linux/drivers/gpu/drm/drm_irq.c
Eric Anholt ed4cb4142b i915: Add support for MSI and interrupt mitigation.
Previous attempts at interrupt mitigation had been foiled by i915_wait_irq's
failure to update the sarea seqno value when the status page indicated that
the seqno had already been passed.  MSI support has been seen to cut CPU
costs by up to 40% in some workloads by avoiding other expensive interrupt
handlers for frequent graphics interrupts.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2008-10-18 07:10:10 +10:00

471 lines
12 KiB
C

/**
* \file drm_irq.c
* IRQ support
*
* \author Rickard E. (Rik) Faith <faith@valinux.com>
* \author Gareth Hughes <gareth@valinux.com>
*/
/*
* 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 "drmP.h"
#include <linux/interrupt.h> /* For task queue support */
/**
* Get interrupt from bus id.
*
* \param inode device inode.
* \param file_priv DRM file private.
* \param cmd command.
* \param arg user argument, pointing to a drm_irq_busid structure.
* \return zero on success or a negative number on failure.
*
* Finds the PCI device with the specified bus id and gets its IRQ number.
* This IOCTL is deprecated, and will now return EINVAL for any busid not equal
* to that of the device that this DRM instance attached to.
*/
int drm_irq_by_busid(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_irq_busid *p = data;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
if ((p->busnum >> 8) != drm_get_pci_domain(dev) ||
(p->busnum & 0xff) != dev->pdev->bus->number ||
p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn))
return -EINVAL;
p->irq = dev->pdev->irq;
DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum,
p->irq);
return 0;
}
/**
* Install IRQ handler.
*
* \param dev DRM device.
* \param irq IRQ number.
*
* Initializes the IRQ related data, and setups drm_device::vbl_queue. Installs the handler, calling the driver
* \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
* before and after the installation.
*/
static int drm_irq_install(struct drm_device * dev)
{
int ret;
unsigned long sh_flags = 0;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
if (dev->pdev->irq == 0)
return -EINVAL;
mutex_lock(&dev->struct_mutex);
/* Driver must have been initialized */
if (!dev->dev_private) {
mutex_unlock(&dev->struct_mutex);
return -EINVAL;
}
if (dev->irq_enabled) {
mutex_unlock(&dev->struct_mutex);
return -EBUSY;
}
dev->irq_enabled = 1;
mutex_unlock(&dev->struct_mutex);
DRM_DEBUG("irq=%d\n", dev->pdev->irq);
if (drm_core_check_feature(dev, DRIVER_IRQ_VBL)) {
init_waitqueue_head(&dev->vbl_queue);
spin_lock_init(&dev->vbl_lock);
INIT_LIST_HEAD(&dev->vbl_sigs);
INIT_LIST_HEAD(&dev->vbl_sigs2);
dev->vbl_pending = 0;
}
/* Before installing handler */
dev->driver->irq_preinstall(dev);
/* Install handler */
if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
sh_flags = IRQF_SHARED;
ret = request_irq(dev->pdev->irq, dev->driver->irq_handler,
sh_flags, dev->devname, dev);
/* Expose the device irq number to drivers that want to export it for
* whatever reason.
*/
dev->irq = dev->pdev->irq;
if (ret < 0) {
mutex_lock(&dev->struct_mutex);
dev->irq_enabled = 0;
mutex_unlock(&dev->struct_mutex);
return ret;
}
/* After installing handler */
dev->driver->irq_postinstall(dev);
return 0;
}
/**
* Uninstall the IRQ handler.
*
* \param dev DRM device.
*
* Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
*/
int drm_irq_uninstall(struct drm_device * dev)
{
int irq_enabled;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
mutex_lock(&dev->struct_mutex);
irq_enabled = dev->irq_enabled;
dev->irq_enabled = 0;
mutex_unlock(&dev->struct_mutex);
if (!irq_enabled)
return -EINVAL;
DRM_DEBUG("irq=%d\n", dev->pdev->irq);
dev->driver->irq_uninstall(dev);
free_irq(dev->pdev->irq, dev);
dev->locked_tasklet_func = NULL;
return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);
/**
* IRQ control ioctl.
