free of charge, to any person obtaining a
     11  * copy of this software and associated documentation files (the "Software"),
     12  * to deal in the Software without restriction, including without limitation
     13  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     14  * and/or sell copies of the Software, and to permit persons to whom the
     15  * Software is furnished to do so, subject to the following conditions:
     16  *
     17  * The above copyright notice and this permission notice (including the next
     18  * paragraph) shall be included in all copies or substantial portions of the
     19  * Software.
     20  *
     21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     24  * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     25  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     26  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     27  * DEALINGS IN THE SOFTWARE.
     28  *
     29  * Authors:
     30  *    Keith Whitwell <keith (at) tungstengraphics.com>
     31  *    Eric Anholt <anholt (at) FreeBSD.org>
     32  */
     33 
     34 #include "drmP.h"
     35 #include "drm.h"
     36 #include "mga_drm.h"
     37 #include "mga_drv.h"
     38 
     39 u32 mga_get_vblank_counter(struct drm_device *dev, unsigned int crtc)
     40 {
     41 	const drm_mga_private_t *const dev_priv =
     42 		(drm_mga_private_t *) dev->dev_private;
     43 
     44 	if (crtc != 0) {
     45 		return 0;
     46 	}
     47 
     48 
     49 	return atomic_read(&dev_priv->vbl_received);
     50 }
     51 
     52 
     53 irqreturn_t mga_driver_irq_handler(DRM_IRQ_ARGS)
     54 {
     55 	struct drm_device *dev = (struct drm_device *) arg;
     56 	drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
     57 	int status;
     58 	int handled = 0;
     59 
     60 	status = MGA_READ(MGA_STATUS);
     61 
     62 	/* VBLANK interrupt */
     63 	if (status & MGA_VLINEPEN) {
     64 		MGA_WRITE(MGA_ICLEAR, MGA_VLINEICLR);
     65 		atomic_inc(&dev_priv->vbl_received);
     66 		drm_handle_vblank(dev, 0);
     67 		handled = 1;
     68 	}
     69 
     70 	/* SOFTRAP interrupt */
     71 	if (status & MGA_SOFTRAPEN) {
     72 		const u32 prim_start = MGA_READ(MGA_PRIMADDRESS);
     73 		const u32 prim_end = MGA_READ(MGA_PRIMEND);
     74 
     75 
     76 		MGA_WRITE(MGA_ICLEAR, MGA_SOFTRAPICLR);
     77 
     78 		/* In addition to clearing the interrupt-pending bit, we
     79 		 * have to write to MGA_PRIMEND to re-start the DMA operation.
     80 		 */
     81 		if ((prim_start & ~0x03) != (prim_end & ~0x03)) {
     82 			MGA_WRITE(MGA_PRIMEND, prim_end);
     83 		}
     84 
     85 		atomic_inc(&dev_priv->last_fence_retired);
     86 		DRM_WAKEUP(&dev_priv->fence_queue);
     87 		handled = 1;
     88 	}
     89 
     90 	if (handled)
     91 		return IRQ_HANDLED;
     92 	return IRQ_NONE;
     93 }
     94 
     95 int mga_enable_vblank(struct drm_device *dev, unsigned int crtc)
     96 {
     97 	drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
     98 
     99 	if (crtc != 0) {
    100 		DRM_ERROR("tried to enable vblank on non-existent crtc %d\n",
    101 			  crtc);
    102 		return 0;
    103 	}
    104 
    105 	MGA_WRITE(MGA_IEN, MGA_VLINEIEN | MGA_SOFTRAPEN);
    106 	return 0;
    107 }
    108 
    109 
    110 void mga_disable_vblank(struct drm_device *dev, unsigned int crtc)
    111 {
    112 	if (crtc != 0) {
    113 		DRM_ERROR("tried to disable vblank on non-existent crtc %d\n",
    114 			  crtc);
    115 	}
    116 
    117 	/* Do *NOT* disable the vertical refresh interrupt.  MGA doesn't have
    118 	 * a nice hardware counter that tracks the number of refreshes when
    119 	 * the interrupt is disabled, and the kernel doesn't know the refresh
    120 	 * rate to calculate an estimate.
    121 	 */
    122 	/* MGA_WRITE(MGA_IEN, MGA_VLINEIEN | MGA_SOFTRAPEN); */
    123 }
    124 
    125 int mga_driver_fence_wait(struct drm_device * dev, unsigned int *sequence)
    126 {
    127 	drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
    128 	unsigned int cur_fence;
    129 	int ret = 0;
    130 
    131 	/* Assume that the user has missed the current sequence number
    132 	 * by about a day rather than she wants to wait for years
    133 	 * using fences.
    134 	 */
    135 	DRM_WAIT_ON(ret, dev_priv->fence_queue, 3 * DRM_HZ,
    136 		    (((cur_fence = atomic_read(&dev_priv->last_fence_retired))
    137 		      - *sequence) <= (1 << 23)));
    138 
    139 	*sequence = cur_fence;
    140 
    141 	return ret;
    142 }
    143 
    144 void mga_driver_irq_preinstall(struct drm_device * dev)
    145 {
    146 	drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
    147 
    148 	/* Disable *all* interrupts */
    149 	MGA_WRITE(MGA_IEN, 0);
    150 	/* Clear bits if they're already high */
    151 	MGA_WRITE(MGA_ICLEAR, ~0);
    152 }
    153 
    154 int mga_driver_irq_postinstall(struct drm_device * dev)
    155 {
    156 	drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
    157 
    158 	DRM_INIT_WAITQUEUE(&dev_priv->fence_queue);
    159 
    160 	/* Turn on soft trap interrupt.  Vertical blank interrupts are enabled
    161 	 * in mga_enable_vblank.
    162 	 */
    163 	MGA_WRITE(MGA_IEN, MGA_SOFTRAPEN);
    164 	return 0;
    165 }
    166 
    167 void mga_driver_irq_uninstall(struct drm_device * dev)
    168 {
    169 	drm_mga_private_t *dev_priv = (drm_mga_private_t *) dev->dev_private;
    170 	if (!dev_priv)
    171 		return;
    172 
    173 	/* Disable *all* interrupts */
    174 	MGA_WRITE(MGA_IEN, 0);
    175 
    176 	dev->irq_enabled = 0;
    177 }
    178