Make NRF52 flash work with SoftDevice

How you write and ersae the flash on the NRF52 changes depending on
whether the SoftDevice is enabled or not.

This change does a runtime check before erasing and writing, and
then chooses the correct function to perform the action.

Author: Marcus Chang

targets/TARGET_NORDIC/TARGET_NRF5/flash_api.c

@@ -36,79 +36,163 @@
  *
  */
 
-#include "flash_api.h"
+#if DEVICE_FLASH
+
+#include "hal/flash_api.h"
+#include "hal/lp_ticker_api.h"
+
+#include "nrf_drv_common.h"
 #include "nrf_nvmc.h"
 #include "nrf_soc.h"
-#include "nrf_sdm.h"
 
-#if DEVICE_FLASH
+#define WORD_WRITE_TIMEOUT_US (1 * 1000)    // Max. value from datasheet: 338 us
+#define PAGE_ERASE_TIMEOUT_US (200 * 1000)  // Max. value from datasheet: 89.7 ms
+
+/* Macro for testing if the SoftDevice is active, regardless of whether the 
+ * application is build with the SoftDevice or not.
+ */
+#if defined(SOFTDEVICE_PRESENT)
+#include "nrf_sdm.h"
+static uint8_t wrapper(void) {
+    uint8_t softdevice_is_enabled;
+    ret_code_t result = sd_softdevice_is_enabled(&softdevice_is_enabled);
+    return ((result == NRF_SUCCESS) && (softdevice_is_enabled == 1));
+}
+#define NRF_HAL_SD_IS_ENABLED() wrapper()
+#else
+#define NRF_HAL_SD_IS_ENABLED() 0
+#endif
 
 int32_t flash_init(flash_t *obj)
 {
     (void)(obj);
-    uint8_t sd_enabled;
-    if ((sd_softdevice_is_enabled(&sd_enabled) == NRF_SUCCESS) && sd_enabled == 1) {
-        return -1;
+
+    /* Initialize low power ticker. Used for timeouts. */
+    static bool first_init = true;
+
+    if (first_init) {
+        first_init = false;
+        lp_ticker_init();
     }
+
     return 0;
 }
 
 int32_t flash_free(flash_t *obj)
 {
     (void)(obj);
+    
     return 0;
 }
 
 int32_t flash_erase_sector(flash_t *obj, uint32_t address)
 {
     (void)(obj);
-    uint8_t sd_enabled;
-    if ((sd_softdevice_is_enabled(&sd_enabled) == NRF_SUCCESS) && sd_enabled == 1) {
-        return -1;
+
+    /* Return value defaults to error. */
+    uint32_t result = NRF_ERROR_BUSY;
+
+    if (NRF_HAL_SD_IS_ENABLED()) {
+
+        /* Convert address to page number. */
+        uint32_t page_number = address / NRF_FICR->CODEPAGESIZE;
+
+        /* Setup stop watch for timeout. */
+        uint32_t start_us = lp_ticker_read();
+        uint32_t now_us = start_us;
+
+        /* Retry if flash is busy until timeout is reached. */
+        while (((now_us - start_us) < PAGE_ERASE_TIMEOUT_US) &&
+               (result == NRF_ERROR_BUSY)) {
+
+            result = sd_flash_page_erase(page_number);
+
+            /* Read timeout timer. */
+            now_us = lp_ticker_read();            
+        }
+
+    } else {
+
+        /* Raw API doesn't return error code, assume success. */
+        nrf_nvmc_page_erase(address);
+        result = NRF_SUCCESS;
     }
-    nrf_nvmc_page_erase(address);
-    return 0;
+
+    /* Convert Nordic error code to mbed HAL error code. */
+    return (result == NRF_SUCCESS) ? 0 : -1;
 }
 
