linux/drivers/gpu/host1x/syncpt.c

555 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Tegra host1x Syncpoints
*
* Copyright (c) 2010-2015, NVIDIA Corporation.
*/
#include <linux/module.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <trace/events/host1x.h>
#include "syncpt.h"
#include "dev.h"
#include "intr.h"
#include "debug.h"
#define SYNCPT_CHECK_PERIOD (2 * HZ)
#define MAX_STUCK_CHECK_COUNT 15
static struct host1x_syncpt_base *
host1x_syncpt_base_request(struct host1x *host)
{
struct host1x_syncpt_base *bases = host->bases;
unsigned int i;
for (i = 0; i < host->info->nb_bases; i++)
if (!bases[i].requested)
break;
if (i >= host->info->nb_bases)
return NULL;
bases[i].requested = true;
return &bases[i];
}
static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
{
if (base)
base->requested = false;
}
static struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
struct host1x_client *client,
unsigned long flags)
{
struct host1x_syncpt *sp = host->syncpt;
unsigned int i;
char *name;
mutex_lock(&host->syncpt_mutex);
for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
;
if (i >= host->info->nb_pts)
goto unlock;
if (flags & HOST1X_SYNCPT_HAS_BASE) {
sp->base = host1x_syncpt_base_request(host);
if (!sp->base)
goto unlock;
}
name = kasprintf(GFP_KERNEL, "%02u-%s", sp->id,
client ? dev_name(client->dev) : NULL);
if (!name)
goto free_base;
sp->client = client;
sp->name = name;
if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
sp->client_managed = true;
else
sp->client_managed = false;
mutex_unlock(&host->syncpt_mutex);
return sp;
free_base:
host1x_syncpt_base_free(sp->base);
sp->base = NULL;
unlock:
mutex_unlock(&host->syncpt_mutex);
return NULL;
}
/**
* host1x_syncpt_id() - retrieve syncpoint ID
* @sp: host1x syncpoint
*
* Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
* often used as a value to program into registers that control how hardware
* blocks interact with syncpoints.
*/
u32 host1x_syncpt_id(struct host1x_syncpt *sp)
{
return sp->id;
}
EXPORT_SYMBOL(host1x_syncpt_id);
/**
* host1x_syncpt_incr_max() - update the value sent to hardware
* @sp: host1x syncpoint
* @incrs: number of increments
*/
u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
{
return (u32)atomic_add_return(incrs, &sp->max_val);
}
EXPORT_SYMBOL(host1x_syncpt_incr_max);
/*
* Write cached syncpoint and waitbase values to hardware.
*/
void host1x_syncpt_restore(struct host1x *host)
{
struct host1x_syncpt *sp_base = host->syncpt;
unsigned int i;
for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
host1x_hw_syncpt_restore(host, sp_base + i);
for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
wmb();
}
/*
* Update the cached syncpoint and waitbase values by reading them
* from the registers.
*/
void host1x_syncpt_save(struct host1x *host)
{
struct host1x_syncpt *sp_base = host->syncpt;
unsigned int i;
for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
if (host1x_syncpt_client_managed(sp_base + i))
host1x_hw_syncpt_load(host, sp_base + i);
else
WARN_ON(!host1x_syncpt_idle(sp_base + i));
}
for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
host1x_hw_syncpt_load_wait_base(host, sp_base + i);
}
/*
* Updates the cached syncpoint value by reading a new value from the hardware
* register
*/
u32 host1x_syncpt_load(struct host1x_syncpt *sp)
{
u32 val;
val = host1x_hw_syncpt_load(sp->host, sp);
trace_host1x_syncpt_load_min(sp->id, val);
return val;
}
/*
* Get the current syncpoint base
*/
u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
{
host1x_hw_syncpt_load_wait_base(sp->host, sp);
return sp->base_val;
}
/**
* host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
* @sp: host1x syncpoint
*/
int host1x_syncpt_incr(struct host1x_syncpt *sp)
{
return host1x_hw_syncpt_cpu_incr(sp->host, sp);
}
EXPORT_SYMBOL(host1x_syncpt_incr);
/*
* Updated sync point form hardware, and returns true if syncpoint is expired,
* false if we may need to wait
*/
static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
{
host1x_hw_syncpt_load(sp->host, sp);
return host1x_syncpt_is_expired(sp, thresh);
}
/**
* host1x_syncpt_wait() - wait for a syncpoint to reach a given value
* @sp: host1x syncpoint
* @thresh: threshold
* @timeout: maximum time to wait for the syncpoint to reach the given value
* @value: return location for the syncpoint value
*/
int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
u32 *value)
{
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
void *ref;
struct host1x_waitlist *waiter;
int err = 0, check_count = 0;
u32 val;
if (value)
*value = 0;
/* first check cache */
if (host1x_syncpt_is_expired(sp, thresh)) {
if (value)
*value = host1x_syncpt_load(sp);
return 0;
}
/* try to read from register */
val = host1x_hw_syncpt_load(sp->host, sp);
if (host1x_syncpt_is_expired(sp, thresh)) {
if (value)
*value = val;
goto done;
}
if (!timeout) {
err = -EAGAIN;
goto done;
}
/* allocate a waiter */
waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
if (!waiter) {
err = -ENOMEM;
goto done;
}
/* schedule a wakeup when the syncpoint value is reached */
err = host1x_intr_add_action(sp->host, sp, thresh,
HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
&wq, waiter, &ref);
if (err)
goto done;
err = -EAGAIN;
/* Caller-specified timeout may be impractically low */
if (timeout < 0)
timeout = LONG_MAX;
/* wait for the syncpoint, or timeout, or signal */
while (timeout) {
long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
int remain;
remain = wait_event_interruptible_timeout(wq,
syncpt_load_min_is_expired(sp, thresh),
check);
if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
if (value)
*value = host1x_syncpt_load(sp);
err = 0;
break;
}
if (remain < 0) {
err = remain;
break;
}
timeout -= check;
if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
dev_warn(sp->host->dev,
"%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
current->comm, sp->id, sp->name,
thresh, timeout);
host1x_debug_dump_syncpts(sp->host);
if (check_count == MAX_STUCK_CHECK_COUNT)
host1x_debug_dump(sp->host);
check_count++;
}
}
host1x_intr_put_ref(sp->host, sp->id, ref);
done:
return err;
}
EXPORT_SYMBOL(host1x_syncpt_wait);
/*
* Returns true if syncpoint is expired, false if we may need to wait
*/
bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
{
u32 current_val;
u32 future_val;
smp_rmb();
current_val = (u32)atomic_read(&sp->min_val);
future_val = (u32)atomic_read(&sp->max_val);
/* 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 (!host1x_syncpt_client_managed(sp))
return future_val - thresh >= current_val - thresh;
else
return (s32)(current_val - thresh) >= 0;
}
int host1x_syncpt_init(struct host1x *host)
{
struct host1x_syncpt_base *bases;
struct host1x_syncpt *syncpt;
unsigned int i;
syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
GFP_KERNEL);
if (!syncpt)
return -ENOMEM;
bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
GFP_KERNEL);
if (!bases)
return -ENOMEM;
for (i = 0; i < host->info->nb_pts; i++) {
syncpt[i].id = i;
syncpt[i].host = host;
/*
* Unassign syncpt from channels for purposes of Tegra186
* syncpoint protection. This prevents any channel from
* accessing it until it is reassigned.
