diff options
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/Kconfig | 31 | ||||
| -rw-r--r-- | drivers/tty/Makefile | 2 | ||||
| -rw-r--r-- | drivers/tty/n_tracerouter.c | 243 | ||||
| -rw-r--r-- | drivers/tty/n_tracesink.c | 238 | ||||
| -rw-r--r-- | drivers/tty/n_tracesink.h | 36 |
5 files changed, 550 insertions, 0 deletions
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index 3fd7199301b6..bd7cc0527999 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -319,3 +319,34 @@ config N_GSM This line discipline provides support for the GSM MUX protocol and presents the mux as a set of 61 individual tty devices. +config TRACE_ROUTER + tristate "Trace data router for MIPI P1149.7 cJTAG standard" + depends on TRACE_SINK + default n + help + The trace router uses the Linux tty line discipline framework to + route trace data coming from a tty port (say UART for example) to + the trace sink line discipline driver and to another tty port (say + USB). This is part of a solution for the MIPI P1149.7, compact JTAG, + standard, which is for debugging mobile devices. The PTI driver in + drivers/misc/pti.c defines the majority of this MIPI solution. + + You should select this driver if the target kernel is meant for + a mobile device containing a modem. Then you will need to select + "Trace data sink for MIPI P1149.7 cJTAG standard" line discipline + driver. + +config TRACE_SINK + tristate "Trace data sink for MIPI P1149.7 cJTAG standard" + default n + help + The trace sink uses the Linux line discipline framework to receive + trace data coming from the trace router line discipline driver + to a user-defined tty port target, like USB. + This is to provide a way to extract modem trace data on + devices that do not have a PTI HW module, or just need modem + trace data to come out of a different HW output port. + This is part of a solution for the P1149.7, compact JTAG, standard. + + If you select this option, you need to select + "Trace data router for MIPI P1149.7 cJTAG standard". diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile index 690522fcb338..ea89b0bd15fe 100644 --- a/drivers/tty/Makefile +++ b/drivers/tty/Makefile @@ -6,6 +6,8 @@ obj-$(CONFIG_AUDIT) += tty_audit.o obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o obj-$(CONFIG_N_HDLC) += n_hdlc.o obj-$(CONFIG_N_GSM) += n_gsm.o +obj-$(CONFIG_TRACE_ROUTER) += n_tracerouter.o +obj-$(CONFIG_TRACE_SINK) += n_tracesink.o obj-$(CONFIG_R3964) += n_r3964.o obj-y += vt/ diff --git a/drivers/tty/n_tracerouter.c b/drivers/tty/n_tracerouter.c new file mode 100644 index 000000000000..1f063d3aa32f --- /dev/null +++ b/drivers/tty/n_tracerouter.c @@ -0,0 +1,243 @@ +/* + * n_tracerouter.c - Trace data router through tty space + * + * Copyright (C) Intel 2011 + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * This trace router uses the Linux line discipline framework to route + * trace data coming from a HW Modem to a PTI (Parallel Trace Module) port. + * The solution is not specific to a HW modem and this line disciple can + * be used to route any stream of data in kernel space. + * This is part of a solution for the P1149.7, compact JTAG, standard. + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/ioctl.h> +#include <linux/tty.h> +#include <linux/tty_ldisc.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <asm-generic/bug.h> +#include "n_tracesink.h" + +/* + * Other ldisc drivers use 65536 which basically means, + * 'I can always accept 64k' and flow control is off. + * This number is deemed appropriate for this driver. + */ +#define RECEIVE_ROOM 65536 +#define DRIVERNAME "n_tracerouter" + +/* + * struct to hold private configuration data for this ldisc. + * opencalled is used to hold if this ldisc has been opened. + * kref_tty holds the tty reference the ldisc sits on top of. + */ +struct tracerouter_data { + u8 opencalled; + struct tty_struct *kref_tty; +}; +static struct tracerouter_data *tr_data; + +/* lock for when tty reference is being used */ +static DEFINE_MUTEX(routelock); + +/** + * n_tracerouter_open() - Called when a tty is opened by a SW entity. + * @tty: terminal device to the ldisc. + * + * Return: + * 0 for success. + * + * Caveats: This should only be opened one time per SW entity. + */ +static int n_tracerouter_open(struct tty_struct *tty) +{ + int retval = -EEXIST; + + mutex_lock(&routelock); + if (tr_data->opencalled == 0) { + + tr_data->kref_tty = tty_kref_get(tty); + if (tr_data->kref_tty == NULL) { + retval = -EFAULT; + } else { + tr_data->opencalled = 1; + tty->disc_data = tr_data; + tty->receive_room = RECEIVE_ROOM; + tty_driver_flush_buffer(tty); + retval = 0; + } + } + mutex_unlock(&routelock); + return retval; +} + +/** + * n_tracerouter_close() - close connection + * @tty: terminal device to the ldisc. + * + * Called when a software entity wants to close a connection. + */ +static void n_tracerouter_close(struct tty_struct *tty) +{ + struct tracerouter_data *tptr = tty->disc_data; + + mutex_lock(&routelock); + WARN_ON(tptr->kref_tty != tr_data->kref_tty); + tty_driver_flush_buffer(tty); + tty_kref_put(tr_data->kref_tty); + tr_data->kref_tty = NULL; + tr_data->opencalled = 0; + tty->disc_data = NULL; + mutex_unlock(&routelock); +} + +/** + * n_tracerouter_read() - read request from user space + * @tty: terminal device passed into the ldisc. + * @file: pointer to open file object. + * @buf: pointer to the data buffer that gets eventually returned. + * @nr: number of bytes of the data buffer that is returned. + * + * function that allows read() functionality in userspace. By default if this + * is not implemented it returns -EIO. This module is functioning like a + * router via n_tracerouter_receivebuf(), and there is no real requirement + * to implement this function. However, an error return value other than + * -EIO should be used just to show that there was an intent not to have + * this function implemented. Return value based on read() man pages. + * + * Return: + * -EINVAL + */ +static ssize_t n_tracerouter_read(struct tty_struct *tty, struct file *file, + unsigned char __user *buf, size_t nr) { + return -EINVAL; +} + +/** + * n_tracerouter_write() - Function that allows write() in userspace. + * @tty: terminal device passed into the ldisc. + * @file: pointer to open file object. + * @buf: pointer to the data buffer that gets eventually returned. + * @nr: number of bytes of the data buffer that is returned. + * + * By default if this is not implemented, it returns -EIO. + * This should not be implemented, ever, because + * 1. this driver is functioning like a router via + * n_tracerouter_receivebuf() + * 2. No writes to HW will ever go through this line discpline driver. + * However, an error return value other than -EIO should be used + * just to show that there was an intent not to have this function + * implemented. Return value based on write() man pages. + * + * Return: + * -EINVAL + */ +static ssize_t n_tracerouter_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr) { + return -EINVAL; +} + +/** + * n_tracerouter_receivebuf() - Routing function for driver. + * @tty: terminal device passed into the ldisc. It's assumed + * tty will never be NULL. + * @cp: buffer, block of characters to be eventually read by + * someone, somewhere (user read() call or some kernel function). + * @fp: flag buffer. + * @count: number of characters (aka, bytes) in cp. + * + * This function takes the input buffer, cp, and passes it to + * an external API function for processing. + */ +static void n_tracerouter_receivebuf(struct tty_struct *tty, + const unsigned char *cp, + char *fp, int count) +{ + mutex_lock(&routelock); + n_tracesink_datadrain((u8 *) cp, count); + mutex_unlock(&routelock); +} + +/* + * Flush buffer is not impelemented as the ldisc has no internal buffering + * so the tty_driver_flush_buffer() is sufficient for this driver's needs. + */ + +static struct tty_ldisc_ops tty_ptirouter_ldisc = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = DRIVERNAME, + .open = n_tracerouter_open, + .close = n_tracerouter_close, + .read = n_tracerouter_read, + .write = n_tracerouter_write, + .receive_buf = n_tracerouter_receivebuf +}; + +/** + * n_tracerouter_init - module initialisation + * + * Registers this module as a line discipline driver. + * + * Return: + * 0 for success, any other value error. + */ +static int __init n_tracerouter_init(void) +{ + int retval; + + tr_data = kzalloc(sizeof(struct tracerouter_data), GFP_KERNEL); + if (tr_data == NULL) + return -ENOMEM; + + + /* Note N_TRACEROUTER is defined in linux/tty.h */ + retval = tty_register_ldisc(N_TRACEROUTER, &tty_ptirouter_ldisc); + if (retval < 0) { + pr_err("%s: Registration failed: %d\n", __func__, retval); + kfree(tr_data); + } + return retval; +} + +/** + * n_tracerouter_exit - module unload + * + * Removes this module as a line discipline driver. + */ +static void __exit n_tracerouter_exit(void) +{ + int retval = tty_unregister_ldisc(N_TRACEROUTER); + + if (retval < 0) + pr_err("%s: Unregistration failed: %d\n", __func__, retval); + else + kfree(tr_data); +} + +module_init(n_tracerouter_init); +module_exit(n_tracerouter_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jay Freyensee"); +MODULE_ALIAS_LDISC(N_TRACEROUTER); +MODULE_DESCRIPTION("Trace router ldisc driver"); diff --git a/drivers/tty/n_tracesink.c b/drivers/tty/n_tracesink.c new file mode 100644 index 000000000000..ddce58b973d2 --- /dev/null +++ b/drivers/tty/n_tracesink.c @@ -0,0 +1,238 @@ +/* + * n_tracesink.c - Trace data router and sink path through tty space. + * + * Copyright (C) Intel 2011 + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * The trace sink uses the Linux line discipline framework to receive + * trace data coming from the PTI source line discipline driver + * to a user-desired tty port, like USB. + * This is to provide a way to extract modem trace data on + * devices that do not have a PTI HW module, or just need modem + * trace data to come out of a different HW output port. + * This is part of a solution for the P1149.7, compact JTAG, standard. + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/ioctl.h> +#include <linux/tty.h> +#include <linux/tty_ldisc.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <asm-generic/bug.h> +#include "n_tracesink.h" + +/* + * Other ldisc drivers use 65536 which basically means, + * 'I can always accept 64k' and flow control is off. + * This number is deemed appropriate for this driver. + */ +#define RECEIVE_ROOM 65536 +#define DRIVERNAME "n_tracesink" + +/* + * there is a quirk with this ldisc is he can write data + * to a tty from anyone calling his kernel API, which + * meets customer requirements in the drivers/misc/pti.c + * project. So he needs to know when he can and cannot write when + * the API is called. In theory, the API can be called + * after an init() but before a successful open() which + * would crash the system if tty is not checked. + */ +static struct tty_struct *this_tty; +static DEFINE_MUTEX(writelock); + +/** + * n_tracesink_open() - Called when a tty is opened by a SW entity. + * @tty: terminal device to the ldisc. + * + * Return: + * 0 for success, + * -EFAULT = couldn't get a tty kref n_tracesink will sit + * on top of + * -EEXIST = open() called successfully once and it cannot + * be called again. + * + * Caveats: open() should only be successful the first time a + * SW entity calls it. + */ +static int n_tracesink_open(struct tty_struct *tty) +{ + int retval = -EEXIST; + + mutex_lock(&writelock); + if (this_tty == NULL) { + this_tty = tty_kref_get(tty); + if (this_tty == NULL) { + retval = -EFAULT; + } else { + tty->disc_data = this_tty; + tty_driver_flush_buffer(tty); + retval = 0; + } + } + mutex_unlock(&writelock); + + return retval; +} + +/** + * n_tracesink_close() - close connection + * @tty: terminal device to the ldisc. + * + * Called when a software entity wants to close a connection. + */ +static void n_tracesink_close(struct tty_struct *tty) +{ + mutex_lock(&writelock); + tty_driver_flush_buffer(tty); + tty_kref_put(this_tty); + this_tty = NULL; + tty->disc_data = NULL; + mutex_unlock(&writelock); +} + +/** + * n_tracesink_read() - read request from user space + * @tty: terminal device passed into the ldisc. + * @file: pointer to open file object. + * @buf: pointer to the data buffer that gets eventually returned. + * @nr: number of bytes of the data buffer that is returned. + * + * function that allows read() functionality in userspace. By default if this + * is not implemented it returns -EIO. This module is functioning like a + * router via n_tracesink_receivebuf(), and there is no real requirement + * to implement this function. However, an error return value other than + * -EIO should be used just to show that there was an intent not to have + * this function implemented. Return value based on read() man pages. + * + * Return: + * -EINVAL + */ +static ssize_t n_tracesink_read(struct tty_struct *tty, struct file *file, + unsigned char __user *buf, size_t nr) { + return -EINVAL; +} + +/** + * n_tracesink_write() - Function that allows write() in userspace. + * @tty: terminal device passed into the ldisc. + * @file: pointer to open file object. + * @buf: pointer to the data buffer that gets eventually returned. + * @nr: number of bytes of the data buffer that is returned. + * + * By default if this is not implemented, it returns -EIO. + * This should not be implemented, ever, because + * 1. this driver is functioning like a router via + * n_tracesink_receivebuf() + * 2. No writes to HW will ever go through this line discpline driver. + * However, an error return value other than -EIO should be used + * just to show that there was an intent not to have this function + * implemented. Return value based on write() man pages. + * + * Return: + * -EINVAL + */ +static ssize_t n_tracesink_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr) { + return -EINVAL; +} + +/** + * n_tracesink_datadrain() - Kernel API function used to route + * trace debugging data to user-defined + * port like USB. + * + * @buf: Trace debuging data buffer to write to tty target + * port. Null value will return with no write occurring. + * @count: Size of buf. Value of 0 or a negative number will + * return with no write occuring. + * + * Caveat: If this line discipline does not set the tty it sits + * on top of via an open() call, this API function will not + * call the tty's write() call because it will have no pointer + * to call the write(). + */ +void n_tracesink_datadrain(u8 *buf, int count) +{ + mutex_lock(&writelock); + + if ((buf != NULL) && (count > 0) && (this_tty != NULL)) + this_tty->ops->write(this_tty, buf, count); + + mutex_unlock(&writelock); +} +EXPORT_SYMBOL_GPL(n_tracesink_datadrain); + +/* + * Flush buffer is not impelemented as the ldisc has no internal buffering + * so the tty_driver_flush_buffer() is sufficient for this driver's needs. + */ + +/* + * tty_ldisc function operations for this driver. + */ +static struct tty_ldisc_ops tty_n_tracesink = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = DRIVERNAME, + .open = n_tracesink_open, + .close = n_tracesink_close, + .read = n_tracesink_read, + .write = n_tracesink_write +}; + +/** + * n_tracesink_init- module initialisation + * + * Registers this module as a line discipline driver. + * + * Return: + * 0 for success, any other value error. + */ +static int __init n_tracesink_init(void) +{ + /* Note N_TRACESINK is defined in linux/tty.h */ + int retval = tty_register_ldisc(N_TRACESINK, &tty_n_tracesink); + + if (retval < 0) + pr_err("%s: Registration failed: %d\n", __func__, retval); + + return retval; +} + +/** + * n_tracesink_exit - module unload + * + * Removes this module as a line discipline driver. + */ +static void __exit n_tracesink_exit(void) +{ + int retval = tty_unregister_ldisc(N_TRACESINK); + + if (retval < 0) + pr_err("%s: Unregistration failed: %d\n", __func__, retval); +} + +module_init(n_tracesink_init); +module_exit(n_tracesink_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jay Freyensee"); +MODULE_ALIAS_LDISC(N_TRACESINK); +MODULE_DESCRIPTION("Trace sink ldisc driver"); diff --git a/drivers/tty/n_tracesink.h b/drivers/tty/n_tracesink.h new file mode 100644 index 000000000000..a68bb44f1ef5 --- /dev/null +++ b/drivers/tty/n_tracesink.h @@ -0,0 +1,36 @@ +/* + * n_tracesink.h - Kernel driver API to route trace data in kernel space. + * + * Copyright (C) Intel 2011 + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * The PTI (Parallel Trace Interface) driver directs trace data routed from + * various parts in the system out through the Intel Penwell PTI port and + * out of the mobile device for analysis with a debugging tool + * (Lauterbach, Fido). This is part of a solution for the MIPI P1149.7, + * compact JTAG, standard. + * + * This header file is used by n_tracerouter to be able to send the + * data of it's tty port to the tty port this module sits. This + * mechanism can also be used independent of the PTI module. + * + */ + +#ifndef N_TRACESINK_H_ +#define N_TRACESINK_H_ + +void n_tracesink_datadrain(u8 *buf, int count); + +#endif |