[patch v15 0/4] JTAG driver introduction

[patch v15 0/4] JTAG driver introduction

[Oleksandr Shamray]

When a need raise up to use JTAG interface for system's devices
programming or CPU debugging, usually the user layer
application implements jtag protocol by bit-bang or using a 
proprietary connection to vendor hardware.
This method can be slow and not generic.
 
We propose to implement general JTAG interface and infrastructure
to communicate with user layer application. In such way, we can
have the standard JTAG interface core part and separation from
specific HW implementation.
This allow new capability to debug the CPU or program system's 
device via BMC without additional devices nor cost. 

This patch purpose is to add JTAG master core infrastructure by 
defining new JTAG class and provide generic JTAG interface
to allow hardware specific drivers to connect this interface.
This will enable all JTAG drivers to use the common interface
part and will have separate for hardware implementation.

The JTAG (Joint Test Action Group) core driver provides minimal generic
JTAG interface, which can be used by hardware specific JTAG master
controllers. By providing common interface for the JTAG controllers,
user space device programing is hardware independent.
 
Modern SoC which in use for embedded system' equipped with
internal JTAG master interface.
This interface is used for programming and debugging system's
hardware components, like CPLD, FPGA, CPU, voltage and
industrial controllers.
Firmware for such devices can be upgraded through JTAG interface during
Runtime. The JTAG standard support for multiple devices programming,
is in case their lines are daisy-chained together.

For example, systems which equipped with host CPU, BMC SoC or/and 
number of programmable devices are capable to connect a pin and
select system components dynamically for programming and debugging,
This is using by the BMC which is equipped with internal SoC master
controller.
For example:

BMC JTAG master --> pin selected to CPLDs chain for programming (filed
upgrade, production) 
BMC JTAG master --> pin selected to voltage monitors for programming 
(field upgrade, production) 
BMC JTAG master --> pin selected to host CPU (on-site debugging 
and developers debugging)

For example, we can have application in user space which using calls
to JTAG driver executes CPLD programming directly from SVF file
 
The JTAG standard (IEEE 1149.1) defines the next connector pins:
- TDI (Test Data In);
- TDO (Test Data Out);
- TCK (Test Clock);
- TMS (Test Mode Select);
- TRST (Test Reset) (Optional);

The SoC equipped with JTAG master controller, performs
device programming on command or vector level. For example
a file in a standard SVF (Serial Vector Format) that contains
boundary scan vectors, can be used by sending each vector
to the JTAG interface and the JTAG controller will execute
the programming.

Initial version provides the system calls set for:
- SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
  number of clocks.

SoC which are not equipped with JTAG master interface, can be built
on top of JTAG core driver infrastructure, by applying bit-banging of
TDI, TDO, TCK and TMS pins within the hardware specific driver.


Oleksandr Shamray (4):
  drivers: jtag: Add JTAG core driver
  drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master
    driver
  Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx
    families     JTAG master driver
  Documentation: jtag: Add ABI documentation

 Documentation/ABI/testing/jtag-dev                 |   27 +
 .../devicetree/bindings/jtag/aspeed-jtag.txt       |   18 +
 Documentation/ioctl/ioctl-number.txt               |    2 +
 MAINTAINERS                                        |   10 +
 drivers/Kconfig                                    |    2 +
 drivers/Makefile                                   |    1 +
 drivers/jtag/Kconfig                               |   30 +
 drivers/jtag/Makefile                              |    2 +
 drivers/jtag/jtag-aspeed.c                         |  774 ++++++++++++++++++++
 drivers/jtag/jtag.c                                |  288 ++++++++
 include/linux/jtag.h                               |   45 ++
 include/uapi/linux/jtag.h                          |  104 +++
 12 files changed, 1303 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/ABI/testing/jtag-dev
 create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
 create mode 100644 drivers/jtag/Kconfig
 create mode 100644 drivers/jtag/Makefile
 create mode 100644 drivers/jtag/jtag-aspeed.c
 create mode 100644 drivers/jtag/jtag.c
 create mode 100644 include/linux/jtag.h
 create mode 100644 include/uapi/linux/jtag.h

[patch v15 1/4] drivers: jtag: Add JTAG core driver

[Oleksandr Shamray]

Initial patch for JTAG 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);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
  number of clocks).
- SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.

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>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
---
v14->v15
v13->v14
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change style of head block comment from /**/ to //

v12->v13
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change jtag.c licence type to
  SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
  and reorder line with license in description
v11->v12
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- Change jtag.h licence type to
  SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
  and reorder line with license in description

Chip Bilbrey <chip@bilbrey.org>
- Remove Apeed reference from uapi jtag.h header
- Remove access mode from xfer and idle transactions
- Add new ioctl JTAG_SIOCMODE for set hw mode
- Add only one open per JTAG port blocking with mutex blocking

v10->v11
Notifications from kbuild test robot <lkp@intel.com>
- include types.h headeri to jtag.h
- fix incompatible type of xfer callback
- remove rdundant class defination
- Fix return order in case of xfer error

V9->v10
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- remove unnecessary alignment for pirv data
- move jtag_copy_to_user and jtag_copy_from_user code just to ioctl
- move int jtag_run_test_idle_op and jtag_xfer_op code
  just to ioctl
- change return error codes to more applicable
- add missing error checks
- fix error check order in ioctl
- remove unnecessary blank lines
- add param validation to ioctl
- remove compat_ioctl
- remove only one open per JTAG port blocking.
  User will care about this.
- Fix idr memory leak on jtag_exit
- change cdev device type to misc

V8->v9
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- use get_user() instead of __get_user().
- change jtag->open type from int to atomic_t
- remove spinlock on jtg_open
- remove mutex on jtag_register
- add unregister_chrdev_region on jtag_init err
- add unregister_chrdev_region on jtag_exit
- remove unnecessary pointer casts
- add *data parameter to xfer function prototype

v7->v8
Comments pointed by Moritz Fischer <moritz.fischer@ettus.com>
- Fix misspelling s/friver/driver

v6->v7
Notifications from kbuild test robot <lkp@intel.com>
- Remove include asm/types.h from jtag.h
- Add include <linux/types.h> to jtag.c

v5->v6
v4->v5

v3->v4
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- change transaction pointer tdio type  to __u64
- change internal status type from enum to __u32
- reorder jtag_xfer members to avoid the implied padding
- add __packed attribute to jtag_xfer and jtag_run_test_idle

v2->v3
Notifications from kbuild test robot <lkp@intel.com>
- Change include path to <linux/types.h> in jtag.h

v1->v2
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- Change license type from GPLv2/BSD to GPLv2
- Change type of variables which crossed user/kernel to __type
- Remove "default n" from Kconfig

Comments pointed by Andrew Lunn <andrew@lunn.ch>
- Change list_add_tail in jtag_unregister to list_del

Comments pointed by Neil Armstrong <narmstrong@baylibre.com>
- Add SPDX-License-Identifier instead of license text

Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Change __copy_to_user to memdup_user
- Change __put_user to put_user
- Change type of variables to __type for compatible 32 and 64-bit systems
- Add check for maximum xfer data size
- Change lookup data mechanism to get jtag data from inode
- Add .compat_ioctl to file ops
- Add mem alignment for jtag priv data

Comments pointed by Tobias Klauser <tklauser@distanz.ch>
- Change function names to avoid match with variable types
- Fix description for jtag_ru_test_idle in uapi jtag.h
- Fix misprints IDEL/IDLE, trough/through
---
 Documentation/ioctl/ioctl-number.txt |    2 +
 MAINTAINERS                          |   10 ++
 drivers/Kconfig                      |    2 +
 drivers/Makefile                     |    1 +
 drivers/jtag/Kconfig                 |   16 ++
 drivers/jtag/Makefile                |    1 +
 drivers/jtag/jtag.c                  |  288 ++++++++++++++++++++++++++++++++++
 include/linux/jtag.h                 |   45 ++++++
 include/uapi/linux/jtag.h            |  104 ++++++++++++
 9 files changed, 469 insertions(+), 0 deletions(-)
 create mode 100644 drivers/jtag/Kconfig
 create mode 100644 drivers/jtag/Makefile
 create mode 100644 drivers/jtag/jtag.c
 create mode 100644 include/linux/jtag.h
 create mode 100644 include/uapi/linux/jtag.h

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 3e3fdae..1af2508 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -321,6 +321,8 @@ Code  Seq#(hex)	Include File		Comments
 0xB0	all	RATIO devices		in development:
 					<mailto:vgo@ratio.de>
 0xB1	00-1F	PPPoX			<mailto:mostrows@styx.uwaterloo.ca>
+0xB2	00-0f	linux/jtag.h		JTAG driver
+					<mailto:oleksandrs@mellanox.com>
 0xB3	00	linux/mmc/ioctl.h
 0xB4	00-0F	linux/gpio.h		<mailto:linux-gpio@vger.kernel.org>
 0xB5	00-0F	uapi/linux/rpmsg.h	<mailto:linux-remoteproc@vger.kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 205d397..dfcf49c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7292,6 +7292,16 @@ L:	linux-serial@vger.kernel.org
 S:	Maintained
 F:	drivers/tty/serial/jsm/
 
+JTAG SUBSYSTEM
+M:	Oleksandr Shamray <oleksandrs@mellanox.com>
+M:	Vadim Pasternak <vadimp@mellanox.com>
+S:	Maintained
+F:	include/linux/jtag.h
+F:	include/uapi/linux/jtag.h
+F:	drivers/jtag/
+F:	Documentation/devicetree/bindings/jtag/
+F:	Documentation/ABI/testing/jtag-cdev
+
 K10TEMP HARDWARE MONITORING DRIVER
 M:	Clemens Ladisch <clemens@ladisch.de>
 L:	linux-hwmon@vger.kernel.org
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 505c676..2214678 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -208,4 +208,6 @@ source "drivers/tee/Kconfig"
 
 source "drivers/mux/Kconfig"
 
