linux/include/media/cec.h
Hans Verkuil 32804fcb61 media: cec: keep track of outstanding transmits
I noticed that repeatedly running 'cec-ctl --playback' would occasionally
select 'Playback Device 2' instead of 'Playback Device 1', even though there
were no other Playback devices in the HDMI topology. This happened both with
'real' hardware and with the vivid CEC emulation, suggesting that this was an
issue in the core code that claims a logical address.

What 'cec-ctl --playback' does is to first clear all existing logical addresses,
and immediately after that configure the new desired device type.

The core code will poll the logical addresses trying to find a free address.
When found it will issue a few standard messages as per the CEC spec and return.
Those messages are queued up and will be transmitted asynchronously.

What happens is that if you run two 'cec-ctl --playback' commands in quick
succession, there is still a message of the first cec-ctl command being transmitted
when you reconfigure the adapter again in the second cec-ctl command.

When the logical addresses are cleared, then all information about outstanding
transmits inside the CEC core is also cleared, and the core is no longer aware
that there is still a transmit in flight.

When the hardware finishes the transmit it calls transmit_done and the CEC core
thinks it is actually in response of a POLL messages that is trying to find a
free logical address. The result of all this is that the core thinks that the
logical address for Playback Device 1 is in use, when it is really an earlier
transmit that ended.

The main transmit thread looks at adap->transmitting to check if a transmit
is in progress, but that is set to NULL when the adapter is unconfigured.
adap->transmitting represents the view of userspace, not that of the hardware.
So when unconfiguring the adapter the message is marked aborted from the point
of view of userspace, but seen from the PoV of the hardware it is still ongoing.

So introduce a new bool transmit_in_progress that represents the hardware state
and use that instead of adap->transmitting. Now the CEC core waits until the
hardware finishes the transmit before starting a new transmit.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org>      # for v4.18 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2018-11-23 05:56:14 -05:00

