12 files changed, 656 insertions, 46 deletions

diff --git a/code/esp32/components/eos/at_urc.c b/code/esp32/components/eos/at_urc.c
new file mode 100644
index 0000000..b362d6f
--- /dev/null
+++ b/code/esp32/components/eos/at_urc.c
@@ -0,0 +1,109 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+
+#include "eos.h"
+#include "at_urc.h"
+
+typedef struct ATURCItem {
+    regex_t re;
+    at_urc_cb_t cb;
+    char pattern[AT_SIZE_PATTERN];
+} ATURCItem;
+
+typedef struct ATURCList {
+    ATURCItem item[AT_SIZE_URC_LIST];
+    int len;
+} ATURCList;
+
+static ATURCList urc_list;
+static ATURCItem *urc_curr;
+static SemaphoreHandle_t mutex;
+
+int at_urc_process(char *urc) {
+    regmatch_t match[AT_SIZE_NMATCH];
+    at_urc_cb_t cb = NULL;
+    regmatch_t *m = NULL;
+
+    xSemaphoreTake(mutex, portMAX_DELAY);
+
+    if (urc_curr == NULL) {
+        int i;
+
+        for (i=0; i<urc_list.len; i++) {
+            if (regexec(&urc_list.item[i].re, urc, AT_SIZE_NMATCH, match, 0) == 0) {
+                urc_curr = &urc_list.item[i];
+                m = match;
+                break;
+            }
+        }
+    }
+    if (urc_curr) cb = urc_curr->cb;
+
+    xSemaphoreGive(mutex);
+
+    if (cb) {
+        int r = cb(urc, m);
+
+        if (r != AT_URC_MORE) {
+            xSemaphoreTake(mutex, portMAX_DELAY);
+            urc_curr = NULL;
+            xSemaphoreGive(mutex);
+        }
+        return 1;
+    }
+    return 0;
+}
+
+int at_urc_insert(char *pattern, at_urc_cb_t cb, int flags) {
+    int r = EOS_OK;
+
+    if (strlen(pattern) >= AT_SIZE_PATTERN) return EOS_ERR;
+
+    r = regcomp(&urc_list.item[urc_list.len].re, pattern, flags);
+    if (r) return EOS_ERR;
+
+    xSemaphoreTake(mutex, portMAX_DELAY);
+
+    if (urc_list.len == AT_SIZE_URC_LIST) r = EOS_ERR_FULL;
+
+    if (!r) {
+        strcpy(urc_list.item[urc_list.len].pattern, pattern);
+        urc_list.item[urc_list.len].cb = cb;
+        urc_list.len++;
+    }
+
+    xSemaphoreGive(mutex);
+
+    return r;
+}
+
+int at_urc_delete(char *pattern) {
+    int i;
+    int r = EOS_ERR_NOTFOUND;
+
+    xSemaphoreTake(mutex, portMAX_DELAY);
+
+    for (i=0; i<urc_list.len; i++) {
+        if ((strcmp(pattern, urc_list.item[i].pattern) == 0)) {
+            if (i != urc_list.len - 1) memmove(&urc_list.item[i], &urc_list.item[i + 1], (urc_list.len - i - 1) * sizeof(ATURCItem));
+            urc_list.len--;
+            if (urc_curr) {
+                if (urc_curr == &urc_list.item[i]) {
+                    urc_curr = NULL;
+                } else if (urc_curr > &urc_list.item[i]) {
+                    urc_curr--;
+                }
+            }
+
+            r = EOS_OK;
+            break;
+        }
+    }
+
+    xSemaphoreGive(mutex);
+
+    return r;
+}
diff --git a/code/esp32/components/eos/bq25895.c b/code/esp32/components/eos/bq25895.c
index 03116ca..0d1bb8d 100644
--- a/code/esp32/components/eos/bq25895.c
+++ b/code/esp32/components/eos/bq25895.c
@@ -1,4 +1,5 @@
-#include <stdio.h>
+#include <stdlib.h>
+
 #include <esp_log.h>
 
 #include "eos.h"
diff --git a/code/esp32/components/eos/cell.c b/code/esp32/components/eos/cell.c
index 26ad454..138a4e4 100644
--- a/code/esp32/components/eos/cell.c
+++ b/code/esp32/components/eos/cell.c
@@ -7,6 +7,8 @@
 #include "net.h"
 #include "cell.h"
 
