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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/serial/v850e_uart.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/serial/v850e_uart.c')
-rw-r--r--drivers/serial/v850e_uart.c549
1 files changed, 549 insertions, 0 deletions
diff --git a/drivers/serial/v850e_uart.c b/drivers/serial/v850e_uart.c
new file mode 100644
index 00000000000..bb482780a41
--- /dev/null
+++ b/drivers/serial/v850e_uart.c
@@ -0,0 +1,549 @@
+/*
+ * drivers/serial/v850e_uart.c -- Serial I/O using V850E on-chip UART or UARTB
+ *
+ * Copyright (C) 2001,02,03 NEC Electronics Corporation
+ * Copyright (C) 2001,02,03 Miles Bader <miles@gnu.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file COPYING in the main directory of this
+ * archive for more details.
+ *
+ * Written by Miles Bader <miles@gnu.org>
+ */
+
+/* This driver supports both the original V850E UART interface (called
+ merely `UART' in the docs) and the newer `UARTB' interface, which is
+ roughly a superset of the first one. The selection is made at
+ configure time -- if CONFIG_V850E_UARTB is defined, then UARTB is
+ presumed, otherwise the old UART -- as these are on-CPU UARTS, a system
+ can never have both.
+
+ The UARTB interface also has a 16-entry FIFO mode, which is not
+ yet supported by this driver. */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+
+#include <asm/v850e_uart.h>
+
+/* Initial UART state. This may be overridden by machine-dependent headers. */
+#ifndef V850E_UART_INIT_BAUD
+#define V850E_UART_INIT_BAUD 115200
+#endif
+#ifndef V850E_UART_INIT_CFLAGS
+#define V850E_UART_INIT_CFLAGS (B115200 | CS8 | CREAD)
+#endif
+
+/* A string used for prefixing printed descriptions; since the same UART
+ macro is actually used on other chips than the V850E. This must be a
+ constant string. */
+#ifndef V850E_UART_CHIP_NAME
+#define V850E_UART_CHIP_NAME "V850E"
+#endif
+
+#define V850E_UART_MINOR_BASE 64 /* First tty minor number */
+
+
+/* Low-level UART functions. */
+
+/* Configure and turn on uart channel CHAN, using the termios `control
+ modes' bits in CFLAGS, and a baud-rate of BAUD. */
+void v850e_uart_configure (unsigned chan, unsigned cflags, unsigned baud)
+{
+ int flags;
+ v850e_uart_speed_t old_speed;
+ v850e_uart_config_t old_config;
+ v850e_uart_speed_t new_speed = v850e_uart_calc_speed (baud);
+ v850e_uart_config_t new_config = v850e_uart_calc_config (cflags);
+
+ /* Disable interrupts while we're twiddling the hardware. */
+ local_irq_save (flags);
+
+#ifdef V850E_UART_PRE_CONFIGURE
+ V850E_UART_PRE_CONFIGURE (chan, cflags, baud);
+#endif
+
+ old_config = V850E_UART_CONFIG (chan);
+ old_speed = v850e_uart_speed (chan);
+
+ if (! v850e_uart_speed_eq (old_speed, new_speed)) {
+ /* The baud rate has changed. First, disable the UART. */
+ V850E_UART_CONFIG (chan) = V850E_UART_CONFIG_FINI;
+ old_config = 0; /* Force the uart to be re-initialized. */
+
+ /* Reprogram the baud-rate generator. */
+ v850e_uart_set_speed (chan, new_speed);
+ }
+
+ if (! (old_config & V850E_UART_CONFIG_ENABLED)) {
+ /* If we are using the uart for the first time, start by
+ enabling it, which must be done before turning on any
+ other bits. */
+ V850E_UART_CONFIG (chan) = V850E_UART_CONFIG_INIT;
+ /* See the initial state. */
+ old_config = V850E_UART_CONFIG (chan);
+ }
+
+ if (new_config != old_config) {
+ /* Which of the TXE/RXE bits we'll temporarily turn off
+ before changing other control bits. */
+ unsigned temp_disable = 0;
+ /* Which of the TXE/RXE bits will be enabled. */
+ unsigned enable = 0;
+ unsigned changed_bits = new_config ^ old_config;
+
+ /* Which of RX/TX will be enabled in the new configuration. */
+ if (new_config & V850E_UART_CONFIG_RX_BITS)
+ enable |= (new_config & V850E_UART_CONFIG_RX_ENABLE);
+ if (new_config & V850E_UART_CONFIG_TX_BITS)
+ enable |= (new_config & V850E_UART_CONFIG_TX_ENABLE);
+
+ /* Figure out which of RX/TX needs to be disabled; note
+ that this will only happen if they're not already
+ disabled. */
+ if (changed_bits & V850E_UART_CONFIG_RX_BITS)
+ temp_disable
+ |= (old_config & V850E_UART_CONFIG_RX_ENABLE);
+ if (changed_bits & V850E_UART_CONFIG_TX_BITS)
+ temp_disable
+ |= (old_config & V850E_UART_CONFIG_TX_ENABLE);
+
+ /* We have to turn off RX and/or TX mode before changing
+ any associated control bits. */
+ if (temp_disable)
+ V850E_UART_CONFIG (chan) = old_config & ~temp_disable;
+
+ /* Write the new control bits, while RX/TX are disabled. */
+ if (changed_bits & ~enable)
+ V850E_UART_CONFIG (chan) = new_config & ~enable;
+
+ v850e_uart_config_delay (new_config, new_speed);
+
+ /* Write the final version, with enable bits turned on. */
+ V850E_UART_CONFIG (chan) = new_config;
+ }
+
+ local_irq_restore (flags);
+}
+
+
+/* Low-level console. */
+
+#ifdef CONFIG_V850E_UART_CONSOLE
+
+static void v850e_uart_cons_write (struct console *co,
+ const char *s, unsigned count)
+{
+ if (count > 0) {
+ unsigned chan = co->index;
+ unsigned irq = V850E_UART_TX_IRQ (chan);
+ int irq_was_enabled, irq_was_pending, flags;
+
+ /* We don't want to get `transmission completed'
+ interrupts, since we're busy-waiting, so we disable them
+ while sending (we don't disable interrupts entirely
+ because sending over a serial line is really slow). We
+ save the status of the tx interrupt and restore it when
+ we're done so that using printk doesn't interfere with
+ normal serial transmission (other than interleaving the
+ output, of course!). This should work correctly even if
+ this function is interrupted and the interrupt printks
+ something. */
+
+ /* Disable interrupts while fiddling with tx interrupt. */
+ local_irq_save (flags);
+ /* Get current tx interrupt status. */
+ irq_was_enabled = v850e_intc_irq_enabled (irq);
+ irq_was_pending = v850e_intc_irq_pending (irq);
+ /* Disable tx interrupt if necessary. */
+ if (irq_was_enabled)
+ v850e_intc_disable_irq (irq);
+ /* Turn interrupts back on. */
+ local_irq_restore (flags);
+
+ /* Send characters. */
+ while (count > 0) {
+ int ch = *s++;
+
+ if (ch == '\n') {
+ /* We don't have the benefit of a tty
+ driver, so translate NL into CR LF. */
+ v850e_uart_wait_for_xmit_ok (chan);
+ v850e_uart_putc (chan, '\r');
+ }
+
+ v850e_uart_wait_for_xmit_ok (chan);
+ v850e_uart_putc (chan, ch);
+
+ count--;
+ }
+
+ /* Restore saved tx interrupt status. */
+ if (irq_was_enabled) {
+ /* Wait for the last character we sent to be
+ completely transmitted (as we'll get an
+ interrupt interrupt at that point). */
+ v850e_uart_wait_for_xmit_done (chan);
+ /* Clear pending interrupts received due
+ to our transmission, unless there was already
+ one pending, in which case we want the
+ handler to be called. */
+ if (! irq_was_pending)
+ v850e_intc_clear_pending_irq (irq);
+ /* ... and then turn back on handling. */
+ v850e_intc_enable_irq (irq);
+ }
+ }
+}
+
+extern struct uart_driver v850e_uart_driver;
+static struct console v850e_uart_cons =
+{
+ .name = "ttyS",
+ .write = v850e_uart_cons_write,
+ .device = uart_console_device,
+ .flags = CON_PRINTBUFFER,
+ .cflag = V850E_UART_INIT_CFLAGS,
+ .index = -1,
+ .data = &v850e_uart_driver,
+};
+
+void v850e_uart_cons_init (unsigned chan)
+{
+ v850e_uart_configure (chan, V850E_UART_INIT_CFLAGS,
+ V850E_UART_INIT_BAUD);
+ v850e_uart_cons.index = chan;
+ register_console (&v850e_uart_cons);
+ printk ("Console: %s on-chip UART channel %d\n",
+ V850E_UART_CHIP_NAME, chan);
+}
+
+/* This is what the init code actually calls. */
+static int v850e_uart_console_init (void)
+{
+ v850e_uart_cons_init (V850E_UART_CONSOLE_CHANNEL);
+ return 0;
+}
+console_initcall(v850e_uart_console_init);
+
+#define V850E_UART_CONSOLE &v850e_uart_cons
+
+#else /* !CONFIG_V850E_UART_CONSOLE */
+#define V850E_UART_CONSOLE 0
+#endif /* CONFIG_V850E_UART_CONSOLE */
+
+/* TX/RX interrupt handlers. */
+
+static void v850e_uart_stop_tx (struct uart_port *port, unsigned tty_stop);
+
+void v850e_uart_tx (struct uart_port *port)
+{
+ struct circ_buf *xmit = &port->info->xmit;
+ int stopped = uart_tx_stopped (port);
+
+ if (v850e_uart_xmit_ok (port->line)) {
+ int tx_ch;
+
+ if (port->x_char) {
+ tx_ch = port->x_char;
+ port->x_char = 0;
+ } else if (!uart_circ_empty (xmit) && !stopped) {
+ tx_ch = xmit->buf[xmit->tail];
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ } else
+ goto no_xmit;
+
+ v850e_uart_putc (port->line, tx_ch);
+ port->icount.tx++;
+
+ if (uart_circ_chars_pending (xmit) < WAKEUP_CHARS)
+ uart_write_wakeup (port);
+ }
+
+ no_xmit:
+ if (uart_circ_empty (xmit) || stopped)
+ v850e_uart_stop_tx (port, stopped);
+}
+
+static irqreturn_t v850e_uart_tx_irq(int irq, void *data, struct pt_regs *regs)
+{
+ struct uart_port *port = data;
+ v850e_uart_tx (port);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t v850e_uart_rx_irq(int irq, void *data, struct pt_regs *regs)
+{
+ struct uart_port *port = data;
+ unsigned ch_stat = TTY_NORMAL;
+ unsigned ch = v850e_uart_getc (port->line);
+ unsigned err = v850e_uart_err (port->line);
+
+ if (err) {
+ if (err & V850E_UART_ERR_OVERRUN) {
+ ch_stat = TTY_OVERRUN;
+ port->icount.overrun++;
+ } else if (err & V850E_UART_ERR_FRAME) {
+ ch_stat = TTY_FRAME;
+ port->icount.frame++;
+ } else if (err & V850E_UART_ERR_PARITY) {
+ ch_stat = TTY_PARITY;
+ port->icount.parity++;
+ }
+ }
+
+ port->icount.rx++;
+
+ tty_insert_flip_char (port->info->tty, ch, ch_stat);
+ tty_schedule_flip (port->info->tty);
+
+ return IRQ_HANDLED;
+}
+
+
+/* Control functions for the serial framework. */
+
+static void v850e_uart_nop (struct uart_port *port) { }
+static int v850e_uart_success (struct uart_port *port) { return 0; }
+
+static unsigned v850e_uart_tx_empty (struct uart_port *port)
+{
+ return TIOCSER_TEMT; /* Can't detect. */
+}
+
+static void v850e_uart_set_mctrl (struct uart_port *port, unsigned mctrl)
+{
+#ifdef V850E_UART_SET_RTS
+ V850E_UART_SET_RTS (port->line, (mctrl & TIOCM_RTS));
+#endif
+}
+
+static unsigned v850e_uart_get_mctrl (struct uart_port *port)
+{
+ /* We don't support DCD or DSR, so consider them permanently active. */
+ int mctrl = TIOCM_CAR | TIOCM_DSR;
+
+ /* We may support CTS. */
+#ifdef V850E_UART_CTS
+ mctrl |= V850E_UART_CTS(port->line) ? TIOCM_CTS : 0;
+#else
+ mctrl |= TIOCM_CTS;
+#endif
+
+ return mctrl;
+}
+
+static void v850e_uart_start_tx (struct uart_port *port, unsigned tty_start)
+{
+ v850e_intc_disable_irq (V850E_UART_TX_IRQ (port->line));
+ v850e_uart_tx (port);
+ v850e_intc_enable_irq (V850E_UART_TX_IRQ (port->line));
+}
+
+static void v850e_uart_stop_tx (struct uart_port *port, unsigned tty_stop)
+{
+ v850e_intc_disable_irq (V850E_UART_TX_IRQ (port->line));
+}
+
+static void v850e_uart_start_rx (struct uart_port *port)
+{
+ v850e_intc_enable_irq (V850E_UART_RX_IRQ (port->line));
+}
+
+static void v850e_uart_stop_rx (struct uart_port *port)
+{
+ v850e_intc_disable_irq (V850E_UART_RX_IRQ (port->line));
+}
+
+static void v850e_uart_break_ctl (struct uart_port *port, int break_ctl)
+{
+ /* Umm, do this later. */
+}
+
+static int v850e_uart_startup (struct uart_port *port)
+{
+ int err;
+
+ /* Alloc RX irq. */
+ err = request_irq (V850E_UART_RX_IRQ (port->line), v850e_uart_rx_irq,
+ SA_INTERRUPT, "v850e_uart", port);
+ if (err)
+ return err;
+
+ /* Alloc TX irq. */
+ err = request_irq (V850E_UART_TX_IRQ (port->line), v850e_uart_tx_irq,
+ SA_INTERRUPT, "v850e_uart", port);
+ if (err) {
+ free_irq (V850E_UART_RX_IRQ (port->line), port);
+ return err;
+ }
+
+ v850e_uart_start_rx (port);
+
+ return 0;
+}
+
+static void v850e_uart_shutdown (struct uart_port *port)
+{
+ /* Disable port interrupts. */
+ free_irq (V850E_UART_TX_IRQ (port->line), port);
+ free_irq (V850E_UART_RX_IRQ (port->line), port);
+
+ /* Turn off xmit/recv enable bits. */
+ V850E_UART_CONFIG (port->line)
+ &= ~(V850E_UART_CONFIG_TX_ENABLE
+ | V850E_UART_CONFIG_RX_ENABLE);
+ /* Then reset the channel. */
+ V850E_UART_CONFIG (port->line) = 0;
+}
+
+static void
+v850e_uart_set_termios (struct uart_port *port, struct termios *termios,
+ struct termios *old)
+{
+ unsigned cflags = termios->c_cflag;
+
+ /* Restrict flags to legal values. */
+ if ((cflags & CSIZE) != CS7 && (cflags & CSIZE) != CS8)
+ /* The new value of CSIZE is invalid, use the old value. */
+ cflags = (cflags & ~CSIZE)
+ | (old ? (old->c_cflag & CSIZE) : CS8);
+
+ termios->c_cflag = cflags;
+
+ v850e_uart_configure (port->line, cflags,
+ uart_get_baud_rate (port, termios, old,
+ v850e_uart_min_baud(),
+ v850e_uart_max_baud()));
+}
+
+static const char *v850e_uart_type (struct uart_port *port)
+{
+ return port->type == PORT_V850E_UART ? "v850e_uart" : 0;
+}
+
+static void v850e_uart_config_port (struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE)
+ port->type = PORT_V850E_UART;
+}
+
+static int
+v850e_uart_verify_port (struct uart_port *port, struct serial_struct *ser)
