tty: Remove metag DA TTY and console driver

Now that arch/metag/ has been removed, remove the metag DA TTY and
console driver. It is of no value without the architecture code.

Signed-off-by: James Hogan <jhogan@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-metag@vger.kernel.org

drivers/tty/Kconfig

@@ -402,19 +402,6 @@ config GOLDFISH_TTY_EARLY_CONSOLE
 	default y if GOLDFISH_TTY=y
 	select SERIAL_EARLYCON
 
-config DA_TTY
-	bool "DA TTY"
-	depends on METAG_DA
-	select SERIAL_NONSTANDARD
-	help
-	  This enables a TTY on a Dash channel.
-
-config DA_CONSOLE
-	bool "DA Console"
-	depends on DA_TTY
-	help
-	  This enables a console on a Dash channel.
-
 config MIPS_EJTAG_FDC_TTY
 	bool "MIPS EJTAG Fast Debug Channel TTY"
 	depends on MIPS_CDMM

drivers/tty/Makefile

@@ -32,7 +32,6 @@ obj-$(CONFIG_SYNCLINKMP)	+= synclinkmp.o
 obj-$(CONFIG_SYNCLINK)		+= synclink.o
 obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o
 obj-$(CONFIG_GOLDFISH_TTY)	+= goldfish.o
-obj-$(CONFIG_DA_TTY)		+= metag_da.o
 obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o
 obj-$(CONFIG_VCC)		+= vcc.o
 

drivers/tty/metag_da.c

@@ -1,665 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- *  dashtty.c - tty driver for Dash channels interface.
- *
- *  Copyright (C) 2007,2008,2012 Imagination Technologies
- */
-
-#include <linux/atomic.h>
-#include <linux/completion.h>
-#include <linux/console.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/kthread.h>
-#include <linux/moduleparam.h>
-#include <linux/mutex.h>
-#include <linux/sched.h>
-#include <linux/serial.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/string.h>
-#include <linux/timer.h>
-#include <linux/tty.h>
-#include <linux/tty_driver.h>
-#include <linux/tty_flip.h>
-#include <linux/uaccess.h>
-
-#include <asm/da.h>
-
-/* Channel error codes */
-#define CONAOK	0
-#define CONERR	1
-#define CONBAD	2
-#define CONPRM	3
-#define CONADR	4
-#define CONCNT	5
-#define CONCBF	6
-#define CONCBE	7
-#define CONBSY	8
-
-/* Default channel for the console */
-#define CONSOLE_CHANNEL      1
-
-#define NUM_TTY_CHANNELS     6
-
-/* Auto allocate */
-#define DA_TTY_MAJOR        0
-
-/* A speedy poll rate helps the userland debug process connection response.
- * But, if you set it too high then no other userland processes get much
- * of a look in.
- */
-#define DA_TTY_POLL (HZ / 50)
-
-/*
- * A short put delay improves latency but has a high throughput overhead
- */
-#define DA_TTY_PUT_DELAY (HZ / 100)
-
-static atomic_t num_channels_need_poll = ATOMIC_INIT(0);
-
-static struct timer_list poll_timer;
-
-static struct tty_driver *channel_driver;
-
-static struct timer_list put_timer;
-static struct task_struct *dashtty_thread;
-
-/*
- * The console_poll parameter determines whether the console channel should be
- * polled for input.
- * By default the console channel isn't polled at all, in order to avoid the
- * overhead, but that means it isn't possible to have a login on /dev/console.
- */
-static bool console_poll;
-module_param(console_poll, bool, S_IRUGO);
-
-#define RX_BUF_SIZE 1024
-
-enum {
-	INCHR = 1,
-	OUTCHR,
-	RDBUF,
-	WRBUF,
-	RDSTAT
-};
-
-/**
- * struct dashtty_port - Wrapper struct for dashtty tty_port.
- * @port:		TTY port data
- * @rx_lock:		Lock for rx_buf.
- *			This protects between the poll timer and user context.
- *			It's also held during read SWITCH operations.
- * @rx_buf:		Read buffer
- * @xmit_lock:		Lock for xmit_*, and port.xmit_buf.
- *			This protects between user context and kernel thread.
- *			It's also held during write SWITCH operations.
- * @xmit_cnt:		Size of xmit buffer contents
- * @xmit_head:		Head of xmit buffer where data is written
- * @xmit_tail:		Tail of xmit buffer where data is read
- * @xmit_empty:		Completion for xmit buffer being empty
- */
-struct dashtty_port {
-	struct tty_port		 port;
-	spinlock_t		 rx_lock;
-	void			*rx_buf;
-	struct mutex		 xmit_lock;
-	unsigned int		 xmit_cnt;
-	unsigned int		 xmit_head;
-	unsigned int		 xmit_tail;
-	struct completion	 xmit_empty;
-};
-
-static struct dashtty_port dashtty_ports[NUM_TTY_CHANNELS];
-
-static atomic_t dashtty_xmit_cnt = ATOMIC_INIT(0);
-static wait_queue_head_t dashtty_waitqueue;
-
-/*
- * Low-level DA channel access routines
- */
-static int chancall(int in_bios_function, int in_channel,
-		    int in_arg2, void *in_arg3,
-		    void *in_arg4)
-{
-	register int   bios_function asm("D1Ar1") = in_bios_function;
-	register int   channel       asm("D0Ar2") = in_channel;
-	register int   arg2          asm("D1Ar3") = in_arg2;
-	register void *arg3          asm("D0Ar4") = in_arg3;
-	register void *arg4          asm("D1Ar5") = in_arg4;
-	register int   bios_call     asm("D0Ar6") = 3;
-	register int   result        asm("D0Re0");
-
-	asm volatile (
-		"MSETL	[A0StP++], %6,%4,%2\n\t"
-		"ADD	A0StP, A0StP, #8\n\t"
-		"SWITCH	#0x0C30208\n\t"
-		"GETD	%0, [A0StP+#-8]\n\t"
-		"SUB	A0StP, A0StP, #(4*6)+8\n\t"
-		: "=d" (result)   /* outs */
-		: "d" (bios_function),
-		  "d" (channel),
-		  "d" (arg2),
-		  "d" (arg3),
-		  "d" (arg4),
-		  "d" (bios_call) /* ins */
-		: "memory");
-
-	return result;
-}
-
-/*
- * Attempts to fetch count bytes from channel and returns actual count.
- */
-static int fetch_data(unsigned int channel)
-{
-	struct dashtty_port *dport = &dashtty_ports[channel];
-	int received = 0;
-
-	spin_lock_bh(&dport->rx_lock);
-	/* check the port isn't being shut down */
-	if (!dport->rx_buf)
-		goto unlock;
-	if (chancall(RDBUF, channel, RX_BUF_SIZE,
-		     (void *)dport->rx_buf, &received) == CONAOK) {
-		if (received) {
-			int space;
-			unsigned char *cbuf;
-
-			space = tty_prepare_flip_string(&dport->port, &cbuf,
-							received);
-
-			if (space <= 0)
-				goto unlock;
-
-			memcpy(cbuf, dport->rx_buf, space);
-			tty_flip_buffer_push(&dport->port);
-		}
-	}
-unlock:
-	spin_unlock_bh(&dport->rx_lock);
-
-	return received;
-}
-
-/**
- * find_channel_to_poll() - Returns number of the next channel to poll.
- * Returns:	The number of the next channel to poll, or -1 if none need
- *		polling.