+static uint8_t cell_mode;
+
 static void cell_handler(unsigned char _mtype, unsigned char *buffer, uint16_t size) {
     uint8_t mtype = buffer[0];
 
@@ -15,10 +17,11 @@ static void cell_handler(unsigned char _mtype, unsigned char *buffer, uint16_t s
             eos_modem_write(buffer+1, size-1);
             break;
         case EOS_CELL_MTYPE_DATA_START:
+            cell_mode = eos_modem_get_mode();
             eos_modem_set_mode(EOS_CELL_UART_MODE_RELAY);
             break;
         case EOS_CELL_MTYPE_DATA_STOP:
-            eos_modem_set_mode(0);
+            eos_modem_set_mode(cell_mode);
             break;
         case EOS_CELL_MTYPE_AUDIO:
             eos_pcm_push(buffer+1, size-1);
diff --git a/code/esp32/components/eos/cell_modem.c b/code/esp32/components/eos/cell_modem.c
index 4c964e1..50aa23a 100644
--- a/code/esp32/components/eos/cell_modem.c
+++ b/code/esp32/components/eos/cell_modem.c
@@ -1,66 +1,132 @@
-#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
 #include <freertos/task.h>
 #include <freertos/queue.h>
+#include <netif/ppp/pppos.h>
+#include <netif/ppp/pppapi.h>
 #include <driver/uart.h>
 #include <driver/gpio.h>
 #include <esp_log.h>
 
 #include "eos.h"
 #include "net.h"
+#include "at_urc.h"
 #include "cell.h"
 
 #define MIN(X, Y)               (((X) < (Y)) ? (X) : (Y))
 #define MAX(X, Y)               (((X) > (Y)) ? (X) : (Y))
 
-#define UART_BUF_SIZE   1024
+#define UART_SIZE_BUF       1024
+#define UART_SIZE_URC_BUF   128
 
-#define UART_GPIO_TXD   16
-#define UART_GPIO_RXD   17
-#define UART_GPIO_DTR   32
-#define UART_GPIO_RI    35
+#define UART_GPIO_TXD       16
+#define UART_GPIO_RXD       17
+#define UART_GPIO_DTR       32
+#define UART_GPIO_RI        35
 
 static QueueHandle_t uart_queue;
 static QueueHandle_t uart_ri_queue;
 
 static const char *TAG = "EOS MODEM";
 
+static SemaphoreHandle_t mutex;
+
+static char at_resp[128];
+static char uart_buf[UART_SIZE_URC_BUF];
+static unsigned int uart_buf_len;
+static uint8_t uart_mode = EOS_CELL_UART_MODE_NONE;
+static SemaphoreHandle_t uart_mutex;
+
+static char ppp_apn[64];
+static char ppp_user[64];
+static char ppp_pass[64];
+static SemaphoreHandle_t ppp_mutex;
+
+static ppp_pcb *ppp_handle;
+static struct netif ppp_netif;
+
+typedef enum {
+    UART_EEVT_MODE = UART_EVENT_MAX
+} uart_eevt_type_t;
+
+static void modem_atcmd_read(size_t bsize);
+
+static void uart_data_read(uint8_t mode) {
+    unsigned char *buf;
+    int rd;
+    size_t bsize;
+
+    uart_get_buffered_data_len(UART_NUM_2, &bsize);
+    switch (mode) {
+        case EOS_CELL_UART_MODE_ATCMD:
+            modem_atcmd_read(bsize);
+            break;
+
+        case EOS_CELL_UART_MODE_PPP:
+            rd = 0;
+
+            do {
+                int _rd = eos_modem_read(uart_buf, MIN(bsize - rd, sizeof(uart_buf)), 100);
+                pppos_input_tcpip(ppp_handle, (uint8_t *)uart_buf, _rd);
+                rd += _rd;
+            } while (rd != bsize);
+            break;
+
+        case EOS_CELL_UART_MODE_RELAY:
+            rd = 0;
+
+            do {
+                int _rd;
+
+                buf = eos_net_alloc();
+                buf[0] = EOS_CELL_MTYPE_DATA;
+                _rd = eos_modem_read(buf + 1, MIN(bsize - rd, EOS_NET_SIZE_BUF - 1), 100);
+                eos_net_send(EOS_NET_MTYPE_CELL, buf, _rd + 1, 0);
+                rd += _rd;
+            } while (rd != bsize);
+            break;
+
+        default:
+            break;
+
+    }
+}
+
 static void uart_event_task(void *pvParameters) {
     char mode = EOS_CELL_UART_MODE_NONE;
+    char _mode = EOS_CELL_UART_MODE_NONE;
     uart_event_t event;
-    size_t len;
-    unsigned char *buf;
 