*
* \param inode device inode.
* \param file_priv DRM file private.
* \param cmd command.
* \param arg user argument, pointing to a drm_control structure.
* \return zero on success or a negative number on failure.
*
* Calls irq_install() or irq_uninstall() according to \p arg.
*/
int drm_control(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_control *ctl = data;
/* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */
switch (ctl->func) {
case DRM_INST_HANDLER:
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return 0;
if (dev->if_version < DRM_IF_VERSION(1, 2) &&
ctl->irq != dev->pdev->irq)
return -EINVAL;
return drm_irq_install(dev);
case DRM_UNINST_HANDLER:
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return 0;
return drm_irq_uninstall(dev);
default:
return -EINVAL;
}
}
/**
* Wait for VBLANK.
*
* \param inode device inode.
* \param file_priv DRM file private.
* \param cmd command.
* \param data user argument, pointing to a drm_wait_vblank structure.
* \return zero on success or a negative number on failure.
*
* Verifies the IRQ is installed.
*
* If a signal is requested checks if this task has already scheduled the same signal
* for the same vblank sequence number - nothing to be done in
* that case. If the number of tasks waiting for the interrupt exceeds 100 the
* function fails. Otherwise adds a new entry to drm_device::vbl_sigs for this
* task.
*
* If a signal is not requested, then calls vblank_wait().
*/
int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
union drm_wait_vblank *vblwait = data;
struct timeval now;
int ret = 0;
unsigned int flags, seq;
if ((!dev->pdev->irq) || (!dev->irq_enabled))
return -EINVAL;
if (vblwait->request.type &
~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
vblwait->request.type,
(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
return -EINVAL;
}
flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
if (!drm_core_check_feature(dev, (flags & _DRM_VBLANK_SECONDARY) ?
DRIVER_IRQ_VBL2 : DRIVER_IRQ_VBL))
return -EINVAL;
seq = atomic_read((flags & _DRM_VBLANK_SECONDARY) ? &dev->vbl_received2
: &dev->vbl_received);
switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
case _DRM_VBLANK_RELATIVE:
vblwait->request.sequence += seq;
vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
case _DRM_VBLANK_ABSOLUTE:
break;
default:
return -EINVAL;
}
if ((flags & _DRM_VBLANK_NEXTONMISS) &&
(seq - vblwait->request.sequence) <= (1<<23)) {
vblwait->request.sequence = seq + 1;
}
if (flags & _DRM_VBLANK_SIGNAL) {
unsigned long irqflags;
struct list_head *vbl_sigs = (flags & _DRM_VBLANK_SECONDARY)
? &dev->vbl_sigs2 : &dev->vbl_sigs;
struct drm_vbl_sig *vbl_sig;
spin_lock_irqsave(&dev->vbl_lock, irqflags);
/* Check if this task has already scheduled the same signal
* for the same vblank sequence number; nothing to be done in
* that case
*/
list_for_each_entry(vbl_sig, vbl_sigs, head) {
if (vbl_sig->sequence == vblwait->request.sequence
&& vbl_sig->info.si_signo ==
vblwait->request.signal
&& vbl_sig->task == current) {
spin_unlock_irqrestore(&dev->vbl_lock,
irqflags);
vblwait->reply.sequence = seq;
goto done;
}
}
if (dev->vbl_pending >= 100) {
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
return -EBUSY;
}
dev->vbl_pending++;
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
if (!