 int32_t flash_program_page(flash_t *obj, uint32_t address, const uint8_t *data, uint32_t size)
 {
-    uint8_t sd_enabled;
-    if ((sd_softdevice_is_enabled(&sd_enabled) == NRF_SUCCESS) && sd_enabled == 1) {
-        return -1;
+    (void)(obj);
+
+    /* Return value defaults to error. */
+    uint32_t result = NRF_ERROR_BUSY;
+
+    /* Convert size to words. */
+    uint32_t words = size / sizeof(uint32_t);
+
+    if (NRF_HAL_SD_IS_ENABLED()) {
+
+        /* Setup stop watch for timeout. */
+        uint32_t start_us = lp_ticker_read();
+        uint32_t now_us = start_us;
+
+        /* Retry if flash is busy until timeout is reached. */
+        while (((now_us - start_us) < (words * WORD_WRITE_TIMEOUT_US)) &&
+               (result == NRF_ERROR_BUSY)) {
+
+            result = sd_flash_write((uint32_t *) address, (const uint32_t *) data, words);
+
+            /* Read timeout timer. */
+            now_us = lp_ticker_read();            
+        }
+
+    } else {
+        /* We will use *_words function to speed up flashing code. Word means 32bit -> 4B
+         * or sizeof(uint32_t).
+         */
+        nrf_nvmc_write_words(address, (const uint32_t *) data, words);
+        result = NRF_SUCCESS;
     }
-    /* We will use *_words function to speed up flashing code. Word means 32bit -> 4B
-     * or sizeof(uint32_t).
-     */
-    nrf_nvmc_write_words(address, (const uint32_t *) data, (size / sizeof(uint32_t)));
-    return 0;
+
+    /* Convert Nordic error code to mbed HAL error code. */
+    return (result == NRF_SUCCESS) ? 0 : -1;
 }
 
 uint32_t flash_get_size(const flash_t *obj)
 {
     (void)(obj);
+
     /* Just count flash size. */
     return NRF_FICR->CODESIZE * NRF_FICR->CODEPAGESIZE;
 }
 
 uint32_t flash_get_sector_size(const flash_t *obj, uint32_t address)
 {
     (void)(obj);
+
     /* Test if passed address is in flash space. */
     if (address < flash_get_size(obj)) {
         return NRF_FICR->CODEPAGESIZE;
     }
+
     /* Something goes wrong, return invalid size error code. */
     return MBED_FLASH_INVALID_SIZE;
 }
 
 uint32_t flash_get_page_size(const flash_t *obj)
 {
     (void)(obj);
-    return NRF_FICR->CODEPAGESIZE;
+
+    /* Return minimum writeable size. Note that this is different from the erase page size. */
+    return 4;
 }
 
 uint32_t flash_get_start_address(const flash_t *obj)
 {
+    (void)(obj);
+
     return 0;
 }
 

targets/targets.json

@@ -3481,7 +3481,7 @@
         "supported_form_factors": ["ARDUINO"],
         "inherits": ["MCU_NRF52"],
         "macros_add": ["BOARD_PCA10040", "NRF52_PAN_12", "NRF52_PAN_15", "NRF52_PAN_58", "NRF52_PAN_55", "NRF52_PAN_54", "NRF52_PAN_31", "NRF52_PAN_30", "NRF52_PAN_51", "NRF52_PAN_36", "NRF52_PAN_53", "S132", "CONFIG_GPIO_AS_PINRESET", "BLE_STACK_SUPPORT_REQD", "SWI_DISABLE0", "NRF52_PAN_20", "NRF52_PAN_64", "NRF52_PAN_62", "NRF52_PAN_63"],
-        "device_has_add": ["ANALOGIN", "I2C", "I2C_ASYNCH", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPI_ASYNCH", "SPISLAVE"],
+        "device_has_add": ["ANALOGIN", "I2C", "I2C_ASYNCH", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPI_ASYNCH", "SPISLAVE", "FLASH"],
         "release_versions": ["2", "5"],
         "device_name": "nRF52832_xxAA"
     },