Re: [Y2038] [PATCH v4 06/10] cec: add HDMI CEC framework: y2038 question

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Ping! (Added Arnd to the CC list)

On 04/27/2015 09:40 AM, Hans Verkuil wrote:
> Added the y2038 mailinglist since I would like to get their input for
> this API.
> 
> Y2038 experts, can you take a look at my comment in the code below?
> 
> Thanks!

Arnd, I just saw your patch series adding struct __kernel_timespec to
uapi/linux/time.h. I get the feeling that it might take a few kernel
cycles before we have a timespec64 available in userspace. Based on that
I think this CEC API should drop the timestamps for now and wait until
timespec64 becomes available before adding it.

The timestamps are a nice-to-have, but not critical. So adding it later
shouldn't be a problem. What is your opinion?

	Hans

> 
> On 04/23/2015 03:03 PM, Kamil Debski wrote:
>> From: Hans Verkuil <hansverk@xxxxxxxxx>
>>
>> The added HDMI CEC framework provides a generic kernel interface for
>> HDMI CEC devices.
>>
>> Signed-off-by: Hans Verkuil <hansverk@xxxxxxxxx>
>> [k.debski@xxxxxxxxxxx: Merged CEC Updates commit by Hans Verkuil]
>> [k.debski@xxxxxxxxxxx: Merged Update author commit by Hans Verkuil]
>> [k.debski@xxxxxxxxxxx: change kthread handling when setting logical
>> address]
>> [k.debski@xxxxxxxxxxx: code cleanup and fixes]
>> [k.debski@xxxxxxxxxxx: add missing CEC commands to match spec]
>> [k.debski@xxxxxxxxxxx: add RC framework support]
>> [k.debski@xxxxxxxxxxx: move and edit documentation]
>> [k.debski@xxxxxxxxxxx: add vendor id reporting]
>> [k.debski@xxxxxxxxxxx: add possibility to clear assigned logical
>> addresses]
>> [k.debski@xxxxxxxxxxx: documentation fixes, clenaup and expansion]
>> [k.debski@xxxxxxxxxxx: reorder of API structs and add reserved fields]
>> [k.debski@xxxxxxxxxxx: fix handling of events and fix 32/64bit timespec
>> problem]
>> [k.debski@xxxxxxxxxxx: add cec.h to include/uapi/linux/Kbuild]
>> Signed-off-by: Kamil Debski <k.debski@xxxxxxxxxxx>
>> ---
>>  Documentation/cec.txt     |  396 ++++++++++++++++
>>  drivers/media/Kconfig     |    6 +
>>  drivers/media/Makefile    |    2 +
>>  drivers/media/cec.c       | 1161 +++++++++++++++++++++++++++++++++++++++++++++
>>  include/media/cec.h       |  140 ++++++
>>  include/uapi/linux/Kbuild |    1 +
>>  include/uapi/linux/cec.h  |  303 ++++++++++++
>>  7 files changed, 2009 insertions(+)
>>  create mode 100644 Documentation/cec.txt
>>  create mode 100644 drivers/media/cec.c
>>  create mode 100644 include/media/cec.h
>>  create mode 100644 include/uapi/linux/cec.h
>>
> 
> <snip>
> 
>> diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
>> index 4842a98..5854cfd 100644
>> --- a/include/uapi/linux/Kbuild
>> +++ b/include/uapi/linux/Kbuild
>> @@ -81,6 +81,7 @@ header-y += capi.h
>>  header-y += cciss_defs.h
>>  header-y += cciss_ioctl.h
>>  header-y += cdrom.h
>> +header-y += cec.h
>>  header-y += cgroupstats.h
>>  header-y += chio.h
>>  header-y += cm4000_cs.h
>> diff --git a/include/uapi/linux/cec.h b/include/uapi/linux/cec.h
>> new file mode 100644
>> index 0000000..bb6d66c
>> --- /dev/null
>> +++ b/include/uapi/linux/cec.h
>> @@ -0,0 +1,303 @@
>> +#ifndef _CEC_H
>> +#define _CEC_H
>> +
>> +#include <linux/types.h>
>> +
>> +struct cec_time {
>> +	__u64 sec;
>> +	__u64 nsec;
>> +};
> 
> I don't like having to introduce a new struct for time here. Basically we are
> only doing this because there is still no public struct timespec64.