- */
-static int find_channel_to_poll(void)
-{
-	static int last_polled_channel;
-	int last = last_polled_channel;
-	int chan;
-	struct dashtty_port *dport;
-
-	for (chan = last + 1; ; ++chan) {
-		if (chan >= NUM_TTY_CHANNELS)
-			chan = 0;
-
-		dport = &dashtty_ports[chan];
-		if (dport->rx_buf) {
-			last_polled_channel = chan;
-			return chan;
-		}
-
-		if (chan == last)
-			break;
-	}
-	return -1;
-}
-
-/**
- * put_channel_data() - Write out a block of channel data.
- * @chan:	DA channel number.
- *
- * Write a single block of data out to the debug adapter. If the circular buffer
- * is wrapped then only the first block is written.
- *
- * Returns:	1 if the remote buffer was too full to accept data.
- *		0 otherwise.
- */
-static int put_channel_data(unsigned int chan)
-{
-	struct dashtty_port *dport;
-	struct tty_struct *tty;
-	int number_written;
-	unsigned int count = 0;
-
-	dport = &dashtty_ports[chan];
-	mutex_lock(&dport->xmit_lock);
-	if (dport->xmit_cnt) {
-		count = min((unsigned int)(SERIAL_XMIT_SIZE - dport->xmit_tail),
-			    dport->xmit_cnt);
-		chancall(WRBUF, chan, count,
-			 dport->port.xmit_buf + dport->xmit_tail,
-			 &number_written);
-		dport->xmit_cnt -= number_written;
-		if (!dport->xmit_cnt) {
-			/* reset pointers to avoid wraps */
-			dport->xmit_head = 0;
-			dport->xmit_tail = 0;
-			complete(&dport->xmit_empty);
-		} else {
-			dport->xmit_tail += number_written;
-			if (dport->xmit_tail >= SERIAL_XMIT_SIZE)
-				dport->xmit_tail -= SERIAL_XMIT_SIZE;
-		}
-		atomic_sub(number_written, &dashtty_xmit_cnt);
-	}
-	mutex_unlock(&dport->xmit_lock);
-
-	/* if we've made more data available, wake up tty */
-	if (count && number_written) {
-		tty = tty_port_tty_get(&dport->port);
-		if (tty) {
-			tty_wakeup(tty);
-			tty_kref_put(tty);
-		}
-	}
-
-	/* did the write fail? */
-	return count && !number_written;
-}
-
-/**
- * put_data() - Kernel thread to write out blocks of channel data to DA.
- * @arg:	Unused.
- *
- * This kernel thread runs while @dashtty_xmit_cnt != 0, and loops over the
- * channels to write out any buffered data. If any of the channels stall due to
- * the remote buffer being full, a hold off happens to allow the debugger to
- * drain the buffer.
- */
-static int put_data(void *arg)
-{
-	unsigned int chan, stall;
-
-	__set_current_state(TASK_RUNNING);
-	while (!kthread_should_stop()) {
-		/*
-		 * For each channel see if there's anything to transmit in the
-		 * port's xmit_buf.
-		 */
-		stall = 0;
-		for (chan = 0; chan < NUM_TTY_CHANNELS; ++chan)
-			stall += put_channel_data(chan);
-
-		/*
-		 * If some of the buffers are full, hold off for a short while
-		 * to allow them to empty.
-		 */
-		if (stall)
-			msleep(25);
-
-		wait_event_interruptible(dashtty_waitqueue,
-					 atomic_read(&dashtty_xmit_cnt));
-	}
-
-	return 0;
-}
-
-/*
- *	This gets called every DA_TTY_POLL and polls the channels for data
- */
-static void dashtty_timer(struct timer_list *poll_timer)
-{
-	int channel;
-
-	/* If there are no ports open do nothing and don't poll again. */
-	if (!atomic_read(&num_channels_need_poll))
-		return;
-
-	channel = find_channel_to_poll();
-
-	/* Did we find a channel to poll? */
-	if (channel >= 0)
-		fetch_data(channel);
-
-	mod_timer(poll_timer, jiffies + DA_TTY_POLL);
-}
-
-static void add_poll_timer(struct timer_list *poll_timer)
-{
-	timer_setup(poll_timer, dashtty_timer, TIMER_PINNED);
-	poll_timer->expires = jiffies + DA_TTY_POLL;
-
-	/*
-	 * Always attach the timer to the boot CPU. The DA channels are per-CPU
-	 * so all polling should be from a single CPU.
