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>

1 files changed, 47 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 */