Preliminary ESP32 port #517

lpereira · 2017-06-15T23:32:56Z

This patch set adds preliminary support for ESP32, both as a SoC, and as a board. I haven't compiled the documentation yet, but the individual commit messages contain much of what's necessary to build Zephyr for this board. I'm submitting this series now in order to gather feedback and raise awareness in the ESP32 community.

Most of the legwork for an Xtensa port has been made available in previous versions, so basic things such as threads, timers, and synchronization primitives are all working fine. The philosophers sample is working as expected, for instance.

A lot of things are missing from the port, though, including I/O (no GPIO, I2C, SPI, analog I/O, PWM, etc) and connectivity (WiFi, BT, and BLE). We're working on these, and I hope to have patches implementing some of them soon. Connectivity is going to take more work, though.

OpenOCD should work fine (as long as you're using the fork from Espressif).

galak · 2017-06-16T12:38:51Z

scripts/support/esp32.sh

+
+	echo "Flashing"
+	${esptool} --chip esp32 \
+		--port /dev/ttyUSB0 \


should provide a means to override the port setting, what happens if you had more than one board connected to a system?

agree, my USB0 is always occupied by something else, I had to change that when testing ESP32.

galak · 2017-06-16T12:41:09Z

scripts/support/esp32.sh

+
+
+cmd_flash() {
+	local esptool=${ESP_IDF_PATH}/components/esptool_py/esptool/esptool.py


should allow for esptool path to be set by user if desired, and default to what you have here.

galak · 2017-06-16T12:41:40Z

boards/xtensa/esp32/Makefile.board

 EMU_PLATFORM ?=
 DEBUG_SCRIPT :=
+FLASH_SCRIPT := esp32.sh


do you expect esp32.sh to do more than flash? if not might rename script to esp32-flash.sh

the support scripts we have are designed to do more than flashing, so I think this is in line with other scripts we have, if we add debugging, then it is added to the same script.

I'm planning to add a debug command to this script as well, to invoke OpenOCD with the right settings.

galak

Some cleanups for esp32.sh script

explora26 · 2017-06-17T06:32:25Z

boards/xtensa/esp32/Kconfig.defconfig

@@ -0,0 +1,11 @@
+# Kconfig - STM32 MINI A15 board configuration


Good catch. Fixed.

Three environment variables must be set to use this variant: export ZEPHYR_GCC_VARIANT="espressif" export ESP_IDF_PATH=/path/to/esp-idf export ESPRESSIF_TOOLCHAIN_PATH=/path/to/xtensa-esp32-elf/ ESP-IDF is the SDK provided by Espressif. It contains, among other things, the HAL and header files for registers and ROM functions used by the Zephyr port. At this stage, with the exception of the HAL library, none of the binary blobs provided by ESP-IDF are used. This can be obtained directly from Espressif, at <https://github.com/espressif/esp-idf>. Instructions on how to obtain the toolchain are detailed in the README for ESP-IDF. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

Due to the configurable nature of the Xtensa platform, the generic name of "LX6" cannot be used to describe an SoC as far as Zephyr goes. So ESP32 is defined both as a SoC and as a board. This is based on work by Rajavardhan Gundi. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

This is based on the work of Rajavardhan Gundi. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

This is a minimal driver enabling console output during the port bringup. While the driver works, only one of the three UART devices are supported, and there isn't any way to change any parameters or use interrupts. This will most likely be superceded by a proper driver after the port has matured. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

This header is included by some files provided by ESP-IDF. Nothing from this header file is actually used: it's only being added allow things to compile with the minimal libc. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

Until ESP32’s flash cache is utilized, .rodata must be stored in RAM. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

Unconditionally use CONFIG_SIMULATOR_XTENSA to determine if XT_SIMULATOR or XT_BOARD should be defined. If CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC, also define XT_CLOCK_FREQ. This isn't ideal as the clock frequency might be changed in runtime and this effectively makes it a constant. Until we can control the clock frequency in runtime, this will suffice. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

The first stage bootloader, part of the ESP32 ROM, already sets up a stack that's sufficient to execute C programs. So, instead of implementing __stack() in assembly, do it in C to simplify things slightly. This ESP32-specific initialization will perform the following: - Disable the watchdog timer that's enabled by the bootloader - Move exception handlers to IRAM - Disable normal interrupts - Disable the second CPU - Zero out the BSS segment Things that might be performed in the future include setting up the CPU frequency, memory protection regions, and enabling the flash cache. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

This flashes Zephyr at 0x1000: that's where the first stage bootloader, part of the ESP32 ROM, expects to find an "image header". The second-stage bootloader, part of ESP-IDF, isn't used by the Zephyr port. However, the bootloader can be used if desired; please refer to the ESP-IDF documentation on how to set up partitions tables and use the bootloader. The following environment variables will affect the ESP32 flashing process: Variable Default value ESP_DEVICE /dev/ttyUSB0 ESP_BAUD_RATE 921600 ESP_FLASH_SIZE detect ESP_FLASH_FREQ 40m ESP_FLASH_MODE dio ESP_TOOL espidf It's impossible to determine which serial port the ESP32 board is connected to, as it uses a generic RS232-USB converter. The default of /dev/ttyUSB0 is provided as that's often the assigned name on a Linux machine without any other such converters. The baud rate of 921600bps is recommended. If experiencing issues when flashing, try halving the value a few times (460800, 230400, 115200, etc). It might be necessary to change the flash frequency or the flash mode; please refer to the esptool documentation for guidance on these settings. If ${ESP_TOOL} is set to "espidf", the esptool.py script found within ESP-IDF will be used. Otherwise, this variable is handled as a path to the tool. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

lpereira · 2017-06-19T20:32:30Z

Rebased and fixed comments.