     while (1) {
         /* Waiting for UART event.
          */
-        if (xQueueReceive(uart_queue, (void * )&event, (portTickType)portMAX_DELAY)) {
+        if (xQueueReceive(uart_queue, (void *)&event, (portTickType)portMAX_DELAY)) {
             switch (event.type) {
                 case UART_DATA:
                     /* Event of UART receiving data
                      */
-                    switch (mode) {
-                        case EOS_CELL_UART_MODE_PPP:
-                            break;
-
-                        case EOS_CELL_UART_MODE_RELAY:
-                            buf = eos_net_alloc();
-                            buf[0] = EOS_CELL_MTYPE_DATA;
-                            len = uart_read_bytes(UART_NUM_2, buf+1, MIN(event.size, EOS_NET_SIZE_BUF-1), 100 / portTICK_RATE_MS);
-                            eos_net_send(EOS_NET_MTYPE_CELL, buf, len+1, 0);
-                            break;
-
-                        default:
-                            break;
+                    if (mode != EOS_CELL_UART_MODE_NONE) uart_data_read(mode);
+                    if ((mode != _mode) && (uart_buf_len == 0)) {
+                        if (_mode == EOS_CELL_UART_MODE_NONE) xSemaphoreGive(uart_mutex);
+                        mode = _mode;
                     }
                     break;
 
-                case UART_EVENT_MAX:
+                case UART_EEVT_MODE:
                     /* Mode change
                      */
-                    mode = (char)event.size;
+                    _mode = (char)event.size;
+                    if ((_mode != mode) && ((uart_buf_len == 0) || (mode == EOS_CELL_UART_MODE_NONE))) {
+                        if (mode == EOS_CELL_UART_MODE_NONE) {
+                            xSemaphoreTake(uart_mutex, portMAX_DELAY);
+                            uart_data_read(_mode);
+                        }
+                        if (_mode == EOS_CELL_UART_MODE_NONE) xSemaphoreGive(uart_mutex);
+                        mode = _mode;
+                    }
                     break;
 
                 default:
@@ -75,11 +141,11 @@ static void uart_ri_event_task(void *pvParameters) {
     int level;
 
     while (1) {
-        if (xQueueReceive(uart_ri_queue, (void * )&level, (portTickType)portMAX_DELAY) && (level == 0)) {
+        if (xQueueReceive(uart_ri_queue, (void *)&level, (portTickType)portMAX_DELAY) && (level == 0)) {
             uint64_t t_start = esp_timer_get_time();
-            if (xQueueReceive(uart_ri_queue, (void * )&level, 200 / portTICK_RATE_MS) && (level == 1)) {
+            if (xQueueReceive(uart_ri_queue, (void *)&level, 200 / portTICK_RATE_MS) && (level == 1)) {
                 uint64_t t_end = esp_timer_get_time();
-                ESP_LOGI(TAG, "TDELTA:%u", (uint32_t)(t_end - t_start));
+                ESP_LOGI(TAG, "URC:%u", (uint32_t)(t_end - t_start));
             } else {
                 ESP_LOGI(TAG, "RING");
             }
@@ -93,6 +159,268 @@ static void IRAM_ATTR uart_ri_isr_handler(void *arg) {
     xQueueSendFromISR(uart_ri_queue, &level, NULL);
 }
 
