deep sleep: add option to delay CPU startup

When ESP32 wakes up from deep sleep, flash is accessed an approximately 900us after power on.
Some flash chips need more time to become ready. This change adds a menuconfig option to add
some delay to the default deep sleep wake stub.

Fixes https://github.com/espressif/esp-idf/issues/117

diff --git a/components/esp32/Kconfig b/components/esp32/Kconfig
index 4112b337203ac916d94361e575692889d689a285..6ee5313b9bf7c705a87769fb3df2c30bf9cd0fe0 100644 (file)
--- a/components/esp32/Kconfig
+++ b/components/esp32/Kconfig
@@ -452,6 +452,25 @@ config ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL
 endchoice
 
 
+config ESP32_DEEP_SLEEP_WAKEUP_DELAY
+       int "Extra delay in deep sleep wake stub (in us)"
+       default 0
+       range 0 5000
+       help
+               When ESP32 exits deep sleep, the CPU and the flash chip are powered on
+               at the same time. CPU will run deep sleep stub first, and then
+               proceed to load code from flash. Some flash chips need sufficient
+               time to pass between power on and first read operation. By default,
+               without any extra delay, this time is approximately 900us.
+               
+               If you are using a flash chip which needs more than 900us to become
+               ready after power on, set this parameter to add extra delay
+               to the default deep sleep stub.
+               
+               If you are seeing "flash read err, 1000" message printed to the
+               console after deep sleep reset, try increasing this value. 
+
+
 config ESP32_PHY_AUTO_INIT
        bool "Initialize PHY in startup code"
        default y

diff --git a/components/esp32/deepsleep.c b/components/esp32/deepsleep.c
index cf9ee852e5d0bbf8f8339230f23ce16645b20914..0b13ce99a8f821cfc3524b1b1556ece94a47d438 100644 (file)
--- a/components/esp32/deepsleep.c
+++ b/components/esp32/deepsleep.c
@@ -26,6 +26,7 @@
 #include "driver/rtc_io.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
+#include "sdkconfig.h"
 
 /* Updating RTC_MEMORY_CRC_REG register via set_rtc_memory_crc()
    is not thread-safe. */
@@ -66,6 +67,12 @@ void RTC_IRAM_ATTR esp_default_wake_deep_sleep(void) {
     /* Clear MMU for CPU 0 */
     REG_SET_BIT(DPORT_PRO_CACHE_CTRL1_REG, DPORT_PRO_CACHE_MMU_IA_CLR);
     REG_CLR_BIT(DPORT_PRO_CACHE_CTRL1_REG, DPORT_PRO_CACHE_MMU_IA_CLR);
+#if CONFIG_ESP32_DEEP_SLEEP_WAKEUP_DELAY > 0
+    // ROM code has not started yet, so we need to set delay factor
+    // used by ets_delay_us first.
+    ets_update_cpu_frequency(ets_get_detected_xtal_freq() / 1000000);
+    ets_delay_us(CONFIG_ESP32_DEEP_SLEEP_WAKEUP_DELAY);
+#endif
 }
 
 void __attribute__((weak, alias("esp_default_wake_deep_sleep"))) esp_wake_deep_sleep(void);