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modem: cmux: Define macros for header size #97333

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Merged
merged 1 commit into from
Oct 14, 2025
Merged

modem: cmux: Define macros for header size #97333

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9 changes: 8 additions & 1 deletion include/zephyr/modem/cmux.h
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Original file line number Diff line number Diff line change
Expand Up @@ -57,8 +57,15 @@ typedef void (*modem_cmux_callback)(struct modem_cmux *cmux, enum modem_cmux_eve
* @cond INTERNAL_HIDDEN
*/

#if CONFIG_MODEM_CMUX_MTU > 127
#define MODEM_CMUX_HEADER_SIZE 7
#else
#define MODEM_CMUX_HEADER_SIZE 6
#endif


/* Total size of the CMUX work buffers */
#define MODEM_CMUX_WORK_BUFFER_SIZE (CONFIG_MODEM_CMUX_MTU + 7 + \
#define MODEM_CMUX_WORK_BUFFER_SIZE (CONFIG_MODEM_CMUX_MTU + MODEM_CMUX_HEADER_SIZE + \
CONFIG_MODEM_CMUX_WORK_BUFFER_SIZE_EXTRA)

enum modem_cmux_state {
Expand Down
28 changes: 15 additions & 13 deletions subsys/modem/modem_cmux.c
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Expand Up @@ -21,14 +21,18 @@ LOG_MODULE_REGISTER(modem_cmux, CONFIG_MODEM_CMUX_LOG_LEVEL);
#define MODEM_CMUX_EA (0x01)
#define MODEM_CMUX_CR (0x02)
#define MODEM_CMUX_PF (0x10)
#define MODEM_CMUX_FRAME_SIZE_MAX (0x07)
#define MODEM_CMUX_DATA_SIZE_MIN (0x08)
#define MODEM_CMUX_DATA_FRAME_SIZE_MIN (MODEM_CMUX_FRAME_SIZE_MAX + \
MODEM_CMUX_DATA_SIZE_MIN)
#define MODEM_CMUX_DATA_SIZE_MIN 8
#define MODEM_CMUX_DATA_FRAME_SIZE_MIN (MODEM_CMUX_HEADER_SIZE + MODEM_CMUX_DATA_SIZE_MIN)
#define MODEM_CMUX_DATA_FRAME_SIZE_MAX (MODEM_CMUX_HEADER_SIZE + CONFIG_MODEM_CMUX_MTU)

#define MODEM_CMUX_CMD_DATA_SIZE_MAX (0x08)
#define MODEM_CMUX_CMD_FRAME_SIZE_MAX (MODEM_CMUX_FRAME_SIZE_MAX + \
MODEM_CMUX_CMD_DATA_SIZE_MAX)
/* Biggest supported Multiplexer control commands in UIH frame
* Modem Status Command (MSC) - 5 bytes when Break is included.
*
* PN would be 10 bytes, but that is not implemented
*/
#define MODEM_CMUX_CMD_DATA_SIZE_MAX 5
#define MODEM_CMUX_CMD_FRAME_SIZE_MAX (MODEM_CMUX_HEADER_SIZE + \
MODEM_CMUX_CMD_DATA_SIZE_MAX)

#define MODEM_CMUX_T1_TIMEOUT (K_MSEC(330))
#define MODEM_CMUX_T2_TIMEOUT (K_MSEC(660))
Expand Down Expand Up @@ -274,13 +278,13 @@ static void modem_cmux_bus_callback(struct modem_pipe *pipe, enum modem_pipe_eve
static uint16_t modem_cmux_transmit_frame(struct modem_cmux *cmux,
const struct modem_cmux_frame *frame)
{
uint8_t buf[MODEM_CMUX_FRAME_SIZE_MAX];
uint8_t buf[MODEM_CMUX_HEADER_SIZE];
uint8_t fcs;
uint16_t space;
uint16_t data_len;
uint16_t buf_idx;

space = ring_buf_space_get(&cmux->transmit_rb) - MODEM_CMUX_FRAME_SIZE_MAX;
space = ring_buf_space_get(&cmux->transmit_rb) - MODEM_CMUX_HEADER_SIZE;
data_len = MIN(space, frame->data_len);
data_len = MIN(data_len, CONFIG_MODEM_CMUX_MTU);

Expand Down Expand Up @@ -1330,11 +1334,9 @@ void modem_cmux_init(struct modem_cmux *cmux, const struct modem_cmux_config *co
__ASSERT_NO_MSG(cmux != NULL);
__ASSERT_NO_MSG(config != NULL);
__ASSERT_NO_MSG(config->receive_buf != NULL);
__ASSERT_NO_MSG(config->receive_buf_size >=
(CONFIG_MODEM_CMUX_MTU + MODEM_CMUX_FRAME_SIZE_MAX));
__ASSERT_NO_MSG(config->receive_buf_size >= MODEM_CMUX_DATA_FRAME_SIZE_MAX);
__ASSERT_NO_MSG(config->transmit_buf != NULL);
__ASSERT_NO_MSG(config->transmit_buf_size >=
(CONFIG_MODEM_CMUX_MTU + MODEM_CMUX_FRAME_SIZE_MAX));
__ASSERT_NO_MSG(config->transmit_buf_size >= MODEM_CMUX_DATA_FRAME_SIZE_MAX);

memset(cmux, 0x00, sizeof(*cmux));
cmux->callback = config->callback;
Expand Down