+static void modem_atcmd_read(size_t bsize) {
+    char *ln_begin, *ln_end, *ln_next;
+    int rd = 0;
+
+    do {
+        int _rd = eos_modem_read(uart_buf + uart_buf_len, MIN(bsize - rd, sizeof(uart_buf) - uart_buf_len - 1), 100);
+        ln_next = uart_buf + uart_buf_len;
+        ln_begin = uart_buf;
+        uart_buf_len += _rd;
+        rd += _rd;
+        uart_buf[uart_buf_len] = '\0';
+        while ((ln_end = strchr(ln_next, '\n'))) {
+            ln_end--;
+            if ((ln_end > ln_begin) && (*ln_end == '\r')) {
+                *ln_end = '\0';
+                at_urc_process(ln_begin);
+            }
+            ln_next = ln_end + 2;
+            ln_begin = ln_next;
+        }
+        if (ln_begin != uart_buf) {
+            uart_buf_len -= ln_begin - uart_buf;
+            if (uart_buf_len) memmove(uart_buf, ln_begin, uart_buf_len);
+        } else if (uart_buf_len == sizeof(uart_buf) - 1) {
+            memcpy(uart_buf, uart_buf + sizeof(uart_buf) / 2, sizeof(uart_buf) / 2);
+            uart_buf_len = sizeof(uart_buf) / 2;
+        }
+    } while (rd != bsize);
+}
+
+static void modem_set_mode(uint8_t mode) {
+    uart_event_t evt;
+
+    evt.type = UART_EEVT_MODE;
+    evt.size = mode;
+    xQueueSend(uart_queue, (void *)&evt, portMAX_DELAY);
+}
+
+static char *memstr(char *mem, size_t size, char *str) {
+    size_t i = 0;
+    char *max_mem;
+
+    if (str[0] == '\0') return NULL;
+
+    max_mem = mem + size;
+
+    while (mem < max_mem) {
+        if (*mem != str[i]) {
+            mem -= i;
+            i = 0;
+        } else {
+            if (str[i+1] == '\0') return mem - i;
+            i++;
+        }
+        mem++;
+    }
+
+    return NULL;
+}
+
+static uint32_t ppp_output_cb(ppp_pcb *pcb, uint8_t *data, uint32_t len, void *ctx) {
+    size_t rv;
+
+	xSemaphoreTake(ppp_mutex, portMAX_DELAY);
+    rv = eos_modem_write(data, len);
+	xSemaphoreGive(ppp_mutex);
+
+    return rv;
+}
+
+/* PPP status callback */
+static void ppp_status_cb(ppp_pcb *pcb, int err_code, void *ctx) {
+    // struct netif *pppif = ppp_netif(pcb);
+    // LWIP_UNUSED_ARG(ctx);
+
+    switch(err_code) {
+        case PPPERR_NONE: {
+            ESP_LOGE(TAG, "status_cb: Connect");
+            break;
+        }
+        case PPPERR_PARAM: {
+            ESP_LOGE(TAG, "status_cb: Invalid parameter");
+            break;
+        }
+        case PPPERR_OPEN: {
+            ESP_LOGE(TAG, "status_cb: Unable to open PPP session");
+            break;
+        }
+        case PPPERR_DEVICE: {
+            ESP_LOGE(TAG, "status_cb: Invalid I/O device for PPP");
+            break;
+        }
+        case PPPERR_ALLOC: {
+            ESP_LOGE(TAG, "status_cb: Unable to allocate resources");
+            break;
+        }
+        case PPPERR_USER: {
+            ESP_LOGE(TAG, "status_cb: User interrupt");
+            break;
+        }
+        case PPPERR_CONNECT: {
+            ESP_LOGE(TAG, "status_cb: Connection lost");
+            break;
+        }
+        case PPPERR_AUTHFAIL: {
+            ESP_LOGE(TAG, "status_cb: Failed authentication challenge");
+            break;
+        }
+        case PPPERR_PROTOCOL: {
+            ESP_LOGE(TAG, "status_cb: Failed to meet protocol");
+            break;
+        }
+        case PPPERR_PEERDEAD: {
+            ESP_LOGE(TAG, "status_cb: Connection timeout");
+            break;
+        }
+        case PPPERR_IDLETIMEOUT: {
+            ESP_LOGE(TAG, "status_cb: Idle Timeout");
+            break;
+        }
+        case PPPERR_CONNECTTIME: {
+            ESP_LOGE(TAG, "status_cb: Max connect time reached");
+            break;
+        }
+        case PPPERR_LOOPBACK: {
+            ESP_LOGE(TAG, "status_cb: Loopback detected");
+            break;
+        }
+        default: {
+            ESP_LOGE(TAG, "status_cb: Unknown error code %d", err_code);
+            break;
+        }
+    }
+}
+
+static int ppp_pause(void) {
+    int done = 0;
+    int len = 0;
+    int ret = EOS_OK;
+    char *ok_str = NULL;
+    uint64_t t_start;
+    uint32_t timeout = 500;
+    uint8_t retries = 1;
+
