bootloader: allow skip image validation on C2

BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP is not supported on C2 due to
no RTC memory, but BOOTLOADER_SKIP_VALIDATE_ALWAYS should still be
supported.

components/bootloader/Kconfig.projbuild

@@ -366,7 +366,7 @@ menu "Bootloader config"
         # only available if both Secure Boot and Check Signature on Boot are disabled
         depends on !SECURE_SIGNED_ON_BOOT
         default n
-        select BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP
+        select BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP if SOC_RTC_FAST_MEM_SUPPORTED
         select BOOTLOADER_SKIP_VALIDATE_ON_POWER_ON
         help
             Selecting this option prevents the bootloader from ever validating the app image before

docs/en/api-guides/performance/speed.rst

@@ -126,7 +126,7 @@ In addition to the overall performance improvements shown above, the following o
 .. list::
 
    - Minimizing the :ref:`CONFIG_LOG_DEFAULT_LEVEL` and :ref:`CONFIG_BOOTLOADER_LOG_LEVEL` has a large impact on startup time. To enable more logging after the app starts up, set the :ref:`CONFIG_LOG_MAXIMUM_LEVEL` as well and then call :cpp:func:`esp_log_level_set` to restore higher level logs. The :example:`system/startup_time` main function shows how to do this.
-   - If using deep sleep, setting :ref:`CONFIG_BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP` allows a faster wake from sleep. Note that if using Secure Boot this represents a security compromise, as Secure Boot validation will not be performed on wake.
+   :SOC_RTC_FAST_MEM_SUPPORTED: - If using deep sleep, setting :ref:`CONFIG_BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP` allows a faster wake from sleep. Note that if using Secure Boot this represents a security compromise, as Secure Boot validation will not be performed on wake.
    - Setting :ref:`CONFIG_BOOTLOADER_SKIP_VALIDATE_ON_POWER_ON` will skip verifying the binary on every boot from power-on reset. How much time this saves depends on the binary size and the flash settings. Note that this setting carries some risk if the flash becomes corrupt unexpectedly. Read the help text of the :ref:`config item <CONFIG_BOOTLOADER_SKIP_VALIDATE_ON_POWER_ON>` for an explanation and recommendations if using this option.
    - It's possible to save a small amount of time during boot by disabling RTC slow clock calibration. To do so, set :ref:`CONFIG_RTC_CLK_CAL_CYCLES` to 0. Any part of the firmware that uses RTC slow clock as a timing source will be less accurate as a result.
 

examples/system/.build-test-rules.yml

@@ -136,12 +136,6 @@ examples/system/select:
       temporary: true
       reason: lack of runners
 
-examples/system/startup_time:
-  disable_test:
-    - if: IDF_TARGET == "esp32s3" or IDF_TARGET == "esp32c2"
-      temporary: true
-      reason: lack of runners
-
 examples/system/sysview_tracing:
   disable_test:
     - if: IDF_TARGET != "esp32"

examples/system/startup_time/pytest_startup_time.py

@@ -0,0 +1,20 @@
+# SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: CC0-1.0
+import logging
+
+import pytest
+from pytest_embedded import Dut
+
+
+@pytest.mark.supported_targets
+@pytest.mark.generic
+@pytest.mark.parametrize('config', [
+    'defaults',
+    'always_skip',
+], indirect=True)
+def test_startup_time_example(dut: Dut) -> None:
+
+    res = dut.expect(r'\((\d+)\) [^:]+: App started!')
+    time = int(res[1])
+
+    logging.info(f'[Performance][startup_time]: {time}')

examples/system/startup_time/sdkconfig.ci.always_skip

@@ -0,0 +1 @@
+CONFIG_BOOTLOADER_SKIP_VALIDATE_ALWAYS=y