On Fri August 10 2012 19:04:52 Konke Radlow wrote:
>
> Signed-off-by: Konke Radlow <korad...@gmail.com>
> ---
> lib/include/libv4l2rds.h | 64 ++++++++
> lib/libv4l2rds/libv4l2rds.c | 340
> ++++++++++++++++++++++++++++++++++++++++++-
> utils/rds-ctl/rds-ctl.cpp | 31 +++-
> 3 files changed, 432 insertions(+), 3 deletions(-)
>
> diff --git a/lib/include/libv4l2rds.h b/lib/include/libv4l2rds.h
> index 37bdd2f..caefc1a 100644
> --- a/lib/include/libv4l2rds.h
> +++ b/lib/include/libv4l2rds.h
> @@ -63,6 +63,9 @@ extern "C" {
> #define V4L2_RDS_AF 0x800 /* AF (alternative freq) available */
> #define V4L2_RDS_ECC 0x1000 /* Extended County Code */
> #define V4L2_RDS_LC 0x2000 /* Language Code */
> +#define V4L2_RDS_TMC_SG 0x4000 /* RDS-TMC single group */
> +#define V4L2_RDS_TMC_MG 0x8000 /* RDS-TMC multi group */
> +#define V4L2_RDS_TMC_SYS 0x10000 /* RDS-TMC system information */
>
> /* Define Constants for the state of the RDS decoding process
> * used to address the relevant bit in the decode_information bitmask */
> @@ -76,6 +79,11 @@ extern "C" {
> #define V4L2_RDS_FLAG_COMPRESSED 0x04
> #define V4L2_RDS_FLAG_STATIC_PTY 0x08
>
> +/* TMC related codes
> + * used to extract TMC fields from RDS groups */
> +#define V4L2_TMC_TUNING_INFO 0x08
> +#define V4L2_TMC_SINGLE_GROUP 0x04
> +
> /* struct to encapsulate one complete RDS group */
> /* This structure is used internally to store data until a complete RDS
> * group was received and group id dependent decoding can be done.
> @@ -137,6 +145,61 @@ struct v4l2_rds_af_set {
> uint32_t af[MAX_AF_CNT]; /* AFs defined in Hz */
> };
>
> +/* struct to encapsulate an additional data field in a TMC message */
> +struct v4l2_tmc_additional {
> + uint8_t label;
> + uint16_t data;
> +};
> +
> +/* struct to encapsulate an arbitrary number of additional data fields
> + * belonging to one TMC message */
> +struct v4l2_tmc_additional_set {
> + uint8_t size;
> + /* 28 is the maximal possible number of fields. Additional data
28 should be a define instead of being hardcoded.
> + * is limited to 112 bit, and the smallest optional tuple has
> + * a size of 4 bit (4 bit identifier + 0 bits of data) */
> + struct v4l2_tmc_additional fields[28];
> +};
> +
> +/* struct to encapsulate a decoded TMC message with optional additional
> + * data field (in case of a multi-group TMC message) */
> +struct v4l2_rds_tmc_msg {
> + uint8_t length; /* length of multi-group message (0..4) */
> + uint8_t sid; /* service identifier at time of reception */
> + uint8_t extent;
> + uint8_t dp; /* duration and persistence */
> + uint16_t event; /* TMC event code */
> + uint16_t location; /* TMC event location */
> + bool follow_diversion; /* indicates if the driver is adviced to
> + * follow the diversion */
> + bool neg_direction; /* indicates negative / positive direction */
> +
> + /* decoded additional information (only available in multi-group
> + * messages) */
> + struct v4l2_tmc_additional_set additional;
> +};
> +
> +/* struct to encapsulate all TMC related information, including TMC System
> + * Information, TMC Tuning information and a buffer for the last decoded
> + * TMC messages */
> +struct v4l2_rds_tmc {
> + uint8_t ltn; /* location_table_number */
> + bool afi; /* alternative frequency indicator */
> + bool enhanced_mode; /* mode of transmission,
> + * if false -> basic => gaps between tmc groups
> + * gap defines timing behavior
> + * if true -> enhanced => t_a, t_w and t_d
> + * define timing behavior of tmc groups */
> + uint8_t mgs; /* message geographical scope */
> + uint8_t sid; /* service identifier (unique ID on national