+    xSemaphoreTake(ppp_mutex, portMAX_DELAY);
+    eos_modem_flush();
+    vTaskDelay(1000 / portTICK_PERIOD_MS);
+    modem_set_mode(EOS_CELL_UART_MODE_NONE);
+    xSemaphoreTake(uart_mutex, portMAX_DELAY);
+    eos_modem_write("+++", 3);
+    t_start = esp_timer_get_time();
+
+    do {
+        len = eos_modem_read(uart_buf + uart_buf_len, sizeof(uart_buf) - uart_buf_len, 10);
+        if (len > 0) {
+            if (uart_buf_len > 5) {
+                ok_str = memstr(uart_buf + uart_buf_len - 5, len + 5, "\r\nOK\r\n");
+            } else {
+                ok_str = memstr(uart_buf, len + uart_buf_len, "\r\nOK\r\n");
+            }
+            uart_buf_len += len;
+        }
+        if (ok_str) {
+            pppos_input_tcpip(ppp_handle, (uint8_t *)uart_buf, ok_str - uart_buf);
+            ok_str += 6;
+            uart_buf_len -= ok_str - uart_buf;
+            if (uart_buf_len) memmove(uart_buf, ok_str, uart_buf_len);
+            done = 1;
+        } else if (uart_buf_len == sizeof(uart_buf)) {
+            pppos_input_tcpip(ppp_handle, (uint8_t *)uart_buf, sizeof(uart_buf) / 2);
+            memcpy(uart_buf, uart_buf + sizeof(uart_buf) / 2, sizeof(uart_buf) / 2);
+            uart_buf_len = sizeof(uart_buf) / 2;
+        }
+        if (timeout && !done && ((uint32_t)((esp_timer_get_time() - t_start) / 1000) > timeout)) {
+            if (!retries) {
+                ret = EOS_ERR_TIMEOUT;
+                done = 1;
+                modem_set_mode(EOS_CELL_UART_MODE_PPP);
+                xSemaphoreGive(uart_mutex);
+                xSemaphoreGive(ppp_mutex);
+            } else {
+                retries--;
+                eos_modem_write("+++", 3);
+                t_start = esp_timer_get_time();
+            }
+        }
+    } while (!done);
+
+    return ret;
+}
+
+static int ppp_resume(void) {
+    int r;
+    int rv = EOS_OK;
+
+    eos_modem_write("ATO\r", 4);
+    r = eos_modem_resp("^CONNECT", "^(ERROR|NO CARRIER)", 1000);
+    if (r <= 0) rv = EOS_ERR;
+
+    modem_set_mode(EOS_CELL_UART_MODE_PPP);
+    xSemaphoreGive(uart_mutex);
+    xSemaphoreGive(ppp_mutex);
+
+    return rv;
+}
+
+static int ppp_setup(void) {
+    int r;
+    char cmd[64];
+    int cmd_len = snprintf(cmd, sizeof(cmd), "AT+CGDCONT=1,\"IP\",\"%s\"\r", ppp_apn);
+
+    if ((cmd_len < 0) || (cmd_len >= sizeof(cmd))) return EOS_ERR;
+
+    modem_set_mode(EOS_CELL_UART_MODE_NONE);
+    xSemaphoreTake(uart_mutex, portMAX_DELAY);
+
+    eos_modem_write(cmd, cmd_len);
+    r = eos_modem_resp("^OK", "^ERROR", 1000);
+    if (r <= 0) {
+        modem_set_mode(uart_mode);
+        xSemaphoreGive(uart_mutex);
+        return EOS_ERR;
+    }
+
+    eos_modem_write("AT+CGDATA=\"PPP\",1\r", 18);
+    r = eos_modem_resp("^CONNECT", "^(ERROR|\\+CME ERROR|NO CARRIER)", 1000);
+    if (r <= 0) {
+        modem_set_mode(uart_mode);
+        xSemaphoreGive(uart_mutex);
+        return EOS_ERR;
+    }
+
+    ppp_handle = pppapi_pppos_create(&ppp_netif, ppp_output_cb, ppp_status_cb, NULL);
+    ppp_set_usepeerdns(ppp_handle, 1);
+    pppapi_set_default(ppp_handle);
+	pppapi_set_auth(ppp_handle, PPPAUTHTYPE_PAP, ppp_user, ppp_pass);
+    pppapi_connect(ppp_handle, 0);
+
+    modem_set_mode(EOS_CELL_UART_MODE_PPP);
+    xSemaphoreGive(uart_mutex);
+
+    return EOS_OK;
+}
+
+static int ppp_disconnect(void) {
+    int rv;
+
+    pppapi_close(ppp_handle, 0);
+
+    rv = ppp_pause();
+    if (rv) return rv;
+
+    eos_modem_write("ATH\r", 4);
+    eos_modem_resp("^OK", NULL, 1000);
+
+    xSemaphoreGive(uart_mutex);
+    xSemaphoreGive(ppp_mutex);
+    ppp_handle = NULL;
+
+    return EOS_OK;
+}
+
 void eos_modem_init(void) {
     /* Configure parameters of an UART driver,
      * communication pins and install the driver */
@@ -105,7 +433,7 @@ void eos_modem_init(void) {
     };
     uart_param_config(UART_NUM_2, &uart_config);
     uart_set_pin(UART_NUM_2, UART_GPIO_TXD, UART_GPIO_RXD, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
-    uart_driver_install(UART_NUM_2, UART_BUF_SIZE, UART_BUF_SIZE, 10, &uart_queue, 0);
+    uart_driver_install(UART_NUM_2, UART_SIZE_BUF, UART_SIZE_BUF, 10, &uart_queue, 0);
 
