drivers: jtag: Add JTAG core driver

JTAG class driver provide infrastructure to support hardware/software
JTAG platform drivers. It provide user layer API interface for flashing
and debugging external devices which equipped with JTAG interface
using standard transactions.

Driver exposes set of IOCTL to user space for:
- XFER:
  SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
  SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
- GIOCSTATUS read the current TAPC state of the JTAG controller
- SIOCSTATE Forces the JTAG TAPC to go into a particular state.
- SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
- IOCBITBANG for low level control of JTAG signals.

Driver core provides set of internal APIs for allocation and
registration:
- jtag_register;
- jtag_unregister;
- jtag_alloc;
- jtag_free;

Platform driver on registration with jtag-core creates the next
entry in dev folder:
/dev/jtagX

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ernesto Corona <ernesto.corona@intel.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Johan Hovold <johan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: Federico Vaga <federico.vaga@cern.ch>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Christian Gromm <christian.gromm@microchip.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Yiwei Zhang <zzyiwei@google.com>
Cc: Alessandro Rubini <rubini@gnudd.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Steven Filary <steven.a.filary@intel.com>
Cc: Vadim Pasternak <vadimp@mellanox.com>
Cc: Amithash Prasad <amithash@fb.com>
Cc: Patrick Williams <patrickw3@fb.com>
Cc: Rgrs <rgrs@protonmail.com>