> level) */
> + uint8_t gap; /* Gap parameters */
> + uint8_t t_a; /* activity time (only if mode = enhanced) */
> + uint8_t t_w; /* window time (only if mode = enhanced */
> + uint8_t t_d; /* delay time (only if mode = enhanced */
> + uint8_t spn[9]; /* service provider name */
> + struct v4l2_rds_tmc_msg tmc_msg;
> +};
> +
> /* struct to encapsulate state and RDS information for current decoding
> process */
> /* This is the structure that will be used by external applications, to
> * communicate with the library and get access to RDS data */
> @@ -172,6 +235,7 @@ struct v4l2_rds {
> struct v4l2_rds_statistics rds_statistics;
> struct v4l2_rds_oda_set rds_oda; /* Open Data Services */
> struct v4l2_rds_af_set rds_af; /* Alternative Frequencies */
> + struct v4l2_rds_tmc tmc; /* TMC information */
> };
>
> /* v4l2_rds_init() - initializes a new decoding process
> diff --git a/lib/libv4l2rds/libv4l2rds.c b/lib/libv4l2rds/libv4l2rds.c
> index 2d6642c..f47adb8 100644
> --- a/lib/libv4l2rds/libv4l2rds.c
> +++ b/lib/libv4l2rds/libv4l2rds.c
> @@ -63,6 +63,22 @@ struct rds_private_state {
> uint8_t utc_minute;
> uint8_t utc_offset;
>
> + /* TMC decoding buffers, to store data before it can be verified,
> + * and before all parts of a multi-group message have been received */
> + uint8_t continuity_id; /* continuity index of current TMC multigroup */
> + uint8_t grp_seq_id; /* group sequence identifier */
> + uint32_t optional_tmc[4]; /* buffer for up to 112 bits of optional
> + * additional data in multi-group
> + * messages */
> +
> + /* TMC groups are only accepted if the same data was received twice,
> + * these structs are used as receive buffers to validate TMC groups */
> + struct v4l2_rds_group prev_tmc_group;
> + struct v4l2_rds_group prev_tmc_sys_group;
> + struct v4l2_rds_tmc_msg new_tmc_msg;
> +
> + /* buffers for rds data, before group type specific decoding can
> + * be done */
> struct v4l2_rds_group rds_group;
> struct v4l2_rds_data rds_data_raw[4];
> };
> @@ -179,6 +195,276 @@ static void rds_decode_d(struct rds_private_state
> *priv_state, struct v4l2_rds_d
> grp->data_d_lsb = rds_data->lsb;
> }
>
> +/* compare two rds-groups for equality */
> +/* used for decoding RDS-TMC, which has the requirement that the same group
> + * is at least received twice before it is accepted */
> +static bool rds_compare_group(const struct v4l2_rds_group *a,
> + const struct v4l2_rds_group *b)
> +{
> + if (a->pi != b->pi)
> + return false;
> + if (a->group_version != b->group_version)
> + return false;
> + if (a->group_id != b->group_id)
> + return false;
> +
> + if (a->data_b_lsb != b->data_b_lsb)
> + return false;
> + if (a->data_c_lsb != b->data_c_lsb || a->data_c_msb != b->data_c_msb)
> + return false;
> + if (a->data_d_lsb != b->data_d_lsb || a->data_d_msb != b->data_d_msb)
> + return false;
> + /* all values are equal */
> + return true;
> +}
> +
> +/* return a bitmask with with bit_cnt bits set to 1 (starting from lsb) */
> +static uint32_t get_bitmask(uint8_t bit_cnt)
> +{
> + return (1 << bit_cnt) - 1;
> +}
> +
> +/* decode additional information of a TMC message into handy representation
> */
> +/* the additional information of TMC messages is submitted in (up to) 4
> blocks of
> + * 28 bits each, which are to be treated as a consecutive bit-array. Each
> additional
> + * information is defined by a 4-bit label, and the length of the following
> data
> + * is known. If the number of required bits for labels & data fields exeeds
> 28,
> + * coding continues without interruption in the next block.
