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[nrf noup] Support intermediary SLM optimized modem UART backend #3021

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Merged
merged 1 commit into from
Jul 11, 2025
Merged

[nrf noup] Support intermediary SLM optimized modem UART backend #3021

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61 changes: 61 additions & 0 deletions include/zephyr/modem/backend/uart_slm.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,61 @@
/*
* Copyright (c) 2025 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/

#include <zephyr/kernel.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/modem/pipe.h>
#include <zephyr/modem/stats.h>

#ifndef ZEPHYR_MODEM_BACKEND_UART_SLM_
#define ZEPHYR_MODEM_BACKEND_UART_SLM_

#ifdef __cplusplus
extern "C" {
#endif

struct slm_rx_queue_event {
uint8_t *buf;
size_t len;
};

struct modem_backend_uart_slm {
const struct device *uart;
struct modem_pipe pipe;
struct k_work_delayable receive_ready_work;
struct k_work transmit_idle_work;

#ifdef CONFIG_MODEM_STATS
struct modem_stats_buffer receive_buf_stats;
struct modem_stats_buffer transmit_buf_stats;
#endif
struct ring_buf transmit_rb;
struct k_work rx_disabled_work;
atomic_t state;

struct k_mem_slab rx_slab;
struct k_msgq rx_queue;
struct slm_rx_queue_event rx_event;
struct slm_rx_queue_event rx_queue_buf[CONFIG_MODEM_BACKEND_UART_SLM_BUFFER_COUNT];
uint32_t rx_buf_size;
uint8_t rx_buf_count;
};

struct modem_backend_uart_slm_config {
const struct device *uart;
uint8_t *receive_buf; /* Address must be word-aligned. */
uint32_t receive_buf_size;
uint8_t *transmit_buf;
uint32_t transmit_buf_size;
};

struct modem_pipe *modem_backend_uart_slm_init(struct modem_backend_uart_slm *backend,
const struct modem_backend_uart_slm_config *config);

#ifdef __cplusplus
}
#endif

#endif /* ZEPHYR_MODEM_BACKEND_UART_SLM_ */
1 change: 1 addition & 0 deletions subsys/modem/backends/CMakeLists.txt
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Expand Up @@ -10,3 +10,4 @@ if(CONFIG_MODEM_BACKEND_UART_ASYNC)
zephyr_library_sources_ifdef(CONFIG_MODEM_BACKEND_UART_ASYNC_HWFC modem_backend_uart_async_hwfc.c)
zephyr_library_sources_ifndef(CONFIG_MODEM_BACKEND_UART_ASYNC_HWFC modem_backend_uart_async.c)
endif()
zephyr_library_sources_ifdef(CONFIG_MODEM_BACKEND_UART_SLM modem_backend_uart_slm.c)
23 changes: 23 additions & 0 deletions subsys/modem/backends/Kconfig
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Expand Up @@ -64,3 +64,26 @@ endif # MODEM_BACKEND_UART_ASYNC_HWFC
endif # MODEM_BACKEND_UART_ASYNC

endif # MODEM_BACKEND_UART

config MODEM_BACKEND_UART_SLM
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Might be a bit confusing to have MODEM_BACKEND_UART be n when using MODEM_BACKEND_UART_SLM.

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Maybe instead you could just add a config MODEM_BACKEND_UART_ASYNC_SLM and make use of the existing MODEM_BACKEND_UART_ASYNC as it has all the configs you need? Well, as you want really.

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This allows for a complete split from the MODEM_BACKEND_UART so that modem_backend_uart.c is not included.

That said, there is going to be further development on this area, which means that this will be reconsidered.

bool "SLM-optimized modem UART backend"
select MODEM_PIPE
select RING_BUFFER
depends on UART_ASYNC_API

if MODEM_BACKEND_UART_SLM

config MODEM_BACKEND_UART_SLM_BUFFER_COUNT
int "SLM modem UART backend buffer count"
range 2 4
default 3

config MODEM_BACKEND_UART_SLM_TRANSMIT_TIMEOUT_MS
int "SLM modem UART transmit timeout in milliseconds"
default 1000

config MODEM_BACKEND_UART_SLM_RECEIVE_IDLE_TIMEOUT_MS
int "SLM modem UART receive idle timeout in milliseconds"
default 30

endif # MODEM_BACKEND_UART_SLM
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