> 
> When will that struct become available for use in a public API? If it is 4.2,
> then we can start using it. If it will take longer, then what alternative can
> we use to prevent having to change the API later?
> 
> One alternative might be to drop it for now and just reserve space in the
> structs to add it later.
> 
> Input from the y2038 experts will be welcome!
> 
> Regards,
> 
> 	Hans
> 
>> +
>> +struct cec_msg {
>> +	struct cec_time ts;
>> +	__u32 len;
>> +	__u32 status;
>> +	__u32 timeout;
>> +	/* timeout (in ms) is used to timeout CEC_RECEIVE.
>> +	   Set to 0 if you want to wait forever. */
>> +	__u8  msg[16];
>> +	__u8  reply;
>> +	/* If non-zero, then wait for a reply with this opcode.
>> +	   If there was an error when sending the msg or FeatureAbort
>> +	   was returned, then reply is set to 0.
>> +	   If reply is non-zero upon return, then len/msg are set to
>> +	   the received message.
>> +	   If reply is zero upon return and status has the
>> +	   CEC_TX_STATUS_FEATURE_ABORT bit set, then len/msg are set to the
>> +	   received feature abort message.
>> +	   If reply is zero upon return and status has the
>> +	   CEC_TX_STATUS_REPLY_TIMEOUT
>> +	   bit set, then no reply was seen at all.
>> +	   This field is ignored with CEC_RECEIVE.
>> +	   If reply is non-zero for CEC_TRANSMIT and the message is a broadcast,
>> +	   then -EINVAL is returned.
>> +	   if reply is non-zero, then timeout is set to 1000 (the required
>> +	   maximum response time).
>> +	 */
>> +	__u8 reserved[31];
>> +};
>> +
>> +static inline __u8 cec_msg_initiator(const struct cec_msg *msg)
>> +{
>> +	return msg->msg[0] >> 4;
>> +}
>> +
>> +static inline __u8 cec_msg_destination(const struct cec_msg *msg)
>> +{
>> +	return msg->msg[0] & 0xf;
>> +}
>> +
>> +static inline bool cec_msg_is_broadcast(const struct cec_msg *msg)
>> +{
>> +	return (msg->msg[0] & 0xf) == 0xf;
>> +}
>> +
>> +/* cec status field */
>> +#define CEC_TX_STATUS_OK            (0)
>> +#define CEC_TX_STATUS_ARB_LOST      (1 << 0)
>> +#define CEC_TX_STATUS_RETRY_TIMEOUT (1 << 1)
>> +#define CEC_TX_STATUS_FEATURE_ABORT (1 << 2)
>> +#define CEC_TX_STATUS_REPLY_TIMEOUT (1 << 3)
>> +#define CEC_RX_STATUS_READY         (0)
>> +
>> +#define CEC_LOG_ADDR_INVALID 0xff
>> +
>> +/* The maximum number of logical addresses one device can be assigned to.