> + * The first label starts at Y11 and is followed immediately by the
> associated data.
> + * The optional bit blocks are represented by an array of 4 uint32_t vars in
> the
> + * rds_private_state struct. The msb of each variable starts at Y11 (bit 11
> of
> + * block 3) and continues down to Z0 (bit 0 of block 4).
> + * The 4 lsb bits are not used (=0) */
> +static struct v4l2_tmc_additional_set *rds_tmc_decode_additional
> + (struct rds_private_state *priv_state)
The returned pointer is never used. This is a left-over from an earlier version,
so this can be replaced by void.
> +{
> + struct v4l2_rds_tmc_msg *msg = &priv_state->handle.tmc.tmc_msg;
> + struct v4l2_tmc_additional *fields = &msg->additional.fields[0];
> + uint32_t *optional = priv_state->optional_tmc;
> + const uint8_t data_len = 28; /* used bits in the fields of the
> + * uint32_t optional array */
> + const uint8_t label_len = 4; /* fixed length of a label */
> + uint8_t label; /* buffer for extracted label */
> + uint16_t data; /* buffer for extracted data */
> + uint8_t pos = 0; /* current position in optional block */
> + uint8_t len; /* length of next data field to be extracted */
> + uint8_t o_len; /* lenght of overhang into next block */
> + uint8_t block_idx = 0; /* index for current optional block */
> + uint8_t *field_idx = &msg->additional.size; /* index for
> + * additional field array */
> + /* LUT for the length of additional data blocks as defined in
> + * ISO 14819-1 sect. 5.5.1 */
> + static const uint8_t additional_lut[16] = {
> + 3, 3, 5, 5, 5, 8, 8, 8, 8, 11, 16, 16, 16, 16, 0, 0
> + };
> +
> + /* reset the additional information from previous messages */
> + *field_idx = 0;
> + memset(fields, 0, sizeof(*fields));
> +
> + /* decode each received optional block */
> + for (int i = 0; i < msg->length; i++) {
> + /* extract the label, handle situation where label is split
> + * across two adjacent RDS-TMC groups */
> + if (pos + label_len > data_len) {
> + o_len = label_len - (data_len - pos); /* overhang
> length */
> + len = data_len - pos; /* remaining data in current
> block*/
> + label = optional[block_idx] >> (32 - pos - len + o_len)
> &
> + get_bitmask(len + o_len);
> + if (++block_idx >= msg->length)
> + break;
> + pos = 0; /* start at beginning of next block */
> + label |= optional[block_idx] >> (32 - pos - o_len);
> + } else {
> + label = optional[block_idx] >> (32 - pos - label_len) &
> + get_bitmask(label_len);
> + pos += label_len % data_len;
> + /* end of optional block reached? */
> + block_idx = (pos == 0) ? block_idx+1 : block_idx;
> + if (block_idx >= msg->length)
> + break;
> + }
> +
> + /* extract the associated data block, handle situation where it
> + * is split across two adjacent RDS-TMC groups */
> + len = additional_lut[label]; /* length of data block */
> + if (pos + len > data_len) {
> + o_len = len - (data_len - pos); /* overhang length */
> + len = data_len - pos; /* remaining data in current
> block*/
> + data = optional[block_idx] >> (32 - pos - len + o_len) &
> + get_bitmask(len + o_len);
> + if (++block_idx >= msg->length)
