Add 2-wire (C2) target interface support

Signed-off-by: Marc Schink <dev@zapb.de>

5 files changed, 369 insertions, 0 deletions

diff --git a/libjaylink/Makefile.am b/libjaylink/Makefile.am
index 8e10212..073591a 100644
--- a/libjaylink/Makefile.am
+++ b/libjaylink/Makefile.am
@@ -30,6 +30,7 @@ endif
 libjaylink_la_SOURCES = \
 	buffer.c \
 	core.c \
+	c2.c \
 	device.c \
 	discovery.c \
 	discovery_tcp.c \
diff --git a/libjaylink/c2.c b/libjaylink/c2.c
new file mode 100644
index 0000000..c13a0fa
--- /dev/null
+++ b/libjaylink/c2.c
@@ -0,0 +1,349 @@
+/*
+ * This file is part of the libjaylink project.
+ *
+ * Copyright (C) 2021-2022 Marc Schink <dev@zapb.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+
+#include "libjaylink.h"
+#include "libjaylink-internal.h"
+
+/**
+ * @file
+ *
+ * Silicon Labs 2-wire (C2) interface functions.
+ */
+
+/** @cond PRIVATE */
+#define CMD_C2_IO		0x17
+
+#define C2_CMD_DATA_READ	0x00
+#define C2_CMD_DATA_WRITE	0x01
+#define C2_CMD_ADDR_READ	0x02
+#define C2_CMD_ADDR_WRITE	0x03
+/** @endcond */
+
+/**
+ * Read the C2 address register.
+ *
+ * @note This function must only be used if the #JAYLINK_TIF_C2 interface is
+ *       available and selected.
+ *
+ * @param[in,out] devh Device handle.
+ * @param[out] address Value read from the address register on success, and
+ *                     undefined on failure.
+ *
+ * @retval JAYLINK_OK Success.
+ * @retval JAYLINK_ERR_ARG Invalid arguments.
+ * @retval JAYLINK_ERR_TIMEOUT A timeout occurred.
+ * @retval JAYLINK_ERR_IO Input/output error.
+ * @retval JAYLINK_ERR_DEV Unspecified device error.
+ * @retval JAYLINK_ERR Other error conditions.
+ *
+ * @since 0.3.0
+ */
+JAYLINK_API int jaylink_c2_read_address(struct jaylink_device_handle *devh,
+		uint8_t *address)
+{
+	int ret;
+	uint8_t buf[6];
+	struct jaylink_context *ctx;
+
+	if (!devh || !address)
+		return JAYLINK_ERR_ARG;
+
+	ctx = devh->dev->ctx;
+
+	ret = transport_start_write_read(devh, 5, 1 + 4, true);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_start_write_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	buf[0] = CMD_C2_IO;
+	buf[1] = C2_CMD_ADDR_READ;
+	buf[2] = 0x00;
+	/* Length is always 1 for this command. */
+	buffer_set_u16(buf, 1, 3);
+
+	ret = transport_write(devh, buf, 5);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_read(devh, address, 1);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_read(devh, buf, 4);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	uint32_t err = buffer_get_u32(buf, 0);
+
+	if (err != 0) {
+		return JAYLINK_ERR_DEV;
+	}
+
+	return JAYLINK_OK;
+}
+
+/**
+ * Write to the C2 address register.
+ *
+ * @note This function must only be used if the #JAYLINK_TIF_C2 interface is
+ *       available and selected.
+ *
+ * @param[in,out] devh Device handle.
+ * @param[in] address Value to write into the address register.
+ *
+ * @retval JAYLINK_OK Success.
+ * @retval JAYLINK_ERR_ARG Invalid arguments.
+ * @retval JAYLINK_ERR_TIMEOUT A timeout occurred.
+ * @retval JAYLINK_ERR_IO Input/output error.
+ * @retval JAYLINK_ERR_DEV Unspecified device error.
+ * @retval JAYLINK_ERR Other error conditions.
+ *
+ * @since 0.3.0
+ */
+JAYLINK_API int jaylink_c2_write_address(struct jaylink_device_handle *devh,
+		uint8_t address)
+{
+	int ret;
+	uint8_t buf[6];
+	struct jaylink_context *ctx;
+
+	if (!devh)
+		return JAYLINK_ERR_ARG;
+
+	ctx = devh->dev->ctx;
+
+	ret = transport_start_write_read(devh, 5 + 1, 4, true);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_start_write_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	buf[0] = CMD_C2_IO;
+	buf[1] = C2_CMD_ADDR_WRITE;
+	/* Length is always 1 for this command. */
+	buffer_set_u16(buf, 1, 2);
+	buf[4] = 0x00;
+	buf[5] = address;
+
+	ret = transport_write(devh, buf, 6);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_read(devh, buf, 4);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	uint32_t err = buffer_get_u32(buf, 0);
+