-	 */
-	add_timer_on(poll_timer, 0);
-}
-
-static int dashtty_port_activate(struct tty_port *port, struct tty_struct *tty)
-{
-	struct dashtty_port *dport = container_of(port, struct dashtty_port,
-						  port);
-	void *rx_buf;
-
-	/* Allocate the buffer we use for writing data */
-	if (tty_port_alloc_xmit_buf(port) < 0)
-		goto err;
-
-	/* Allocate the buffer we use for reading data */
-	rx_buf = kzalloc(RX_BUF_SIZE, GFP_KERNEL);
-	if (!rx_buf)
-		goto err_free_xmit;
-
-	spin_lock_bh(&dport->rx_lock);
-	dport->rx_buf = rx_buf;
-	spin_unlock_bh(&dport->rx_lock);
-
-	/*
-	 * Don't add the poll timer if we're opening a console. This
-	 * avoids the overhead of polling the Dash but means it is not
-	 * possible to have a login on /dev/console.
-	 *
-	 */
-	if (console_poll || dport != &dashtty_ports[CONSOLE_CHANNEL])
-		if (atomic_inc_return(&num_channels_need_poll) == 1)
-			add_poll_timer(&poll_timer);
-
-	return 0;
-err_free_xmit:
-	tty_port_free_xmit_buf(port);
-err:
-	return -ENOMEM;
-}
-
-static void dashtty_port_shutdown(struct tty_port *port)
-{
-	struct dashtty_port *dport = container_of(port, struct dashtty_port,
-						  port);
-	void *rx_buf;
-	unsigned int count;
-
-	/* stop reading */
-	if (console_poll || dport != &dashtty_ports[CONSOLE_CHANNEL])
-		if (atomic_dec_and_test(&num_channels_need_poll))
-			del_timer_sync(&poll_timer);
-
-	mutex_lock(&dport->xmit_lock);
-	count = dport->xmit_cnt;
-	mutex_unlock(&dport->xmit_lock);
-	if (count) {
-		/*
-		 * There's still data to write out, so wake and wait for the
-		 * writer thread to drain the buffer.
-		 */
-		del_timer(&put_timer);
-		wake_up_interruptible(&dashtty_waitqueue);
-		wait_for_completion(&dport->xmit_empty);
-	}
-
-	/* Null the read buffer (timer could still be running!) */
-	spin_lock_bh(&dport->rx_lock);
-	rx_buf = dport->rx_buf;
-	dport->rx_buf = NULL;
-	spin_unlock_bh(&dport->rx_lock);
-	/* Free the read buffer */
-	kfree(rx_buf);
-
-	/* Free the write buffer */
-	tty_port_free_xmit_buf(port);
-}
-
-static const struct tty_port_operations dashtty_port_ops = {
-	.activate	= dashtty_port_activate,
-	.shutdown	= dashtty_port_shutdown,
-};
-
-static int dashtty_install(struct tty_driver *driver, struct tty_struct *tty)
-{
-	return tty_port_install(&dashtty_ports[tty->index].port, driver, tty);
-}
-
-static int dashtty_open(struct tty_struct *tty, struct file *filp)
-{
-	return tty_port_open(tty->port, tty, filp);
-}
-
-static void dashtty_close(struct tty_struct *tty, struct file *filp)
-{
-	return tty_port_close(tty->port, tty, filp);
-}
-
-static void dashtty_hangup(struct tty_struct *tty)
-{
-	int channel;
-	struct dashtty_port *dport;
-
-	channel = tty->index;
-	dport = &dashtty_ports[channel];
-
-	/* drop any data in the xmit buffer */
-	mutex_lock(&dport->xmit_lock);
-	if (dport->xmit_cnt) {
-		atomic_sub(dport->xmit_cnt, &dashtty_xmit_cnt);
-		dport->xmit_cnt = 0;
-		dport->xmit_head = 0;
-		dport->xmit_tail = 0;
-		complete(&dport->xmit_empty);
-	}
-	mutex_unlock(&dport->xmit_lock);
-
-	tty_port_hangup(tty->port);
-}
-
-/**
- * dashtty_put_timer() - Delayed wake up of kernel thread.
- * @ignored:	unused
- *
- * This timer function wakes up the kernel thread if any data exists in the
- * buffers. It is used to delay the expensive writeout until the writer has
- * stopped writing.
- */
-static void dashtty_put_timer(struct timer_list *unused)
-{
-	if (atomic_read(&dashtty_xmit_cnt))
-		wake_up_interruptible(&dashtty_waitqueue);
-}
-
-static int dashtty_write(struct tty_struct *tty, const unsigned char *buf,
-			 int total)
-{
-	int channel, count, block;
-	struct dashtty_port *dport;
-
-	/* Determine the channel */
-	channel = tty->index;
-	dport = &dashtty_ports[channel];
-
-	/*
-	 * Write to output buffer.
-	 *
-	 * The reason that we asynchronously write the buffer is because if we
-	 * were to write the buffer synchronously then because DA channels are
-	 * per-CPU the buffer would be written to the channel of whatever CPU
-	 * we're running on.
-	 *
-	 * What we actually want to happen is have all input and output done on
-	 * one CPU.
-	 */
-	mutex_lock(&dport->xmit_lock);
-	/* work out how many bytes we can write to the xmit buffer */
-	total = min(total, (int)(SERIAL_XMIT_SIZE - dport->xmit_cnt));
-	atomic_add(total, &dashtty_xmit_cnt);
-	dport->xmit_cnt += total;
-	/* write the actual bytes (may need splitting if it wraps) */
-	for (count = total; count; count -= block) {
-		block = min(count, (int)(SERIAL_XMIT_SIZE - dport->xmit_head));
-		memcpy(dport->port.xmit_buf + dport->xmit_head, buf, block);
-		dport->xmit_head += block;
-		if (dport->xmit_head >= SERIAL_XMIT_SIZE)
-			dport->xmit_head -= SERIAL_XMIT_SIZE;
-		buf += block;
-	}
-	count = dport->xmit_cnt;
-	/* xmit buffer no longer empty? */
-	if (count)
-		reinit_completion(&dport->xmit_empty);
-	mutex_unlock(&dport->xmit_lock);
-
-	if (total) {
-		/*
-		 * If the buffer is full, wake up the kthread, otherwise allow
-		 * some more time for the buffer to fill up a bit before waking
-		 * it.
