From 3cb655eaabd136700071c9225f33715ea4915917 Mon Sep 17 00:00:00 2001
From: KonstantinKondrashov <konstantin@espressif.com>
Date: Thu, 2 Apr 2020 14:27:33 +0800
Subject: [PATCH] spi_flash(LEGACY_IMPL): Add vTaskDelay while a long erasing

Added Kconfig options to enable yield operation during flash erase

Closes: https://github.com/espressif/esp-idf/issues/2083
Closes: https://github.com/espressif/esp-idf/issues/4916
Closes: IDFGH-261
---
 components/spi_flash/Kconfig     | 22 ++++++++++++++++++++++
 components/spi_flash/flash_ops.c | 14 ++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/components/spi_flash/Kconfig b/components/spi_flash/Kconfig
index 7135d076736f..c9dd305a1fc6 100644
--- a/components/spi_flash/Kconfig
+++ b/components/spi_flash/Kconfig
@@ -100,6 +100,28 @@ menu "SPI Flash driver"
             this option, and the lock will be bypassed on SPI1 bus. Otherwise if extra devices
             are needed to attach to SPI1 bus, enable this option.
 
+    config SPI_FLASH_YIELD_DURING_ERASE
+        bool "Enables yield operation during flash erase"
+        default y
+        help
+            This allows to yield the CPUs between erase commands.
+            Prevents starvation of other tasks.
+
+    config SPI_FLASH_ERASE_YIELD_DURATION_MS
+        int "Duration of erasing to yield CPUs (ms)"
+        depends on SPI_FLASH_YIELD_DURING_ERASE
+        default 20
+        help
+            If a duration of one erase command is large
+            then it will yield CPUs after finishing a current command.
+
+    config SPI_FLASH_ERASE_YIELD_TICKS
+        int "CPU release time (tick)"
+        depends on SPI_FLASH_YIELD_DURING_ERASE
+        default 1
+        help
+            Defines how many ticks will be before returning to continue a erasing.
+
     menu "Auto-detect flash chips"
 
         config SPI_FLASH_SUPPORT_ISSI_CHIP
diff --git a/components/spi_flash/flash_ops.c b/components/spi_flash/flash_ops.c
index 5629e2973067..91d77c77c7b5 100644
--- a/components/spi_flash/flash_ops.c
+++ b/components/spi_flash/flash_ops.c
@@ -44,6 +44,7 @@
 #include "cache_utils.h"
 #include "esp_flash.h"
 #include "esp_attr.h"
+#include "esp_timer.h"
 
 esp_rom_spiflash_result_t IRAM_ATTR spi_flash_write_encrypted_chip(size_t dest_addr, const void *src, size_t size);
 
@@ -238,7 +239,13 @@ esp_err_t IRAM_ATTR spi_flash_erase_range(size_t start_addr, size_t size)
     esp_rom_spiflash_result_t rc;
     rc = spi_flash_unlock();
     if (rc == ESP_ROM_SPIFLASH_RESULT_OK) {
+#ifdef CONFIG_SPI_FLASH_YIELD_DURING_ERASE
+        int64_t no_yield_time_us = 0;
+#endif
         for (size_t sector = start; sector != end && rc == ESP_ROM_SPIFLASH_RESULT_OK; ) {
+#ifdef CONFIG_SPI_FLASH_YIELD_DURING_ERASE
+            int64_t start_time_us = esp_timer_get_time();
+#endif
             spi_flash_guard_start();
             if (sector % sectors_per_block == 0 && end - sector >= sectors_per_block) {
                 rc = esp_rom_spiflash_erase_block(sector / sectors_per_block);
@@ -250,6 +257,13 @@ esp_err_t IRAM_ATTR spi_flash_erase_range(size_t start_addr, size_t size)
                 COUNTER_ADD_BYTES(erase, SPI_FLASH_SEC_SIZE);
             }
             spi_flash_guard_end();
+#ifdef CONFIG_SPI_FLASH_YIELD_DURING_ERASE
+            no_yield_time_us += (esp_timer_get_time() - start_time_us);
+            if (no_yield_time_us / 1000 >= CONFIG_SPI_FLASH_ERASE_YIELD_DURATION_MS) {
+                no_yield_time_us = 0;
+                vTaskDelay(CONFIG_SPI_FLASH_ERASE_YIELD_TICKS);
+            }
+#endif
         }
     }
     COUNTER_STOP(erase);