+	if (err != 0) {
+		return JAYLINK_ERR_DEV;
+	}
+
+	return JAYLINK_OK;
+}
+
+/**
+ * Read the C2 data register.
+ *
+ * @note This function must only be used if the #JAYLINK_TIF_C2 interface is
+ *       available and selected.
+ *
+ * @param[in,out] devh Device handle.
+ * @param[out] data Buffer to store the read data on success. Its content is
+ *                  undefined on failure.
+ * @param[in] length Number of bytes to read, but not more than
+ *                   #JAYLINK_C2_MAX_LENGTH.
+ *
+ * @retval JAYLINK_OK Success.
+ * @retval JAYLINK_ERR_ARG Invalid arguments.
+ * @retval JAYLINK_ERR_TIMEOUT A timeout occurred.
+ * @retval JAYLINK_ERR_IO Input/output error.
+ * @retval JAYLINK_ERR_DEV Unspecified device error.
+ * @retval JAYLINK_ERR Other error conditions.
+ *
+ * @since 0.3.0
+ */
+JAYLINK_API int jaylink_c2_read_data(struct jaylink_device_handle *devh,
+		uint8_t *data, uint8_t length)
+{
+	int ret;
+	struct jaylink_context *ctx;
+	uint8_t buf[5];
+
+	if (!devh || !data)
+		return JAYLINK_ERR_ARG;
+
+	if (length > JAYLINK_C2_MAX_LENGTH)
+		return JAYLINK_ERR_ARG;
+
+	ctx = devh->dev->ctx;
+
+	ret = transport_start_write_read(devh, 5, 4 + length, true);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_start_write_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	buf[0] = CMD_C2_IO;
+	buf[1] = C2_CMD_DATA_READ;
+	buf[2] = 0x00;
+	buffer_set_u16(buf, length, 3);
+
+	ret = transport_write(devh, buf, 5);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_read(devh, data, length);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_read(devh, buf, 4);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	uint32_t err = buffer_get_u32(buf, 0);
+
+	if (err != 0) {
+		return JAYLINK_ERR_DEV;
+	}
+
+	return JAYLINK_OK;
+}
+
+/**
+ * Write to the C2 data register.
+ *
+ * @note This function must only be used if the #JAYLINK_TIF_C2 interface is
+ *       available and selected.
+ *
+ * @param[in,out] devh Device handle.
+ * @param[in] data Buffer to be written into the data register.
+ * @param[in] length Number of bytes to write, but not more than
+ *                   #JAYLINK_C2_MAX_LENGTH.
+ *
+ * @retval JAYLINK_OK Success.
+ * @retval JAYLINK_ERR_ARG Invalid arguments.
+ * @retval JAYLINK_ERR_TIMEOUT A timeout occurred.
+ * @retval JAYLINK_ERR_IO Input/output error.
+ * @retval JAYLINK_ERR_DEV Unspecified device error.
+ * @retval JAYLINK_ERR Other error conditions.
+ *
+ * @since 0.3.0
+ */
+JAYLINK_API int jaylink_c2_write_data(struct jaylink_device_handle *devh,
+		const uint8_t *data, uint8_t length)
+{
+	int ret;
+	uint8_t buf[5];
+	struct jaylink_context *ctx;
+
+	if (!devh || !data)
+		return JAYLINK_ERR_ARG;
+
+	if (length > JAYLINK_C2_MAX_LENGTH)
+		return JAYLINK_ERR_ARG;
+
+	ctx = devh->dev->ctx;
+
+	ret = transport_start_write_read(devh, 5 + length, 4, true);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_start_write_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	buf[0] = CMD_C2_IO;
+	buf[1] = C2_CMD_DATA_WRITE;
+	buffer_set_u16(buf, length, 2);
+	buf[4] = 0x00;
+
+	ret = transport_write(devh, buf, 5);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_write(devh, data, length);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_read(devh, buf, 4);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	uint32_t err = buffer_get_u32(buf, 0);
+
+	if (err != 0) {
+		return JAYLINK_ERR_DEV;
+	}
+
+	return JAYLINK_OK;
+}
diff --git a/libjaylink/libjaylink.h b/libjaylink/libjaylink.h
index d89913c..22fc825 100644
--- a/libjaylink/libjaylink.h
+++ b/libjaylink/libjaylink.h
@@ -246,6 +246,8 @@ enum jaylink_target_interface {
 	JAYLINK_TIF_2W_JTAG_PIC32 = 4,
 	/** Serial Peripheral Interface (SPI). */
 	JAYLINK_TIF_SPI = 5,
+	/** Silicon Labs 2-wire interface (C2). */
+	JAYLINK_TIF_C2 = 6,
 	/** Compact JTAG (cJTAG). **/
 	JAYLINK_TIF_CJTAG = 7,
 };
@@ -425,6 +427,9 @@ struct jaylink_connection {
  */
 #define JAYLINK_EMUCOM_CHANNEL_USER	0x10000
 
