i2c: Add binding for MCTP over I2C transport
Implements DSP0237. This has a fixed neighbor table (currently 4
entries), with neighbors learned on reception, or set with
mctp_i2c_set_neighbour().
Change-Id: I9b1e2c3673149cd0b9fee0d8113f3cac0e336bc7
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
diff --git a/i2c-internal.h b/i2c-internal.h
new file mode 100644
index 0000000..95ab81d
--- /dev/null
+++ b/i2c-internal.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
+#pragma once
+
+#include <assert.h>
+#include "libmctp.h"
+#include "libmctp-i2c.h"
+
+/* Limited by bytecount field */
+static_assert(I2C_BTU <= 254);
+
+#ifndef MCTP_I2C_NEIGH_COUNT
+#define MCTP_I2C_NEIGH_COUNT 4
+#endif
+
+struct mctp_i2c_hdr {
+ uint8_t dest;
+ uint8_t cmd;
+ uint8_t bytecount;
+ uint8_t source;
+};
+
+struct mctp_i2c_neigh {
+ bool used;
+ /* 7-bit address */
+ uint8_t addr;
+ uint8_t eid;
+ /* from platform_now(), for LRU eviction */
+ uint64_t last_seen_timestamp;
+};
+
+struct mctp_binding_i2c {
+ struct mctp_binding binding;
+
+ struct mctp_i2c_neigh neigh[MCTP_I2C_NEIGH_COUNT];
+
+ uint8_t own_addr;
+
+ uint8_t tx_storage[sizeof(struct mctp_i2c_hdr) +
+ MCTP_PKTBUF_SIZE(I2C_BTU)] __attribute((aligned(8)));
+ uint8_t rx_storage[sizeof(struct mctp_i2c_hdr) +
+ MCTP_PKTBUF_SIZE(I2C_BTU)] __attribute((aligned(8)));
+
+ mctp_i2c_tx_fn tx_fn;
+ void *tx_ctx;
+};