(vbl_sig =
drm_alloc(sizeof(struct drm_vbl_sig), DRM_MEM_DRIVER))) {
return -ENOMEM;
}
memset((void *)vbl_sig, 0, sizeof(*vbl_sig));
vbl_sig->sequence = vblwait->request.sequence;
vbl_sig->info.si_signo = vblwait->request.signal;
vbl_sig->task = current;
spin_lock_irqsave(&dev->vbl_lock, irqflags);
list_add_tail(&vbl_sig->head, vbl_sigs);
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
vblwait->reply.sequence = seq;
} else {
if (flags & _DRM_VBLANK_SECONDARY) {
if (dev->driver->vblank_wait2)
ret = dev->driver->vblank_wait2(dev, &vblwait->request.sequence);
} else if (dev->driver->vblank_wait)
ret =
dev->driver->vblank_wait(dev,
&vblwait->request.sequence);
do_gettimeofday(&now);
vblwait->reply.tval_sec = now.tv_sec;
vblwait->reply.tval_usec = now.tv_usec;
}
done:
return ret;
}
/**
* Send the VBLANK signals.
*
* \param dev DRM device.
*
* Sends a signal for each task in drm_device::vbl_sigs and empties the list.
*
* If a signal is not requested, then calls vblank_wait().
*/
void drm_vbl_send_signals(struct drm_device * dev)
{
unsigned long flags;
int i;
spin_lock_irqsave(&dev->vbl_lock, flags);
for (i = 0; i < 2; i++) {
struct drm_vbl_sig *vbl_sig, *tmp;
struct list_head *vbl_sigs = i ? &dev->vbl_sigs2 : &dev->vbl_sigs;
unsigned int vbl_seq = atomic_read(i ? &dev->vbl_received2 :
&dev->vbl_received);
list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
vbl_sig->info.si_code = vbl_seq;
send_sig_info(vbl_sig->info.si_signo,
&vbl_sig->info, vbl_sig->task);
list_del(&vbl_sig->head);
drm_free(vbl_sig, sizeof(*vbl_sig),
DRM_MEM_DRIVER);
dev->vbl_pending--;
}
}
}
spin_unlock_irqrestore(&dev->vbl_lock, flags);
}
EXPORT_SYMBOL(drm_vbl_send_signals);
/**
* Tasklet wrapper function.
*
* \param data DRM device in disguise.
*
* Attempts to grab the HW lock and calls the driver callback on success. On
* failure, leave the lock marked as contended so the callback can be called
* from drm_unlock().
*/
static void drm_locked_tasklet_func(unsigned long data)
{
struct drm_device *dev = (struct drm_device *)data;
unsigned long irqflags;
void (*tasklet_func)(struct drm_device *);
spin_lock_irqsave(&dev->tasklet_lock, irqflags);
tasklet_func = dev->locked_tasklet_func;
spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
if (!tasklet_func ||
!drm_lock_take(&dev->lock,
DRM_KERNEL_CONTEXT)) {
return;
}
dev->lock.lock_time = jiffies;
atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
spin_lock_irqsave(&dev->tasklet_lock, irqflags);
tasklet_func = dev->locked_tasklet_func;
dev->locked_tasklet_func = NULL;
spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
if (tasklet_func != NULL)
tasklet_func(dev);
drm_lock_free(&dev->lock,
DRM_KERNEL_CONTEXT);
}
/**
* Schedule a tasklet to call back a driver hook with the HW lock held.
*
* \param dev DRM device.
* \param func Driver callback.
*
* This is intended for triggering actions that require the HW lock from an
* interrupt handler. The lock will be grabbed ASAP after the interrupt handler
* completes. Note that the callback may be called from interrupt or process
* context, it must not make any assumptions about this. Also, the HW lock will
* be held with the kernel context or any client context.
*/
void drm_locked_tasklet(struct drm_device *dev, void (*func)(struct drm_device *))
{
unsigned long irqflags;
static DECLARE_TASKLET(drm_tasklet, drm_locked_tasklet_func, 0);
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ) ||
test_bit(TASKLET_STATE_SCHED, &drm_tasklet.state))
return;
spin_lock_irqsave(&dev->tasklet_lock, irqflags);
if (dev->locked_tasklet_func) {
spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
return;
}
dev->locked_tasklet_func = func;
spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
drm_tasklet.data = (unsigned long)dev;
tasklet_hi_schedule(&drm_tasklet);
}
EXPORT_SYMBOL(drm_locked_tasklet);