+/** Maximum length of a 2-wire (C2) interface data transfer. */
+#define JAYLINK_C2_MAX_LENGTH		64
+
 /**
  * @struct jaylink_context
  *
@@ -475,6 +480,17 @@ JAYLINK_API int jaylink_init(struct jaylink_context **ctx);
 JAYLINK_API int jaylink_exit(struct jaylink_context *ctx);
 JAYLINK_API bool jaylink_library_has_cap(enum jaylink_capability cap);
 
+/*--- c2.c ------------------------------------------------------------------*/
+
+JAYLINK_API int jaylink_c2_read_address(struct jaylink_device_handle *devh,
+		uint8_t *address);
+JAYLINK_API int jaylink_c2_write_address(struct jaylink_device_handle *devh,
+		uint8_t address);
+JAYLINK_API int jaylink_c2_read_data(struct jaylink_device_handle *devh,
+		uint8_t *data, uint8_t length);
+JAYLINK_API int jaylink_c2_write_data(struct jaylink_device_handle *devh,
+		const uint8_t *data, uint8_t length);
+
 /*--- device.c --------------------------------------------------------------*/
 
 JAYLINK_API int jaylink_get_devices(struct jaylink_context *ctx,
diff --git a/libjaylink/strutil.c b/libjaylink/strutil.c
index 0f344c1..913a5a5 100644
--- a/libjaylink/strutil.c
+++ b/libjaylink/strutil.c
@@ -118,6 +118,8 @@ JAYLINK_API const char *jaylink_target_interface_string(
 		return "2-wire JTAG for PIC32";
 	case JAYLINK_TIF_SPI:
 		return "SPI";
+	case JAYLINK_TIF_C2:
+		return "C2";
 	case JAYLINK_TIF_CJTAG:
 		return "cJTAG";
 	default:
diff --git a/libjaylink/target.c b/libjaylink/target.c
index c51ebcd..6715662 100644
--- a/libjaylink/target.c
+++ b/libjaylink/target.c
@@ -218,6 +218,7 @@ JAYLINK_API int jaylink_select_interface(struct jaylink_device_handle *devh,
 	case JAYLINK_TIF_FINE:
 	case JAYLINK_TIF_2W_JTAG_PIC32:
 	case JAYLINK_TIF_SPI:
+	case JAYLINK_TIF_C2:
 	case JAYLINK_TIF_CJTAG:
 		break;
 	default: