Add smd_tty driver which provides tty device interface to 'DS' and 'GPSNMEA' streaming SMD ports.
Cc: Brian Swetland <[email protected]> Signed-off-by: Niranjana Vishwanathapura <[email protected]> --- drivers/char/Kconfig | 8 ++ drivers/char/Makefile | 2 + drivers/char/msm_smd_tty.c | 226 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 236 insertions(+), 0 deletions(-) create mode 100644 drivers/char/msm_smd_tty.c diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 43d3395..3d53383 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -1144,5 +1144,13 @@ config RAMOOPS This enables panic and oops messages to be logged to a circular buffer in RAM where it can be read back at some later point. +config MSM_SMD_TTY + bool "Enable tty device interface for some SMD ports" + default n + depends on MSM_SMD + help + Enables userspace clients to read and write to some streaming SMD + ports via tty device interface for MSM chipset. + endmenu diff --git a/drivers/char/Makefile b/drivers/char/Makefile index ba53ec9..78e3c15 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -98,3 +98,5 @@ obj-$(CONFIG_RAMOOPS) += ramoops.o obj-$(CONFIG_JS_RTC) += js-rtc.o js-rtc-y = rtc.o + +obj-$(CONFIG_MSM_SMD_TTY) += msm_smd_tty.o diff --git a/drivers/char/msm_smd_tty.c b/drivers/char/msm_smd_tty.c new file mode 100644 index 0000000..7e0b963 --- /dev/null +++ b/drivers/char/msm_smd_tty.c @@ -0,0 +1,226 @@ +/* arch/arm/mach-msm/smd_tty.c + * + * Copyright (C) 2007 Google, Inc. + * Copyright (c) 2010, Code Aurora Forum. All rights reserved. + * Author: Brian Swetland <[email protected]> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * 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. + * + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/cdev.h> +#include <linux/device.h> +#include <linux/wait.h> + +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> + +#include <mach/msm_smd.h> + +#define MAX_SMD_TTYS 32 + +static DEFINE_MUTEX(smd_tty_lock); + +struct smd_tty_info { + smd_channel_t *ch; + struct tty_struct *tty; + int open_count; +}; + +struct smd_tty_channel_desc { + int id; + const char *name; +}; + +static struct smd_tty_info smd_tty[MAX_SMD_TTYS]; + +static const struct smd_tty_channel_desc smd_default_tty_channels[] = { + { .id = 0, .name = "SMD_DS" }, + { .id = 27, .name = "SMD_GPSNMEA" }, +}; + +static const struct smd_tty_channel_desc *smd_tty_channels = + smd_default_tty_channels; +static int smd_tty_channels_len = ARRAY_SIZE(smd_default_tty_channels); + +static void smd_tty_notify(void *priv, unsigned event) +{ + unsigned char *ptr; + int avail; + struct smd_tty_info *info = priv; + struct tty_struct *tty = info->tty; + + if (!tty) + return; + + if (event != SMD_EVENT_DATA) + return; + + for (;;) { + if (test_bit(TTY_THROTTLED, &tty->flags)) + break; + avail = smd_read_avail(info->ch); + if (avail == 0) + break; + + avail = tty_prepare_flip_string(tty, &ptr, avail); + + if (smd_read(info->ch, ptr, avail) != avail) { + /* shouldn't be possible since we're in interrupt + ** context here and nobody else could 'steal' our + ** characters. + */ + printk(KERN_ERR "OOPS - smd_tty_buffer mismatch?!"); + } + + tty_flip_buffer_push(tty); + } + + /* XXX only when writable and necessary */ + tty_wakeup(tty); +} + +static int smd_tty_open(struct tty_struct *tty, struct file *f) +{ + int res = 0; + int n = tty->index; + struct smd_tty_info *info; + const char *name = NULL; + int i; + + for (i = 0; i < smd_tty_channels_len; i++) { + if (smd_tty_channels[i].id == n) { + name = smd_tty_channels[i].name; + break; + } + } + if (!name) + return -ENODEV; + + info = smd_tty + n; + + mutex_lock(&smd_tty_lock); + tty->driver_data = info; + + if (info->open_count++ == 0) { + info->tty = tty; + if (info->ch) + smd_kick(info->ch); + else + res = smd_open(name, &info->ch, info, smd_tty_notify); + } + mutex_unlock(&smd_tty_lock); + + return res; +} + +static void smd_tty_close(struct tty_struct *tty, struct file *f) +{ + struct smd_tty_info *info = tty->driver_data; + + if (info == 0) + return; + + mutex_lock(&smd_tty_lock); + if (--info->open_count == 0) { + info->tty = 0; + tty->driver_data = 0; + if (info->ch) { + smd_close(info->ch); + info->ch = 0; + } + } + mutex_unlock(&smd_tty_lock); +} + +static int smd_tty_write(struct tty_struct *tty, + const unsigned char *buf, int len) +{ + struct smd_tty_info *info = tty->driver_data; + int avail; + + /* if we're writing to a packet channel we will + ** never be able to write more data than there + ** is currently space for + */ + avail = smd_write_avail(info->ch); + if (len > avail) + len = avail; + + return smd_write(info->ch, buf, len); +} + +static int smd_tty_write_room(struct tty_struct *tty) +{ + struct smd_tty_info *info = tty->driver_data; + return smd_write_avail(info->ch); +} + +static int smd_tty_chars_in_buffer(struct tty_struct *tty) +{ + struct smd_tty_info *info = tty->driver_data; + return smd_read_avail(info->ch); +} + +static void smd_tty_unthrottle(struct tty_struct *tty) +{ + struct smd_tty_info *info = tty->driver_data; + smd_kick(info->ch); +} + +static const struct tty_operations smd_tty_ops = { + .open = smd_tty_open, + .close = smd_tty_close, + .write = smd_tty_write, + .write_room = smd_tty_write_room, + .chars_in_buffer = smd_tty_chars_in_buffer, + .unthrottle = smd_tty_unthrottle, +}; + +static struct tty_driver *smd_tty_driver; + +static int __init smd_tty_init(void) +{ + int ret, i; + + smd_tty_driver = alloc_tty_driver(MAX_SMD_TTYS); + if (smd_tty_driver == 0) + return -ENOMEM; + + smd_tty_driver->owner = THIS_MODULE; + smd_tty_driver->driver_name = "smd_tty_driver"; + smd_tty_driver->name = "smd"; + smd_tty_driver->major = 0; + smd_tty_driver->minor_start = 0; + smd_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; + smd_tty_driver->subtype = SERIAL_TYPE_NORMAL; + smd_tty_driver->init_termios = tty_std_termios; + smd_tty_driver->init_termios.c_iflag = 0; + smd_tty_driver->init_termios.c_oflag = 0; + smd_tty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; + smd_tty_driver->init_termios.c_lflag = 0; + smd_tty_driver->flags = TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; + tty_set_operations(smd_tty_driver, &smd_tty_ops); + + ret = tty_register_driver(smd_tty_driver); + if (ret) + return ret; + + for (i = 0; i < smd_tty_channels_len; i++) + tty_register_device(smd_tty_driver, smd_tty_channels[i].id, 0); + + return 0; +} + +module_init(smd_tty_init); -- 1.5.6.3 Sent by an employee of the Qualcomm Innovation Center, Inc. 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