+source "drivers/jtag/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index dfdcda0..6a2059b 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -182,3 +182,4 @@ obj-$(CONFIG_FPGA)		+= fpga/
 obj-$(CONFIG_FSI)		+= fsi/
 obj-$(CONFIG_TEE)		+= tee/
 obj-$(CONFIG_MULTIPLEXER)	+= mux/
+obj-$(CONFIG_JTAG)		+= jtag/
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
new file mode 100644
index 0000000..0fad1a3
--- /dev/null
+++ b/drivers/jtag/Kconfig
@@ -0,0 +1,16 @@
+menuconfig JTAG
+	tristate "JTAG support"
+	---help---
+	  This provides basic core functionality support for jtag class devices
+	  Hardware equipped with JTAG microcontroller which can be built
+	  on top of this drivers. Driver exposes the set of IOCTL to the
+	  user space for:
+	  SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
+	  SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
+	  RUNTEST (Forces IEEE 1149.1 bus to a run state for specified
+	  number of clocks).
+
+	  If you want this support, you should say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called jtag.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
new file mode 100644
index 0000000..af37493
--- /dev/null
+++ b/drivers/jtag/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_JTAG)		+= jtag.o
diff --git a/drivers/jtag/jtag.c b/drivers/jtag/jtag.c
new file mode 100644
index 0000000..39cbce9
--- /dev/null
+++ b/drivers/jtag/jtag.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+// drivers/jtag/jtag.c
+//
+// Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define JTAG_NAME	"jtag0"
+#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 5)
+
+struct jtag {
+	struct miscdevice miscdev;
+	struct device *dev;
+	const struct jtag_ops *ops;
+	int id;
+	bool opened;
+	struct mutex open_lock;
+	unsigned long priv[0];
+};
+
+static DEFINE_IDA(jtag_ida);
+
+void *jtag_priv(struct jtag *jtag)
+{
+	return jtag->priv;
+}
+EXPORT_SYMBOL_GPL(jtag_priv);
+
+static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct jtag *jtag = file->private_data;
+	struct jtag_run_test_idle idle;
+	struct jtag_xfer xfer;
+	u8 *xfer_data;
+	u32 data_size;
+	u32 value;
+	int err;
+
+	if (!arg)
+		return -EINVAL;
+
+	switch (cmd) {
+	case JTAG_GIOCFREQ:
+
+		if (jtag->ops->freq_get)
+			err = jtag->ops->freq_get(jtag, &value);
+		else
+			err = -EOPNOTSUPP;
+		if (err)
+			break;
+
+		if (put_user(value, (__u32 *)arg))
+			err = -EFAULT;
+		break;
+
+	case JTAG_SIOCFREQ:
+		if (get_user(value, (__u32 *)arg))
+			return -EFAULT;
+		if (value == 0)
+			return -EINVAL;
+
+		if (jtag->ops->freq_set)
+			err = jtag->ops->freq_set(jtag, value);
+		else
+			err = -EOPNOTSUPP;
+		break;
+
+	case JTAG_IOCRUNTEST:
+		if (copy_from_user(&idle, (void *)arg,
+				   sizeof(struct jtag_run_test_idle)))
+			return -EFAULT;
+
+		if (idle.endstate > JTAG_STATE_PAUSEDR)
+			return -EINVAL;
+
+		if (jtag->ops->idle)
+			err = jtag->ops->idle(jtag, &idle);
+		else
+			err = -EOPNOTSUPP;
+		break;
+
+	case JTAG_IOCXFER:
+		if (copy_from_user(&xfer, (void *)arg,
+				   sizeof(struct jtag_xfer)))
+			return -EFAULT;
+
+		if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
+			return -EINVAL;
+
+		if (xfer.type > JTAG_SDR_XFER)
+			return -EINVAL;
+
+		if (xfer.direction > JTAG_WRITE_XFER)
+			return -EINVAL;
+
+		if (xfer.endstate > JTAG_STATE_PAUSEDR)
+			return -EINVAL;
+
+		data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
+		xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
+
+		if (!xfer_data)
+			return -EFAULT;
+
+		if (jtag->ops->xfer) {
+			err = jtag->ops->xfer(jtag, &xfer, xfer_data);
+		} else {
+			kfree(xfer_data);
+			return -EOPNOTSUPP;
+		}
+
+		if (err) {
+			kfree(xfer_data);
+			return -EFAULT;
+		}
+
+		err = copy_to_user(u64_to_user_ptr(xfer.tdio),
+				   (void *)(xfer_data), data_size);
+
+		if (err) {
+			kfree(xfer_data);
+			return -EFAULT;
+		}
+
+		kfree(xfer_data);
+		if (copy_to_user((void *)arg, &xfer, sizeof(struct jtag_xfer)))
+			return -EFAULT;
+		break;
+
+	case JTAG_GIOCSTATUS:
+		if (jtag->ops->status_get)
+			err = jtag->ops->status_get(jtag, &value);
+		else
+			err = -EOPNOTSUPP;
+		if (err)
+			break;
+
+		err = put_user(value, (__u32 *)arg);
+		if (err)
+			err = -EFAULT;
+		break;
+	case JTAG_SIOCMODE:
+		if (get_user(value, (__u32 *)arg))
+			return -EFAULT;
+		if (value == 0)
+			return -EINVAL;
+
+		if (jtag->ops->mode_set)
+			err = jtag->ops->mode_set(jtag, value);
+		else
+			err = -EOPNOTSUPP;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return err;
+}
+
+static int jtag_open(struct inode *inode, struct file *file)
+{
+	struct jtag *jtag = container_of(file->private_data, struct jtag,
+					 miscdev);
+
+	if (mutex_lock_interruptible(&jtag->open_lock))
+		return -ERESTARTSYS;
+
+	if (jtag->opened) {
+		mutex_unlock(&jtag->open_lock);
+		return -EINVAL;
+	}
+
+	nonseekable_open(inode, file);
+	file->private_data = jtag;
+	jtag->opened = true;
+	mutex_unlock(&jtag->open_lock);
+	return 0;
+}
+
+static int jtag_release(struct inode *inode, struct file *file)
+{
+	struct jtag *jtag = file->private_data;
+
+	mutex_lock(&jtag->open_lock);
+	jtag->opened = false;
+	mutex_unlock(&jtag->open_lock);
+	return 0;
+}
+
+static const struct file_operations jtag_fops = {
+	.owner		= THIS_MODULE,
+	.open		= jtag_open,
+	.release	= jtag_release,
+	.llseek		= noop_llseek,
+	.unlocked_ioctl = jtag_ioctl,
+};
+
+struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops)
+{
+	struct jtag *jtag;
+
+	jtag = kzalloc(sizeof(*jtag) + round_up(priv_size, ARCH_DMA_MINALIGN),
+		       GFP_KERNEL);
+	if (!jtag)
+		return NULL;
+
+	jtag->ops = ops;
+	return jtag;
+}
+EXPORT_SYMBOL_GPL(jtag_alloc);
+
+void jtag_free(struct jtag *jtag)
+{
+	kfree(jtag);
+}
+EXPORT_SYMBOL_GPL(jtag_free);
+
+int jtag_register(struct jtag *jtag)
+{
+	char *name;
+	int err;
+	int id;
+
+	id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	jtag->id = id;
+
+	name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
+	if (!name) {
+		err = -ENOMEM;
+		goto err_jtag_alloc;
+	}
+
+	err = snprintf(name, MAX_JTAG_NAME_LEN, "jtag%d", id);
+	if (err < 0)
+		goto err_jtag_name;
+
+	mutex_init(&jtag->open_lock);
+	jtag->miscdev.fops =  &jtag_fops;
+	jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
+	jtag->miscdev.name = name;
+
+	err = misc_register(&jtag->miscdev);
+	if (err)
+		dev_err(jtag->dev, "Unable to register device\n");
+	else
+		return 0;
+	jtag->opened = false;
+
+err_jtag_name:
+	kfree(name);
+err_jtag_alloc:
+	ida_simple_remove(&jtag_ida, id);
+	return err;
+}
+EXPORT_SYMBOL_GPL(jtag_register);
+
+void jtag_unregister(struct jtag *jtag)
+{
+	misc_deregister(&jtag->miscdev);
+	kfree(jtag->miscdev.name);
+	ida_simple_remove(&jtag_ida, jtag->id);
+}
+EXPORT_SYMBOL_GPL(jtag_unregister);
+
+static void __exit jtag_exit(void)
+{
+	ida_destroy(&jtag_ida);
+}
+
+module_exit(jtag_exit);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("Generic jtag support");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/jtag.h b/include/linux/jtag.h
new file mode 100644
index 0000000..312c641
--- /dev/null
+++ b/include/linux/jtag.h
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/linux/jtag.h - JTAG class driver
+//
+// Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#ifndef __JTAG_H
+#define __JTAG_H
+
+#include <uapi/linux/jtag.h>
+
+#ifndef ARCH_DMA_MINALIGN
+#define ARCH_DMA_MINALIGN 1
+#endif
+
+#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
+
+#define JTAG_MAX_XFER_DATA_LEN 65535
+
+struct jtag;
+/**
+ * struct jtag_ops - callbacks for jtag control functions:
+ *
+ * @freq_get: get frequency function. Filled by device driver
+ * @freq_set: set frequency function. Filled by device driver
+ * @status_get: set status function. Filled by device driver
+ * @idle: set JTAG to idle state function. Filled by device driver
+ * @xfer: send JTAG xfer function. Filled by device 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 (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
+	int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
+	int (*mode_set)(struct jtag *jtag, u32 mode_mask);
+};
+
+void *jtag_priv(struct jtag *jtag);
+int jtag_register(struct jtag *jtag);
+void jtag_unregister(struct jtag *jtag);
+struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops);
+void jtag_free(struct jtag *jtag);
+
+#endif /* __JTAG_H */
diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
new file mode 100644
index 0000000..cda2520
--- /dev/null
+++ b/include/uapi/linux/jtag.h
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+// include/uapi/linux/jtag.h - JTAG class driver uapi
+//
+// Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#ifndef __UAPI_LINUX_JTAG_H
+#define __UAPI_LINUX_JTAG_H
+
+#include <linux/types.h>
+/*
+ * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived or bitbang
+ * mode. This is bitmask param of ioctl JTAG_SIOCMODE command
+ */
+#define  JTAG_XFER_HW_MODE 1
+
+/**
+ * enum jtag_endstate:
+ *
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ */
+enum jtag_endstate {
+	JTAG_STATE_IDLE,
+	JTAG_STATE_PAUSEIR,
+	JTAG_STATE_PAUSEDR,
+};
+
+/**
+ * enum jtag_xfer_type:
+ *
+ * @JTAG_SIR_XFER: SIR transfer
+ * @JTAG_SDR_XFER: SDR transfer
+ */
+enum jtag_xfer_type {
+	JTAG_SIR_XFER,
+	JTAG_SDR_XFER,
+};
+
+/**
+ * enum jtag_xfer_direction:
+ *
+ * @JTAG_READ_XFER: read transfer
+ * @JTAG_WRITE_XFER: write transfer
+ */
+enum jtag_xfer_direction {
+	JTAG_READ_XFER,
+	JTAG_WRITE_XFER,
+};
+
+/**
+ * struct jtag_run_test_idle - forces JTAG state machine to
+ * RUN_TEST/IDLE 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 represents interface to JTAG device for jtag idle
+ * execution.
+ */
+struct jtag_run_test_idle {
+	__u8	reset;
+	__u8	endstate;
+	__u8	tck;
+};
+
+/**
+ * struct jtag_xfer - jtag xfer:
+ *
+ * @type: transfer type
+ * @direction: xfer direction
+ * @length: xfer bits len
+ * @tdio : xfer data array
+ * @endir: xfer end state
+ *
+ * Structure represents interface to JTAG device for jtag sdr xfer
+ * execution.
+ */
+struct jtag_xfer {
+	__u8	type;
+	__u8	direction;
+	__u8	endstate;
+	__u32	length;
+	__u64	tdio;
+};
+
+/* ioctl interface */
+#define __JTAG_IOCTL_MAGIC	0xb2
+
+#define JTAG_IOCRUNTEST	_IOW(__JTAG_IOCTL_MAGIC, 0,\
+			     struct jtag_run_test_idle)
+#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_endstate)
+#define JTAG_SIOCMODE	_IOW(__JTAG_IOCTL_MAGIC, 5, unsigned int)
+
+#define JTAG_FIRST_MINOR 0
+#define JTAG_MAX_DEVICES 32
+
+#endif /* __UAPI_LINUX_JTAG_H */
-- 
1.7.1

[patch v15 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver

[Oleksandr Shamray]

Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller.

Driver implements the following jtag ops:
- freq_get;
- freq_set;
- status_get;
- idle;
- xfer;

It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
---
v14->v15
Comments pointed by Joel Stanley <joel.stan@gmail.com>
- Add ARCH_ASPEED || COMPILE_TEST to Kconfig
- remove unused offset variable
- remove "aspeed_jtag" from dev_err and dev_dbg messages
- change clk_prepare_enable initialisation order

v13->v14
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change style of head block comment from /**/ to //

v12->v13
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change jtag-aspeed.c licence type to
  SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
  and reorder line with license in description
Comments pointed by Kun Yi <kunyi@google.com>
- Changed capability check for aspeed,ast2400-jtag/ast200-jtag

v11->v12
Comments pointed by Chip Bilbrey <chip@bilbrey.org>
- Remove access mode from xfer and idle transactions
- Add new ioctl JTAG_SIOCMODE for set hw mode

v10->v11
v9->v10
V8->v9
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- add *data parameter to xfer function prototype

v7->v8
Comments pointed by Joel Stanley <joel.stan@gmail.com>
- aspeed_jtag_init replace goto to return;
- change input variables type from __u32 to u32
  in functios freq_get, freq_set, status_get
- change sm_ variables type from char to u8
- in jatg_init add disable clocks on error case
- remove release_mem_region on error case
- remove devm_free_irq on jtag_deinit
- Fix misspelling Disabe/Disable
- Change compatible string to ast2400 and ast2000

v6->v7
Notifications from kbuild test robot <lkp@intel.com>
- Add include <linux/types.h> to jtag-asapeed.c

v5->v6
v4->v5
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Added HAS_IOMEM dependence in Kconfig to avoid
  "undefined reference to `devm_ioremap_resource'" error,
  because in some arch this not supported

v3->v4
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- change transaction pointer tdio type  to __u64
- change internal status type from enum to __u32

v2->v3

v1->v2
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- change license type from GPLv2/BSD to GPLv2

Comments pointed by Neil Armstrong <narmstrong@baylibre.com>
- Add clk_prepare_enable/clk_disable_unprepare in clock init/deinit
- Change .compatible to soc-specific compatible names
  aspeed,aspeed4000-jtag/aspeed5000-jtag
- Added dt-bindings

Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Reorder functions and removed the forward declarations
- Add static const qualifier to state machine states transitions
- Change .compatible to soc-specific compatible names
  aspeed,aspeed4000-jtag/aspeed5000-jtag
- Add dt-bindings

Comments pointed by Randy Dunlap <rdunlap@infradead.org>
- Change module name jtag-aspeed in description in Kconfig

Comments pointed by kbuild test robot <lkp@intel.com>
- Remove invalid include <asm/mach-types.h>
- add resource_size instead of calculation
---
 drivers/jtag/Kconfig       |   14 +
 drivers/jtag/Makefile      |    1 +
 drivers/jtag/jtag-aspeed.c |  774 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 789 insertions(+), 0 deletions(-)
 create mode 100644 drivers/jtag/jtag-aspeed.c

diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
index 0fad1a3..63ddf1f 100644
--- a/drivers/jtag/Kconfig
+++ b/drivers/jtag/Kconfig
@@ -14,3 +14,17 @@ menuconfig JTAG
 
 	  To compile this driver as a module, choose M here: the module will
 	  be called jtag.
+
+menuconfig JTAG_ASPEED
+	tristate "Aspeed SoC JTAG controller support"
+	depends on JTAG && HAS_IOMEM
+	depends on ARCH_ASPEED || COMPILE_TEST
+	---help---
+	  This provides a support for Aspeed JTAG device, equipped on
+	  Aspeed SoC 24xx and 25xx families. Drivers allows programming
+	  of hardware devices, connected to SoC through the JTAG interface.
+
+	  If you want this support, you should say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called jtag-aspeed.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
index af37493..04a855e 100644
--- a/drivers/jtag/Makefile
+++ b/drivers/jtag/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_JTAG)		+= jtag.o
+obj-$(CONFIG_JTAG_ASPEED)	+= jtag-aspeed.o
diff --git a/drivers/jtag/jtag-aspeed.c b/drivers/jtag/jtag-aspeed.c
new file mode 100644
index 0000000..db496a4
--- /dev/null
+++ b/drivers/jtag/jtag-aspeed.c
@@ -0,0 +1,774 @@
+// SPDX-License-Identifier: GPL-2.0
+// drivers/jtag/aspeed-jtag.c
+//
+// Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2017 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define ASPEED_JTAG_DATA		0x00
+#define ASPEED_JTAG_INST		0x04
+#define ASPEED_JTAG_CTRL		0x08
+#define ASPEED_JTAG_ISR			0x0C
+#define ASPEED_JTAG_SW			0x10
+#define ASPEED_JTAG_TCK			0x14
+#define ASPEED_JTAG_EC			0x18
+
+#define ASPEED_JTAG_DATA_MSB		0x01
+#define ASPEED_JTAG_DATA_CHUNK_SIZE	0x20
+
+/* ASPEED_JTAG_CTRL: Engine Control */
+#define ASPEED_JTAG_CTL_ENG_EN		BIT(31)
+#define ASPEED_JTAG_CTL_ENG_OUT_EN	BIT(30)
+#define ASPEED_JTAG_CTL_FORCE_TMS	BIT(29)
+#define ASPEED_JTAG_CTL_INST_LEN(x)	((x) << 20)
+#define ASPEED_JTAG_CTL_LASPEED_INST	BIT(17)
+#define ASPEED_JTAG_CTL_INST_EN		BIT(16)
+#define ASPEED_JTAG_CTL_DR_UPDATE	BIT(10)
+#define ASPEED_JTAG_CTL_DATA_LEN(x)	((x) << 4)
+#define ASPEED_JTAG_CTL_LASPEED_DATA	BIT(1)
+#define ASPEED_JTAG_CTL_DATA_EN		BIT(0)
+
+/* ASPEED_JTAG_ISR : Interrupt status and enable */
+#define ASPEED_JTAG_ISR_INST_PAUSE	BIT(19)
+#define ASPEED_JTAG_ISR_INST_COMPLETE	BIT(18)
+#define ASPEED_JTAG_ISR_DATA_PAUSE	BIT(17)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE	BIT(16)
+#define ASPEED_JTAG_ISR_INST_PAUSE_EN	BIT(3)
+#define ASPEED_JTAG_ISR_INST_COMPLETE_EN BIT(2)
+#define ASPEED_JTAG_ISR_DATA_PAUSE_EN	BIT(1)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE_EN BIT(0)
+#define ASPEED_JTAG_ISR_INT_EN_MASK	GENMASK(3, 0)
+#define ASPEED_JTAG_ISR_INT_MASK	GENMASK(19, 16)
+
+/* ASPEED_JTAG_SW : Software Mode and Status */
+#define ASPEED_JTAG_SW_MODE_EN		BIT(19)
+#define ASPEED_JTAG_SW_MODE_TCK		BIT(18)
+#define ASPEED_JTAG_SW_MODE_TMS		BIT(17)
+#define ASPEED_JTAG_SW_MODE_TDIO	BIT(16)
+
+/* ASPEED_JTAG_TCK : TCK Control */
+#define ASPEED_JTAG_TCK_DIVISOR_MASK	GENMASK(10, 0)
+#define ASPEED_JTAG_TCK_GET_DIV(x)	((x) & ASPEED_JTAG_TCK_DIVISOR_MASK)
+
+/* ASPEED_JTAG_EC : Controller set for go to IDLE */
+#define ASPEED_JTAG_EC_GO_IDLE		BIT(0)
+
+#define ASPEED_JTAG_IOUT_LEN(len)	(ASPEED_JTAG_CTL_ENG_EN |\
+					 ASPEED_JTAG_CTL_ENG_OUT_EN |\
+					 ASPEED_JTAG_CTL_INST_LEN(len))
+
+#define ASPEED_JTAG_DOUT_LEN(len)	(ASPEED_JTAG_CTL_ENG_EN |\
+					 ASPEED_JTAG_CTL_ENG_OUT_EN |\
+					 ASPEED_JTAG_CTL_DATA_LEN(len))
+
+#define ASPEED_JTAG_TCK_WAIT		10
+#define ASPEED_JTAG_RESET_CNTR		10
+
+#define ASPEED_JTAG_NAME		"jtag-aspeed"
+
+struct aspeed_jtag {
+	void __iomem			*reg_base;
+	struct device			*dev;
+	struct clk			*pclk;
+	enum jtag_endstate		status;
+	int				irq;
+	u32				flag;
+	wait_queue_head_t		jtag_wq;
+	u32				mode;
+};
+
+static char *end_status_str[] = {"idle", "ir pause", "drpause"};
+
+static u32 aspeed_jtag_read(struct aspeed_jtag *aspeed_jtag, u32 reg)
+{
+	return readl(aspeed_jtag->reg_base + reg);
+}
+
+static void
+aspeed_jtag_write(struct aspeed_jtag *aspeed_jtag, u32 val, u32 reg)
+{
+	writel(val, aspeed_jtag->reg_base + reg);
+}
+
+static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+	unsigned long apb_frq;
+	u32 tck_val;
+	u16 div;
+
+	apb_frq = clk_get_rate(aspeed_jtag->pclk);
+	div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 : (apb_frq / freq);
+	tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+	aspeed_jtag_write(aspeed_jtag,
+			  (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,
+			  ASPEED_JTAG_TCK);
+	return 0;
+}
+
+static int aspeed_jtag_freq_get(struct jtag *jtag, u32 *frq)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+	u32 pclk;
+	u32 tck;
+
+	pclk = clk_get_rate(aspeed_jtag->pclk);
+	tck = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+	*frq = pclk / (ASPEED_JTAG_TCK_GET_DIV(tck) + 1);
+
+	return 0;
+}
+
+static int aspeed_jtag_mode_set(struct jtag *jtag, u32 mode)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+	aspeed_jtag->mode = mode;
+	return 0;
+}
+
+static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, int cnt)
+{
+	int i;
+
+	for (i = 0; i < cnt; i++)
+		aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);
+}
+
+static char aspeed_jtag_tck_cycle(struct aspeed_jtag *aspeed_jtag,
+				  u8 tms, u8 tdi)
+{
+	char tdo = 0;
+
+	/* TCK = 0 */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  (tms * ASPEED_JTAG_SW_MODE_TMS) |
+			  (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+	aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+	/* TCK = 1 */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TCK |
+			  (tms * ASPEED_JTAG_SW_MODE_TMS) |
+			  (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+	if (aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW) &
+	    ASPEED_JTAG_SW_MODE_TDIO)
+		tdo = 1;
+
+	aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+	/* TCK = 0 */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  (tms * ASPEED_JTAG_SW_MODE_TMS) |
+			  (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+	return tdo;
+}
+
+static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_INST_PAUSE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE;
+}
+
+static void
+aspeed_jtag_wait_instruction_complete(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_INST_COMPLETE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_COMPLETE;
+}
+
+static void
+aspeed_jtag_wait_data_pause_complete(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_DATA_PAUSE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_PAUSE;
+}
+
+static void aspeed_jtag_wait_data_complete(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_DATA_COMPLETE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_COMPLETE;
+}
+
+static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag, const u8 *tms,
+				 int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0);
+}
+
+static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag *aspeed_jtag,
+					 struct jtag_run_test_idle *runtest)
+{
+	static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};
+	static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};
+	static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0};
+	static const u8 sm_idle_drpause[] = {1, 0, 1, 0};
+	static const u8 sm_pause_idle[] = {1, 1, 0};
+	int i;
+
+	/* SW mode from idle/pause-> to pause/idle */
+	if (runtest->reset) {
+		for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)
+			aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);
+	}
+
+	switch (aspeed_jtag->status) {
+	case JTAG_STATE_IDLE:
+		switch (runtest->endstate) {
+		case JTAG_STATE_PAUSEIR:
+			/* ->DRSCan->IRSCan->IRCap->IRExit1->PauseIR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_irpause,
+					     sizeof(sm_idle_irpause));
+
+			aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+			break;
+		case JTAG_STATE_PAUSEDR:
+			/* ->DRSCan->DRCap->DRExit1->PauseDR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_drpause,
+					     sizeof(sm_idle_drpause));
+
+			aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+			break;
+		case JTAG_STATE_IDLE:
+			/* IDLE */
+			aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+			aspeed_jtag->status = JTAG_STATE_IDLE;
+			break;
+		default:
+			break;
+		}
+		break;
+
+	case JTAG_STATE_PAUSEIR:
+	/* Fall-through */
+	case JTAG_STATE_PAUSEDR:
+		/* From IR/DR Pause */
+		switch (runtest->endstate) {
+		case JTAG_STATE_PAUSEIR:
+			/*
+			 * to Exit2 IR/DR->Updt IR/DR->DRSCan->IRSCan->IRCap->
+			 * IRExit1->PauseIR
+			 */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_irpause,
+					     sizeof(sm_pause_irpause));
+
+			aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+			break;
+		case JTAG_STATE_PAUSEDR:
+			/*
+			 * to Exit2 IR/DR->Updt IR/DR->DRSCan->DRCap->
+			 * DRExit1->PauseDR
+			 */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_drpause,
+					     sizeof(sm_pause_drpause));
+			aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+			break;
+		case JTAG_STATE_IDLE:
+			/* to Exit2 IR/DR->Updt IR/DR->IDLE */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+					     sizeof(sm_pause_idle));
+			aspeed_jtag->status = JTAG_STATE_IDLE;
+			break;
+		default:
+			break;
+		}
+		break;
+
+	default:
+		dev_err(aspeed_jtag->dev, "aspeed_jtag_run_test_idle error\n");
+		break;
+	}
+
+	/* Stay on IDLE for at least  TCK cycle */
+	for (i = 0; i < runtest->tck; i++)
+		aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+}
+
+/**
+ * aspeed_jtag_run_test_idle:
+ * JTAG reset: generates at least 9 TMS high and 1 TMS low to force
+ * devices into Run-Test/Idle State.
+ */
+static int aspeed_jtag_idle(struct jtag *jtag,
+			    struct jtag_run_test_idle *runtest)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+	dev_dbg(aspeed_jtag->dev, "runtest, status:%d, mode:%s, state:%s, reset:%d, tck:%d\n",
+		aspeed_jtag->status,
+		aspeed_jtag->mode & JTAG_XFER_HW_MODE ? "HW" : "SW",
+		end_status_str[runtest->endstate], runtest->reset,
+		runtest->tck);
+
+	if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
+		aspeed_jtag_run_test_idle_sw(aspeed_jtag, runtest);
+		return 0;
+	}
+
+	/* Disable sw mode */
+	aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+	/* x TMS high + 1 TMS low */
+	if (runtest->reset)
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+				  ASPEED_JTAG_CTL_ENG_OUT_EN |
+				  ASPEED_JTAG_CTL_FORCE_TMS, ASPEED_JTAG_CTRL);
+	else
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,
+				  ASPEED_JTAG_EC);
+
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+	aspeed_jtag->status = JTAG_STATE_IDLE;
+	return 0;
+}
+
+static void aspeed_jtag_xfer_sw(struct aspeed_jtag *aspeed_jtag,
+				struct jtag_xfer *xfer, unsigned long *data)
+{
+	unsigned long remain_xfer = xfer->length;
+	unsigned long shift_bits = 0;
+	unsigned long index = 0;
+	unsigned long tdi;
+	char          tdo;
+
+	if (xfer->direction == JTAG_READ_XFER)
+		tdi = UINT_MAX;
+	else
+		tdi = data[index];
+
+	while (remain_xfer > 1) {
+		tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 0,
+					    tdi & ASPEED_JTAG_DATA_MSB);
+		data[index] |= tdo << (shift_bits %
+					    ASPEED_JTAG_DATA_CHUNK_SIZE);
+
+		tdi >>= 1;
+		shift_bits++;
+		remain_xfer--;
+
+		if (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE == 0) {
+			dev_dbg(aspeed_jtag->dev, "R/W data[%lu]:%lx\n",
+				index, data[index]);
+
+			tdo = 0;
+			index++;
+
+			if (xfer->direction == JTAG_READ_XFER)
+				tdi = UINT_MAX;
+			else
+				tdi = data[index];
+		}
+	}
+
+	tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi & ASPEED_JTAG_DATA_MSB);
+	data[index] |= tdo << (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE);
+}
+
+static void aspeed_jtag_xfer_push_data(struct aspeed_jtag *aspeed_jtag,
+				       enum jtag_xfer_type type, u32 bits_len)
+{
+	dev_dbg(aspeed_jtag->dev, "shift bits %d\n", bits_len);
+
+	if (type == JTAG_SIR_XFER) {
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_IOUT_LEN(bits_len),
+				  ASPEED_JTAG_CTRL);
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+				  ASPEED_JTAG_CTL_INST_EN, ASPEED_JTAG_CTRL);
+	} else {
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len),
+				  ASPEED_JTAG_CTRL);
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+				  ASPEED_JTAG_CTL_DATA_EN, ASPEED_JTAG_CTRL);
+	}
+}
+
+static void aspeed_jtag_xfer_push_data_last(struct aspeed_jtag *aspeed_jtag,
+					    enum jtag_xfer_type type,
+					    u32 shift_bits,
+					    enum jtag_endstate endstate)
+{
+	if (endstate != JTAG_STATE_IDLE) {
+		if (type == JTAG_SIR_XFER) {
+			dev_dbg(aspeed_jtag->dev, "IR Keep Pause\n");
+
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits),
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_INST_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_instruction_pause(aspeed_jtag);
+		} else {
+			dev_dbg(aspeed_jtag->dev, "DR Keep Pause\n");
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_DR_UPDATE,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_DR_UPDATE |
+					  ASPEED_JTAG_CTL_DATA_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_data_pause_complete(aspeed_jtag);
+		}
+	} else {
+		if (type == JTAG_SIR_XFER) {
+			dev_dbg(aspeed_jtag->dev, "IR go IDLE\n");
+
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_INST,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_INST |
+					  ASPEED_JTAG_CTL_INST_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_instruction_complete(aspeed_jtag);
+		} else {
+			dev_dbg(aspeed_jtag->dev, "DR go IDLE\n");
+
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_DATA,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_DATA |
+					  ASPEED_JTAG_CTL_DATA_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_data_complete(aspeed_jtag);
+		}
+	}
+}
+
+static void aspeed_jtag_xfer_hw(struct aspeed_jtag *aspeed_jtag,
+				struct jtag_xfer *xfer, unsigned long *data)
+{
+	unsigned long remain_xfer = xfer->length;
+	unsigned long index = 0;
+	char shift_bits;
+	u32 data_reg;
+
+	data_reg = xfer->type == JTAG_SIR_XFER ?
+		   ASPEED_JTAG_INST : ASPEED_JTAG_DATA;
+	while (remain_xfer) {
+		if (xfer->direction == JTAG_WRITE_XFER) {
+			dev_dbg(aspeed_jtag->dev, "W dr->dr_data[%lu]:%lx\n",
+				index, data[index]);
+
+			aspeed_jtag_write(aspeed_jtag, data[index], data_reg);
+		} else {
+			aspeed_jtag_write(aspeed_jtag, 0, data_reg);
+		}
+
+		if (remain_xfer > ASPEED_JTAG_DATA_CHUNK_SIZE) {
+			shift_bits = ASPEED_JTAG_DATA_CHUNK_SIZE;
+
+			/*
+			 * Read bytes were not equals to column length
+			 * and go to Pause-DR
+			 */
+			aspeed_jtag_xfer_push_data(aspeed_jtag, xfer->type,
+						   shift_bits);
+		} else {
+			/*
+			 * Read bytes equals to column length =>
+			 * Update-DR
+			 */
+			shift_bits = remain_xfer;
+			aspeed_jtag_xfer_push_data_last(aspeed_jtag, xfer->type,
+							shift_bits,
+							xfer->endstate);
+		}
+
+		if (xfer->direction == JTAG_READ_XFER) {
+			if (shift_bits < ASPEED_JTAG_DATA_CHUNK_SIZE) {
+				data[index] = aspeed_jtag_read(aspeed_jtag,
+							       data_reg);
+
+				data[index] >>= ASPEED_JTAG_DATA_CHUNK_SIZE -
+								shift_bits;
+			} else {
+				data[index] = aspeed_jtag_read(aspeed_jtag,
+							       data_reg);
+			}
+			dev_dbg(aspeed_jtag->dev, "R dr->dr_data[%lu]:%lx\n",
+				index, data[index]);
+		}
+
+		remain_xfer = remain_xfer - shift_bits;
+		index++;
+		dev_dbg(aspeed_jtag->dev, "remain_xfer %lu\n", remain_xfer);
+	}
+}
+
+static int aspeed_jtag_xfer(struct jtag *jtag, struct jtag_xfer *xfer,
+			    u8 *xfer_data)
+{
+	static const u8 sm_update_shiftir[] = {1, 1, 0, 0};
+	static const u8 sm_update_shiftdr[] = {1, 0, 0};
+	static const u8 sm_pause_idle[] = {1, 1, 0};
+	static const u8 sm_pause_update[] = {1, 1};
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+	unsigned long *data = (unsigned long *)xfer_data;
+	unsigned long remain_xfer = xfer->length;
+	char dbg_str[256];
+	int pos = 0;
+	int i;
+
+	for (i = 0; i <= xfer->length / BITS_PER_BYTE; i++) {
+		pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos,
+				"0x%02x ", xfer_data[i]);
+	}
+
+	dev_dbg(aspeed_jtag->dev, " %s %s xfer, mode:%s, END:%d, len:%lu, TDI[%s]\n",
+		xfer->type == JTAG_SIR_XFER ? "SIR" : "SDR",
+		xfer->direction == JTAG_READ_XFER ? "READ" : "WRITE",
+		aspeed_jtag->mode & JTAG_XFER_HW_MODE ? "HW" : "SW",
+		xfer->endstate, remain_xfer, dbg_str);
+
+	if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
+		/* SW mode */
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+				  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+		if (aspeed_jtag->status != JTAG_STATE_IDLE) {
+			/*IR/DR Pause->Exit2 IR / DR->Update IR /DR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_update,
+					     sizeof(sm_pause_update));
+		}
+
+		if (xfer->type == JTAG_SIR_XFER)
+			/* ->IRSCan->CapIR->ShiftIR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftir,
+					     sizeof(sm_update_shiftir));
+		else
+			/* ->DRScan->DRCap->DRShift */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftdr,
+					     sizeof(sm_update_shiftdr));
+
+		aspeed_jtag_xfer_sw(aspeed_jtag, xfer, data);
+
+		/* DIPause/DRPause */
+		aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+
+		if (xfer->endstate == JTAG_STATE_IDLE) {
+			/* ->DRExit2->DRUpdate->IDLE */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+					     sizeof(sm_pause_idle));
+		}
+	} else {
+		/* hw mode */
+		aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+		aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);
+	}
+
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+	aspeed_jtag->status = xfer->endstate;
+	return 0;
+}
+
+static int aspeed_jtag_status_get(struct jtag *jtag, u32 *status)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+	*status = aspeed_jtag->status;
+	return 0;
+}
+
+static irqreturn_t aspeed_jtag_interrupt(s32 this_irq, void *dev_id)
+{
+	struct aspeed_jtag *aspeed_jtag = dev_id;
+	irqreturn_t ret;
+	u32 status;
+
+	status = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_ISR);
+	dev_dbg(aspeed_jtag->dev, "status %x\n", status);
+
+	if (status & ASPEED_JTAG_ISR_INT_MASK) {
+		aspeed_jtag_write(aspeed_jtag,
+				  (status & ASPEED_JTAG_ISR_INT_MASK)
+				  | (status & ASPEED_JTAG_ISR_INT_EN_MASK),
+				  ASPEED_JTAG_ISR);
+		aspeed_jtag->flag |= status & ASPEED_JTAG_ISR_INT_MASK;
+	}
+
+	if (aspeed_jtag->flag) {
+		wake_up_interruptible(&aspeed_jtag->jtag_wq);
+		ret = IRQ_HANDLED;
+	} else {
+		dev_err(aspeed_jtag->dev, "irq status:%x\n",
+			status);
+		ret = IRQ_NONE;
+	}
+	return ret;
+}
+
+int aspeed_jtag_init(struct platform_device *pdev,
+		     struct aspeed_jtag *aspeed_jtag)
+{
+	struct resource *res;
+	int err;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	aspeed_jtag->reg_base = devm_ioremap_resource(aspeed_jtag->dev, res);
+	if (IS_ERR(aspeed_jtag->reg_base))
+		return -ENOMEM;
+
+	aspeed_jtag->pclk = devm_clk_get(aspeed_jtag->dev, NULL);
+	if (IS_ERR(aspeed_jtag->pclk)) {
+		dev_err(aspeed_jtag->dev, "devm_clk_get failed\n");
+		return PTR_ERR(aspeed_jtag->pclk);
+	}
+
+	aspeed_jtag->irq = platform_get_irq(pdev, 0);
+	if (aspeed_jtag->irq < 0) {
+		dev_err(aspeed_jtag->dev, "no irq specified\n");
+		return -ENOENT;
+	}
+
+	clk_prepare_enable(aspeed_jtag->pclk);
+
+	/* Enable clock */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+			  ASPEED_JTAG_CTL_ENG_OUT_EN, ASPEED_JTAG_CTRL);
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+	err = devm_request_irq(aspeed_jtag->dev, aspeed_jtag->irq,
+			       aspeed_jtag_interrupt, 0,
+			       "aspeed-jtag", aspeed_jtag);
+	if (err) {
+		dev_err(aspeed_jtag->dev, "unable to get IRQ");
+		goto clk_unprep;
+	}
+	dev_dbg(&pdev->dev, "IRQ %d.\n", aspeed_jtag->irq);
+
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_ISR_INST_PAUSE |
+			  ASPEED_JTAG_ISR_INST_COMPLETE |
+			  ASPEED_JTAG_ISR_DATA_PAUSE |
+			  ASPEED_JTAG_ISR_DATA_COMPLETE |
+			  ASPEED_JTAG_ISR_INST_PAUSE_EN |
+			  ASPEED_JTAG_ISR_INST_COMPLETE_EN |
+			  ASPEED_JTAG_ISR_DATA_PAUSE_EN |
+			  ASPEED_JTAG_ISR_DATA_COMPLETE_EN,
+			  ASPEED_JTAG_ISR);
+
+	aspeed_jtag->flag = 0;
+	aspeed_jtag->mode = 0;
+	init_waitqueue_head(&aspeed_jtag->jtag_wq);
+	return 0;
+
+clk_unprep:
+	clk_disable_unprepare(aspeed_jtag->pclk);
+	return err;
+}
+
+int aspeed_jtag_deinit(struct platform_device *pdev,
+		       struct aspeed_jtag *aspeed_jtag)
+{
+	aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_ISR);
+	/* Disable clock */
+	aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_CTRL);
+	clk_disable_unprepare(aspeed_jtag->pclk);
+	return 0;
+}
+
+static const struct jtag_ops aspeed_jtag_ops = {
+	.freq_get = aspeed_jtag_freq_get,
+	.freq_set = aspeed_jtag_freq_set,
+	.status_get = aspeed_jtag_status_get,
+	.idle = aspeed_jtag_idle,
+	.xfer = aspeed_jtag_xfer,
+	.mode_set = aspeed_jtag_mode_set
+};
+
+static int aspeed_jtag_probe(struct platform_device *pdev)
+{
+	struct aspeed_jtag *aspeed_jtag;
+	struct device *dev;
+	struct jtag *jtag;
+	int err;
+
+	dev = &pdev->dev;
+	jtag = jtag_alloc(sizeof(*aspeed_jtag), &aspeed_jtag_ops);
+	if (!jtag)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, jtag);
+	aspeed_jtag = jtag_priv(jtag);
+	aspeed_jtag->dev = &pdev->dev;
+
+	/* Initialize device*/
+	err = aspeed_jtag_init(pdev, aspeed_jtag);
+	if (err)
+		goto err_jtag_init;
+
+	/* Initialize JTAG core structure*/
+	err = jtag_register(jtag);
+	if (err)
+		goto err_jtag_register;
+
+	return 0;
+
+err_jtag_register:
+	aspeed_jtag_deinit(pdev, aspeed_jtag);
+err_jtag_init:
+	jtag_free(jtag);
+	return err;
+}
+
+static int aspeed_jtag_remove(struct platform_device *pdev)
+{
+	struct jtag *jtag;
+
+	jtag = platform_get_drvdata(pdev);
+	aspeed_jtag_deinit(pdev, jtag_priv(jtag));
+	jtag_unregister(jtag);
+	jtag_free(jtag);
+	return 0;
+}
+
+static const struct of_device_id aspeed_jtag_of_match[] = {
+	{ .compatible = "aspeed,ast2400-jtag", },
+	{ .compatible = "aspeed,ast2500-jtag", },
+	{}
+};
+
+static struct platform_driver aspeed_jtag_driver = {
+	.probe = aspeed_jtag_probe,
+	.remove = aspeed_jtag_remove,
+	.driver = {
+		.name = ASPEED_JTAG_NAME,
+		.of_match_table = aspeed_jtag_of_match,
+	},
+};
+module_platform_driver(aspeed_jtag_driver);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("ASPEED JTAG driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.1