2 files changed, 282 insertions, 0 deletions

diff --git a/include/linux/jtag.h b/include/linux/jtag.h
new file mode 100644
index 000000000000..fab12dc4fc5e
--- /dev/null
+++ b/include/linux/jtag.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Mellanox Technologies. All rights reserved. */
+/* Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com> */
+/* Copyright (c) 2019 Intel Corporation */
+
+#ifndef __LINUX_JTAG_H
+#define __LINUX_JTAG_H
+
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define JTAG_MAX_XFER_DATA_LEN 65535
+
+struct jtag;
+/**
+ * struct jtag_ops - callbacks for JTAG control functions:
+ *
+ * @freq_get: get frequency function. Filled by dev driver
+ * @freq_set: set frequency function. Filled by dev driver
+ * @status_get: get JTAG TAPC state function. Mandatory, Filled by dev driver
+ * @status_set: set JTAG TAPC state function. Mandatory, Filled by dev driver
+ * @xfer: send JTAG xfer function. Mandatory func. Filled by dev driver
+ * @mode_set: set specific work mode for JTAG. Filled by dev driver
+ * @bitbang: set low level bitbang operations. Filled by dev driver
+ * @enable: enables JTAG interface in master mode. Filled by dev driver
+ * @disable: disables JTAG interface master mode. Filled by dev driver
+ */
+struct jtag_ops {
+	int (*freq_get)(struct jtag *jtag, u32 *freq);
+	int (*freq_set)(struct jtag *jtag, u32 freq);
+	int (*status_get)(struct jtag *jtag, u32 *state);
+	int (*status_set)(struct jtag *jtag, struct jtag_tap_state *endst);
+	int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
+	int (*mode_set)(struct jtag *jtag, struct jtag_mode *jtag_mode);
+	int (*bitbang)(struct jtag *jtag, struct bitbang_packet *bitbang,
+		       struct tck_bitbang *bitbang_data);
+	int (*enable)(struct jtag *jtag);
+	int (*disable)(struct jtag *jtag);
+};
+
+void *jtag_priv(struct jtag *jtag);
+int devm_jtag_register(struct device *dev, struct jtag *jtag);
+struct jtag *jtag_alloc(struct device *host, size_t priv_size,
+			const struct jtag_ops *ops);
+void jtag_free(struct jtag *jtag);
+
+#endif /* __LINUX_JTAG_H */
diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
new file mode 100644
index 000000000000..220ffabe81cd
--- /dev/null
+++ b/include/uapi/linux/jtag.h
@@ -0,0 +1,235 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Mellanox Technologies. All rights reserved. */
+/* Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com> */
+/* Copyright (c) 2019 Intel Corporation */
+
+#ifndef __UAPI_LINUX_JTAG_H
+#define __UAPI_LINUX_JTAG_H
+
+/*
+ * JTAG_XFER_MODE: JTAG transfer mode. Used to set JTAG controller transfer mode
+ * This is bitmask for feature param in jtag_mode for ioctl JTAG_SIOCMODE
+ */
+#define  JTAG_XFER_MODE 0
+/*
+ * JTAG_CONTROL_MODE: JTAG controller mode. Used to set JTAG controller mode
+ * This is bitmask for feature param in jtag_mode for ioctl JTAG_SIOCMODE
+ */
+#define  JTAG_CONTROL_MODE 1
+/*
+ * JTAG_MASTER_OUTPUT_DISABLE: JTAG master mode output disable, it is used to
+ * enable other devices to own the JTAG bus.
+ * This is bitmask for mode param in jtag_mode for ioctl JTAG_SIOCMODE
+ */
+#define  JTAG_MASTER_OUTPUT_DISABLE 0
+/*
+ * JTAG_MASTER_MODE: JTAG master mode. Used to set JTAG controller master mode
+ * This is bitmask for mode param in jtag_mode for ioctl JTAG_SIOCMODE
+ */
+#define  JTAG_MASTER_MODE 1
+/*
+ * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived or bitbang
+ * mode. This is bitmask for mode param in jtag_mode for ioctl JTAG_SIOCMODE
+ */
+#define  JTAG_XFER_HW_MODE 1
+/*
+ * JTAG_XFER_SW_MODE: JTAG software mode. Used to set SW drived or bitbang
+ * mode. This is bitmask for mode param in jtag_mode for ioctl JTAG_SIOCMODE
+ */
+#define  JTAG_XFER_SW_MODE 0
+
+/**
+ * enum jtag_tapstate:
+ *
+ * @JTAG_STATE_TLRESET: JTAG state machine Test Logic Reset state
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_SELECTDR: JTAG state machine SELECT_DR state
+ * @JTAG_STATE_CAPTUREDR: JTAG state machine CAPTURE_DR state
+ * @JTAG_STATE_SHIFTDR: JTAG state machine SHIFT_DR state
+ * @JTAG_STATE_EXIT1DR: JTAG state machine EXIT-1 DR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ * @JTAG_STATE_EXIT2DR: JTAG state machine EXIT-2 DR state
+ * @JTAG_STATE_UPDATEDR: JTAG state machine UPDATE DR state
+ * @JTAG_STATE_SELECTIR: JTAG state machine SELECT_IR state
+ * @JTAG_STATE_CAPTUREIR: JTAG state machine CAPTURE_IR state
+ * @JTAG_STATE_SHIFTIR: JTAG state machine SHIFT_IR state
+ * @JTAG_STATE_EXIT1IR: JTAG state machine EXIT-1 IR state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_EXIT2IR: JTAG state machine EXIT-2 IR state
