swim: abstract the transport in stm8 target

SWIM is implemented by (ab)using the HLA API. This was acceptable
when OpenOCD code did not provided a clear separation between
transports and related APIs. Still today SWIM in OpenOCD is only
supported by STLink, so the decision to re-use the HLA API was the
simpler way to implement it.
After commit efd1d642220a ("adapter: switch from struct
jtag_interface to adapter_driver") the transports API are better
split and SWIM can be implemented as a separate set of API. This
would open the possibility to extend OpenOCD for other adapters
that provide SWIM, e.g. versaloon, or through SPI emulation [1].

Introduce a new set of files swim.[ch] to handle the SWIM API.
Beside the API that almost match the transport low-level data
communication (system_reset, read_mem, write_mem), add a further
API reconnect. Today, inside HLA STLink code, the reconnect is
implemented by hacking the HLA API state(). Please notice that
due to this hack the return type is incorrect; stlink_usb_state()
returns ERROR_OK in SWIM mode, while its return type is enum
target_state. Ignore the type mismatch and still call the HLA API
state in the new SWIM API reconnect. Further commit will fix it.

[1] http://kuku.eu.org/?projects/stm8spi/stm8spi

Change-Id: I52018e1e2200cbd41af8e5031f7b35dc761b61d6
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5528
Tested-by: jenkins

1 files changed, 65 insertions, 0 deletions

diff --git a/src/jtag/swim.h b/src/jtag/swim.h
new file mode 100644
index 0000000..d0ae18e
--- /dev/null
+++ b/src/jtag/swim.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/*
+ * Copyright (C) 2020 by Antonio Borneo <borneo.antonio@gmail.com
+ */
+
+/**
+ * @file
+ * This file implements support for STMicroelectronics debug protocol SWIM
+ * (Single Wire Interface Module).
+ */
+
+#ifndef OPENOCD_JTAG_SWIM_H
+#define OPENOCD_JTAG_SWIM_H
+
+struct swim_driver {
+	/**
+	 * Send SRST (system reset) command to target.
+	 *
+	 * @return ERROR_OK on success, else a fault code.
+	 */
+	int (*srst)(void);
+
+	/**
+	 * Read target memory through ROTF (read on-the-fly) command.
+	 *
+	 * @param addr Start address to read data from target memory.
+	 * @param size Size in bytes of data units, 1, 2 or 4.
+	 * @param count Number of units (size units, not bytes) to read.
+	 * @param buffer Data buffer to receive data.
+	 * @return ERROR_OK on success, else a fault code.
+	 */
+	int (*read_mem)(uint32_t addr, uint32_t size, uint32_t count,
+					uint8_t *buffer);
+
+	/**
+	 * Write target memory through WOTF (write on-the-fly) command.
+	 *
+	 * @param addr Start address to write data to target memory.
+	 * @param size Size in bytes of data units, 1, 2 or 4.
+	 * @param count Number of units (size units, not bytes) to write.
+	 * @param buffer Data buffer to write.
+	 * @return ERROR_OK on success, else a fault code.
+	 */
+	int (*write_mem)(uint32_t addr, uint32_t size, uint32_t count,
+					 const uint8_t *buffer);
+
+	/**
+	 * Reconnect to the target.
+	 * Should be reworked to be more generic and not linked to current
+	 * implementation in stlink driver.
+	 *
+	 * @return ERROR_OK on success, else a fault code.
+	 */
+	int (*reconnect)(void);
+};
+
+int swim_system_reset(void);
+int swim_read_mem(uint32_t addr, uint32_t size, uint32_t count,
+				  uint8_t *buffer);
+int swim_write_mem(uint32_t addr, uint32_t size, uint32_t count,
+				   const uint8_t *buffer);
+int swim_reconnect(void);
+
+#endif /* OPENOCD_JTAG_SWIM_H */