[patch v15 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver

[Oleksandr Shamray]

It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.

Signed-off-by: Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Jiri Pirko <jiri-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
v14->v15
v13->v14
v12->v13
v11->v12
v10->v11
v9->v10
v8->v9
v7->v8
Comments pointed by pointed by Joel Stanley <joel.stan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
- Change compatible string to ast2400 and ast2000

V6->v7
Comments pointed by Tobias Klauser <tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org>
 - Fix spell "Doccumentation" -> "Documentation"

v5->v6
Comments pointed by Tobias Klauser <tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org>
- Small nit: s/documentation/Documentation/

v4->v5

V3->v4
Comments pointed by Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
- delete unnecessary "status" and "reg-shift" descriptions in
  bndings file

v2->v3
Comments pointed by Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
- split Aspeed jtag driver and binding to sepatrate patches
- delete unnecessary "status" and "reg-shift" descriptions in
  bndings file
---
 .../devicetree/bindings/jtag/aspeed-jtag.txt       |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt

diff --git a/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
new file mode 100644
index 0000000..8cfc610
--- /dev/null
+++ b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
@@ -0,0 +1,18 @@
+Aspeed JTAG driver for ast2400 and ast2500 SoC
+
+Required properties:
+- compatible:		Should be one of
+      - "aspeed,ast2400-jtag"
+      - "aspeed,ast2500-jtag"
+- reg			contains the offset and length of the JTAG memory
+			region
+- clocks		root clock of bus, should reference the APB clock
+- interrupts		should contain JTAG controller interrupt
+
+Example:
+jtag: jtag@1e6e4000 {
+	compatible = "aspeed,ast2500-jtag";
+	reg = <0x1e6e4000 0x1c>;
+	clocks = <&clk_apb>;
+	interrupts = <43>;
+};
-- 
1.7.1

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[patch v15 4/4] Documentation: jtag: Add ABI documentation

[Oleksandr Shamray]

Added document that describe the ABI for JTAG class drivrer

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
v14->v15
v13->v14
v12->v13
v11->v12
Tobias Klauser <tklauser@distanz.ch>
- rename /Documentation/ABI/testing/jatg-dev -> jtag-dev
- Typo: s/interfase/interface
v10->v11
v9->v10
Fixes added by Oleksandr:
- change jtag-cdev to jtag-dev in documentation
- update Kernel Version and Date in jtag-dev documentation;
v8->v9
v7->v8
v6->v7
Comments pointed by Pavel Machek <pavel@ucw.cz>
- Added jtag-cdev documentation to Documentation/ABI/testing folder
---
 Documentation/ABI/testing/jtag-dev |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/ABI/testing/jtag-dev

diff --git a/Documentation/ABI/testing/jtag-dev b/Documentation/ABI/testing/jtag-dev
new file mode 100644
index 0000000..cab867d
--- /dev/null
+++ b/Documentation/ABI/testing/jtag-dev
@@ -0,0 +1,27 @@
+What:		/dev/jtag[0-9]+
+Date:		October 2017
+KernelVersion:	4.15
+Contact:	oleksandrs@mellanox.com
+Description:
+		The misc device files /dev/jtag* are the interface
+		between JTAG master interface and userspace.
+
+		The ioctl(2)-based ABI is defined and documented in
+		[include/uapi]<linux/jtag.h>.
+
+		The following file operations are supported:
+
+		open(2)
+		The argument flag currently support only one access
+		mode O_RDWR.
+
+		ioctl(2)
+		Initiate various actions.
+		See the inline documentation in [include/uapi]<linux/jtag.h>
+		for descriptions of all ioctls.
+
+		close(2)
+		Stops and free up the I/O contexts that was associated
+		with the file descriptor.
+
+Users:		TBD
\ No newline at end of file
-- 
1.7.1

Re: [patch v15 1/4] drivers: jtag: Add JTAG core driver

[Florian Fainelli]

Le 12/25/17 à 03:53, Oleksandr Shamray a écrit :
> Initial patch for JTAG 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);
> - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
>   number of clocks).
> - SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
> 
> 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

Just some general comment, I am really surprised to see that there is
not a whole lot of generic code, actually, there is none, which tries to
manage the JTAG devices command queue, e.g: ala OpenOCD. All that this
is doing here is create a special character device with a bunch of
custom ioctl(), which means that a lot of code is going to be put within
in individual drivers. Have you given some thoughts on how you would
expand this framework for non ASPEED JTAG adapters? For instance, one
expectation is to see a bit-banged GPIO master, since that's quite
common, what would it look like here? How much code would I have to write?

[snip]

> +
> +void *jtag_priv(struct jtag *jtag)
> +{
> +	return jtag->priv;
> +}
> +EXPORT_SYMBOL_GPL(jtag_priv);

Can't you just create a static inline function in the public header for
that? This is usually what subsystems do, I can understand why you would
not want to expose struct jtag to other parts of the kernel, but still,
this looks ugly, so maybe consider splitting the header between provider
and consumer?

> +
> +static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> +	struct jtag *jtag = file->private_data;
> +	struct jtag_run_test_idle idle;
> +	struct jtag_xfer xfer;
> +	u8 *xfer_data;
> +	u32 data_size;
> +	u32 value;
> +	int err;
> +
> +	if (!arg)
> +		return -EINVAL;
> +
> +	switch (cmd) {
> +	case JTAG_GIOCFREQ:
> +
> +		if (jtag->ops->freq_get)
> +			err = jtag->ops->freq_get(jtag, &value);
> +		else
> +			err = -EOPNOTSUPP;
> +		if (err)
> +			break;
> +
> +		if (put_user(value, (__u32 *)arg))
> +			err = -EFAULT;
> +		break;
> +
> +	case JTAG_SIOCFREQ:
> +		if (get_user(value, (__u32 *)arg))
> +			return -EFAULT;
> +		if (value == 0)
> +			return -EINVAL;
> +
> +		if (jtag->ops->freq_set)
> +			err = jtag->ops->freq_set(jtag, value);
> +		else
> +			err = -EOPNOTSUPP;

You should check that before get_user()

> +		break;
> +
> +	case JTAG_IOCRUNTEST:
> +		if (copy_from_user(&idle, (void *)arg,
> +				   sizeof(struct jtag_run_test_idle)))
> +			return -EFAULT;
> +
> +		if (idle.endstate > JTAG_STATE_PAUSEDR)
> +			return -EINVAL;
> +
> +		if (jtag->ops->idle)
> +			err = jtag->ops->idle(jtag, &idle);
> +		else
> +			err = -EOPNOTSUPP;
> +		break;

Same here.

> +
> +	case JTAG_IOCXFER:
> +		if (copy_from_user(&xfer, (void *)arg,
> +				   sizeof(struct jtag_xfer)))
> +			return -EFAULT;
> +
> +		if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
> +			return -EINVAL;
> +
> +		if (xfer.type > JTAG_SDR_XFER)
> +			return -EINVAL;
> +
> +		if (xfer.direction > JTAG_WRITE_XFER)
> +			return -EINVAL;
> +
> +		if (xfer.endstate > JTAG_STATE_PAUSEDR)
> +			return -EINVAL;
> +
> +		data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
> +		xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
> +
> +		if (!xfer_data)
> +			return -EFAULT;
> +
> +		if (jtag->ops->xfer) {
> +			err = jtag->ops->xfer(jtag, &xfer, xfer_data);
> +		} else {
> +			kfree(xfer_data);
> +			return -EOPNOTSUPP;
> +		}

Why don't you move all of the code here into a function which will make
the error handling consistent? Also, checking whether the jtag adapter
implements ops->xfer should probably be done before you do the
memdup_user().

> +
> +		if (err) {
> +			kfree(xfer_data);
> +			return -EFAULT;
> +		}
> +
> +		err = copy_to_user(u64_to_user_ptr(xfer.tdio),
> +				   (void *)(xfer_data), data_size);
> +
> +		if (err) {
> +			kfree(xfer_data);
> +			return -EFAULT;
> +		}
> +
> +		kfree(xfer_data);
> +		if (copy_to_user((void *)arg, &xfer, sizeof(struct jtag_xfer)))
> +			return -EFAULT;
> +		break;
> +
> +	case JTAG_GIOCSTATUS:
> +		if (jtag->ops->status_get)
> +			err = jtag->ops->status_get(jtag, &value);
> +		else
> +			err = -EOPNOTSUPP;
> +		if (err)
> +			break;
> +
> +		err = put_user(value, (__u32 *)arg);
> +		if (err)
> +			err = -EFAULT;
> +		break;
> +	case JTAG_SIOCMODE:
> +		if (get_user(value, (__u32 *)arg))
> +			return -EFAULT;
> +		if (value == 0)
> +			return -EINVAL;
> +
> +		if (jtag->ops->mode_set)
> +			err = jtag->ops->mode_set(jtag, value);
> +		else
> +			err = -EOPNOTSUPP;
> +		break;

Same here, this can be checked before get_user().

