linux/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
Sean Paul be91a983ea drm/rockchip: Fix up bug in psr state machine
The ->set() callback would always be called when transitioning
from FLUSH->DISABLE since we assign state to psr->state right
above the skip condition.

Reported-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
2016-09-21 06:55:49 -07:00

276 lines
6.7 KiB
C

/*
* Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
* Author: Yakir Yang <ykk@rock-chips.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <drm/drmP.h>
#include <drm/drm_crtc_helper.h>
#include "rockchip_drm_drv.h"
#include "rockchip_drm_psr.h"
#define PSR_FLUSH_TIMEOUT msecs_to_jiffies(100)
enum psr_state {
PSR_FLUSH,
PSR_ENABLE,
PSR_DISABLE,
};
struct psr_drv {
struct list_head list;
struct drm_encoder *encoder;
spinlock_t lock;
bool active;
enum psr_state state;
struct timer_list flush_timer;
void (*set)(struct drm_encoder *encoder, bool enable);
};
static struct psr_drv *find_psr_by_crtc(struct drm_crtc *crtc)
{
struct rockchip_drm_private *drm_drv = crtc->dev->dev_private;
struct psr_drv *psr;
unsigned long flags;
spin_lock_irqsave(&drm_drv->psr_list_lock, flags);
list_for_each_entry(psr, &drm_drv->psr_list, list) {
if (psr->encoder->crtc == crtc)
goto out;
}
psr = ERR_PTR(-ENODEV);
out:
spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags);
return psr;
}
static void psr_set_state_locked(struct psr_drv *psr, enum psr_state state)
{
/*
* Allowed finite state machine:
*
* PSR_ENABLE < = = = = = > PSR_FLUSH
* | ^ |
* | | |
* v | |
* PSR_DISABLE < - - - - - - - - -
*/
if (state == psr->state || !psr->active)
return;
/* Already disabled in flush, change the state, but not the hardware */
if (state == PSR_DISABLE && psr->state == PSR_FLUSH) {
psr->state = state;
return;
}
psr->state = state;
/* Actually commit the state change to hardware */
switch (psr->state) {
case PSR_ENABLE:
psr->set(psr->encoder, true);
break;
case PSR_DISABLE:
case PSR_FLUSH:
psr->set(psr->encoder, false);
break;
}
}
static void psr_set_state(struct psr_drv *psr, enum psr_state state)
{
unsigned long flags;
spin_lock_irqsave(&psr->lock, flags);
psr_set_state_locked(psr, state);
spin_unlock_irqrestore(&psr->lock, flags);
}
static void psr_flush_handler(unsigned long data)
{
struct psr_drv *psr = (struct psr_drv *)data;
unsigned long flags;
/* If the state has changed since we initiated the flush, do nothing */
spin_lock_irqsave(&psr->lock, flags);
if (psr->state == PSR_FLUSH)
psr_set_state_locked(psr, PSR_ENABLE);
spin_unlock_irqrestore(&psr->lock, flags);
}
/**
* rockchip_drm_psr_activate - activate PSR on the given pipe
* @crtc: CRTC to obtain the PSR encoder
*
* Returns:
* Zero on success, negative errno on failure.
*/
int rockchip_drm_psr_activate(struct drm_crtc *crtc)
{
struct psr_drv *psr = find_psr_by_crtc(crtc);
unsigned long flags;
if (IS_ERR(psr))
return PTR_ERR(psr);
spin_lock_irqsave(&psr->lock, flags);
psr->active = true;
spin_unlock_irqrestore(&psr->lock, flags);
return 0;
}
EXPORT_SYMBOL(rockchip_drm_psr_activate);
/**
* rockchip_drm_psr_deactivate - deactivate PSR on the given pipe
* @crtc: CRTC to obtain the PSR encoder
*
* Returns:
* Zero on success, negative errno on failure.
*/
int rockchip_drm_psr_deactivate(struct drm_crtc *crtc)
