Add initial SPI support

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

5 files changed, 179 insertions, 1 deletions

diff --git a/libjaylink/Makefile.am b/libjaylink/Makefile.am
index 62c5489..8e10212 100644
--- a/libjaylink/Makefile.am
+++ b/libjaylink/Makefile.am
@@ -40,6 +40,7 @@ libjaylink_la_SOURCES = \
 	list.c \
 	log.c \
 	socket.c \
+	spi.c \
 	strutil.c \
 	swd.c \
 	swo.c \
diff --git a/libjaylink/libjaylink.h b/libjaylink/libjaylink.h
index 8f48c3d..8798e42 100644
--- a/libjaylink/libjaylink.h
+++ b/libjaylink/libjaylink.h
@@ -156,7 +156,9 @@ enum jaylink_device_capability {
 	/** Device supports EMUCOM. */
 	JAYLINK_DEV_CAP_EMUCOM = 33,
 	/** Device supports ethernet connectivity. */
-	JAYLINK_DEV_CAP_ETHERNET = 38
+	JAYLINK_DEV_CAP_ETHERNET = 38,
+	/** Device supports SPI. */
+	JAYLINK_DEV_CAP_SPI = 56,
 };
 
 /** Hardware information. */
@@ -240,6 +242,8 @@ enum jaylink_target_interface {
 	JAYLINK_TIF_FINE = 3,
 	/** 2-wire JTAG for PIC32 compliant devices. */
 	JAYLINK_TIF_2W_JTAG_PIC32 = 4,
+	/** Serial Peripheral Interface (SPI). */
+	JAYLINK_TIF_SPI = 5,
 	/** Compact JTAG (cJTAG). **/
 	JAYLINK_TIF_CJTAG = 7,
 };
@@ -268,6 +272,22 @@ enum jaylink_swo_mode {
 	JAYLINK_SWO_MODE_UART = 0
 };
 
+/** Serial Peripheral Interface (SPI) flags. */
+enum jaylink_spi_flag {
+	/** Do not drive chip select (CS) before the transfer begins. */
+	JAYLINK_SPI_FLAG_CS_START_U = 0x00,
+	/** Drive chip select (CS) low before the transfer begins. */
+	JAYLINK_SPI_FLAG_CS_START_0 = 0x02,
+	/** Drive chip select (CS) high before the transfer begins. */
+	JAYLINK_SPI_FLAG_CS_START_1 = 0x03,
+	/** Do not drive chip select (CS) after the transfer is complete. */
+	JAYLINK_SPI_FLAG_CS_END_U = 0x00,
+	/** Drive chip select (CS) low after the transfer is complete. */
+	JAYLINK_SPI_FLAG_CS_END_0 = 0x08,
+	/** Drive chip select (CS) high after the transfer is complete. */
+	JAYLINK_SPI_FLAG_CS_END_1 = 0x0c,
+};
+
 /** Target interface speed information. */
 struct jaylink_speed {
 	/** Base frequency in Hz. */
@@ -569,6 +589,12 @@ JAYLINK_API int jaylink_log_set_domain(struct jaylink_context *ctx,
 JAYLINK_API const char *jaylink_log_get_domain(
 		const struct jaylink_context *ctx);
 
+/*--- spi.c -----------------------------------------------------------------*/
+
+JAYLINK_API int jaylink_spi_io(struct jaylink_device_handle *devh,
+		const uint8_t *mosi, uint8_t *miso, uint32_t length,
+		uint32_t flags);
+
 /*--- strutil.c -------------------------------------------------------------*/
 
