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linux_dsm_epyc7002/drivers/media/cec/cec-api.c
Hans Verkuil ea5c8ef296 media: cec-pin: add low-level pin hardware support 
Add support for CEC hardware that relies on low-level pin polling or
GPIO interrupts.

One example is the Allwinner SoC. But any GPIO-based CEC implementation can
use this as well.

A GPIO implementation is very suitable as well for debugging: it can use
interrupts to detect state changes and report it. Userspace can then verify
if the bus traffic is correct. This also makes error injection possible.

The disadvantage is that it is hard to get the timings right since linux
isn't a hard realtime system.

In general on an idle system it works quite well, but under load the timer
will miss its mark every so often.

The debugfs file /sys/kernel/debug/cec/cecX/status gives some statistics
with respect to the timer overruns.

When the adapter is unconfigured and the low-level driver supports
interrupts, then the interrupt will be used to detect changes. This should
be quite accurate. But when the adapter is configured a hrtimer has to be
used.

The hrtimer implements a state machine where for each state the code will
read the bus or drive the bus and go on to the next state. It will re-arm
the timer with a delay based on the next state.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-18 12:57:18 -03:00

646 lines
16 KiB
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/*
* cec-api.c - HDMI Consumer Electronics Control framework - API
*
* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*
* This program is free software; you may redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* 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 THE AUTHORS OR COPYRIGHT HOLDERS
* 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 <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/ktime.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/version.h>
#include <media/cec-pin.h>
#include "cec-priv.h"
static inline struct cec_devnode *cec_devnode_data(struct file *filp)
{
struct cec_fh *fh = filp->private_data;
return &fh->adap->devnode;
}
/* CEC file operations */
static unsigned int cec_poll(struct file *filp,
struct poll_table_struct *poll)
{
struct cec_devnode *devnode = cec_devnode_data(filp);
struct cec_fh *fh = filp->private_data;
struct cec_adapter *adap = fh->adap;
unsigned int res = 0;
if (!devnode->registered)
return POLLERR | POLLHUP;
mutex_lock(&adap->lock);
if (adap->is_configured &&
adap->transmit_queue_sz < CEC_MAX_MSG_TX_QUEUE_SZ)
res |= POLLOUT | POLLWRNORM;
if (fh->queued_msgs)
res |= POLLIN | POLLRDNORM;
if (fh->total_queued_events)
res |= POLLPRI;
poll_wait(filp, &fh->wait, poll);
mutex_unlock(&adap->lock);
return res;
}
static bool cec_is_busy(const struct cec_adapter *adap,
const struct cec_fh *fh)
{
bool valid_initiator = adap->cec_initiator && adap->cec_initiator == fh;
bool valid_follower = adap->cec_follower && adap->cec_follower == fh;
/*
* Exclusive initiators and followers can always access the CEC adapter
*/
if (valid_initiator || valid_follower)
return false;
/*
* All others can only access the CEC adapter if there is no
* exclusive initiator and they are in INITIATOR mode.
