port_esp_hosted_host_spi.h File Reference

esp-hosted port header: full-duplex SPI transport buffer size. More...

#include <stdint.h>
#include "esp_hosted_transport.h"

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Macros
#define	MAX_TRANSPORT_BUFFER_SIZE   (ESP_TRANSPORT_SPI_MAX_BUF_SIZE)
	Bytes clocked in one full-duplex SPI transaction.

Detailed Description

esp-hosted port header: full-duplex SPI transport buffer size.

Tag

[Ring 4 / PORT] {World: NS}

The vendored esp-hosted core includes this header BY NAME from host/drivers/transport/transport_drv.h whenever H_TRANSPORT_IN_USE == H_TRANSPORT_SPI. Upstream ships it under host/port/, which this project excludes (see docs/SOUP/esp-hosted-host.md); this file is its first-party replacement and must therefore keep the upstream file name and the upstream macro spelling exactly.

It supplies exactly one symbol, MAX_TRANSPORT_BUFFER_SIZE – the number of bytes clocked in a single full-duplex transaction. Both ends of the link must agree on it or every frame mis-decodes:

• the RA8 host takes it from ESP_TRANSPORT_SPI_MAX_BUF_SIZE in the vendored common/transport/esp_hosted_transport.h;
• the ESP32-C6 co-processor image built from coprocessor/esp32c6/ reports the same 1600 in its sdkconfig;
• the landed link probe examples/ek_ra8d2/hw_validated/c6/c6_spi_probe hand-decodes frames against its own k_c6_proto_buf_size, also 1600.

Deriving it from the vendored constant rather than restating 1600 keeps those three in lockstep: a future upstream bump changes one place.

Copyright

Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since

0.1.0

Definition in file port_esp_hosted_host_spi.h.

Macro Definition Documentation

MAX_TRANSPORT_BUFFER_SIZE

#define MAX_TRANSPORT_BUFFER_SIZE   (ESP_TRANSPORT_SPI_MAX_BUF_SIZE)

Bytes clocked in one full-duplex SPI transaction.

Derived from the vendored ESP_TRANSPORT_SPI_MAX_BUF_SIZE (1600) so host and co-processor cannot drift apart. Every transmit and receive buffer the SPI driver allocates is exactly this large, regardless of how few payload bytes a frame actually carries.

Note

Read-only build configuration; consumed by the vendored spi_drv.c through MAX_SPI_BUFFER_SIZE.

Warning

Changing this without rebuilding the C6 image breaks the link.

Example:

static uint8_t rx_buf[MAX_TRANSPORT_BUFFER_SIZE];

Since

0.1.0

Definition at line 63 of file port_esp_hosted_host_spi.h.