chore(zephyr): upgrade to Zephyr v3.7.0 (#10)

### Summary

There are several fixes for this app to build with Zephyr 3.7.0 and the latest
Memfault SDK:

- Updated s3 board overlay & board argument to match hardware model v2
- Updated heap pool size to eliminate warning compile message -- they increased it
- Removed enabling of `CONFIG_MEMFAULT_TLS_CERTS_USE_DER` since it is now the
  default
- Updated readme with new args for `wifi connect` shell command
- Enabled `CONFIG_MBEDTLS_AES_ROM_TABLES` explicitly -- this used to be enabled
  by default. It saves ~8kB in RAM space.

With the jump to 3.7.0, the build for the esp32c3 overflowed by 70kb:

```
/Users/gminnehan/.local/zephyr-sdk-0.16.1-rc1/riscv64-zephyr-elf/bin/../lib/gcc/riscv64-zephyr-elf/12.2.0/../../../../riscv64-zephyr-elf/bin/ld.bfd: zephyr/zephyr_pre0.elf section `.dram0.bss' will not fit in region `dram0_0_seg'
/Users/gminnehan/.local/zephyr-sdk-0.16.1-rc1/riscv64-zephyr-elf/bin/../lib/gcc/riscv64-zephyr-elf/12.2.0/../../../../riscv64-zephyr-elf/bin/ld.bfd: DRAM segment data does not fit.
/Users/gminnehan/.local/zephyr-sdk-0.16.1-rc1/riscv64-zephyr-elf/bin/../lib/gcc/riscv64-zephyr-elf/12.2.0/../../../../riscv64-zephyr-elf/bin/ld.bfd: region `dram0_0_seg' overflowed by 71104 bytes
```

After investigating, there appears to be a few culprits, including a drop in the
DRAM segment by 20kB in 3.7.0. To unblock build testing with Memfault for both
the RISC-V and Xtensa arch on Zephyr 3.7.0, the MBEDTLS heap has been shrunk for
the c3 build for now. Users can still test out Memfault shell commands but will
have to post chunks via the chunks debug log. Since this support has been
removed, the default board is now the s3.

### Test Plan

CI, also flashed a esp32s3 locally & uploaded chunks successfully

----
Related: MCU-569

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
 
           west build --sysbuild \
             --pristine=always \
-            --board=esp32s3_devkitm zephyr-esp32-example \
+            --board=esp32s3_devkitm/esp32s3/procpu zephyr-esp32-example \
             -- \
             -DCONFIG_MEMFAULT_PROJECT_KEY=\"1234\"
 

CMakeLists.txt

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 # Default board
-set(BOARD esp32c3_devkitm)
+set(BOARD esp32s3_devkitm/esp32s3/procpu)
 
 cmake_minimum_required(VERSION 3.20.0)
 

README.md

@@ -4,8 +4,10 @@ This sample app is based on the Zephyr `samples/net/wifi` example. It
 demonstrates a Zephyr + ESP32 integration with the Memfault SDK. It has been
 tested on the following boards:
 
-- `esp32c3_devkitm` (default board)
-- `esp32s3_devkitm`
+- `esp32s3_devkitm/esp32s3/procpu` (default board)
+- `esp32c3_devkitm`*
+
+\* _NOTE: Currently does not have support for data upload. Export chunks to memfault with `mflt export` and upload via the [chunks debug log](https://mflt.io/chunks-debug).
 
 ## Getting Started
 
@@ -56,7 +58,7 @@ To try out this example app:
    [00:09:21.911,000] <inf> mflt: HW version: esp32c3_devkitm
 
    # connect wifi
-   uart:~$ wifi connect <ssid> <pw>
+   uart:~$ wifi connect -s "<ssid>" -k <key type> -p "<pw>"
 
    # test memfault export over uart
    uart:~$ mflt export

boards/esp32c3_devkitm.conf

@@ -11,4 +11,12 @@ CONFIG_NET_IPV4=y
 CONFIG_NET_DHCPV4=y
 CONFIG_ESP32_WIFI_STA_AUTO_DHCPV4=y
 
-CONFIG_NET_LOG=y
+# Override selections from prj.conf to save space on this chip
+CONFIG_LOG=y
+CONFIG_NET_LOG=n
+CONFIG_MEMFAULT_LOGGING_ENABLE=n
+CONFIG_NET_SHELL=n
+
+# TODO: Add support for TLS on this chip
+# Removed to free up RAM and allow build check to succeed.
+CONFIG_MBEDTLS_HEAP_SIZE=0

prj.conf

@@ -41,24 +41,26 @@ CONFIG_NET_L2_WIFI_SHELL=y
 CONFIG_MEMFAULT=y
 CONFIG_MEMFAULT_LOGGING_ENABLE=y
 CONFIG_MEMFAULT_HTTP_ENABLE=y
-CONFIG_MEMFAULT_TLS_CERTS_USE_DER=y
 CONFIG_MEMFAULT_HTTP_PERIODIC_UPLOAD=y
 
 # Additional network configuration for Memfault features
 CONFIG_DNS_RESOLVER=y
+CONFIG_POSIX_API=y
 CONFIG_NET_SOCKETS=y
 CONFIG_TLS_CREDENTIALS=y
 CONFIG_NET_SOCKETS_SOCKOPT_TLS=y
 CONFIG_NET_STATISTICS=y
 CONFIG_NET_STATISTICS_USER_API=y
 
 # MbedTLS config
+CONFIG_MBEDTLS_SHA1=y
 CONFIG_MBEDTLS_SERVER_NAME_INDICATION=y
 CONFIG_MBEDTLS_ENABLE_HEAP=y
 CONFIG_MBEDTLS_HEAP_SIZE=30000
 CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN=4096
 CONFIG_MBEDTLS_MEMORY_DEBUG=y
 CONFIG_MBEDTLS_SHELL=y
+CONFIG_MBEDTLS_AES_ROM_TABLES=y
 
 # More verbose Memfault component logs
 CONFIG_MEMFAULT_LOG_LEVEL_DBG=y
@@ -76,7 +78,7 @@ CONFIG_MEMFAULT_COREDUMP_COLLECT_TASKS_REGIONS=n
 # Memfault's http client needs a small amount of heap. Zephyr requires a minimum
 # heap size for the applied configuration, so select that here to prevent a
 # build time message
-CONFIG_HEAP_MEM_POOL_SIZE=51200
+CONFIG_HEAP_MEM_POOL_SIZE=52224
 CONFIG_SYS_HEAP_RUNTIME_STATS=y
 CONFIG_SHELL_STACK_SIZE=4096
 CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

west.yml

@@ -2,7 +2,7 @@ manifest:
   projects:
     - name: zephyr
       url: https://github.com/zephyrproject-rtos/zephyr
-      revision: v3.6.0
+      revision: v3.7.0
       import:
         # Limit the Zephyr modules to the required set
         name-allowlist:
@@ -13,4 +13,4 @@ manifest:
     - name: memfault-firmware-sdk
       url: https://github.com/memfault/memfault-firmware-sdk
       path: modules/lib/memfault-firmware-sdk
-      revision: 1.10.1
+      revision: 1.11.4