> +
> +	default:
> +		return -EINVAL;
> +	}
> +	return err;
> +}
> +
> +static int jtag_open(struct inode *inode, struct file *file)
> +{
> +	struct jtag *jtag = container_of(file->private_data, struct jtag,
> +					 miscdev);
> +
> +	if (mutex_lock_interruptible(&jtag->open_lock))
> +		return -ERESTARTSYS;
> +
> +	if (jtag->opened) {
> +		mutex_unlock(&jtag->open_lock);
> +		return -EINVAL;

-EBUSY maybe?

> +	}
> +
> +	nonseekable_open(inode, file);
> +	file->private_data = jtag;
> +	jtag->opened = true;
> +	mutex_unlock(&jtag->open_lock);
> +	return 0;
> +}
> +
> +static int jtag_release(struct inode *inode, struct file *file)
> +{
> +	struct jtag *jtag = file->private_data;
> +
> +	mutex_lock(&jtag->open_lock);
> +	jtag->opened = false;
> +	mutex_unlock(&jtag->open_lock);
> +	return 0;
> +}
> +
> +static const struct file_operations jtag_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= jtag_open,
> +	.release	= jtag_release,
> +	.llseek		= noop_llseek,
> +	.unlocked_ioctl = jtag_ioctl,
> +};
> +
> +struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops)
> +{
> +	struct jtag *jtag;
> +
> +	jtag = kzalloc(sizeof(*jtag) + round_up(priv_size, ARCH_DMA_MINALIGN),
> +		       GFP_KERNEL);
> +	if (!jtag)
> +		return NULL;

If you set ARCH_DMA_MINALIGN to 1 when not defined, what is this
achieving that kmalloc() is not already doing?

> +
> +	jtag->ops = ops;
> +	return jtag;
> +}
> +EXPORT_SYMBOL_GPL(jtag_alloc);
> +
> +void jtag_free(struct jtag *jtag)
> +{
> +	kfree(jtag);
> +}
> +EXPORT_SYMBOL_GPL(jtag_free);
> +
> +int jtag_register(struct jtag *jtag)
> +{
> +	char *name;
> +	int err;
> +	int id;
> +
> +	id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
> +	if (id < 0)
> +		return id;
> +
> +	jtag->id = id;
> +
> +	name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
> +	if (!name) {
> +		err = -ENOMEM;
> +		goto err_jtag_alloc;
> +	}

Can't you use jtag->miscdev.dev here to simplify the allocation error
handling?

> +
> +	err = snprintf(name, MAX_JTAG_NAME_LEN, "jtag%d", id);
> +	if (err < 0)
> +		goto err_jtag_name;
> +
> +	mutex_init(&jtag->open_lock);
> +	jtag->miscdev.fops =  &jtag_fops;
> +	jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
> +	jtag->miscdev.name = name;
> +
> +	err = misc_register(&jtag->miscdev);
> +	if (err)
> +		dev_err(jtag->dev, "Unable to register device\n");
> +	else
> +		return 0;
> +	jtag->opened = false;
> +
> +err_jtag_name:
> +	kfree(name);
> +err_jtag_alloc:
> +	ida_simple_remove(&jtag_ida, id);
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(jtag_register);
> +
> +void jtag_unregister(struct jtag *jtag)
> +{
> +	misc_deregister(&jtag->miscdev);
> +	kfree(jtag->miscdev.name);
> +	ida_simple_remove(&jtag_ida, jtag->id);
> +}
> +EXPORT_SYMBOL_GPL(jtag_unregister);
> +
> +static void __exit jtag_exit(void)
> +{
> +	ida_destroy(&jtag_ida);
> +}
> +
> +module_exit(jtag_exit);
> +
> +MODULE_AUTHOR("Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>");
> +MODULE_DESCRIPTION("Generic jtag support");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/jtag.h b/include/linux/jtag.h
> new file mode 100644
> index 0000000..312c641
> --- /dev/null
> +++ b/include/linux/jtag.h
> @@ -0,0 +1,45 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// include/linux/jtag.h - JTAG class driver
> +//
> +// Copyright (c) 2017 Mellanox Technologies. All rights reserved.
> +// Copyright (c) 2017 Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> +
> +#ifndef __JTAG_H
> +#define __JTAG_H
> +
> +#include <uapi/linux/jtag.h>
> +
> +#ifndef ARCH_DMA_MINALIGN
> +#define ARCH_DMA_MINALIGN 1
> +#endif

Why?

> +
> +#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
> +
> +#define JTAG_MAX_XFER_DATA_LEN 65535
> +
> +struct jtag;
> +/**
> + * struct jtag_ops - callbacks for jtag control functions:
> + *
> + * @freq_get: get frequency function. Filled by device driver
> + * @freq_set: set frequency function. Filled by device driver
> + * @status_get: set status function. Filled by device driver
> + * @idle: set JTAG to idle state function. Filled by device driver
> + * @xfer: send JTAG xfer function. Filled by device 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 (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
> +	int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
> +	int (*mode_set)(struct jtag *jtag, u32 mode_mask);
> +};
> +
> +void *jtag_priv(struct jtag *jtag);
> +int jtag_register(struct jtag *jtag);
> +void jtag_unregister(struct jtag *jtag);
> +struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops);
> +void jtag_free(struct jtag *jtag);
> +
> +#endif /* __JTAG_H */
> diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
> new file mode 100644
> index 0000000..cda2520
> --- /dev/null
> +++ b/include/uapi/linux/jtag.h

[snip]

> +struct jtag_xfer {
> +	__u8	type;
> +	__u8	direction;

Can these two be an enum referring to what you defined earlier?

> +	__u8	endstate;
> +	__u32	length;
> +	__u64	tdio;
> +};
-- 
Florian
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Re: [patch v15 0/4] JTAG driver introduction

[Florian Fainelli]

Le 12/25/17 à 03:53, Oleksandr Shamray a écrit :
> When a need raise up to use JTAG interface for system's devices
> programming or CPU debugging, usually the user layer
> application implements jtag protocol by bit-bang or using a 
> proprietary connection to vendor hardware.
> This method can be slow and not generic.
>  
> We propose to implement general JTAG interface and infrastructure
> to communicate with user layer application. In such way, we can
> have the standard JTAG interface core part and separation from
> specific HW implementation.

Well, the framework in its current shape is still extremely simplistic,
therefore leaving a lot of room (read: bugs, inconsistencies) within the
hands of the driver, so while the user-space interface is standard
through the proposed character device, the user experience, likely might
not.

> This allow new capability to debug the CPU or program system's 
> device via BMC without additional devices nor cost. 

If that is the case, should not we leverage the kernel's device driver
model and expect the JTAG framework to create specific devices for the
different pieces of HW discovered on the scan chain? That would also
presumably allow the core JTAG framework to retain the necessary state
changes in order to address one particular device within the scan chain.

> 
> This patch purpose is to add JTAG master core infrastructure by 
> defining new JTAG class and provide generic JTAG interface
> to allow hardware specific drivers to connect this interface.
> This will enable all JTAG drivers to use the common interface
> part and will have separate for hardware implementation.

Let's consider I want to get rid of OpenOCD, or rather, move its driver
interface within the kernel and replace it on the OpenOCD side with a
generic character device interface. I could presumably amortize the
costly operations which are currently I/O and/or system call limiting
when running in user-space, what would it look like with your proposed
framework, have you given some thoughts about that?

Thanks!
-- 
Florian
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Re: [patch v15 1/4] drivers: jtag: Add JTAG core driver

[Jiri Pirko]

Tue, Dec 26, 2017 at 12:09:08AM CET, f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>Le 12/25/17 à 03:53, Oleksandr Shamray a écrit :

[...]

>[snip]
>
>> +
>> +void *jtag_priv(struct jtag *jtag)
>> +{
>> +	return jtag->priv;
>> +}
>> +EXPORT_SYMBOL_GPL(jtag_priv);
>
>Can't you just create a static inline function in the public header for
>that? This is usually what subsystems do, I can understand why you would
>not want to expose struct jtag to other parts of the kernel, but still,
>this looks ugly, so maybe consider splitting the header between provider
>and consumer?

Other subsystems expose the struct. Here, it is intentional to don't
expose the struct, that's why we have this helper. What is ugly about
that? :)

Re: [patch v15 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver

[Joel Stanley]

On Mon, Dec 25, 2017 at 3:53 AM, Oleksandr Shamray
<oleksandrs@mellanox.com> wrote:
> Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller.
>
> Driver implements the following jtag ops:
> - freq_get;
> - freq_set;
> - status_get;
> - idle;
> - xfer;
>
> It has been tested on Mellanox system with BMC equipped with
> Aspeed 2520 SoC for programming CPLD devices.
>
> Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Philippe Ombredanne <pombredanne@nexb.com>

Acked-by: Joel Stanley <joel@jms.id.au>

Cheers,

Joel

Re: [patch v15 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver

[Joel Stanley]

On Mon, Dec 25, 2017 at 3:53 AM, Oleksandr Shamray
<oleksandrs@mellanox.com> wrote:
> It has been tested on Mellanox system with BMC equipped with
> Aspeed 2520 SoC for programming CPLD devices.
>
> Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
> Acked-by: Rob Herring <robh@kernel.org>
> ---
> v14->v15
> v13->v14
> v12->v13
> v11->v12
> v10->v11
> v9->v10
> v8->v9
> v7->v8
> Comments pointed by pointed by Joel Stanley <joel.stan@gmail.com>
> - Change compatible string to ast2400 and ast2000
>
> V6->v7
> Comments pointed by Tobias Klauser <tklauser@distanz.ch>
>  - Fix spell "Doccumentation" -> "Documentation"
>
> v5->v6
> Comments pointed by Tobias Klauser <tklauser@distanz.ch>
> - Small nit: s/documentation/Documentation/
>
> v4->v5
>
> V3->v4
> Comments pointed by Rob Herring <robh@kernel.org>
> - delete unnecessary "status" and "reg-shift" descriptions in
>   bndings file
>
> v2->v3
> Comments pointed by Rob Herring <robh@kernel.org>
> - split Aspeed jtag driver and binding to sepatrate patches
> - delete unnecessary "status" and "reg-shift" descriptions in
>   bndings file
> ---
>  .../devicetree/bindings/jtag/aspeed-jtag.txt       |   18 ++++++++++++++++++
>  1 files changed, 18 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
>
> diff --git a/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
> new file mode 100644
> index 0000000..8cfc610
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
> @@ -0,0 +1,18 @@
> +Aspeed JTAG driver for ast2400 and ast2500 SoC
> +
> +Required properties:
> +- compatible:          Should be one of
> +      - "aspeed,ast2400-jtag"
> +      - "aspeed,ast2500-jtag"
> +- reg                  contains the offset and length of the JTAG memory
> +                       region
> +- clocks               root clock of bus, should reference the APB clock
> +- interrupts           should contain JTAG controller interrupt
> +
> +Example:
> +jtag: jtag@1e6e4000 {
> +       compatible = "aspeed,ast2500-jtag";
> +       reg = <0x1e6e4000 0x1c>;
> +       clocks = <&clk_apb>;

We've now got a proper clock driver upstream. Can you update the
example to match the newly added bindings?

 clocks = <&syscon ASPEED_CLK_APB>;

Cheers,

Joel

Re: [patch v15 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver

[Joel Stanley]

On Thu, Jan 11, 2018 at 9:50 AM, Joel Stanley <joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org> wrote:
> On Mon, Dec 25, 2017 at 3:53 AM, Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> wrote:
>> +jtag: jtag@1e6e4000 {
>> +       compatible = "aspeed,ast2500-jtag";
>> +       reg = <0x1e6e4000 0x1c>;
>> +       clocks = <&clk_apb>;
>
> We've now got a proper clock driver upstream. Can you update the
> example to match the newly added bindings?
>
>  clocks = <&syscon ASPEED_CLK_APB>;
>

I think we need to ensure the reset is deasserted as well. You will need:

 resets = <&syscon ASPEED_RESET_JTAG_MASTER>;

In addition, we need to make sure the reset line is deasserted in the
driver. Take a look at how I did this in the i2c driver:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=edd20e95bca4a5434f264d8ab40d729761479825

+       bus->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
+       if (IS_ERR(bus->rst)) {
+               dev_err(&pdev->dev,
+                       "missing or invalid reset controller device
tree entry");
+               return PTR_ERR(bus->rst);
+       }
+       reset_control_deassert(bus->rst);

Please give this a test with an upstream kernel from a fresh power on.

Cheers,

Joel

RE: [patch v15 1/4] drivers: jtag: Add JTAG core driver

[Oleksandr Shamray]

> -----Original Message-----
> From: Florian Fainelli [mailto:f.fainelli@gmail.com]
> Sent: 26 декабря 2017 г. 1:09
> To: Oleksandr Shamray <oleksandrs@mellanox.com>;
> gregkh@linuxfoundation.org; arnd@arndb.de
> Cc: linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; openbmc@lists.ozlabs.org; joel@jms.id.au;
> jiri@resnulli.us; tklauser@distanz.ch; linux-serial@vger.kernel.org; Vadim
> Pasternak <vadimp@mellanox.com>; system-sw-low-level <system-sw-low-
> level@mellanox.com>; robh+dt@kernel.org; openocd-devel-
> owner@lists.sourceforge.net; linux-api@vger.kernel.org;
> davem@davemloft.net; mchehab@kernel.org; Jiri Pirko
> <jiri@mellanox.com>
> Subject: Re: [patch v15 1/4] drivers: jtag: Add JTAG core driver
> 
> 

[snip]

> > +
> > +	case JTAG_IOCXFER:
> > +		if (copy_from_user(&xfer, (void *)arg,
> > +				   sizeof(struct jtag_xfer)))
> > +			return -EFAULT;
> > +
> > +		if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
> > +			return -EINVAL;
> > +
> > +		if (xfer.type > JTAG_SDR_XFER)
> > +			return -EINVAL;
> > +
> > +		if (xfer.direction > JTAG_WRITE_XFER)
> > +			return -EINVAL;
> > +
> > +		if (xfer.endstate > JTAG_STATE_PAUSEDR)
> > +			return -EINVAL;
> > +
> > +		data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
> > +		xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio),
> data_size);
> > +
> > +		if (!xfer_data)
> > +			return -EFAULT;
> > +
> > +		if (jtag->ops->xfer) {
> > +			err = jtag->ops->xfer(jtag, &xfer, xfer_data);
> > +		} else {
> > +			kfree(xfer_data);
> > +			return -EOPNOTSUPP;
> > +		}
> 
> Why don't you move all of the code here into a function which will make the
> error handling consistent? Also, checking whether the jtag adapter

Greg KH <gregkh@linuxfoundation.org> Say to move all of this insight ioctl 

> implements ops->xfer should probably be done before you do the
> memdup_user().

Yes

> > +		if (err) {
> > +			kfree(xfer_data);
> > +			return -EFAULT;
> > +		}
> > +
> > +		if (jtag->ops->mode_set)
> > +			err = jtag->ops->mode_set(jtag, value);
> > +		else
> > +			err = -EOPNOTSUPP;
> > +		break;
> 
> Same here, this can be checked before get_user().
> 

Yes

> > +	if (jtag->opened) {
> > +		mutex_unlock(&jtag->open_lock);
> > +		return -EINVAL;
> 
> -EBUSY maybe?
> 

Yes


> > +
> > +	jtag = kzalloc(sizeof(*jtag) + round_up(priv_size,
> ARCH_DMA_MINALIGN),
> > +		       GFP_KERNEL);
> > +	if (!jtag)
> > +		return NULL;
> 
> If you set ARCH_DMA_MINALIGN to 1 when not defined, what is this
> achieving that kmalloc() is not already doing?
> 

Removed ARCH_DMA_MINALIGN

> > +
> > +	jtag->ops = ops;
> > +	return jtag;
> > +}
> > +EXPORT_SYMBOL_GPL(jtag_alloc);
> > +
> > +void jtag_free(struct jtag *jtag)
> > +{
> > +	kfree(jtag);
> > +}
> > +EXPORT_SYMBOL_GPL(jtag_free);
> > +
> > +int jtag_register(struct jtag *jtag)
> > +{
> > +	char *name;
> > +	int err;
> > +	int id;
> > +
> > +	id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
> > +	if (id < 0)
> > +		return id;
> > +
> > +	jtag->id = id;
> > +
> > +	name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
> > +	if (!name) {
> > +		err = -ENOMEM;
> > +		goto err_jtag_alloc;
> > +	}
> 
> Can't you use jtag->miscdev.dev here to simplify the allocation error
> handling?
> 

How, what you mean?

> > +#ifndef ARCH_DMA_MINALIGN
> > +#define ARCH_DMA_MINALIGN 1
> > +#endif
> 
> Why?
> 

Not used now, Deleted

> > +#endif /* __JTAG_H */
> > diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h new
> > file mode 100644 index 0000000..cda2520
> > --- /dev/null
> > +++ b/include/uapi/linux/jtag.h
> 
> [snip]
> 
> > +struct jtag_xfer {
> > +	__u8	type;
> > +	__u8	direction;
> 
> Can these two be an enum referring to what you defined earlier?
> 

Greg KH <gregkh@linuxfoundation.org> say:

"All structures that cross the user/kernel boundry have to use the __ type variables.
No "unsigned char", it has to be "__u8", no "unsigned short", it has to be "__u16", and so on.
Also, watch out for your enumerated types, what's the packing end up looking like on these structures?  Have you verified it works with a 64bit kernel and 32bit userspace all correctly?"

So I use __u8 type instead of enum to avoid errors while crossing 64bit kernel and 32bit userspace.

> > +	__u8	endstate;
> > +	__u32	length;
> > +	__u64	tdio;
> > +};
> --
> Florian

Thaks.

Re: [patch v15 4/4] Documentation: jtag: Add ABI documentation

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 2176 bytes --]

On Mon 2017-12-25 13:53:28, Oleksandr Shamray wrote:
> Added document that describe the ABI for JTAG class drivrer
> 
> Signed-off-by: Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Acked-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
> ---
> v14->v15
> v13->v14
> v12->v13
> v11->v12
> Tobias Klauser <tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org>
> - rename /Documentation/ABI/testing/jatg-dev -> jtag-dev
> - Typo: s/interfase/interface
> v10->v11
> v9->v10
> Fixes added by Oleksandr:
> - change jtag-cdev to jtag-dev in documentation
> - update Kernel Version and Date in jtag-dev documentation;
> v8->v9
> v7->v8
> v6->v7
> Comments pointed by Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>
> - Added jtag-cdev documentation to Documentation/ABI/testing folder
> ---
>  Documentation/ABI/testing/jtag-dev |   27 +++++++++++++++++++++++++++
>  1 files changed, 27 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/ABI/testing/jtag-dev
> 
> diff --git a/Documentation/ABI/testing/jtag-dev b/Documentation/ABI/testing/jtag-dev
> new file mode 100644
> index 0000000..cab867d
> --- /dev/null
> +++ b/Documentation/ABI/testing/jtag-dev
> @@ -0,0 +1,27 @@
> +What:		/dev/jtag[0-9]+
> +Date:		October 2017
> +KernelVersion:	4.15
> +Contact:	oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org
> +Description:
> +		The misc device files /dev/jtag* are the interface
> +		between JTAG master interface and userspace.
> +
> +		The ioctl(2)-based ABI is defined and documented in
> +		[include/uapi]<linux/jtag.h>.
> +
> +		The following file operations are supported:
> +
> +		open(2)
> +		The argument flag currently support only one access
> +		mode O_RDWR.
> +
> +		ioctl(2)
> +		Initiate various actions.
> +		See the inline documentation in [include/uapi]<linux/jtag.h>
> +		for descriptions of all ioctls.

Sorry, can we have real docs? I tried to decipher it from jtag.h, but
its not easy. We should have API docs...


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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