Add JTAG bitbang driver

Signed-off-by: Wjatscheslaw Stoljarski <wjatscheslaw.stoljarski@kiwigrid.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 109 insertions, 0 deletions

diff --git a/include/jtag.h b/include/jtag.h
new file mode 100644
index 0000000000..26c95fb307
--- /dev/null
+++ b/include/jtag.h
@@ -0,0 +1,109 @@
+/*
+ * include/linux/jtag.h
+ *
+ * Written Aug 2009 by Davide Rizzo <elpa.rizzo@gmail.com>
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * This driver manages one or more jtag chains controlled by host pins.
+ * Jtag chains must be defined during setup using jtag_platdata structs.
+ * All operations must be done from user programs using ioctls to /dev/jtag
+ * Typical operation sequence is:
+ * - open() the device (normally /dev/jtag)
+ * - ioctl JTAG_GET_DEVICES reads how many devices in the chain
+ * (repeat for each chip in the chain)
+ * - ioctl JTAG_GET_ID identifies the chip
+ * - ioctl JTAG_SET_IR_LENGTH sets the instruction register length
+ * Before accessing the data registers, instruction registers' lenghtes
+ *  MUST be programmed for all chips.
+ * After this initialization, you can execute JTAG_IR_WR, JTAG_DR_RD, JTAG_DR_WR
+ *  commands in any sequence.
+ */
+
+#ifndef __JTAG_H__
+#define __JTAG_H__
+
+/* Controller's gpio_tdi must be connected to last device's gpio_tdo */
+/* Controller's gpio_tdo must be connected to first device's gpio_tdi */
+struct jtag_platdata {
+	unsigned int gpio_tclk;
+	unsigned int gpio_tms;
+	unsigned int gpio_tdi;
+	unsigned int gpio_tdo;
+	unsigned int gpio_trst;
+	int use_gpio_trst;
+};
+
+#define JTAG_NAME "jtag"
+
+/* structures used for passing arguments to ioctl */
+
+struct jtag_rd_id {
+	int device; /* Device in the chain */
+	unsigned long id;
+};
+
+struct jtag_cmd {
+	int device; /* Device in the chain (-1 = all devices) */
+	unsigned int bitlen; /* Bit length of the register to be transfered */
+	unsigned long *data; /* Data to be transfered */
+};
+
+/* Use 'j' as magic number */
+#define JTAG_IOC_MAGIC		'j'
+
+/* ioctl commands */
+
+/* Resets jtag chain status, arg is ignored */
+#define JTAG_RESET		_IO(JTAG_IOC_MAGIC, 0)
+
+/* Returns the number of devices in the jtag chain, arg is ignored. */
+#define JTAG_GET_DEVICES	_IO(JTAG_IOC_MAGIC, 1)
+
+/* arg must point to a jtag_rd_id structure.
+   Fills up the id field with ID of selected device */
+#define JTAG_GET_ID		_IOR(JTAG_IOC_MAGIC, 2, struct jtag_rd_id)
+
+/* arg must point to a struct jtag_cmd.
+   Programs the Instruction Register length of specified device at bitlen value.
+   *data is ignored. */
+#define JTAG_SET_IR_LENGTH	_IOW(JTAG_IOC_MAGIC, 3, struct jtag_rd_id)
+
+/* arg must point to a struct jtag_cmd.
+   Writes *data in the Instruction Register of selected device, and BYPASS
+    instruction into Instruction Registers of all other devices in the chain.
+   If device == -1, the Instruction Registers of all devices are programmed
+    to the same value.
+   bitlen is always ignored, before using this command you have to program all
+    Instruction Register's lengthes with JTAG_SET_IR_LENGTH command. */
+#define JTAG_IR_WR		_IOW(JTAG_IOC_MAGIC, 4, struct jtag_cmd)
+
+/* arg must point to a struct jtag_cmd.
+   Reads data register of selected device, with length bitlen */
+#define JTAG_DR_RD		_IOR(JTAG_IOC_MAGIC, 5, struct jtag_cmd)
+
+/* arg must point to a struct jtag_cmd.
+   Writes data register of selected device, with length bitlen.
+   If device == -1, writes same data on all devices. */
+#define JTAG_DR_WR		_IOW(JTAG_IOC_MAGIC, 6, struct jtag_cmd)
+
+/* Generates arg pulses on TCLK pin */
+#define JTAG_CLK		_IOW(JTAG_IOC_MAGIC, 7, unsigned int *)
+
+#define JTAG_IOC_MAXNR		9
+
+#endif /* __JTAG_H__ */