*/
return adap->cec_initiator ||
fh->mode_initiator == CEC_MODE_NO_INITIATOR;
}
static long cec_adap_g_caps(struct cec_adapter *adap,
struct cec_caps __user *parg)
{
struct cec_caps caps = {};
strlcpy(caps.driver, adap->devnode.dev.parent->driver->name,
sizeof(caps.driver));
strlcpy(caps.name, adap->name, sizeof(caps.name));
caps.available_log_addrs = adap->available_log_addrs;
caps.capabilities = adap->capabilities;
caps.version = LINUX_VERSION_CODE;
if (copy_to_user(parg, &caps, sizeof(caps)))
return -EFAULT;
return 0;
}
static long cec_adap_g_phys_addr(struct cec_adapter *adap,
__u16 __user *parg)
{
u16 phys_addr;
mutex_lock(&adap->lock);
phys_addr = adap->phys_addr;
mutex_unlock(&adap->lock);
if (copy_to_user(parg, &phys_addr, sizeof(phys_addr)))
return -EFAULT;
return 0;
}
static long cec_adap_s_phys_addr(struct cec_adapter *adap, struct cec_fh *fh,
bool block, __u16 __user *parg)
{
u16 phys_addr;
long err;
if (!(adap->capabilities & CEC_CAP_PHYS_ADDR))
return -ENOTTY;
if (copy_from_user(&phys_addr, parg, sizeof(phys_addr)))
return -EFAULT;
err = cec_phys_addr_validate(phys_addr, NULL, NULL);
if (err)
return err;
mutex_lock(&adap->lock);
if (cec_is_busy(adap, fh))
err = -EBUSY;
else
__cec_s_phys_addr(adap, phys_addr, block);
mutex_unlock(&adap->lock);
return err;
}
static long cec_adap_g_log_addrs(struct cec_adapter *adap,
struct cec_log_addrs __user *parg)
{
struct cec_log_addrs log_addrs;
mutex_lock(&adap->lock);
log_addrs = adap->log_addrs;
if (!adap->is_configured)
memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
sizeof(log_addrs.log_addr));
mutex_unlock(&adap->lock);
if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
return -EFAULT;
return 0;
}
static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
bool block, struct cec_log_addrs __user *parg)
{
struct cec_log_addrs log_addrs;
long err = -EBUSY;
if (!(adap->capabilities & CEC_CAP_LOG_ADDRS))
return -ENOTTY;
if (copy_from_user(&log_addrs, parg, sizeof(log_addrs)))
return -EFAULT;
log_addrs.flags &= CEC_LOG_ADDRS_FL_ALLOW_UNREG_FALLBACK |
CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU |
CEC_LOG_ADDRS_FL_CDC_ONLY;
mutex_lock(&adap->lock);
if (!adap->is_configuring &&
(!log_addrs.num_log_addrs || !adap->is_configured) &&
!cec_is_busy(adap, fh)) {
err = __cec_s_log_addrs(adap, &log_addrs, block);
if (!err)
log_addrs = adap->log_addrs;
}
mutex_unlock(&adap->lock);
if (err)
return err;
if (copy_to_user(parg, &log_addrs, sizeof(log_addrs)))
return -EFAULT;
return 0;
}
static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
bool block, struct cec_msg __user *parg)
{
struct cec_msg msg = {};
long err = 0;
if (!(adap->capabilities & CEC_CAP_TRANSMIT))
return -ENOTTY;
if (copy_from_user(&msg, parg, sizeof(msg)))
return -EFAULT;
/* A CDC-Only device can only send CDC messages */
if ((adap->log_addrs.flags & CEC_LOG_ADDRS_FL_CDC_ONLY) &&
(msg.len == 1 || msg.msg[1] != CEC_MSG_CDC_MESSAGE))
return -EINVAL;
mutex_lock(&adap->lock);
if (adap->log_addrs.num_log_addrs == 0)
err = -EPERM;
else if (adap->is_configuring)
err = -ENONET;
else if (!adap->is_configured &&
(adap->needs_hpd || msg.msg[0] != 0xf0))
err = -ENONET;
else if (cec_is_busy(adap, fh))
err = -EBUSY;
else
err = cec_transmit_msg_fh(adap, &msg, fh, block);
mutex_unlock(&adap->lock);
if (err)
return err;
if (copy_to_user(parg, &msg, sizeof(msg)))
return -EFAULT;
return 0;
}
/* Called by CEC_RECEIVE: wait for a message to arrive */
static int cec_receive_msg(struct cec_fh *fh, struct cec_msg *msg, bool block)
{
u32 timeout = msg->timeout;
int res;
do {
mutex_lock(&fh->lock);
/* Are there received messages queued up? */
if (fh->queued_msgs) {