454 lines
12 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* cec - HDMI Consumer Electronics Control support header
*
* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*/
#ifndef _MEDIA_CEC_H
#define _MEDIA_CEC_H
#include <linux/poll.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/kthread.h>
#include <linux/timer.h>
#include <linux/cec-funcs.h>
#include <media/rc-core.h>
#include <media/cec-notifier.h>
#define CEC_CAP_DEFAULTS (CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | \
CEC_CAP_PASSTHROUGH | CEC_CAP_RC)
/**
* struct cec_devnode - cec device node
* @dev: cec device
* @cdev: cec character device
* @minor: device node minor number
* @registered: the device was correctly registered
* @unregistered: the device was unregistered
* @fhs_lock: lock to control access to the filehandle list
* @fhs: the list of open filehandles (cec_fh)
*
* This structure represents a cec-related device node.
*
* The @parent is a physical device. It must be set by core or device drivers
* before registering the node.
*/
struct cec_devnode {
/* sysfs */
struct device dev;
struct cdev cdev;
/* device info */
int minor;
bool registered;
bool unregistered;
struct list_head fhs;
struct mutex lock;
};
struct cec_adapter;
struct cec_data;
struct cec_pin;
struct cec_data {
struct list_head list;
struct list_head xfer_list;
struct cec_adapter *adap;
struct cec_msg msg;
struct cec_fh *fh;
struct delayed_work work;
struct completion c;
u8 attempts;
bool blocking;
bool completed;
};
struct cec_msg_entry {
struct list_head list;
struct cec_msg msg;
};
struct cec_event_entry {
struct list_head list;
struct cec_event ev;
};
#define CEC_NUM_CORE_EVENTS 2
#define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH
struct cec_fh {
struct list_head list;
struct list_head xfer_list;
struct cec_adapter *adap;
u8 mode_initiator;
u8 mode_follower;
/* Events */
wait_queue_head_t wait;
struct mutex lock;
struct list_head events[CEC_NUM_EVENTS]; /* queued events */
u16 queued_events[CEC_NUM_EVENTS];
unsigned int total_queued_events;
struct cec_event_entry core_events[CEC_NUM_CORE_EVENTS];
struct list_head msgs; /* queued messages */
unsigned int queued_msgs;
};
#define CEC_SIGNAL_FREE_TIME_RETRY 3
#define CEC_SIGNAL_FREE_TIME_NEW_INITIATOR 5
#define CEC_SIGNAL_FREE_TIME_NEXT_XFER 7
/* The nominal data bit period is 2.4 ms */
#define CEC_FREE_TIME_TO_USEC(ft) ((ft) * 2400)
struct cec_adap_ops {
/* Low-level callbacks */
int (*adap_enable)(struct cec_adapter *adap, bool enable);
int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
int (*adap_monitor_pin_enable)(struct cec_adapter *adap, bool enable);
int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
u32 signal_free_time, struct cec_msg *msg);
void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
void (*adap_free)(struct cec_adapter *adap);
/* Error injection callbacks */
int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
/* High-level CEC message callback */
int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
};
/*
* The minimum message length you can receive (excepting poll messages) is 2.
* With a transfer rate of at most 36 bytes per second this makes 18 messages
* per second worst case.
*
* We queue at most 3 seconds worth of received messages. The CEC specification
* requires that messages are replied to within a second, so 3 seconds should
* give more than enough margin. Since most messages are actually more than 2
* bytes, this is in practice a lot more than 3 seconds.
*/
#define CEC_MAX_MSG_RX_QUEUE_SZ (18 * 3)
/*
* The transmit queue is limited to 1 second worth of messages (worst case).
* Messages can be transmitted by userspace and kernel space. But for both it
* makes no sense to have a lot of messages queued up. One second seems
* reasonable.
*/
#define CEC_MAX_MSG_TX_QUEUE_SZ (18 * 1)
struct cec_adapter {
struct module *owner;
char name[32];
struct cec_devnode devnode;
struct mutex lock;
struct rc_dev *rc;
struct list_head transmit_queue;
unsigned int transmit_queue_sz;
struct list_head wait_queue;
struct cec_data *transmitting;
bool transmit_in_progress;
struct task_struct *kthread_config;
struct completion config_completion;
struct task_struct *kthread;
wait_queue_head_t kthread_waitq;
wait_queue_head_t waitq;
const struct cec_adap_ops *ops;
void *priv;
u32 capabilities;
u8 available_log_addrs;
u16 phys_addr;
bool needs_hpd;
bool is_configuring;
bool is_configured;
bool cec_pin_is_high;
u8 last_initiator;
u32 monitor_all_cnt;
u32 monitor_pin_cnt;
u32 follower_cnt;
struct cec_fh *cec_follower;
struct cec_fh *cec_initiator;
bool passthrough;
struct cec_log_addrs log_addrs;
u32 tx_timeouts;
#ifdef CONFIG_CEC_NOTIFIER
struct cec_notifier *notifier;
#endif
#ifdef CONFIG_CEC_PIN
struct cec_pin *pin;
#endif
struct dentry *cec_dir;
struct dentry *status_file;
struct dentry *error_inj_file;
u16 phys_addrs[15];
u32 sequence;
char input_phys[32];
};
static inline void *cec_get_drvdata(const struct cec_adapter *adap)
{
return adap->priv;
}
static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
{
return adap->log_addrs.log_addr_mask & (1 << log_addr);
}
static inline bool cec_is_sink(const struct cec_adapter *adap)
{
return adap->phys_addr == 0;
}
/**
* cec_is_registered() - is the CEC adapter registered?
*
* @adap: the CEC adapter, may be NULL.
*
* Return: true if the adapter is registered, false otherwise.
*/
static inline bool cec_is_registered(const struct cec_adapter *adap)
{
return adap && adap->devnode.registered;
}
#define cec_phys_addr_exp(pa) \
((pa) >> 12), ((pa) >> 8) & 0xf, ((pa) >> 4) & 0xf, (pa) & 0xf
struct edid;
#if IS_REACHABLE(CONFIG_CEC_CORE)
struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