 JAYLINK_API int jaylink_parse_serial_number(const char *str,
diff --git a/libjaylink/spi.c b/libjaylink/spi.c
new file mode 100644
index 0000000..4f8ab04
--- /dev/null
+++ b/libjaylink/spi.c
@@ -0,0 +1,148 @@
+/*
+ * This file is part of the libjaylink project.
+ *
+ * Copyright (C) 2016-2020 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
+ *
+ * Serial Peripheral Interface (SPI) functions.
+ */
+
+/** @cond PRIVATE */
+#define CMD_SPI			0x15
+
+#define SPI_CMD_IO		0x01
+/** @endcond */
+
+/**
+ * Perform SPI I/O operation.
+ *
+ * The device acts as master and operates in mode 3 (CPOL = 1, CPHA = 1). Data
+ * is transferred with the most significant bit (MSB) first.
+ *
+ * @note This function must only be used if the device has the
+ *       #JAYLINK_DEV_CAP_SPI capability and if the #JAYLINK_TIF_SPI interface
+ *       is available and selected.
+ *
+ * @param[in,out] devh Device handle.
+ * @param[in] mosi Buffer to read MOSI data from. Can be NULL.
+ * @param[out] miso Buffer to store MISO data on success. Its content
+ *                  is undefined on failure. The buffer must be large enough to
+ *                  contain at least the specified number of bytes to transfer.
+ *                  Can be NULL.
+ * @param[in] length Number of bytes to transfer.
+ * @param[in] flags Flags, see #jaylink_spi_flag for more details.
+ *
+ * @retval JAYLINK_OK Success.
+ * @retval JAYLINK_ERR_ARG Invalid arguments.
+ * @retval JAYLINK_ERR_TIMEOUT A timeout occurred.
+ * @retval JAYLINK_ERR_PROTO Protocol violation.
+ * @retval JAYLINK_ERR Other error conditions.
+ *
+ * @since 0.3.0
+ */
+JAYLINK_API int jaylink_spi_io(struct jaylink_device_handle *devh,
+		const uint8_t *mosi, uint8_t *miso, uint32_t length,
+		uint32_t flags)
+{
+	int ret;
+	struct jaylink_context *ctx;
+	uint8_t buf[20];
+	uint32_t mosi_length;
+	uint32_t miso_length;
+	uint32_t num_transferred_bytes;
+
+	if (!devh || !length)
+		return JAYLINK_ERR_ARG;
+
+	if (!mosi && !miso)
+		return JAYLINK_ERR_ARG;
+
+	mosi_length = (mosi) ? length : 0;
+	miso_length = (miso) ? length : 0;
+	ctx = devh->dev->ctx;
+
+	buf[0] = CMD_SPI;
+	buf[1] = SPI_CMD_IO;
+	buf[2] = 0x00;
+	buf[3] = 0x00;
+
+	buffer_set_u32(buf, mosi_length + 8, 4);
+	buffer_set_u32(buf, miso_length + 4, 8);
+	buffer_set_u32(buf, length * 8, 12);
+	buffer_set_u32(buf, flags, 16);
+
+	ret = transport_start_write_read(devh, 20 + mosi_length,
+		miso_length + 4, true);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_start_write_read() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	ret = transport_write(devh, buf, 20);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %s",
+			jaylink_strerror(ret));
+		return ret;
+	}
+
+	if (mosi) {
+		ret = transport_write(devh, mosi, mosi_length);
+
+		if (ret != JAYLINK_OK) {
+			log_err(ctx, "transport_write() failed: %s",
+				jaylink_strerror(ret));
+			return ret;
+		}
+	}
+
+	if (miso) {
+		ret = transport_read(devh, miso, miso_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;
+	}
+
+	num_transferred_bytes = buffer_get_u32(buf, 0);
+
+	if (num_transferred_bytes != length) {
+		log_err(ctx, "Unexpected number of transferred bytes");
+		return JAYLINK_ERR_PROTO;
+	}
+
+	return JAYLINK_OK;
+}
diff --git a/libjaylink/strutil.c b/libjaylink/strutil.c
index 3658683..0f344c1 100644
--- a/libjaylink/strutil.c
+++ b/libjaylink/strutil.c
@@ -116,6 +116,8 @@ JAYLINK_API const char *jaylink_target_interface_string(
 		return "FINE";
 	case JAYLINK_TIF_2W_JTAG_PIC32:
 		return "2-wire JTAG for PIC32";
+	case JAYLINK_TIF_SPI:
+		return "SPI";
 	case JAYLINK_TIF_CJTAG:
 		return "cJTAG";
 	default:
diff --git a/libjaylink/target.c b/libjaylink/target.c
index 8df96af..c51ebcd 100644
--- a/libjaylink/target.c
+++ b/libjaylink/target.c
@@ -217,6 +217,7 @@ JAYLINK_API int jaylink_select_interface(struct jaylink_device_handle *devh,
 	case JAYLINK_TIF_BDM3:
 	case JAYLINK_TIF_FINE:
 	case JAYLINK_TIF_2W_JTAG_PIC32:
+	case JAYLINK_TIF_SPI:
 	case JAYLINK_TIF_CJTAG:
 		break;
 	default: