# Rust needs more stack than C for the main task and for the threads esp-idf-svc
# spawns internally.
CONFIG_ESP_MAIN_TASK_STACK_SIZE=8192
CONFIG_ESP_SYSTEM_EVENT_TASK_STACK_SIZE=4096
CONFIG_FREERTOS_IDLE_TASK_STACKSIZE=4096
CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT=4096

# Run the CPU at 240 MHz.
#
# This is the single biggest win in this file and it is free. ESP-IDF v5.5's
# Kconfig defaults the ESP32-S3 to *160* MHz (see
# components/esp_system/port/soc/esp32s3/Kconfig.cpu), so a stock build quietly
# leaves half the CPU on the table. Camera capture, the JPEG search in
# esp32-camera, lwIP and the HTTP server are all CPU-bound here, so this moves
# all of them at once.
CONFIG_ESP_DEFAULT_CPU_FREQ_MHZ_240=y

# ESP32-S3-N16R8: 16 MB flash, 8 MB octal PSRAM.
#
# DIO at 40 MHz, not the QIO/80 MHz this part is rated for: the flash on the
# test module has a defective byte (see README) and quad mode pushes it over
# the edge into a boot loop. Drop back to QIO/80 MHz on a healthy module.
#
# QIO would speed up *code* execution noticeably, since the app runs from flash
# and the flash cache misses go straight to this bus.
CONFIG_ESPTOOLPY_FLASHSIZE_16MB=y
CONFIG_ESPTOOLPY_FLASHMODE_DIO=y
CONFIG_ESPTOOLPY_FLASHFREQ_40M=y

# Code runs from flash, so instruction cache is the cheapest way to hide the
# slow flash bus. 32 KB instead of the 16 KB default.
CONFIG_ESP32S3_INSTRUCTION_CACHE_32KB=y

# Without this ESP-IDF uses partitions_singleapp.csv, whose factory partition is
# only 1 MB - smaller than the ~1.15 MB this firmware produces, so the image
# overflows the partition.
#
# The custom table also moves the app to 0x40000, which is what keeps the image
# off the module's defective flash byte; see partitions.csv for why.
CONFIG_PARTITION_TABLE_CUSTOM=y
CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="../../../../../../partitions.csv"
CONFIG_PARTITION_TABLE_OFFSET=0x8000

# Octal PSRAM is mandatory for the N16R8 module (R8 == 8 MB OPI PSRAM). The
# camera frame buffers live in it, so this is what makes VGA possible.
CONFIG_SPIRAM=y
CONFIG_SPIRAM_MODE_OCT=y
CONFIG_SPIRAM_SPEED_80M=y
CONFIG_SPIRAM_USE_MALLOC=y
CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=16384
CONFIG_SPIRAM_MEMTEST=y

# Keep the WiFi and lwIP buffers in internal RAM.
#
# This was previously set to `y` on the reasoning that PSRAM is plentiful, which
# is exactly backwards: WiFi descriptors and TCP segments are touched on every
# packet, and internal SRAM is an order of magnitude faster to reach than PSRAM
# behind the memory bus. Putting them in PSRAM shows up as high latency and poor
# throughput no matter how much PSRAM is free. The frame buffers, which are large
# and touched rarely by comparison, stay in PSRAM.
CONFIG_SPIRAM_TRY_ALLOCATE_WIFI_LWIP=n

CONFIG_ESP_WIFI_IRAM_OPT=y
CONFIG_ESP_WIFI_RX_IRAM_OPT=y

# Socket buffers sized for a video frame rather than for a text request.
#
# A VGA JPEG is ~20 kB. lwIP's 5760-byte default send buffer splits that into
# four segments, each one a separate pass through the WiFi driver; 17408 is the
# lwIP-recommended size for bulk transfers and covers a frame in one or two.
CONFIG_LWIP_TCP_SND_BUF_DEFAULT=17408
CONFIG_LWIP_TCP_WND_DEFAULT=17408

# Camera component
CONFIG_CAMERA_TASK_STACK_SIZE=4096

# Run the camera task on CPU1.
#
# The WiFi task is pinned to CPU0. esp32-camera's capture task spends its time
# in short, latency-sensitive bursts (DMA completion, the JPEG marker search,
# the copy into the frame buffer) and gets preempted on a shared core, which
# lengthens every frame. On a two-core part there is no reason to share.
CONFIG_CAMERA_CORE0=n

# PSRAM DMA is left off deliberately.
#
# With it on, esp32-camera writes frame buffers in PSRAM straight from GDMA and
# then looks for the JPEG end-of-image marker only inside the last DMA node
# (1 KB here). If the marker lands outside that window the frame is thrown away
# with "NO-EOI", and on this board that is most of them - after a few frames the
# driver stops handing out frames at all and never recovers.
#
# Off, the driver DMAs into an internal-RAM bounce buffer and copies the frame
# into PSRAM, which costs one extra memcpy of ~23 KB per frame and searches the
# whole buffer for the marker. That is the right trade for a working stream.
CONFIG_CAMERA_PSRAM_DMA=n
# Largest contiguous DMA chunk the driver may ask for.
CONFIG_CAMERA_DMA_BUFFER_SIZE_MAX=32768

# ESP-IDF 5.3+ links both the legacy driver/i2c.h and the new driver_ng I2C
# driver, and refuses to run both in one image. esp32-camera picks one of them
# for the SCCB bus; whichever it picks, the other has to stay out of the image,
# so the conflict check is skipped here.
CONFIG_I2C_SKIP_LEGACY_CONFLICT_CHECK=y