Add $NVM command for supporting User Storage Space

Use AT$NVM=0,123 to store value 123 in user space 0
+OK=1,123
Use AT$NVM=0 to read value previously stored
+OK=123

It currently supports 4 user spaces (0 to 3) and values are 8 bits unsigned

src/cmd.c

@@ -2055,6 +2055,27 @@ static void get_session(void)
 }
 
 
+
+// Read and Store a User data into the NVM area
+// AT$NVM=0 read data at address 0
+// AT$NVM=0,223 write 223 at address 0
+static void set_nvm(atci_param_t *param) {
+    uint32_t adr, value;
+    if (!atci_param_get_uint(param, &adr)) abort(ERR_PARAM);
+    if (adr >= USER_NVM_MAX_SIZE) abort(ERR_PARAM);
+    if (param->offset < param->length) {
+        if (!atci_param_is_comma(param)) abort(ERR_PARAM);
+        if (!atci_param_get_uint(param, &value)) abort(ERR_PARAM);
+        if (value >= 256) abort(ERR_PARAM);
+        user_nvm.values[adr] = value;
+        userNvm_process();
+        OK("%d,%d",(int)adr,(int)value);
+    } else {
+        OK("%d",user_nvm.values[adr]);
+    }
+}
+
+
 static const atci_command_t cmds[] = {
     {"+UART",        NULL,    set_uart,         get_uart,         NULL, "Configure UART interface"},
     {"+VER",         NULL,    NULL,             get_version_comp, NULL, "Firmware version and build time"},
@@ -2125,6 +2146,7 @@ static const atci_command_t cmds[] = {
     {"$SESSION",     NULL,    NULL,             get_session,      NULL, "Get network session information"},
     {"$CW",          cw,      NULL,             NULL,             NULL, "Start continuous carrier wave transmission"},
     {"$CM",          cm,      NULL,             NULL,             NULL, "Start continuous modulated FSK transmission"},
+    {"$NVM",         NULL,    set_nvm,          NULL,             NULL, "Store / Read data from Non Volatile Memory"},
     ATCI_COMMAND_CLAC,
     ATCI_COMMAND_HELP};
 

src/nvm.c

@@ -1,6 +1,7 @@
 #include "nvm.h"
 #include <assert.h>
 #include <string.h>
+#include <strings.h>
 #include <stm/include/stm32l072xx.h>
 #include <loramac-node/src/mac/LoRaMacTypes.h>
 #include <loramac-node/src/mac/LoRaMac.h>
@@ -11,7 +12,7 @@
 #include "part.h"
 #include "utils.h"
 
-#define NUMBER_OF_PARTS 8
+#define NUMBER_OF_PARTS 9
 
 
 /* The following partition sizes have been derived from the in-memory size of
@@ -30,6 +31,7 @@
 #define REGION1_PART_SIZE   32
 #define REGION2_PART_SIZE 1536
 #define CLASSB_PART_SIZE    32
+#define USER_NVM_PART_SIZE  12
 
 
 // Make sure each data structure fits into its fixed-size partition
@@ -41,6 +43,7 @@ static_assert(sizeof(SecureElementNvmData_t) <= SE_PART_SIZE, "SecureElement NVM
 static_assert(sizeof(RegionNvmDataGroup1_t) <= REGION1_PART_SIZE, "RegionGroup1 NVM data too long");
 static_assert(sizeof(RegionNvmDataGroup2_t) <= REGION2_PART_SIZE, "RegionGroup2 NVM data too long");
 static_assert(sizeof(LoRaMacClassBNvmData_t) <= CLASSB_PART_SIZE, "ClassB NVM data too long");
+static_assert(sizeof(userNvm_t) <= USER_NVM_PART_SIZE, "User NVM data too long");
 
 
 // And also make sure that NVM data fits into the EEPROM twice. This is
@@ -53,7 +56,8 @@ static_assert(
     SE_PART_SIZE      +
     REGION1_PART_SIZE +
     REGION2_PART_SIZE +
-    CLASSB_PART_SIZE
+    CLASSB_PART_SIZE  +
+    USER_NVM_PART_SIZE
     <= (DATA_EEPROM_BANK2_END - DATA_EEPROM_BASE + 1 - PART_TABLE_SIZE(NUMBER_OF_PARTS)) / 2,
     "NVM data does not fit into a single EEPROM bank");
 
@@ -71,6 +75,8 @@ static part_block_t nvm = {
 
 struct nvm_parts nvm_parts;
 
+userNvm_t user_nvm = { 0 };
+
 sysconf_t sysconf = {
     .uart_baudrate = DEFAULT_UART_BAUDRATE,
     .uart_timeout = 1000,
@@ -147,6 +153,11 @@ void nvm_init(void)
         nvm_parts.classb.dsc->size != CLASSB_PART_SIZE)
         goto retry;
 
+    if ((part_find(&nvm_parts.user, &nvm, "user") &&
+        part_create(&nvm_parts.user, &nvm, "user", USER_NVM_PART_SIZE)) ||
+        nvm_parts.user.dsc->size != USER_NVM_PART_SIZE)
+        goto retry;
+
     size_t size;
     const uint8_t *p = part_mmap(&size, &nvm_parts.sysconf);
     if (check_block_crc(p, sizeof(sysconf))) {
@@ -155,6 +166,17 @@ void nvm_init(void)
     } else {
         log_debug("Invalid system configuration checksum, using defaults");
     }
+
+    p = part_mmap(&size, &nvm_parts.user);
+    if (check_block_crc(p, sizeof(user_nvm))) {
+        log_debug("Restoring user data from NVM");
+        memcpy(&user_nvm, p, sizeof(user_nvm));
+    } else {
+        log_debug("Invalid user data checksum, using defaults");
+        user_nvm.magic = USER_NVM_MAGIC;
+        bzero(user_nvm.values,USER_NVM_MAX_SIZE);
+    }
+
     return;
 
 retry:
@@ -192,3 +214,14 @@ void sysconf_process(void)
     sysconf_modified = false;
 }
 
+
+void userNvm_process(void)
+{
+
+    if (update_block_crc(&user_nvm, sizeof(user_nvm))) {
+        log_debug("Saving user data to NVM");
+        if (!part_write(&nvm_parts.user, 0, &user_nvm, sizeof(user_nvm)))
+            log_error("Error while writing user data to NVM");
+    }
+
+}

src/nvm.h

@@ -66,18 +66,29 @@ struct nvm_parts {
     part_t region1;
     part_t region2;
     part_t classb;
+    part_t user;
 };
 
+#define USER_NVM_MAX_SIZE   4     // maximum allows values inside the User Nvm area
+#define USER_NVM_MAGIC      0xD15C9101
+typedef struct userNvm_s {
+    uint32_t    magic;
+    uint8_t     values[USER_NVM_MAX_SIZE];
+    uint32_t    crc32;
+} userNvm_t;
+
 
 extern struct nvm_parts nvm_parts;
 extern sysconf_t sysconf;
 extern bool sysconf_modified;
 extern uint16_t nvm_flags;
+extern userNvm_t user_nvm;
 
 void nvm_init(void);
 
 int nvm_erase(void);
 
 void sysconf_process(void);
+void userNvm_process(void);
 
 #endif // _NVM_H_