     // Configuration for the DTR/RI lines
     gpio_config_t io_conf;
@@ -125,6 +453,15 @@ void eos_modem_init(void) {
     io_conf.pull_down_en = 0;
     gpio_config(&io_conf);
 
+    mutex = xSemaphoreCreateBinary();
+    xSemaphoreGive(mutex);
+
+    uart_mutex = xSemaphoreCreateBinary();
+    xSemaphoreGive(uart_mutex);
+
+    ppp_mutex = xSemaphoreCreateBinary();
+    xSemaphoreGive(ppp_mutex);
+
     uart_ri_queue = xQueueCreate(4, sizeof(int));
     // Create a task to handle uart event from ISR
     xTaskCreate(uart_event_task, "uart_event", EOS_TASK_SSIZE_UART, NULL, EOS_TASK_PRIORITY_UART, NULL);
@@ -134,14 +471,142 @@ void eos_modem_init(void) {
     ESP_LOGI(TAG, "INIT");
 }
 
-ssize_t eos_modem_write(void *data, size_t size) {
+void eos_modem_flush(void){
+    uart_wait_tx_done(UART_NUM_2, portMAX_DELAY);
+}
+
+size_t eos_modem_write(void *data, size_t size) {
     return uart_write_bytes(UART_NUM_2, (const char *)data, size);
 }
 
-void eos_modem_set_mode(char mode) {
-    uart_event_t evt;
+size_t eos_modem_read(void *data, size_t size, uint32_t timeout) {
+    return uart_read_bytes(UART_NUM_2, (uint8_t *)data, size, timeout / portTICK_RATE_MS);
+}
 
