/*
* drivers/video/tegra/host/nvhost_syncpt.c
*
* Tegra Graphics Host Syncpoints
*
* Copyright (c) 2010-2012, NVIDIA Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/nvhost_ioctl.h>
#include <linux/platform_device.h>
#include "nvhost_syncpt.h"
#include "dev.h"
#define MAX_STUCK_CHECK_COUNT 15
/**
* Resets syncpoint and waitbase values to sw shadows
*/
void nvhost_syncpt_reset(struct nvhost_syncpt *sp)
{
u32 i;
BUG_ON(!(syncpt_op(sp).reset && syncpt_op(sp).reset_wait_base));
for (i = 0; i < sp->nb_pts; i++)
syncpt_op(sp).reset(sp, i);
for (i = 0; i < sp->nb_bases; i++)
syncpt_op(sp).reset_wait_base(sp, i);
wmb();
}
/**
* Updates sw shadow state for client managed registers
*/
void nvhost_syncpt_save(struct nvhost_syncpt *sp)
{
u32 i;
BUG_ON(!(syncpt_op(sp).update_min && syncpt_op(sp).read_wait_base));
for (i = 0; i < sp->nb_pts; i++) {
if (client_managed(i))
syncpt_op(sp).update_min(sp, i);
else
BUG_ON(!nvhost_syncpt_min_eq_max(sp, i));
}
for (i = 0; i < sp->nb_bases; i++)
syncpt_op(sp).read_wait_base(sp, i);
}
/**
* Updates the last value read from hardware.
*/
u32 nvhost_syncpt_update_min(struct nvhost_syncpt *sp, u32 id)
{
BUG_ON(!syncpt_op(sp).update_min);
return syncpt_op(sp).update_min(sp, id);
}
/**
* Get the current syncpoint value
*/
u32 nvhost_syncpt_read(struct nvhost_syncpt *sp, u32 id)
{
u32 val;
BUG_ON(!syncpt_op(sp).update_min);
nvhost_module_busy(syncpt_to_dev(sp)->dev);
val = syncpt_op(sp).update_min(sp, id);
nvhost_module_idle(syncpt_to_dev(sp)->dev);
return val;
}
/**
* Get the current syncpoint base
*/
u32 nvhost_syncpt_read_wait_base(struct nvhost_syncpt *sp, u32 id)
{
u32 val;
BUG_ON(!syncpt_op(sp).read_wait_base);
nvhost_module_busy(syncpt_to_dev(sp)->dev);
syncpt_op(sp).read_wait_base(sp, id);
val = sp->base_val[id];
nvhost_module_idle(syncpt_to_dev(sp)->dev);
return val;
}
/**
* Write a cpu syncpoint increment to the hardware, without touching
* the cache. Caller is responsible for host being powered.
*/
void nvhost_syncpt_cpu_incr(struct nvhost_syncpt *sp, u32 id)
{
BUG_ON(!syncpt_op(sp).cpu_incr);
syncpt_op(sp).cpu_incr(sp, id);
}
/**
* Increment syncpoint value from cpu, updating cache
*/
void nvhost_syncpt_incr(struct nvhost_syncpt *sp, u32 id)
{
if (client_managed(id))
nvhost_syncpt_incr_max(sp, id, 1);
nvhost_module_busy(syncpt_to_dev(sp)->dev);
nvhost_syncpt_cpu_incr(sp, id);
nvhost_module_idle(syncpt_to_dev(sp)->dev);
}
/**
* Main entrypoint for syncpoint value waits.