>> + * The CEC 2.0 spec allows for only 2 logical addresses at the moment. The
>> + * Analog Devices CEC hardware supports 3. So let's go wild and go for 4. */
>> +#define CEC_MAX_LOG_ADDRS 4
>> +
>> +/* The "Primary Device Type" */
>> +#define CEC_PRIM_DEVTYPE_TV		0
>> +#define CEC_PRIM_DEVTYPE_RECORD		1
>> +#define CEC_PRIM_DEVTYPE_TUNER		3
>> +#define CEC_PRIM_DEVTYPE_PLAYBACK	4
>> +#define CEC_PRIM_DEVTYPE_AUDIOSYSTEM	5
>> +#define CEC_PRIM_DEVTYPE_SWITCH		6
>> +#define CEC_PRIM_DEVTYPE_VIDEOPROC	7
>> +
>> +/* The "All Device Types" flags (CEC 2.0) */
>> +#define CEC_FL_ALL_DEVTYPE_TV		(1 << 7)
>> +#define CEC_FL_ALL_DEVTYPE_RECORD	(1 << 6)
>> +#define CEC_FL_ALL_DEVTYPE_TUNER	(1 << 5)
>> +#define CEC_FL_ALL_DEVTYPE_PLAYBACK	(1 << 4)
>> +#define CEC_FL_ALL_DEVTYPE_AUDIOSYSTEM	(1 << 3)
>> +#define CEC_FL_ALL_DEVTYPE_SWITCH	(1 << 2)
>> +/* And if you wondering what happened to VIDEOPROC devices: those should
>> + * be mapped to a SWITCH. */
>> +
>> +/* The logical address types that the CEC device wants to claim */
>> +#define CEC_LOG_ADDR_TYPE_TV		0
>> +#define CEC_LOG_ADDR_TYPE_RECORD	1
>> +#define CEC_LOG_ADDR_TYPE_TUNER		2
>> +#define CEC_LOG_ADDR_TYPE_PLAYBACK	3
>> +#define CEC_LOG_ADDR_TYPE_AUDIOSYSTEM	4
>> +#define CEC_LOG_ADDR_TYPE_SPECIFIC	5
>> +#define CEC_LOG_ADDR_TYPE_UNREGISTERED	6
>> +/* Switches should use UNREGISTERED.
>> + * Video processors should use SPECIFIC. */
>> +
>> +/* The CEC version */
>> +#define CEC_VERSION_1_4B		5
>> +#define CEC_VERSION_2_0			6
>> +
>> +struct cec_event {
>> +	struct cec_time ts;
>> +	__u32 event;
>> +	__u8 reserved[4];
>> +};
>> +
>> +/* The CEC state */
>> +#define CEC_STATE_DISABLED		0
>> +#define CEC_STATE_ENABLED		1
>> +
>> +/* Userspace has to configure the adapter state (enable/disable) */
>> +#define CEC_CAP_STATE		(1 << 0)
>> +/* Userspace has to configure the physical address */
>> +#define CEC_CAP_PHYS_ADDR	(1 << 1)
>> +/* Userspace has to configure the logical addresses */
>> +#define CEC_CAP_LOG_ADDRS	(1 << 2)
>> +/* Userspace can transmit messages */
>> +#define CEC_CAP_TRANSMIT	(1 << 3)
>> +/* Userspace can receive messages */
>> +#define CEC_CAP_RECEIVE		(1 << 4)
>> +/* Userspace has to configure the vendor id */
>> +#define CEC_CAP_VENDOR_ID	(1 << 5)
>> +/* The hardware has the possibility to work in the promiscuous mode */
>> +#define CEC_CAP_PROMISCUOUS	(1 << 6)
>> +
>> +struct cec_caps {
>> +	__u32 available_log_addrs;
>> +	__u32 capabilities;
>> +	__u32 vendor_id;
>> +	__u8  version;
>> +	__u8  reserved[11];
>> +};
>> +
>> +struct cec_log_addrs {
>> +	__u8 cec_version;
>> +	__u8 num_log_addrs;
>> +	__u8 primary_device_type[CEC_MAX_LOG_ADDRS];
>> +	__u8 log_addr_type[CEC_MAX_LOG_ADDRS];
>> +	__u8 log_addr[CEC_MAX_LOG_ADDRS];
>> +
>> +	/* CEC 2.0 */
>> +	__u8 all_device_types;
>> +	__u8 features[CEC_MAX_LOG_ADDRS][12];
>> +