+{
+ if (ser->type != PORT_UNKNOWN && ser->type != PORT_V850E_UART)
+ return -EINVAL;
+ if (ser->irq != V850E_UART_TX_IRQ (port->line))
+ return -EINVAL;
+ return 0;
+}
+
+static struct uart_ops v850e_uart_ops = {
+ .tx_empty = v850e_uart_tx_empty,
+ .get_mctrl = v850e_uart_get_mctrl,
+ .set_mctrl = v850e_uart_set_mctrl,
+ .start_tx = v850e_uart_start_tx,
+ .stop_tx = v850e_uart_stop_tx,
+ .stop_rx = v850e_uart_stop_rx,
+ .enable_ms = v850e_uart_nop,
+ .break_ctl = v850e_uart_break_ctl,
+ .startup = v850e_uart_startup,
+ .shutdown = v850e_uart_shutdown,
+ .set_termios = v850e_uart_set_termios,
+ .type = v850e_uart_type,
+ .release_port = v850e_uart_nop,
+ .request_port = v850e_uart_success,
+ .config_port = v850e_uart_config_port,
+ .verify_port = v850e_uart_verify_port,
+};
+
+/* Initialization and cleanup. */
+
+static struct uart_driver v850e_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "v850e_uart",
+ .devfs_name = "tts/",
+ .dev_name = "ttyS",
+ .major = TTY_MAJOR,
+ .minor = V850E_UART_MINOR_BASE,
+ .nr = V850E_UART_NUM_CHANNELS,
+ .cons = V850E_UART_CONSOLE,
+};
+
+
+static struct uart_port v850e_uart_ports[V850E_UART_NUM_CHANNELS];
+
+static int __init v850e_uart_init (void)
+{
+ int rval;
+
+ printk (KERN_INFO "%s on-chip UART\n", V850E_UART_CHIP_NAME);
+
+ rval = uart_register_driver (&v850e_uart_driver);
+ if (rval == 0) {
+ unsigned chan;
+
+ for (chan = 0; chan < V850E_UART_NUM_CHANNELS; chan++) {
+ struct uart_port *port = &v850e_uart_ports[chan];
+
+ memset (port, 0, sizeof *port);
+
+ port->ops = &v850e_uart_ops;
+ port->line = chan;
+ port->iotype = SERIAL_IO_MEM;
+ port->flags = UPF_BOOT_AUTOCONF;
+
+ /* We actually use multiple IRQs, but the serial
+ framework seems to mainly use this for
+ informational purposes anyway. Here we use the TX
+ irq. */
+ port->irq = V850E_UART_TX_IRQ (chan);
+
+ /* The serial framework doesn't really use these
+ membase/mapbase fields for anything useful, but
+ it requires that they be something non-zero to
+ consider the port `valid', and also uses them
+ for informational purposes. */
+ port->membase = (void *)V850E_UART_BASE_ADDR (chan);
+ port->mapbase = V850E_UART_BASE_ADDR (chan);
+
+ /* The framework insists on knowing the uart's master
+ clock freq, though it doesn't seem to do anything
+ useful for us with it. We must make it at least
+ higher than (the maximum baud rate * 16), otherwise
+ the framework will puke during its internal
+ calculations, and force the baud rate to be 9600.
+ To be accurate though, just repeat the calculation
+ we use when actually setting the speed. */
+ port->uartclk = v850e_uart_max_clock() * 16;
+
+ uart_add_one_port (&v850e_uart_driver, port);
+ }
+ }
+
+ return rval;
+}
+
+static void __exit v850e_uart_exit (void)
+{
+ unsigned chan;
+
+ for (chan = 0; chan < V850E_UART_NUM_CHANNELS; chan++)
+ uart_remove_one_port (&v850e_uart_driver,
+ &v850e_uart_ports[chan]);
+
+ uart_unregister_driver (&v850e_uart_driver);
+}
+
+module_init (v850e_uart_init);
+module_exit (v850e_uart_exit);
+
+MODULE_AUTHOR ("Miles Bader");
+MODULE_DESCRIPTION ("NEC " V850E_UART_CHIP_NAME " on-chip UART");
+MODULE_LICENSE ("GPL");