[nrf fromtree] drivers: flash: nrf_rram: add support for RRAM throttling

Some applications need to throttle RRAM writes to handle peak current
management.
Add CONFIG_NRF_RRAM_THROTTLING_DATA_BLOCK which defines the maximum
chunk length that can be written at once.
Add CONFIG_NRF_RRAM_THROTTLING_DELAY which configures the sleep delay in
microseconds after each write.

Signed-off-by: Riadh Ghaddab <[email protected]>
(cherry picked from commit a4f5d9f)

Author: rghaddab

drivers/flash/Kconfig.nrf_rram

@@ -56,8 +56,15 @@ config SOC_FLASH_NRF_RADIO_SYNC_NONE
 	bool "none"
 	help
 	  disable synchronization between flash memory driver and radio.
+
 endchoice
 
+config SOC_FLASH_NRF_THROTTLING
+	bool "Nordic nRFx throttling for flash write operations"
+	help
+	  Enable throttling for flash write operations to avoid overloading the
+	  flash memory controller.
+
 config SOC_FLASH_NRF_TIMEOUT_MULTIPLIER
 	int "Multiplier for flash operation timeouts [x0.1]"
 	depends on !SOC_FLASH_NRF_RADIO_SYNC_NONE
@@ -81,4 +88,20 @@ config NRF_RRAM_REGION_SIZE_UNIT
 	help
 	  Base unit for the size of RRAMC's region protection.
 
+config NRF_RRAM_THROTTLING_DELAY
+	int "Delay between flash write operations"
+	depends on SOC_FLASH_NRF_THROTTLING
+	default 2000
+	help
+	  This is the delay (in microseconds) between consecutive flash write
+	  operations when throttling is enabled.
+
+config NRF_RRAM_THROTTLING_DATA_BLOCK
+	int "Number of Data blocks for each flash write operations"
+	depends on SOC_FLASH_NRF_THROTTLING
+	default 16
+	help
+	  This is the number of data blocks (in number of 128-bit words) for flash write
+	  operations when throttling is enabled.
+
 endif # SOC_FLASH_NRF_RRAM

drivers/flash/soc_flash_nrf_rram.c

@@ -164,11 +164,24 @@ static void rram_write(off_t addr, const void *data, size_t len)
 	nrf_rramc_config_set(NRF_RRAMC, &config);
 #endif
 
-	if (data) {
-		memcpy((void *)addr, data, len);
-	} else {
-		memset((void *)addr, ERASE_VALUE, len);
+	size_t chunk_len = len;
+
+#ifdef CONFIG_SOC_FLASH_NRF_THROTTLING
+	while (len > 0) {
+		chunk_len = MIN(len, CONFIG_NRF_RRAM_THROTTLING_DATA_BLOCK * WRITE_LINE_SIZE);
+#endif /* CONFIG_SOC_FLASH_NRF_THROTTLING */
+		if (data) {
+			memcpy((void *)addr, data, chunk_len);
+		} else {
+			memset((void *)addr, ERASE_VALUE, chunk_len);
+		}
+#ifdef CONFIG_SOC_FLASH_NRF_THROTTLING
+		addr += chunk_len;
+		data = (const uint8_t *)data + chunk_len;
+		len -= chunk_len;
+		k_usleep(CONFIG_NRF_RRAM_THROTTLING_DELAY);
 	}
+#endif /* CONFIG_SOC_FLASH_NRF_THROTTLING */
 
 	barrier_dmem_fence_full(); /* Barrier following our last write. */