-		 */
-		if (count == SERIAL_XMIT_SIZE) {
-			del_timer(&put_timer);
-			wake_up_interruptible(&dashtty_waitqueue);
-		} else {
-			mod_timer(&put_timer, jiffies + DA_TTY_PUT_DELAY);
-		}
-	}
-	return total;
-}
-
-static int dashtty_write_room(struct tty_struct *tty)
-{
-	struct dashtty_port *dport;
-	int channel;
-	int room;
-
-	channel = tty->index;
-	dport = &dashtty_ports[channel];
-
-	/* report the space in the xmit buffer */
-	mutex_lock(&dport->xmit_lock);
-	room = SERIAL_XMIT_SIZE - dport->xmit_cnt;
-	mutex_unlock(&dport->xmit_lock);
-
-	return room;
-}
-
-static int dashtty_chars_in_buffer(struct tty_struct *tty)
-{
-	struct dashtty_port *dport;
-	int channel;
-	int chars;
-
-	channel = tty->index;
-	dport = &dashtty_ports[channel];
-
-	/* report the number of bytes in the xmit buffer */
-	mutex_lock(&dport->xmit_lock);
-	chars = dport->xmit_cnt;
-	mutex_unlock(&dport->xmit_lock);
-
-	return chars;
-}
-
-static const struct tty_operations dashtty_ops = {
-	.install		= dashtty_install,
-	.open			= dashtty_open,
-	.close			= dashtty_close,
-	.hangup			= dashtty_hangup,
-	.write			= dashtty_write,
-	.write_room		= dashtty_write_room,
-	.chars_in_buffer	= dashtty_chars_in_buffer,
-};
-
-static int __init dashtty_init(void)
-{
-	int ret;
-	int nport;
-	struct dashtty_port *dport;
-
-	if (!metag_da_enabled())
-		return -ENODEV;
-
-	channel_driver = tty_alloc_driver(NUM_TTY_CHANNELS,
-					  TTY_DRIVER_REAL_RAW);
-	if (IS_ERR(channel_driver))
-		return PTR_ERR(channel_driver);
-
-	channel_driver->driver_name = "metag_da";
-	channel_driver->name = "ttyDA";
-	channel_driver->major = DA_TTY_MAJOR;
-	channel_driver->minor_start = 0;
-	channel_driver->type = TTY_DRIVER_TYPE_SERIAL;
-	channel_driver->subtype = SERIAL_TYPE_NORMAL;
-	channel_driver->init_termios = tty_std_termios;
-	channel_driver->init_termios.c_cflag |= CLOCAL;
-
-	tty_set_operations(channel_driver, &dashtty_ops);
-	for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) {
-		dport = &dashtty_ports[nport];
-		tty_port_init(&dport->port);
-		dport->port.ops = &dashtty_port_ops;
-		spin_lock_init(&dport->rx_lock);
-		mutex_init(&dport->xmit_lock);
-		/* the xmit buffer starts empty, i.e. completely written */
-		init_completion(&dport->xmit_empty);
-		complete(&dport->xmit_empty);
-	}
-
-	timer_setup(&put_timer, dashtty_put_timer, 0);
-
-	init_waitqueue_head(&dashtty_waitqueue);
-	dashtty_thread = kthread_create(put_data, NULL, "ttyDA");
-	if (IS_ERR(dashtty_thread)) {
-		pr_err("Couldn't create dashtty thread\n");
-		ret = PTR_ERR(dashtty_thread);
-		goto err_destroy_ports;
-	}
-	/*
-	 * Bind the writer thread to the boot CPU so it can't migrate.
-	 * DA channels are per-CPU and we want all channel I/O to be on a single
-	 * predictable CPU.
-	 */
-	kthread_bind(dashtty_thread, 0);
-	wake_up_process(dashtty_thread);
-
-	ret = tty_register_driver(channel_driver);
-
-	if (ret < 0) {
-		pr_err("Couldn't install dashtty driver: err %d\n",
-		       ret);
-		goto err_stop_kthread;
-	}
-
-	return 0;
-
-err_stop_kthread:
-	kthread_stop(dashtty_thread);
-err_destroy_ports:
-	for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) {
-		dport = &dashtty_ports[nport];
-		tty_port_destroy(&dport->port);
-	}
-	put_tty_driver(channel_driver);
-	return ret;
-}
-device_initcall(dashtty_init);
-
-#ifdef CONFIG_DA_CONSOLE
-
-static void dash_console_write(struct console *co, const char *s,
-			       unsigned int count)
-{
-	int actually_written;
-
-	chancall(WRBUF, CONSOLE_CHANNEL, count, (void *)s, &actually_written);
-}
-
-static struct tty_driver *dash_console_device(struct console *c, int *index)
-{
-	*index = c->index;
-	return channel_driver;
-}
-
-struct console dash_console = {
-	.name = "ttyDA",
-	.write = dash_console_write,
-	.device = dash_console_device,
-	.flags = CON_PRINTBUFFER,
-	.index = 1,
-};
-
-#endif