*/
int nvhost_syncpt_wait_timeout(struct nvhost_syncpt *sp, u32 id,
u32 thresh, u32 timeout, u32 *value)
{
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
void *ref;
void *waiter;
int err = 0, check_count = 0, low_timeout = 0;
u32 val;
if (value)
*value = 0;
/* first check cache */
if (nvhost_syncpt_is_expired(sp, id, thresh)) {
if (value)
*value = nvhost_syncpt_read_min(sp, id);
return 0;
}
/* keep host alive */
nvhost_module_busy(syncpt_to_dev(sp)->dev);
/* try to read from register */
val = syncpt_op(sp).update_min(sp, id);
if (nvhost_syncpt_is_expired(sp, id, thresh)) {
if (value)
*value = val;
goto done;
}
if (!timeout) {
err = -EAGAIN;
goto done;
}
/* schedule a wakeup when the syncpoint value is reached */
waiter = nvhost_intr_alloc_waiter();
if (!waiter) {
err = -ENOMEM;
goto done;
}
err = nvhost_intr_add_action(&(syncpt_to_dev(sp)->intr), id, thresh,
NVHOST_INTR_ACTION_WAKEUP_INTERRUPTIBLE, &wq,
waiter,
&ref);
if (err)
goto done;
err = -EAGAIN;
/* Caller-specified timeout may be impractically low */
if (timeout < SYNCPT_CHECK_PERIOD)
low_timeout = timeout;
/* wait for the syncpoint, or timeout, or signal */
while (timeout) {
u32 check = min_t(u32, SYNCPT_CHECK_PERIOD, timeout);
int remain = wait_event_interruptible_timeout(wq,
nvhost_syncpt_is_expired(sp, id, thresh),
check);
if (remain > 0) {
if (value)
*value = nvhost_syncpt_read_min(sp, id);
err = 0;
break;
}
if (remain < 0) {
err = remain;
break;
}
if (timeout != NVHOST_NO_TIMEOUT)
timeout -= check;
if (timeout) {
dev_warn(&syncpt_to_dev(sp)->dev->dev,
"%s: syncpoint id %d (%s) stuck waiting %d, timeout=%d\n",
current->comm, id, syncpt_op(sp).name(sp, id),
thresh, timeout);
syncpt_op(sp).debug(sp);
if (check_count > MAX_STUCK_CHECK_COUNT) {
if (low_timeout) {
dev_warn(&syncpt_to_dev(sp)->dev->dev,
"is timeout %d too low?\n",
low_timeout);
}
nvhost_debug_dump(syncpt_to_dev(sp));
BUG();
}
check_count++;
}
}
nvhost_intr_put_ref(&(syncpt_to_dev(sp)->intr), ref);
done:
nvhost_module_idle(syncpt_to_dev(sp)->dev);
return err;
}
/**
* Returns true if syncpoint is expired, false if we may need to wait
*/
bool nvhost_syncpt_is_expired(
struct nvhost_syncpt *sp,
u32 id,
u32 thresh)
{
u32 current_val;
u32 future_val;
smp_rmb();
current_val = (u32)atomic_read(&sp->min_val[id]);
future_val = (u32)atomic_read(&sp->max_val[id]);
/* Note the use of unsigned arithmetic here (mod 1<<32).
*
* c = current_val = min_val = the current value of the syncpoint.
* t = thresh = the value we are checking
* f = future_val = max_val = the value c will reach when all
* outstanding increments have completed.
*
* Note that c always chases f until it reaches f.
*
* Dtf = (f - t)
* Dtc = (c - t)
*
* Consider all cases:
*
* A) .....c..t..f..... Dtf < Dtc need to wait
* B) .....c.....f..t.. Dtf > Dtc expired
* C) ..t..c.....f..... Dtf > Dtc expired (Dct very large)
*
* Any case where f==c: always expired (for any t). Dtf == Dcf
* Any case where t==c: always expired (for any f). Dtf >= Dtc (because Dtc==0)
* Any case where t==f!=c: always wait. Dtf < Dtc (because Dtf==0,
* Dtc!=0)
*
* Other cases:
*
* A) .....t..f..c..... Dtf < Dtc need to wait
* A) .....f..c..t..... Dtf < Dtc need to wait
* A) .....f..t..c..... Dtf > Dtc expired
*
* So:
* Dtf >= Dtc implies EXPIRED (return true)
* Dtf < Dtc implies WAIT (return false)
*
* Note: If t is expired then we *cannot* wait on it. We would wait
* forever (hang the system).
*
* Note: do NOT get clever and remove the -thresh from both sides. It
* is NOT the same.
*
* If future valueis zero, we have a client managed sync point. In that
* case we do a direct comparison.
*/
if (!client_managed(id))
return future_val - thresh >= current_val - thresh;
else
return (s32)(current_val - thresh) >= 0;
}
void nvhost_syncpt_debug(struct nvhost_syncpt *sp)
{
syncpt_op(sp).debug(sp);
}
int nvhost_mutex_try_lock(struct nvhost_syncpt *sp, int idx)
{
struct nvhost_master *host = syncpt_to_dev(sp);
u32 reg;
nvhost_module_busy(host->dev);
reg = syncpt_op(sp).mutex_try_lock(sp, idx);
if (reg) {
nvhost_module_idle(host->dev);
return -EBUSY;
}
atomic_inc(&sp->lock_counts[idx]);
return 0;
}
void nvhost_mutex_unlock(struct nvhost_syncpt *sp, int idx)
{
syncpt_op(sp).mutex_unlock(sp, idx);
nvhost_module_idle(syncpt_to_dev(sp)->dev);
atomic_dec(&sp->lock_counts[idx]);
}
/* check for old WAITs to be removed (avoiding a wrap) */
int nvhost_syncpt_wait_check(struct nvhost_syncpt *sp,
struct nvmap_client *nvmap,
u32 waitchk_mask,
struct nvhost_waitchk *wait,
int num_waitchk)
{
return syncpt_op(sp).wait_check(sp, nvmap,
waitchk_mask, wait, num_waitchk);
}