-    evt.type = UART_EVENT_MAX;  /* my type */
-    evt.size = mode;
-    xQueueSend(uart_queue, (void *)&evt, portMAX_DELAY);
+int eos_modem_readln(char *buf, size_t buf_size, uint32_t timeout) {
+    int done = 0;
+    int len = 0;
+    int ret = EOS_OK;
+    char *ln_end = NULL;
+    uint64_t t_start = esp_timer_get_time();
+
+    ln_end = strchr(uart_buf, '\n');
+
+    do {
+        if (ln_end == NULL) {
+            len = eos_modem_read(uart_buf + uart_buf_len, sizeof(uart_buf) - uart_buf_len - 1, 10);
+            if (len > 0) {
+                uart_buf[uart_buf_len + len] = '\0';
+                ln_end = strchr(uart_buf + uart_buf_len, '\n');
+                uart_buf_len += len;
+            }
+        }
+        if (ln_end) {
+            ln_end--;
+            if ((ln_end >= uart_buf) && (*ln_end == '\r')) {
+                if (buf_size > ln_end - uart_buf) {
+                    memcpy(buf, uart_buf, ln_end - uart_buf);
+                    buf[ln_end - uart_buf] = '\0';
+                    ret = EOS_OK;
+                } else {
+                    ret = EOS_ERR;
+                }
+                done = 1;
+            }
+            ln_end += 2;
+            uart_buf_len -= ln_end - uart_buf;
+            if (uart_buf_len) memmove(uart_buf, ln_end, uart_buf_len);
+            ln_end = NULL;
+        } else if (uart_buf_len == sizeof(uart_buf) - 1) {
+            memcpy(uart_buf, uart_buf + sizeof(uart_buf) / 2, sizeof(uart_buf) / 2);
+            uart_buf_len = sizeof(uart_buf) / 2;
+        }
+        if (timeout && !done && ((uint32_t)((esp_timer_get_time() - t_start) / 1000) > timeout)) {
+            ret = EOS_ERR_TIMEOUT;
+            done = 1;
+        }
+    } while (!done);
+
+    return ret;
+}
+
+int eos_modem_resp(char *ok_str, char *err_str, uint32_t timeout) {
+    int rv;
+    regex_t re;
+    uint32_t e = 0;
+    uint64_t t_start = esp_timer_get_time();
+
+    do {
+        rv = eos_modem_readln(at_resp, sizeof(at_resp), timeout - e);
+        if (rv) return EOS_ERR;
+
+        if (ok_str) {
+            rv = regcomp(&re, ok_str, REG_EXTENDED | REG_NOSUB);
+            if (rv) return EOS_ERR;
+            if (regexec(&re, at_resp, 0, NULL, 0) == 0) return 1;
+        }
+
+        if (err_str) {
+            rv = regcomp(&re, err_str, REG_EXTENDED | REG_NOSUB);
+            if (rv) return EOS_ERR;
+            if (regexec(&re, at_resp, 0, NULL, 0) == 0) return 0;
+        }
+
+        at_urc_process(at_resp);
+        e = (uint32_t)(esp_timer_get_time() - t_start) / 1000;
+        if (e >= timeout) return EOS_ERR;
+    } while (1);
+}
+
+uint8_t eos_modem_get_mode(void) {
+    uint8_t ret;
+
+    xSemaphoreTake(mutex, portMAX_DELAY);
+    ret = uart_mode;
+    xSemaphoreGive(mutex);
+
+    return ret;
+}
+
+int eos_modem_set_mode(uint8_t mode) {
+    int rv = EOS_OK;
+
+    xSemaphoreTake(mutex, portMAX_DELAY);
+    if (mode != uart_mode) {
+        if (uart_mode == EOS_CELL_UART_MODE_PPP) rv = ppp_disconnect();
+        if (!rv) {
+            if (mode == EOS_CELL_UART_MODE_PPP) {
+                rv = ppp_setup();
+            } else {
+                modem_set_mode(mode);
+            }
+            if (!rv) uart_mode = mode;
+        }
+    }
+    xSemaphoreGive(mutex);
+
+    return rv;
+}
+
+int eos_modem_take(void) {
+    int rv = EOS_OK;
+
+    xSemaphoreTake(mutex, portMAX_DELAY);
+    if (uart_mode == EOS_CELL_UART_MODE_PPP) {
+        rv = ppp_pause();
+    } else {
+        modem_set_mode(EOS_CELL_UART_MODE_NONE);
+        xSemaphoreTake(uart_mutex, portMAX_DELAY);
+    }
+    return rv;
+}
+
+void eos_modem_give(void) {
+    if (uart_mode == EOS_CELL_UART_MODE_PPP) {
+        ppp_resume();
+    } else {
+        modem_set_mode(uart_mode);
+        xSemaphoreGive(uart_mutex);
+    }
+    xSemaphoreGive(mutex);
 }
diff --git a/code/esp32/components/eos/cell_pcm.c b/code/esp32/components/eos/cell_pcm.c
index 79d654a..46c64d9 100644
--- a/code/esp32/components/eos/cell_pcm.c
+++ b/code/esp32/components/eos/cell_pcm.c
@@ -1,7 +1,8 @@
-#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
 #include <freertos/task.h>
 #include <freertos/queue.h>
 #include <driver/i2s.h>
diff --git a/code/esp32/components/eos/drv2605l.c b/code/esp32/components/eos/drv2605l.c
index 023367e..3944289 100644
--- a/code/esp32/components/eos/drv2605l.c
+++ b/code/esp32/components/eos/drv2605l.c
@@ -1,4 +1,5 @@
-#include <stdio.h>
+#include <stdlib.h>
+
 #include <esp_log.h>
 
