tty: Add msm_smd_tty driver
Niranjana Vishwanathapura [Wed, 9 Feb 2011 19:16:34 +0000 (11:16 -0800)]
msm_smd_tty driver provides tty device interface
to 'DS' and 'GPSNMEA' streaming SMD ports.

Cc: Brian Swetland <swetland@google.com>
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/tty/serial/Kconfig
drivers/tty/serial/Makefile
drivers/tty/serial/msm_smd_tty.c [new file with mode: 0644]

index aaedbad..90d939a 100644 (file)
@@ -1600,4 +1600,13 @@ config SERIAL_PCH_UART
          Output Hub) which is for IVI(In-Vehicle Infotainment) use.
          ML7213 is companion chip for Intel Atom E6xx series.
          ML7213 is completely compatible for Intel EG20T PCH.
+
+config SERIAL_MSM_SMD
+       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
index 8ea92e9..0c6aefb 100644 (file)
@@ -92,3 +92,4 @@ obj-$(CONFIG_SERIAL_MRST_MAX3110)     += mrst_max3110.o
 obj-$(CONFIG_SERIAL_MFD_HSU)   += mfd.o
 obj-$(CONFIG_SERIAL_IFX6X60)   += ifx6x60.o
 obj-$(CONFIG_SERIAL_PCH_UART)  += pch_uart.o
+obj-$(CONFIG_SERIAL_MSM_SMD)   += msm_smd_tty.o
diff --git a/drivers/tty/serial/msm_smd_tty.c b/drivers/tty/serial/msm_smd_tty.c
new file mode 100644 (file)
index 0000000..beeff1e
--- /dev/null
@@ -0,0 +1,236 @@
+/* drivers/tty/serial/msm_smd_tty.c
+ *
+ * Copyright (C) 2007 Google, Inc.
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
+ * Author: Brian Swetland <swetland@google.com>
+ *
+ * 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
+
+struct smd_tty_info {
+       struct tty_port port;
+       smd_channel_t *ch;
+};
+
+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;
+
+       if (event != SMD_EVENT_DATA)
+               return;
+
+       tty = tty_port_tty_get(&info->port);
+       if (!tty)
+               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.
+                       */
+                       pr_err("OOPS - smd_tty_buffer mismatch?!");
+               }
+
+               tty_flip_buffer_push(tty);
+       }
+
+       /* XXX only when writable and necessary */
+       tty_wakeup(tty);
+       tty_kref_put(tty);
+}
+
+static int smd_tty_port_activate(struct tty_port *tport, struct tty_struct *tty)
+{
+       int i, res = 0;
+       int n = tty->index;
+       const char *name = NULL;
+       struct smd_tty_info *info = smd_tty + n;
+
+       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;
+
+       if (info->ch)
+               smd_kick(info->ch);
+       else
+               res = smd_open(name, &info->ch, info, smd_tty_notify);
+
+       if (!res)
+               tty->driver_data = info;
+
+       return res;
+}
+
+static void smd_tty_port_shutdown(struct tty_port *tport)
+{
+       struct smd_tty_info *info;
+       struct tty_struct *tty = tty_port_tty_get(tport);
+
+       info = tty->driver_data;
+       if (info->ch) {
+               smd_close(info->ch);
+               info->ch = 0;
+       }
+
+       tty->driver_data = 0;
+       tty_kref_put(tty);
+}
+
+static int smd_tty_open(struct tty_struct *tty, struct file *f)
+{
+       struct smd_tty_info *info = smd_tty + tty->index;
+
+       return tty_port_open(&info->port, tty, f);
+}
+
+static void smd_tty_close(struct tty_struct *tty, struct file *f)
+{
+       struct smd_tty_info *info = tty->driver_data;
+
+       tty_port_close(&info->port, tty, f);
+}
+
+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_port_operations smd_tty_port_ops = {
+       .shutdown = smd_tty_port_shutdown,
+       .activate = smd_tty_port_activate,
+};
+
+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_port_init(&smd_tty[smd_tty_channels[i].id].port);
+               smd_tty[smd_tty_channels[i].id].port.ops = &smd_tty_port_ops;
+               tty_register_device(smd_tty_driver, smd_tty_channels[i].id, 0);
+       }
+
+       return 0;
+}
+
+module_init(smd_tty_init);