+ * @JTAG_STATE_UPDATEIR: JTAG state machine UPDATE IR state
+ * @JTAG_STATE_CURRENT: JTAG current state, saved by driver
+ */
+enum jtag_tapstate {
+	JTAG_STATE_TLRESET,
+	JTAG_STATE_IDLE,
+	JTAG_STATE_SELECTDR,
+	JTAG_STATE_CAPTUREDR,
+	JTAG_STATE_SHIFTDR,
+	JTAG_STATE_EXIT1DR,
+	JTAG_STATE_PAUSEDR,
+	JTAG_STATE_EXIT2DR,
+	JTAG_STATE_UPDATEDR,
+	JTAG_STATE_SELECTIR,
+	JTAG_STATE_CAPTUREIR,
+	JTAG_STATE_SHIFTIR,
+	JTAG_STATE_EXIT1IR,
+	JTAG_STATE_PAUSEIR,
+	JTAG_STATE_EXIT2IR,
+	JTAG_STATE_UPDATEIR,
+	JTAG_STATE_CURRENT
+};
+
+/**
+ * enum jtag_reset:
+ *
+ * @JTAG_NO_RESET: JTAG run TAP from current state
+ * @JTAG_FORCE_RESET: JTAG force TAP to reset state
+ */
+enum jtag_reset {
+	JTAG_NO_RESET = 0,
+	JTAG_FORCE_RESET = 1,
+};
+
+/**
+ * enum jtag_xfer_type:
+ *
+ * @JTAG_SIR_XFER: SIR transfer
+ * @JTAG_SDR_XFER: SDR transfer
+ */
+enum jtag_xfer_type {
+	JTAG_SIR_XFER = 0,
+	JTAG_SDR_XFER = 1,
+};
+
+/**
+ * enum jtag_xfer_direction:
+ *
+ * @JTAG_READ_XFER: read transfer
+ * @JTAG_WRITE_XFER: write transfer
+ * @JTAG_READ_WRITE_XFER: read & write transfer
+ */
+enum jtag_xfer_direction {
+	JTAG_READ_XFER = 1,
+	JTAG_WRITE_XFER = 2,
+	JTAG_READ_WRITE_XFER = 3,
+};
+
+/**
+ * struct jtag_tap_state - forces JTAG state machine to go into a TAPC
+ * state
+ *
+ * @reset: 0 - run IDLE/PAUSE from current state
+ *         1 - go through TEST_LOGIC/RESET state before  IDLE/PAUSE
+ * @end: completion flag
+ * @tck: clock counter
+ *
+ * Structure provide interface to JTAG device for JTAG set state execution.
+ */
+struct jtag_tap_state {
+	__u8	reset;
+	__u8	from;
+	__u8	endstate;
+	__u8	tck;
+};
+
+/**
+ * union pad_config - Padding Configuration:
+ *
+ * @type: transfer type
+ * @pre_pad_number: Number of prepadding bits bit[11:0]
+ * @post_pad_number: Number of prepadding bits bit[23:12]
+ * @pad_data : Bit value to be used by pre and post padding bit[24]
+ * @int_value: unsigned int packed padding configuration value bit[32:0]
+ *
+ * Structure provide pre and post padding configuration in a single __u32
+ */
+union pad_config {
+	struct {
+		__u32 pre_pad_number	: 12;
+		__u32 post_pad_number	: 12;
+		__u32 pad_data		: 1;
+		__u32 rsvd		: 7;
+	};
+	__u32 int_value;
+};
+
+/**
+ * struct jtag_xfer - jtag xfer:
+ *
+ * @type: transfer type
+ * @direction: xfer direction
+ * @from: xfer current state
+ * @endstate: xfer end state
+ * @padding: xfer padding
+ * @length: xfer bits length
+ * @tdio : xfer data array
+ *
+ * Structure provide interface to JTAG device for JTAG SDR/SIR xfer execution.
+ */
+struct jtag_xfer {
+	__u8	type;
+	__u8	direction;
+	__u8	from;
+	__u8	endstate;
+	__u32	padding;
+	__u32	length;
+	__u64	tdio;
+};
+
+/**
+ * struct bitbang_packet - jtag bitbang array packet:
+ *
+ * @data:   JTAG Bitbang struct array pointer(input/output)
+ * @length: array size (input)
+ *
+ * Structure provide interface to JTAG device for JTAG bitbang bundle execution
+ */
+struct bitbang_packet {
+	struct tck_bitbang *data;
+	__u32	length;
+} __attribute__((__packed__));
+
+/**
+ * struct jtag_bitbang - jtag bitbang:
+ *
+ * @tms: JTAG TMS
+ * @tdi: JTAG TDI (input)
+ * @tdo: JTAG TDO (output)
+ *
+ * Structure provide interface to JTAG device for JTAG bitbang execution.
+ */
+struct tck_bitbang {
+	__u8	tms;
+	__u8	tdi;
+	__u8	tdo;
+} __attribute__((__packed__));
+
+/**
+ * struct jtag_mode - jtag mode:
+ *
+ * @feature: 0 - JTAG feature setting selector for JTAG controller HW/SW
+ *           1 - JTAG feature setting selector for controller bus master
+ *               mode output (enable / disable).
+ * @mode:    (0 - SW / 1 - HW) for JTAG_XFER_MODE feature(0)
+ *           (0 - output disable / 1 - output enable) for JTAG_CONTROL_MODE
+ *                                                    feature(1)
+ *
+ * Structure provide configuration modes to JTAG device.
+ */
+struct jtag_mode {
+	__u32	feature;
+	__u32	mode;
+};
+
+/* ioctl interface */
+#define __JTAG_IOCTL_MAGIC	0xb2
+
+#define JTAG_SIOCSTATE	_IOW(__JTAG_IOCTL_MAGIC, 0, struct jtag_tap_state)
+#define JTAG_SIOCFREQ	_IOW(__JTAG_IOCTL_MAGIC, 1, unsigned int)
+#define JTAG_GIOCFREQ	_IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
+#define JTAG_IOCXFER	_IOWR(__JTAG_IOCTL_MAGIC, 3, struct jtag_xfer)
+#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum jtag_tapstate)
+#define JTAG_SIOCMODE	_IOW(__JTAG_IOCTL_MAGIC, 5, unsigned int)
+#define JTAG_IOCBITBANG	_IOW(__JTAG_IOCTL_MAGIC, 6, unsigned int)
+
+#endif /* __UAPI_LINUX_JTAG_H */