Add SLM optimized modem UART backend.

To be combined with 43b455c.

Signed-off-by: Markus Lassila <[email protected]>

Author: MarkusLassila

drivers/modem/Kconfig.cellular

@@ -64,9 +64,4 @@ config MODEM_CELLULAR_NEW_BAUDRATE_DELAY
 	default 100 if DT_HAS_U_BLOX_LARA_R6_ENABLED
 	default 300
 
-config MODEM_CELLULAR_USE_MODEM_BACKEND_UART_SLM
-	bool "Use the SLM optimized modem UART backend"
-	depends on MODEM_BACKEND_UART_SLM
-	default y
-
 endif

drivers/modem/modem_cellular.c

@@ -14,11 +14,7 @@
 #include <zephyr/modem/pipe.h>
 #include <zephyr/modem/pipelink.h>
 #include <zephyr/modem/ppp.h>
-#if CONFIG_MODEM_CELLULAR_USE_MODEM_BACKEND_UART_SLM
-#include <zephyr/modem/backend/uart_slm.h>
-#else
 #include <zephyr/modem/backend/uart.h>
-#endif
 #include <zephyr/net/ppp.h>
 #include <zephyr/pm/device.h>
 #include <zephyr/sys/atomic.h>
@@ -90,13 +86,7 @@ enum modem_cellular_event {
 struct modem_cellular_data {
 	/* UART backend */
 	struct modem_pipe *uart_pipe;
-#if CONFIG_MODEM_CELLULAR_USE_MODEM_BACKEND_UART_SLM
-#include <zephyr/modem/backend/uart_slm.h>
-	struct modem_backend_uart_slm uart_backend;
-#else
 	struct modem_backend_uart uart_backend;
-#endif
-
 	uint8_t uart_backend_receive_buf[CONFIG_MODEM_CELLULAR_UART_BUFFER_SIZES];
 	uint8_t uart_backend_transmit_buf[CONFIG_MODEM_CELLULAR_UART_BUFFER_SIZES];
 
@@ -1826,11 +1816,6 @@ static int modem_cellular_init(const struct device *dev)
 		gpio_pin_configure_dt(&config->reset_gpio, GPIO_OUTPUT_ACTIVE);
 	}
 
-#if CONFIG_MODEM_CELLULAR_USE_MODEM_BACKEND_UART_SLM
-	{
-		/* TODO modem_cellular_modem_backend_uart_slm_init() here */
-	}
-#else
 	{
 		const struct modem_backend_uart_config uart_backend_config = {
 			.uart = config->uart,
@@ -1845,7 +1830,6 @@ static int modem_cellular_init(const struct device *dev)
 
 		data->cmd_pipe = NULL;
 	}
-#endif
 
 	{
 		const struct modem_cmux_config cmux_config = {

include/zephyr/modem/backend/uart_slm.h

@@ -16,12 +16,39 @@
 extern "C" {
 #endif
 
-struct modem_backend_uart_slm {
+struct 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;
+
+#if 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 rx_queue_event rx_event;
+	struct 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,

subsys/modem/backends/Kconfig

@@ -63,8 +63,28 @@ endif # MODEM_BACKEND_UART_ASYNC_HWFC
 
 endif # MODEM_BACKEND_UART_ASYNC
 
+endif # MODEM_BACKEND_UART
+
 config MODEM_BACKEND_UART_SLM
 	bool "SLM optimized modem UART backend"
+	default n
+	select MODEM_PIPE
+	select RING_BUFFER
 	depends on UART_ASYNC_API
 
-endif # MODEM_BACKEND_UART
+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