/* Yes, return the first one */
struct cec_msg_entry *entry =
list_first_entry(&fh->msgs,
struct cec_msg_entry, list);
list_del(&entry->list);
*msg = entry->msg;
kfree(entry);
fh->queued_msgs--;
mutex_unlock(&fh->lock);
/* restore original timeout value */
msg->timeout = timeout;
return 0;
}
/* No, return EAGAIN in non-blocking mode or wait */
mutex_unlock(&fh->lock);
/* Return when in non-blocking mode */
if (!block)
return -EAGAIN;
if (msg->timeout) {
/* The user specified a timeout */
res = wait_event_interruptible_timeout(fh->wait,
fh->queued_msgs,
msecs_to_jiffies(msg->timeout));
if (res == 0)
res = -ETIMEDOUT;
else if (res > 0)
res = 0;
} else {
/* Wait indefinitely */
res = wait_event_interruptible(fh->wait,
fh->queued_msgs);
}
/* Exit on error, otherwise loop to get the new message */
} while (!res);
return res;
}
static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
bool block, struct cec_msg __user *parg)
{
struct cec_msg msg = {};
long err;
if (copy_from_user(&msg, parg, sizeof(msg)))
return -EFAULT;
err = cec_receive_msg(fh, &msg, block);
if (err)
return err;
msg.flags = 0;
if (copy_to_user(parg, &msg, sizeof(msg)))
return -EFAULT;
return 0;
}
static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
bool block, struct cec_event __user *parg)
{
struct cec_event_entry *ev = NULL;
u64 ts = ~0ULL;
unsigned int i;
unsigned int ev_idx;
long err = 0;
mutex_lock(&fh->lock);
while (!fh->total_queued_events && block) {
mutex_unlock(&fh->lock);
err = wait_event_interruptible(fh->wait,
fh->total_queued_events);
if (err)
return err;
mutex_lock(&fh->lock);
}
/* Find the oldest event */
for (i = 0; i < CEC_NUM_EVENTS; i++) {
struct cec_event_entry *entry =
list_first_entry_or_null(&fh->events[i],
struct cec_event_entry, list);
if (entry && entry->ev.ts <= ts) {
ev = entry;
ev_idx = i;
ts = ev->ev.ts;
}
}
if (!ev) {
err = -EAGAIN;
goto unlock;
}
list_del(&ev->list);
if (copy_to_user(parg, &ev->ev, sizeof(ev->ev)))
err = -EFAULT;
if (ev_idx >= CEC_NUM_CORE_EVENTS)
kfree(ev);
fh->queued_events[ev_idx]--;
fh->total_queued_events--;
unlock:
mutex_unlock(&fh->lock);
return err;
}
static long cec_g_mode(struct cec_adapter *adap, struct cec_fh *fh,
u32 __user *parg)
{
u32 mode = fh->mode_initiator | fh->mode_follower;
if (copy_to_user(parg, &mode, sizeof(mode)))
return -EFAULT;
return 0;
}
static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
u32 __user *parg)
{
u32 mode;
u8 mode_initiator;
u8 mode_follower;
long err = 0;
if (copy_from_user(&mode, parg, sizeof(mode)))
return -EFAULT;
if (mode & ~(CEC_MODE_INITIATOR_MSK | CEC_MODE_FOLLOWER_MSK))
return -EINVAL;
mode_initiator = mode & CEC_MODE_INITIATOR_MSK;
mode_follower = mode & CEC_MODE_FOLLOWER_MSK;
if (mode_initiator > CEC_MODE_EXCL_INITIATOR ||
mode_follower > CEC_MODE_MONITOR_ALL)
return -EINVAL;
if (mode_follower == CEC_MODE_MONITOR_ALL &&
!(adap->capabilities & CEC_CAP_MONITOR_ALL))
return -EINVAL;
if (mode_follower == CEC_MODE_MONITOR_PIN &&
!(adap->capabilities & CEC_CAP_MONITOR_PIN))
return -EINVAL;
/* Follower modes should always be able to send CEC messages */
if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
!(adap->capabilities & CEC_CAP_TRANSMIT)) &&
mode_follower >= CEC_MODE_FOLLOWER &&
mode_follower <= CEC_MODE_EXCL_FOLLOWER_PASSTHRU)
return -EINVAL;
/* Monitor modes require CEC_MODE_NO_INITIATOR */
if (mode_initiator && mode_follower >= CEC_MODE_MONITOR_PIN)
return -EINVAL;
/* Monitor modes require CAP_NET_ADMIN */
if (mode_follower >= CEC_MODE_MONITOR_PIN && !capable(CAP_NET_ADMIN))
return -EPERM;
mutex_lock(&adap->lock);
/*
* You can't become exclusive follower if someone else already
* has that job.