> + break;
> + pos = 0; /* start at beginning of next block */
> + label |= optional[block_idx] >> (32 - pos - o_len);
> + } else {
> + data = optional[block_idx] >> (32 - pos - len) &
> + get_bitmask(len);
> + data += len % data_len;
> + /* end of optional block reached? */
> + block_idx = (pos == 0) ? block_idx+1 : block_idx;
> + }
> +
> + /* if the label is not "reserved for future use", store
> + * the extracted additional information */
> + if (label == 15) {
> + continue;
> + }
> + fields[*field_idx].label = label;
> + fields[*field_idx].data = data;
> + *field_idx += 1;
> + }
> + return &msg->additional;
> +}
> +
> +/* decode the TMC system information that is contained in type 3A groups
> + * that announce the presence of TMC */
> +static uint32_t rds_decode_tmc_system(struct rds_private_state *priv_state)
> +{
> + struct v4l2_rds_group *group = &priv_state->rds_group;
> + struct v4l2_rds_tmc *tmc = &priv_state->handle.tmc;
> + uint8_t variant_code;
> +
> + /* check if the same group was received twice. If not, store new
> + * group and return early */
> + if (!rds_compare_group(&priv_state->prev_tmc_sys_group,
> &priv_state->rds_group)) {
> + priv_state->prev_tmc_sys_group = priv_state->rds_group;
> + return 0x00;
> + }
> + /* bits 14-15 of block 3 contain the variant code */
> + variant_code = priv_state->rds_group.data_c_msb >> 6;
> + switch (variant_code) {
> + case 0x00:
> + /* bits 11-16 of block 3 contain the LTN */
> + tmc->ltn = (((group->data_c_msb & 0x0f) << 2)) |
> + (group->data_c_lsb >> 6);
> + /* bit 5 of block 3 contains the AFI */
> + tmc->afi = group->data_c_lsb & 0x20;
> + /* bit 4 of block 3 contains the Mode */
> + tmc->enhanced_mode = group->data_c_lsb & 0x10;
> + /* bits 0-3 of block 3 contain the MGS */
> + tmc->mgs = group->data_c_lsb & 0x0f;
> + break;
> + case 0x01:
> + /* bits 12-13 of block 3 contain the Gap parameters */
> + tmc->gap = (group->data_c_msb & 0x30) >> 4;
> + /* bits 11-16 of block 3 contain the SID */
> + tmc->sid = (((group->data_c_msb & 0x0f) << 2)) |
> + (group->data_c_lsb >> 6);
> + /* timing information is only valid in enhanced mode */
> + if (!tmc->enhanced_mode)
> + break;
> + /* bits 4-5 of block 3 contain the activity time */
> + tmc->t_a = (group->data_c_lsb & 0x30) >> 4;
> + /* bits 2-3 of block 3 contain the window time */
> + tmc->t_w = (group->data_c_lsb & 0x0c) >> 2;
> + /* bits 0-1 of block 3 contain the delay time */
> + tmc->t_d = group->data_c_lsb & 0x03;
> + break;
> + }
> + return V4L2_RDS_TMC_SYS;
> +}
> +
> +/* decode a single group TMC message */
> +static uint32_t rds_decode_tmc_single_group(struct rds_private_state
> *priv_state)
> +{
> + struct v4l2_rds_group *grp = &priv_state->rds_group;
> + struct v4l2_rds_tmc_msg msg;
> +
> + /* bits 0-2 of group 2 contain the duration value */
> + msg.dp = grp->data_b_lsb & 0x07;
> + /* bit 15 of block 3 indicates follow diversion advice */
> + msg.follow_diversion = (bool)(grp->data_c_msb & 0x80);
No need for this cast.
> + /* bit 14 of block 3 indicates the direction */
> + msg.neg_direction = (bool)(grp->data_c_msb & 0x40);
Ditto.