{
struct psr_drv *psr = find_psr_by_crtc(crtc);
unsigned long flags;
if (IS_ERR(psr))
return PTR_ERR(psr);
spin_lock_irqsave(&psr->lock, flags);
psr->active = false;
spin_unlock_irqrestore(&psr->lock, flags);
del_timer_sync(&psr->flush_timer);
return 0;
}
EXPORT_SYMBOL(rockchip_drm_psr_deactivate);
static void rockchip_drm_do_flush(struct psr_drv *psr)
{
mod_timer(&psr->flush_timer,
round_jiffies_up(jiffies + PSR_FLUSH_TIMEOUT));
psr_set_state(psr, PSR_FLUSH);
}
/**
* rockchip_drm_psr_flush - flush a single pipe
* @crtc: CRTC of the pipe to flush
*
* Returns:
* 0 on success, -errno on fail
*/
int rockchip_drm_psr_flush(struct drm_crtc *crtc)
{
struct psr_drv *psr = find_psr_by_crtc(crtc);
if (IS_ERR(psr))
return PTR_ERR(psr);
rockchip_drm_do_flush(psr);
return 0;
}
EXPORT_SYMBOL(rockchip_drm_psr_flush);
/**
* rockchip_drm_psr_flush_all - force to flush all registered PSR encoders
* @dev: drm device
*
* Disable the PSR function for all registered encoders, and then enable the
* PSR function back after PSR_FLUSH_TIMEOUT. If encoder PSR state have been
* changed during flush time, then keep the state no change after flush
* timeout.
*
* Returns:
* Zero on success, negative errno on failure.
*/
void rockchip_drm_psr_flush_all(struct drm_device *dev)
{
struct rockchip_drm_private *drm_drv = dev->dev_private;
struct psr_drv *psr;
unsigned long flags;
spin_lock_irqsave(&drm_drv->psr_list_lock, flags);
list_for_each_entry(psr, &drm_drv->psr_list, list)
rockchip_drm_do_flush(psr);
spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags);
}
EXPORT_SYMBOL(rockchip_drm_psr_flush_all);
/**
* rockchip_drm_psr_register - register encoder to psr driver
* @encoder: encoder that obtain the PSR function
* @psr_set: call back to set PSR state
*
* Returns:
* Zero on success, negative errno on failure.
*/
int rockchip_drm_psr_register(struct drm_encoder *encoder,
void (*psr_set)(struct drm_encoder *, bool enable))
{
struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
struct psr_drv *psr;
unsigned long flags;
if (!encoder || !psr_set)
return -EINVAL;
psr = kzalloc(sizeof(struct psr_drv), GFP_KERNEL);
if (!psr)
return -ENOMEM;
setup_timer(&psr->flush_timer, psr_flush_handler, (unsigned long)psr);
spin_lock_init(&psr->lock);
psr->active = true;
psr->state = PSR_DISABLE;
psr->encoder = encoder;
psr->set = psr_set;
spin_lock_irqsave(&drm_drv->psr_list_lock, flags);
list_add_tail(&psr->list, &drm_drv->psr_list);
spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags);
return 0;
}
EXPORT_SYMBOL(rockchip_drm_psr_register);
/**
* rockchip_drm_psr_unregister - unregister encoder to psr driver
* @encoder: encoder that obtain the PSR function
* @psr_set: call back to set PSR state
*
* Returns:
* Zero on success, negative errno on failure.
*/
void rockchip_drm_psr_unregister(struct drm_encoder *encoder)
{
struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
struct psr_drv *psr, *n;
unsigned long flags;
spin_lock_irqsave(&drm_drv->psr_list_lock, flags);
list_for_each_entry_safe(psr, n, &drm_drv->psr_list, list) {
if (psr->encoder == encoder) {
del_timer(&psr->flush_timer);
list_del(&psr->list);
kfree(psr);
}
}
spin_unlock_irqrestore(&drm_drv->psr_list_lock, flags);
}
EXPORT_SYMBOL(rockchip_drm_psr_unregister);