>> +	__u8 reserved[9];
>> +};
>> +
>> +/* Commands */
>> +
>> +/* One Touch Play Feature */
>> +#define CEC_OP_ACTIVE_SOURCE			0x82
>> +#define CEC_OP_IMAGE_VIEW_ON			0x04
>> +#define CEC_OP_TEXT_VIEW_ON			0x0d
>> +
>> +/* Routing Control Feature */
>> +#define CEC_OP_ACTIVE_SOURCE			0x82
>> +#define CEC_OP_INACTIVE_SOURCE			0x9d
>> +#define CEC_OP_REQUEST_ACTIVE_SOURCE		0x85
>> +#define CEC_OP_ROUTING_CHANGE			0x80
>> +#define CEC_OP_ROUTING_INFORMATION		0x81
>> +#define CEC_OP_SET_STREAM_PATH			0x86
>> +
>> +/* Standby Feature */
>> +#define CEC_OP_STANDBY				0x36
>> +
>> +/* One Touch Record Feature */
>> +#define CEC_OP_RECORD_OFF			0x0b
>> +#define CEC_OP_RECORD_ON			0x09
>> +#define CEC_OP_RECORD_STATUS			0x0a
>> +#define CEC_OP_RECORD_TV_SCREEN			0x0f
>> +
>> +/* Timer Programming Feature */
>> +#define CEC_OP_CLEAR_ANALOGUE_TIMER		0x33
>> +#define CEC_OP_CLEAR_DIGITAL_TIMER		0x99
>> +#define CEC_OP_CLEAR_EXT_TIMER			0xa1
>> +#define CEC_OP_SET_ANALOGUE_TIMER		0x34
>> +#define CEC_OP_SET_DIGITAL_TIMER		0x97
>> +#define CEC_OP_SET_EXT_TIMER			0xa2
>> +#define CEC_OP_SET_EXT_PROGRAM_TIMER		0x67
>> +#define CEC_OP_TIMER_CLEARED_STATUS		0x43
>> +#define CEC_OP_TIMER_STATUS			0x35
>> +
>> +/* System Information Feature */
>> +#define CEC_OP_CEC_VERSION			0x9e
>> +#define CEC_OP_GET_CEC_VERSION			0x9f
>> +#define CEC_OP_GIVE_PHYSICAL_ADDR		0x83
>> +#define CEC_OP_GET_MENU_LANGUAGE		0x91
>> +#define CEC_OP_REPORT_PHYSICAL_ADDR		0x84
>> +#define CEC_OP_SET_MENU_LANGUAGE		0x32
>> +
>> +/* Deck Control Feature */
>> +#define CEC_OP_DECK_CONTROL			0x42
>> +#define CEC_OP_DECK_STATUS			0x1b
>> +#define CEC_OP_GIVE_DECK_STATUS			0x1a
>> +#define CEC_OP_PLAY				0x41
>> +
>> +/* Tuner Control Feature */
>> +#define CEC_OP_GIVE_TUNER_DEVICE_STATUS		0x08
>> +#define CEC_OP_SELECT_ANALOGUE_SERVICE		0x92
>> +#define CEC_OP_SELECT_DIGITAL_SERVICE		0x93
>> +#define CEC_OP_TUNER_DEVICE_STATUS		0x07
>> +#define CEC_OP_TUNER_STEP_DECREMENT		0x06
>> +#define CEC_OP_TUNER_STEP_INCREMENT		0x05
>> +
>> +/* Vendor Specific Commands Feature */
>> +#define CEC_OP_CEC_VERSION			0x9e
>> +#define CEC_OP_DEVICE_VENDOR_ID			0x87
>> +#define CEC_OP_GET_CEC_VERSION			0x9f
>> +#define CEC_OP_GIVE_DEVICE_VENDOR_ID		0x8c
>> +#define CEC_OP_VENDOR_COMMAND			0x89
>> +#define CEC_OP_VENDOR_COMMAND_WITH_ID		0xa0
>> +#define CEC_OP_VENDOR_REMOTE_BUTTON_DOWN	0x8a
>> +#define CEC_OP_VENDOR_REMOTE_BUTTON_UP		0x8b
>> +
>> +/* OSD Display Feature */
>> +#define CEC_OP_SET_OSD_STRING			0x64
>> +
>> +/* Device OSD Transfer Feature */
>> +#define CEC_OP_GIVE_OSD_NAME			0x46
>> +#define CEC_OP_SET_OSD_NAME			0x47
>> +
>> +/* Device Menu Control Feature */
>> +#define CEC_OP_MENU_REQUEST			0x8d
>> +#define CEC_OP_MENU_STATUS			0x8e
>> +#define CEC_OP_USER_CONTROL_PRESSED		0x44
>> +#define CEC_OP_USER_CONTROL_RELEASED		0x45
>> +