*/
if ((mode_follower == CEC_MODE_EXCL_FOLLOWER ||
mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) &&
adap->cec_follower && adap->cec_follower != fh)
err = -EBUSY;
/*
* You can't become exclusive initiator if someone else already
* has that job.
*/
if (mode_initiator == CEC_MODE_EXCL_INITIATOR &&
adap->cec_initiator && adap->cec_initiator != fh)
err = -EBUSY;
if (!err) {
bool old_mon_all = fh->mode_follower == CEC_MODE_MONITOR_ALL;
bool new_mon_all = mode_follower == CEC_MODE_MONITOR_ALL;
if (old_mon_all != new_mon_all) {
if (new_mon_all)
err = cec_monitor_all_cnt_inc(adap);
else
cec_monitor_all_cnt_dec(adap);
}
}
if (err) {
mutex_unlock(&adap->lock);
return err;
}
if (fh->mode_follower == CEC_MODE_FOLLOWER)
adap->follower_cnt--;
if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
adap->monitor_pin_cnt--;
if (mode_follower == CEC_MODE_FOLLOWER)
adap->follower_cnt++;
if (mode_follower == CEC_MODE_MONITOR_PIN) {
#ifdef CONFIG_CEC_PIN
struct cec_event ev = {
.flags = CEC_EVENT_FL_INITIAL_STATE,
};
ev.event = adap->pin->cur_value ? CEC_EVENT_PIN_HIGH :
CEC_EVENT_PIN_LOW;
cec_queue_event_fh(fh, &ev, 0);
#endif
adap->monitor_pin_cnt++;
}
if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
adap->passthrough =
mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU;
adap->cec_follower = fh;
} else if (adap->cec_follower == fh) {
adap->passthrough = false;
adap->cec_follower = NULL;
}
if (mode_initiator == CEC_MODE_EXCL_INITIATOR)
adap->cec_initiator = fh;
else if (adap->cec_initiator == fh)
adap->cec_initiator = NULL;
fh->mode_initiator = mode_initiator;
fh->mode_follower = mode_follower;
mutex_unlock(&adap->lock);
return 0;
}
static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct cec_devnode *devnode = cec_devnode_data(filp);
struct cec_fh *fh = filp->private_data;
struct cec_adapter *adap = fh->adap;
bool block = !(filp->f_flags & O_NONBLOCK);
void __user *parg = (void __user *)arg;
if (!devnode->registered)
return -ENODEV;
switch (cmd) {
case CEC_ADAP_G_CAPS:
return cec_adap_g_caps(adap, parg);
case CEC_ADAP_G_PHYS_ADDR:
return cec_adap_g_phys_addr(adap, parg);
case CEC_ADAP_S_PHYS_ADDR:
return cec_adap_s_phys_addr(adap, fh, block, parg);
case CEC_ADAP_G_LOG_ADDRS:
return cec_adap_g_log_addrs(adap, parg);
case CEC_ADAP_S_LOG_ADDRS:
return cec_adap_s_log_addrs(adap, fh, block, parg);
case CEC_TRANSMIT:
return cec_transmit(adap, fh, block, parg);
case CEC_RECEIVE:
return cec_receive(adap, fh, block, parg);
case CEC_DQEVENT:
return cec_dqevent(adap, fh, block, parg);
case CEC_G_MODE:
return cec_g_mode(adap, fh, parg);
case CEC_S_MODE:
return cec_s_mode(adap, fh, parg);
default:
return -ENOTTY;
}
}
static int cec_open(struct inode *inode, struct file *filp)
{
struct cec_devnode *devnode =
container_of(inode->i_cdev, struct cec_devnode, cdev);
struct cec_adapter *adap = to_cec_adapter(devnode);
struct cec_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
/*
* Initial events that are automatically sent when the cec device is
* opened.