> + /* bits 11-13 of block 3 contain the extend of the event */
> + msg.extent = (grp->data_c_msb & 0x38) >> 3;
> + /* bits 0-10 of block 3 contain the event */
> + msg.event = ((grp->data_c_msb & 0x07) << 8) | grp->data_c_lsb;
> + /* bits 0-15 of block 4 contain the location */
> + msg.location = (grp->data_d_msb << 8) | grp->data_c_lsb;
> +
> + /* decoding done, store the new message */
> + priv_state->handle.tmc.tmc_msg = msg;
> + priv_state->handle.valid_fields |= V4L2_RDS_TMC_SG;
> + priv_state->handle.valid_fields &= ~V4L2_RDS_TMC_MG;
> +
> + return V4L2_RDS_TMC_SG;
> +}
> +
> +/* decode a multi group TMC message and decode the additional fields once
> + * a complete group was decoded */
> +static uint32_t rds_decode_tmc_multi_group(struct rds_private_state
> *priv_state)
> +{
> + struct v4l2_rds_group *grp = &priv_state->rds_group;
> + struct v4l2_rds_tmc_msg *msg = &priv_state->new_tmc_msg;
> + uint32_t *optional = priv_state->optional_tmc;
> + bool message_completed = false;
> + uint8_t grp_seq_id;
> + uint64_t buffer;
> +
> + /* bits 12-13 of block 3 contain the group sequence id, for all
> + * multi groups except the first group */
> + grp_seq_id = (grp->data_c_msb & 0x30) >> 4;
> +
> + /* beginning of a new multigroup ? */
> + /* bit 15 of block 3 is the first group indicator */
> + if (grp->data_c_msb & 0x80) {
> + /* begine decoding of new message */
> + memset(msg, 0, sizeof(msg));
> + /* bits 0-3 of block 2 contain continuity index */
> + priv_state->continuity_id = grp->data_b_lsb & 0x07;
> + /* bit 15 of block 3 indicates follow diversion advice */
> + msg->follow_diversion = (bool)(grp->data_c_msb & 0x80);
No need for cast.
> + /* bit 14 of block 3 indicates the direction */
> + msg->neg_direction = (bool)(grp->data_c_msb & 0x40);
Ditto.
> + /* bits 11-13 of block 3 contain the extend of the event */
> + msg->extent = (grp->data_c_msb & 0x38) >> 3;
> + /* bits 0-10 of block 3 contain the event */
> + msg->event = ((grp->data_c_msb & 0x07) << 8) | grp->data_c_lsb;
> + /* bits 0-15 of block 4 contain the location */
> + msg->location = (grp->data_d_msb << 8) | grp->data_c_lsb;
> + }
> + /* second group of multigroup ? */
> + /* bit 14 of block 3 ist the second group indicator, and the
> + * group continuity id has to match */
> + else if (grp->data_c_msb & 0x40 &&
> + (grp->data_b_lsb & 0x07) == priv_state->continuity_id) {
> + priv_state->grp_seq_id = grp_seq_id;
> + /* store group for later decoding */
> + buffer = grp->data_c_msb << 28 | grp->data_c_lsb << 20 |
> + grp->data_d_msb << 12 | grp->data_d_lsb << 4;
> + optional[0] = buffer;
> + msg->length = 1;
> + if (grp_seq_id == 0)
> + message_completed = true;
> + }
> + /* subsequent groups of multigroup ? */
> + /* group continuity id has to match, and group sequence number has
> + * to be smaller by one than the group sequence id */
> + else if ((grp->data_b_lsb & 0x07) == priv_state->continuity_id &&
> + (grp_seq_id == priv_state->grp_seq_id-1)) {
> + priv_state->grp_seq_id = grp_seq_id;
> + /* store group for later decoding */
> + buffer = grp->data_c_msb << 28 | grp->data_c_lsb << 20 |
> + grp->data_d_msb << 12 | grp->data_d_lsb << 4;
> + optional[msg->length++] = buffer;
> + if (grp_seq_id == 0)
> + message_completed = true;
> + }
> +
> + /* complete message received -> decode additional fields and store
> + * the new message */
> + if (message_completed) {
> + priv_state->handle.tmc.tmc_msg = *msg;
> + rds_tmc_decode_additional(priv_state);
> + priv_state->handle.valid_fields |= V4L2_RDS_TMC_MG;
> + priv_state->handle.valid_fields &= ~V4L2_RDS_TMC_SG;
> + }
> +
> + return V4L2_RDS_TMC_MG;
> +}
> +
> static bool rds_add_oda(struct rds_private_state *priv_state, struct
> v4l2_rds_oda oda)
> {
> struct v4l2_rds *handle = &priv_state->handle;
> @@ -526,6 +812,12 @@ static uint32_t rds_decode_group3(struct
> rds_private_state *priv_state)
> handle->decode_information |= V4L2_RDS_ODA;
> updated_fields |= V4L2_RDS_ODA;
> }
> +
> + /* if it's a TMC announcement decode the contained information */
> + if (new_oda.aid == 0xcd46 || new_oda.aid == 0xcd47) {
> + rds_decode_tmc_system(priv_state);
> + }
> +
> return updated_fields;
> }
>
> @@ -623,6 +915,50 @@ static uint32_t rds_decode_group4(struct
> rds_private_state *priv_state)
> return updated_fields;
> }
>
> +/* group 8A: TMC */
> +static uint32_t rds_decode_group8(struct rds_private_state *priv_state)
> +{
> + struct v4l2_rds_group *grp = &priv_state->rds_group;
> + uint8_t tuning_variant = 0x00;
No need to initialize.