>> +/* Power Status Feature */
>> +#define CEC_OP_GIVE_DEVICE_POWER_STATUS		0x8f
>> +#define CEC_OP_REPORT_POWER_STATUS		0x90
>> +#define CEC_OP_FEATURE_ABORT			0x00
>> +#define CEC_OP_ABORT				0xff
>> +
>> +/* System Audio Control Feature */
>> +#define CEC_OP_GIVE_AUDIO_STATUS		0x71
>> +#define CEC_OP_GIVE_SYSTEM_AUDIO_MODE_STATUS	0x7d
>> +#define CEC_OP_REPORT_AUDIO_STATUS		0x7a
>> +#define CEC_OP_SET_SYSTEM_AUDIO_MODE		0x72
>> +#define CEC_OP_SYSTEM_AUDIO_MODE_REQUEST	0x70
>> +#define CEC_OP_SYSTEM_AUDIO_MODE_STATUS		0x7e
>> +
>> +/* Audio Rate Control Feature */
>> +#define CEC_OP_SET_AUDIO_RATE			0x9a
>> +
>> +/* Events */
>> +/* Event that occurs when a cable is connected */
>> +#define CEC_EVENT_CONNECT	1
>> +/* Event that occurs when all logical addresses were claimed */
>> +#define CEC_EVENT_READY		2
>> +/* Event that is sent when the cable is disconnected */
>> +#define CEC_EVENT_DISCONNECT	3
>> +
>> +/* ioctls */
>> +
>> +/* issue a CEC command */
>> +#define CEC_G_CAPS		_IOWR('a', 0, struct cec_caps)
>> +#define CEC_TRANSMIT		_IOWR('a', 1, struct cec_msg)
>> +#define CEC_RECEIVE		_IOWR('a', 2, struct cec_msg)
>> +
>> +/*
>> +   Configure the CEC adapter. It sets the device type and which
>> +   logical types it will try to claim. It will return which
>> +   logical addresses it could actually claim.
>> +   An error is returned if the adapter is disabled or if there
>> +   is no physical address assigned.
>> + */
>> +
>> +#define CEC_G_ADAP_LOG_ADDRS	_IOR('a', 3, struct cec_log_addrs)
>> +#define CEC_S_ADAP_LOG_ADDRS	_IOWR('a', 4, struct cec_log_addrs)
>> +
>> +/*
>> +   Enable/disable the adapter. The Set state ioctl may not
>> +   be available if that is handled internally.
>> + */
>> +#define CEC_G_ADAP_STATE	_IOR('a', 5, __u32)
>> +#define CEC_S_ADAP_STATE	_IOW('a', 6, __u32)
>> +
>> +/*
>> +   phys_addr is either 0 (if this is the CEC root device)
>> +   or a valid physical address obtained from the sink's EDID
>> +   as read by this CEC device (if this is a source device)
>> +   or a physical address obtained and modified from a sink
>> +   EDID and used for a sink CEC device.
>> +   If nothing is connected, then phys_addr is 0xffff.
>> +   See HDMI 1.4b, section 8.7 (Physical Address).
>> +
>> +   The Set ioctl may not be available if that is handled
>> +   internally.
>> + */
>> +#define CEC_G_ADAP_PHYS_ADDR	_IOR('a', 7, __u16)
>> +#define CEC_S_ADAP_PHYS_ADDR	_IOW('a', 8, __u16)
>> +
>> +#define CEC_G_EVENT		_IOWR('a', 9, struct cec_event)
>> +/*
>> +   Read and set the vendor ID of the CEC adapter.
>> + */
>> +#define CEC_G_VENDOR_ID		_IOR('a', 9, __u32)
>> +#define CEC_S_VENDOR_ID		_IOW('a', 10, __u32)
>> +
>> +#endif
>>
> 
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> https://lists.linaro.org/mailman/listinfo/y2038
> 

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