*/
struct cec_event ev_state = {
.event = CEC_EVENT_STATE_CHANGE,
.flags = CEC_EVENT_FL_INITIAL_STATE,
};
unsigned int i;
int err;
if (!fh)
return -ENOMEM;
INIT_LIST_HEAD(&fh->msgs);
INIT_LIST_HEAD(&fh->xfer_list);
for (i = 0; i < CEC_NUM_EVENTS; i++)
INIT_LIST_HEAD(&fh->events[i]);
mutex_init(&fh->lock);
init_waitqueue_head(&fh->wait);
fh->mode_initiator = CEC_MODE_INITIATOR;
fh->adap = adap;
err = cec_get_device(devnode);
if (err) {
kfree(fh);
return err;
}
mutex_lock(&devnode->lock);
if (list_empty(&devnode->fhs) &&
!adap->needs_hpd &&
adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
err = adap->ops->adap_enable(adap, true);
if (err) {
mutex_unlock(&devnode->lock);
kfree(fh);
return err;
}
}
filp->private_data = fh;
/* Queue up initial state events */
ev_state.state_change.phys_addr = adap->phys_addr;
ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
cec_queue_event_fh(fh, &ev_state, 0);
list_add(&fh->list, &devnode->fhs);
mutex_unlock(&devnode->lock);
return 0;
}
/* Override for the release function */
static int cec_release(struct inode *inode, struct file *filp)
{
struct cec_devnode *devnode = cec_devnode_data(filp);
struct cec_adapter *adap = to_cec_adapter(devnode);
struct cec_fh *fh = filp->private_data;
unsigned int i;
mutex_lock(&adap->lock);
if (adap->cec_initiator == fh)
adap->cec_initiator = NULL;
if (adap->cec_follower == fh) {
adap->cec_follower = NULL;
adap->passthrough = false;
}
if (fh->mode_follower == CEC_MODE_FOLLOWER)
adap->follower_cnt--;
if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
adap->monitor_pin_cnt--;
if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
cec_monitor_all_cnt_dec(adap);
mutex_unlock(&adap->lock);
mutex_lock(&devnode->lock);
list_del(&fh->list);
if (list_empty(&devnode->fhs) &&
!adap->needs_hpd &&
adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
WARN_ON(adap->ops->adap_enable(adap, false));
}
mutex_unlock(&devnode->lock);
/* Unhook pending transmits from this filehandle. */
mutex_lock(&adap->lock);
while (!list_empty(&fh->xfer_list)) {
struct cec_data *data =
list_first_entry(&fh->xfer_list, struct cec_data, xfer_list);
data->blocking = false;
data->fh = NULL;
list_del(&data->xfer_list);
}
mutex_unlock(&adap->lock);
while (!list_empty(&fh->msgs)) {
struct cec_msg_entry *entry =
list_first_entry(&fh->msgs, struct cec_msg_entry, list);
list_del(&entry->list);
kfree(entry);
}
for (i = CEC_NUM_CORE_EVENTS; i < CEC_NUM_EVENTS; i++) {
while (!list_empty(&fh->events[i])) {
struct cec_event_entry *entry =
list_first_entry(&fh->events[i],
struct cec_event_entry, list);
list_del(&entry->list);
kfree(entry);
}
}
kfree(fh);
cec_put_device(devnode);
filp->private_data = NULL;
return 0;
}
const struct file_operations cec_devnode_fops = {
.owner = THIS_MODULE,
.open = cec_open,
.unlocked_ioctl = cec_ioctl,
.release = cec_release,
.poll = cec_poll,
.llseek = no_llseek,
};
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