*/
host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
}
for (i = 0; i < host->info->nb_bases; i++)
bases[i].id = i;
mutex_init(&host->syncpt_mutex);
host->syncpt = syncpt;
host->bases = bases;
host1x_syncpt_restore(host);
host1x_hw_syncpt_enable_protection(host);
/* Allocate sync point to use for clearing waits for expired fences */
host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
if (!host->nop_sp)
return -ENOMEM;
return 0;
}
/**
* host1x_syncpt_request() - request a syncpoint
* @client: client requesting the syncpoint
* @flags: flags
*
* host1x client drivers can use this function to allocate a syncpoint for
* subsequent use. A syncpoint returned by this function will be reserved for
* use by the client exclusively. When no longer using a syncpoint, a host1x
* client driver needs to release it using host1x_syncpt_free().
*/
struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
unsigned long flags)
{
struct host1x *host = dev_get_drvdata(client->parent->parent);
return host1x_syncpt_alloc(host, client, flags);
}
EXPORT_SYMBOL(host1x_syncpt_request);
/**
* host1x_syncpt_free() - free a requested syncpoint
* @sp: host1x syncpoint
*
* Release a syncpoint previously allocated using host1x_syncpt_request(). A
* host1x client driver should call this when the syncpoint is no longer in
* use. Note that client drivers must ensure that the syncpoint doesn't remain
* under the control of hardware after calling this function, otherwise two
* clients may end up trying to access the same syncpoint concurrently.
*/
void host1x_syncpt_free(struct host1x_syncpt *sp)
{
if (!sp)
return;
mutex_lock(&sp->host->syncpt_mutex);
host1x_syncpt_base_free(sp->base);
kfree(sp->name);
sp->base = NULL;
sp->client = NULL;
sp->name = NULL;
sp->client_managed = false;
mutex_unlock(&sp->host->syncpt_mutex);
}
EXPORT_SYMBOL(host1x_syncpt_free);
void host1x_syncpt_deinit(struct host1x *host)
{
struct host1x_syncpt *sp = host->syncpt;
unsigned int i;
for (i = 0; i < host->info->nb_pts; i++, sp++)
kfree(sp->name);
}
/**
* host1x_syncpt_read_max() - read maximum syncpoint value
* @sp: host1x syncpoint
*
* The maximum syncpoint value indicates how many operations there are in
* queue, either in channel or in a software thread.
*/
u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
{
smp_rmb();
return (u32)atomic_read(&sp->max_val);
}
EXPORT_SYMBOL(host1x_syncpt_read_max);
/**
* host1x_syncpt_read_min() - read minimum syncpoint value
* @sp: host1x syncpoint
*
* The minimum syncpoint value is a shadow of the current sync point value in
* hardware.
*/
u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
{
smp_rmb();
return (u32)atomic_read(&sp->min_val);
}
EXPORT_SYMBOL(host1x_syncpt_read_min);
/**
* host1x_syncpt_read() - read the current syncpoint value
* @sp: host1x syncpoint
*/
u32 host1x_syncpt_read(struct host1x_syncpt *sp)
{
return host1x_syncpt_load(sp);
}
EXPORT_SYMBOL(host1x_syncpt_read);
unsigned int host1x_syncpt_nb_pts(struct host1x *host)
{
return host->info->nb_pts;
}
unsigned int host1x_syncpt_nb_bases(struct host1x *host)
{
return host->info->nb_bases;
}
unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
{
return host->info->nb_mlocks;
}
/**
* host1x_syncpt_get() - obtain a syncpoint by ID
* @host: host1x controller
* @id: syncpoint ID
*/
struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
{
if (id >= host->info->nb_pts)
return NULL;
return host->syncpt + id;
}
EXPORT_SYMBOL(host1x_syncpt_get);
/**
* host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
* @sp: host1x syncpoint
*/
struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
{
return sp ? sp->base : NULL;
}
EXPORT_SYMBOL(host1x_syncpt_get_base);
/**
* host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
* @base: host1x syncpoint wait base
*/
u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
{
return base->id;
}
EXPORT_SYMBOL(host1x_syncpt_base_id);