andrewboie · 2017-06-20T16:28:49Z

boards/xtensa/esp32/Kconfig.board

+config BOARD_ESP32
+	bool "ESP32 Development Board"
+	depends on XTENSA
+	select BOARD_XTENSA


Ugh, at some point we should just use y/n values of CONFIG_SIMULATOR_XTENSA instead of having both CONFIG_SIMULATOR_XTENSA and CONFIG_BOARD_XTENSA

This is sort of done inside xtensa_rtos.h now: if CONFIG_SIMULATOR_XTENSA is defined, XT_SIMULATOR is defined; otherwise, XT_BOARD gets defined. This select can be removed from Kconfig.board.

andrewboie · 2017-06-20T16:29:55Z

scripts/support/esp32.sh

+   flash)
+   	cmd_flash "$@"
+   	;;
+   *)


do we plan on adding a 'debugserver' target?

andrewboie · 2017-06-20T16:30:32Z

arch/xtensa/soc/esp32/soc.c

+	/* The watchdog timer is enabled in the bootloader.  We're done booting,
+	 * so disable it.
+	 */
+	*wdt_rtc_reg &= ~RTC_CNTL_WDT_FLASHBOOT_MOD_EN;


suggest adding a story in the backlog to implement a WDT driver

andrewboie · 2017-06-20T16:34:02Z

arch/xtensa/soc/esp32/Kconfig.defconfig

+	default esp32
+
+config IRQ_OFFLOAD_INTNUM
+	default 7


Assuming this value has been tested.
If unsure, run tests/kernel/irq_offload

IRQ offload isn't working yet. I've tried with two IRQ nos. that are available for software interrupts, and all I get is an exception. There are more pressing matters at the moment but this is something that have to be fixed eventually.

)

lpereira requested review from nashif, andrewboie, andyross and pfalcon June 15, 2017 23:32

galak reviewed Jun 16, 2017

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galak requested changes Jun 16, 2017

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lpereira force-pushed the esp32 branch 2 times, most recently from 63e8be1 to 541d9c2 Compare June 16, 2017 17:41

explora26 reviewed Jun 17, 2017

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lpereira and others added 10 commits June 19, 2017 12:50

boards: xtensa: Add ESP32 board

f4816bb

This is based on the work of Rajavardhan Gundi. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

libc: minimal: Add empty sys/cdefs.h

fa9d0e4

This header is included by some files provided by ESP-IDF. Nothing from this header file is actually used: it's only being added allow things to compile with the minimal libc. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

xtensa: esp32: place .rodata into DRAM

ba6c5f1

Until ESP32’s flash cache is utilized, .rodata must be stored in RAM. Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

xtensa: esp32: configure default UART using ROM functions

7a3a043

Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>

lpereira force-pushed the esp32 branch from 541d9c2 to 2ad543e Compare June 19, 2017 20:15

andrewboie reviewed Jun 20, 2017

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andrewboie approved these changes Jun 20, 2017

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andrewboie reviewed Jun 20, 2017

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nashif approved these changes Jun 21, 2017

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nashif merged commit f0b4e17 into zephyrproject-rtos:master Jun 21, 2017

This was referenced Sep 18, 2017

ESP32 Architecture Configuration zephyriot/zep-jira14#1872

Closed

Espressif Open-source Toolchain Support zephyriot/zep-jira14#1873

Closed

This was referenced Sep 18, 2017

UART support for ESP32 zephyriot/zep-jira14#1930

Closed

ESP32 Architecture Configuration zephyriot/zephyr-issues#1872

Closed

Espressif Open-source Toolchain Support zephyriot/zephyr-issues#1873

Closed

UART support for ESP32 zephyriot/zephyr-issues#1930

Closed

This was referenced Sep 23, 2017

ESP32 Architecture Configuration #3472

Closed

Espressif Open-source Toolchain Support #3473

Closed

UART support for ESP32 #3530

Closed

nagineni pushed a commit to nagineni/zephyr that referenced this pull request Nov 20, 2017

[tests] Update test-timer.js for testpoint added (zephyrproject-rtos#517

fb04e66

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zephyrbot mentioned this pull request Sep 16, 2019

arc: hsdk: bug fixes and new feature supports #19173

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Preliminary ESP32 port #517

Preliminary ESP32 port #517

lpereira commented Jun 15, 2017

galak Jun 16, 2017

nashif Jun 16, 2017

galak Jun 16, 2017

lpereira Jun 16, 2017

galak Jun 16, 2017

nashif Jun 16, 2017

lpereira Jun 16, 2017

galak left a comment

explora26 Jun 17, 2017

lpereira Jun 19, 2017

lpereira commented Jun 19, 2017

andrewboie Jun 20, 2017

lpereira Jun 20, 2017

andrewboie Jun 20, 2017

lpereira Jun 20, 2017

andrewboie Jun 20, 2017

lpereira Jun 20, 2017

andrewboie Jun 20, 2017

lpereira Jun 20, 2017



		cmd_flash() {
		local esptool=${ESP_IDF_PATH}/components/esptool_py/esptool/esptool.py

		@@ -0,0 +1,11 @@
		# Kconfig - STM32 MINI A15 board configuration

Preliminary ESP32 port #517

Preliminary ESP32 port #517

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lpereira commented Jun 15, 2017

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lpereira commented Jun 19, 2017

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