void *priv, const char *name, u32 caps, u8 available_las);
int cec_register_adapter(struct cec_adapter *adap, struct device *parent);
void cec_unregister_adapter(struct cec_adapter *adap);
void cec_delete_adapter(struct cec_adapter *adap);
int cec_s_log_addrs(struct cec_adapter *adap, struct cec_log_addrs *log_addrs,
bool block);
void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
bool block);
void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
const struct edid *edid);
int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
bool block);
/* Called by the adapter */
void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
u8 error_cnt, ktime_t ts);
static inline void cec_transmit_done(struct cec_adapter *adap, u8 status,
u8 arb_lost_cnt, u8 nack_cnt,
u8 low_drive_cnt, u8 error_cnt)
{
cec_transmit_done_ts(adap, status, arb_lost_cnt, nack_cnt,
low_drive_cnt, error_cnt, ktime_get());
}
/*
* Simplified version of cec_transmit_done for hardware that doesn't retry
* failed transmits. So this is always just one attempt in which case
* the status is sufficient.
*/
void cec_transmit_attempt_done_ts(struct cec_adapter *adap,
u8 status, ktime_t ts);
static inline void cec_transmit_attempt_done(struct cec_adapter *adap,
u8 status)
{
cec_transmit_attempt_done_ts(adap, status, ktime_get());
}
void cec_received_msg_ts(struct cec_adapter *adap,
struct cec_msg *msg, ktime_t ts);
static inline void cec_received_msg(struct cec_adapter *adap,
struct cec_msg *msg)
{
cec_received_msg_ts(adap, msg, ktime_get());
}
/**
* cec_queue_pin_cec_event() - queue a CEC pin event with a given timestamp.
*
* @adap: pointer to the cec adapter
* @is_high: when true the CEC pin is high, otherwise it is low
* @dropped_events: when true some events were dropped
* @ts: the timestamp for this event
*
*/
void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high,
bool dropped_events, ktime_t ts);
/**
* cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
*
* @adap: pointer to the cec adapter
* @is_high: when true the HPD pin is high, otherwise it is low
* @ts: the timestamp for this event
*
*/
void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
/**
* cec_queue_pin_5v_event() - queue a pin event with a given timestamp.
*
* @adap: pointer to the cec adapter
* @is_high: when true the 5V pin is high, otherwise it is low
* @ts: the timestamp for this event
*
*/
void cec_queue_pin_5v_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
/**
* cec_get_edid_phys_addr() - find and return the physical address
*
* @edid: pointer to the EDID data
* @size: size in bytes of the EDID data
* @offset: If not %NULL then the location of the physical address
* bytes in the EDID will be returned here. This is set to 0
* if there is no physical address found.
*
* Return: the physical address or CEC_PHYS_ADDR_INVALID if there is none.
*/
u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
unsigned int *offset);
#else
static inline int cec_register_adapter(struct cec_adapter *adap,
struct device *parent)
{
return 0;
}
static inline void cec_unregister_adapter(struct cec_adapter *adap)
{
}
static inline void cec_delete_adapter(struct cec_adapter *adap)
{
}
static inline void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
bool block)
{
}
static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
const struct edid *edid)
{
}
static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
unsigned int *offset)
{
if (offset)
*offset = 0;
return CEC_PHYS_ADDR_INVALID;
}
#endif
/**
* cec_phys_addr_invalidate() - set the physical address to INVALID
*
* @adap: the CEC adapter
*
* This is a simple helper function to invalidate the physical
* address.
*/
static inline void cec_phys_addr_invalidate(struct cec_adapter *adap)
{
cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
}
/**
* cec_get_edid_spa_location() - find location of the Source Physical Address
*
* @edid: the EDID
* @size: the size of the EDID
*
* This EDID is expected to be a CEA-861 compliant, which means that there are
* at least two blocks and one or more of the extensions blocks are CEA-861
* blocks.
*
* The returned location is guaranteed to be <= size-2.
*
* This is an inline function since it is used by both CEC and V4L2.
* Ideally this would go in a module shared by both, but it is overkill to do
* that for just a single function.
*/
static inline unsigned int cec_get_edid_spa_location(const u8 *edid,
unsigned int size)
{
unsigned int blocks = size / 128;
unsigned int block;
u8 d;
/* Sanity check: at least 2 blocks and a multiple of the block size */
if (blocks < 2 || size % 128)
return 0;
/*
* If there are fewer extension blocks than the size, then update
* 'blocks'. It is allowed to have more extension blocks than the size,
* since some hardware can only read e.g. 256 bytes of the EDID, even
* though more blocks are present. The first CEA-861 extension block
* should normally be in block 1 anyway.
*/
if (edid[0x7e] + 1 < blocks)
blocks = edid[0x7e] + 1;
for (block = 1; block < blocks; block++) {
unsigned int offset = block * 128;
/* Skip any non-CEA-861 extension blocks */
if (edid[offset] != 0x02 || edid[offset + 1] != 0x03)
continue;
/* search Vendor Specific Data Block (tag 3) */
d = edid[offset + 2] & 0x7f;
/* Check if there are Data Blocks */
if (d <= 4)
continue;
if (d > 4) {
unsigned int i = offset + 4;
unsigned int end = offset + d;
/* Note: 'end' is always < 'size' */
do {
u8 tag = edid[i] >> 5;
u8 len = edid[i] & 0x1f;
if (tag == 3 && len >= 5 && i + len <= end &&
edid[i + 1] == 0x03 &&
edid[i + 2] == 0x0c &&
edid[i + 3] == 0x00)
return i + 4;
i += len + 1;
} while (i < end);
}
}
return 0;
}
#endif /* _MEDIA_CEC_H */