> +
> + /* TMC uses version A exclusively */
> + if (grp->group_version != 'A')
> + return 0x00;
> +
> + /* check if the same group was received twice, store new rds group
> + * and return early if the old group doesn't match the new one */
> + if (!rds_compare_group(&priv_state->prev_tmc_group,
> &priv_state->rds_group)) {
> + priv_state->prev_tmc_group = priv_state->rds_group;
> + return 0x00;
> + }
> + /* modify the old group, to prevent that the same TMC message is decoded
> + * again in the next iteration (the default number of repetitions for
> + * RDS-TMC groups is 3) */
> + priv_state->prev_tmc_group.group_version = 0x00;
> +
> + /* handle the new TMC data depending on the message type */
> + /* -> single group message */
> + if ((grp->data_b_lsb & V4L2_TMC_SINGLE_GROUP) &&
> + !(grp->data_b_lsb & V4L2_TMC_TUNING_INFO)) {
> + return rds_decode_tmc_single_group(priv_state);
> + }
> + /* -> multi group message */
> + if (!(grp->data_b_lsb & V4L2_TMC_SINGLE_GROUP) &&
> + !(grp->data_b_lsb & V4L2_TMC_TUNING_INFO)) {
> + return rds_decode_tmc_multi_group(priv_state);
> + }
> + /* -> tuning information message, defined for variants 4..9, submitted
> + * in bits 0-3 of block 2 */
> + tuning_variant = grp->data_b_lsb & 0x0f;
> + if ((grp->data_b_lsb & V4L2_TMC_TUNING_INFO) && tuning_variant >= 4 &&
> + tuning_variant <= 9) {
> + /* TODO: Implement tuning information decoding */
Let's not forget this! :-)
It will extend the rds struct, so it would be nice to have this implemented
before an official release is made of this library.
> + return 0x00;
> + }
> +
> + return 0x00;
> +}
> +
> /* group 10: Program Type Name */
> static uint32_t rds_decode_group10(struct rds_private_state *priv_state)
> {
> @@ -685,6 +1021,7 @@ static const decode_group_func decode_group[16] = {
> [2] = rds_decode_group2,
> [3] = rds_decode_group3,
> [4] = rds_decode_group4,
> + [8] = rds_decode_group8,
> [10] = rds_decode_group10,
> };
>
> @@ -956,8 +1293,7 @@ const char *v4l2_rds_get_coverage_str(const struct
> v4l2_rds *handle)
> return coverage_lut[coverage];
> }
>
> -const struct v4l2_rds_group *v4l2_rds_get_group
> - (const struct v4l2_rds *handle)
> +const struct v4l2_rds_group *v4l2_rds_get_group(const struct v4l2_rds
> *handle)
> {
> struct rds_private_state *priv_state = (struct rds_private_state *)
> handle;
> return &priv_state->rds_group;
Regards,
Hans
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