 #include "eos.h"
diff --git a/code/esp32/components/eos/i2c.c b/code/esp32/components/eos/i2c.c
index 38ad6ba..5b8fcc7 100644
--- a/code/esp32/components/eos/i2c.c
+++ b/code/esp32/components/eos/i2c.c
@@ -1,4 +1,5 @@
-#include <stdio.h>
+#include <stdlib.h>
+
 #include <esp_log.h>
 #include <driver/i2c.h>
 
diff --git a/code/esp32/components/eos/include/at_urc.h b/code/esp32/components/eos/include/at_urc.h
new file mode 100644
index 0000000..9a4c641
--- /dev/null
+++ b/code/esp32/components/eos/include/at_urc.h
@@ -0,0 +1,17 @@
+#include <sys/types.h>
+#include <stdint.h>
+#include <regex.h>
+
+#define AT_SIZE_NMATCH      4
+#define AT_SIZE_PATTERN     64
+
+#define AT_SIZE_URC_LIST    16
+
+#define AT_URC_OK           0
+#define AT_URC_MORE         1
+
+typedef int (*at_urc_cb_t) (char *, regmatch_t[]);
+
+int at_urc_process(char *urc);
+int at_urc_insert(char *pattern, at_urc_cb_t cb, int flags);
+int at_urc_delete(char *pattern);
\ No newline at end of file
diff --git a/code/esp32/components/eos/include/cell.h b/code/esp32/components/eos/include/cell.h
index f3eb89d..4a2cfbc 100644
--- a/code/esp32/components/eos/include/cell.h
+++ b/code/esp32/components/eos/include/cell.h
@@ -11,7 +11,8 @@
 
 #define EOS_CELL_UART_MODE_NONE     0
 #define EOS_CELL_UART_MODE_PPP      1
-#define EOS_CELL_UART_MODE_RELAY    2
+#define EOS_CELL_UART_MODE_ATCMD    2
+#define EOS_CELL_UART_MODE_RELAY    3
 
 void eos_pcm_init(void);
 
@@ -21,7 +22,16 @@ void eos_pcm_start(void);
 void eos_pcm_stop(void);
 
 void eos_modem_init(void);
-ssize_t eos_modem_write(void *data, size_t size);
-void eos_modem_set_mode(char mode);
+
+void eos_modem_flush(void);
+size_t eos_modem_write(void *data, size_t size);
+size_t eos_modem_read(void *data, size_t size, uint32_t timeout);
+int eos_modem_readln(char *buf, size_t buf_size, uint32_t timeout);
+int eos_modem_resp(char *ok_str, char *err_str, uint32_t timeout);
+
+uint8_t eos_modem_get_mode(void);
+int eos_modem_set_mode(uint8_t mode);
+int eos_modem_take(void);
+void eos_modem_give(void);
 
 void eos_cell_init(void);
\ No newline at end of file
diff --git a/code/esp32/components/eos/include/eos.h b/code/esp32/components/eos/include/eos.h
index c3f83bb..59f0ddb 100644
--- a/code/esp32/components/eos/include/eos.h
+++ b/code/esp32/components/eos/include/eos.h
@@ -1,7 +1,10 @@
 #define EOS_OK                      0
 #define EOS_ERR                     -1
+#define EOS_ERR_TIMEOUT             -2
+
 #define EOS_ERR_FULL                -10
 #define EOS_ERR_EMPTY               -11
+#define EOS_ERR_NOTFOUND            -12
 
 #define EOS_TASK_PRIORITY_UART      1
 #define EOS_TASK_PRIORITY_UART_RI   1
diff --git a/code/esp32/components/eos/net.c b/code/esp32/components/eos/net.c
index 7fb2dc7..4eb4983 100644
--- a/code/esp32/components/eos/net.c
+++ b/code/esp32/components/eos/net.c
@@ -1,11 +1,10 @@
-#include <stdio.h>
+#include <stdlib.h>
 #include <stdint.h>
-#include <stddef.h>
 #include <string.h>
 
 #include <freertos/FreeRTOS.h>
-#include <freertos/task.h>
 #include <freertos/semphr.h>
+#include <freertos/task.h>
 
 #include <esp_system.h>
 #include <esp_log.h>
diff --git a/code/esp32/components/eos/sock.c b/code/esp32/components/eos/sock.c
index 8994b62..17357e4 100644
--- a/code/esp32/components/eos/sock.c
+++ b/code/esp32/components/eos/sock.c
@@ -3,8 +3,8 @@
 #include <string.h>
 
 #include <freertos/FreeRTOS.h>
-#include <freertos/task.h>
 #include <freertos/semphr.h>
+#include <freertos/task.h>
 
 #include <esp_system.h>
 #include <esp_event.h>