input: Add generic keyboard input handler

Add a module which understands converting key codes (or scan codes)
to ASCII characters. It includes FIFO support and can call back to
drivers to read new characters when its FIFO is empty.

Keycode maps are provided for un-modified, shift and ctrl keys.

The plan is to use this module where such mapping is required.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

3 files changed, 578 insertions, 0 deletions

diff --git a/drivers/input/Makefile b/drivers/input/Makefile
index 1f4dad3..d06acb9 100644
--- a/drivers/input/Makefile
+++ b/drivers/input/Makefile
@@ -30,6 +30,7 @@ ifdef CONFIG_PS2KBD
 COBJS-y += keyboard.o pc_keyb.o
 COBJS-$(CONFIG_PS2MULT) += ps2mult.o ps2ser.o
 endif
+COBJS-y += input.o
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)
diff --git a/drivers/input/input.c b/drivers/input/input.c
new file mode 100644
index 0000000..4eadd77
--- /dev/null
+++ b/drivers/input/input.c
@@ -0,0 +1,430 @@
+/*
+ * Translate key codes into ASCII
+ *
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <stdio_dev.h>
+#include <input.h>
+#include <linux/input.h>
+
+enum {
+	/* These correspond to the lights on the keyboard */
+	FLAG_NUM_LOCK		= 1 << 0,
+	FLAG_CAPS_LOCK		= 1 << 1,
+	FLAG_SCROLL_LOCK	= 1 << 2,
+
+	/* Special flag ORed with key code to indicate release */
+	KEY_RELEASE		= 1 << 15,
+	KEY_MASK		= 0xfff,
+};
+
+/*
+ * These takes map key codes to ASCII. 0xff means no key, or special key.
+ * Three tables are provided - one for plain keys, one for when the shift
+ * 'modifier' key is pressed and one for when the ctrl modifier key is
+ * pressed.
+ */
+static const uchar kbd_plain_xlate[] = {
+	0xff, 0x1b, '1',  '2',  '3',  '4',  '5',  '6',
+	'7',  '8',  '9',  '0',  '-',  '=', '\b', '\t',	/* 0x00 - 0x0f */
+	'q',  'w',  'e',  'r',  't',  'y',  'u',  'i',
+	'o',  'p',  '[',  ']', '\r', 0xff,  'a',  's',  /* 0x10 - 0x1f */
+	'd',  'f',  'g',  'h',  'j',  'k',  'l',  ';',
+	'\'',  '`', 0xff, '\\', 'z',  'x',  'c',  'v',	/* 0x20 - 0x2f */
+	'b',  'n',  'm',  ',' ,  '.', '/', 0xff, 0xff, 0xff,
+	' ', 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,	/* 0x30 - 0x3f */
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  '7',
+	'8',  '9',  '-',  '4',  '5',  '6',  '+',  '1',	/* 0x40 - 0x4f */
+	'2',  '3',  '0',  '.', 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,	/* 0x50 - 0x5F */
+	'\r', 0xff, 0xff
+};
+
+static unsigned char kbd_shift_xlate[] = {
+	0xff, 0x1b, '!', '@', '#', '$', '%', '^',
+	'&', '*', '(', ')', '_', '+', '\b', '\t',	/* 0x00 - 0x0f */
+	'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I',
+	'O', 'P', '{', '}', '\r', 0xff, 'A', 'S',	/* 0x10 - 0x1f */
+	'D', 'F', 'G', 'H', 'J', 'K', 'L', ':',
+	'"', '~', 0xff, '|', 'Z', 'X', 'C', 'V',	/* 0x20 - 0x2f */
+	'B', 'N', 'M', '<', '>', '?', 0xff, 0xff, 0xff,
+	' ', 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,	/* 0x30 - 0x3f */
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, '7',
+	'8', '9', '-', '4', '5', '6', '+', '1',	/* 0x40 - 0x4f */
+	'2', '3', '0', '.', 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,	/* 0x50 - 0x5F */
+	'\r', 0xff, 0xff
+};
+
+static unsigned char kbd_ctrl_xlate[] = {
+	0xff, 0x1b, '1', 0x00, '3', '4', '5', 0x1E,
+	'7', '8', '9', '0', 0x1F, '=', '\b', '\t',	/* 0x00 - 0x0f */
+	0x11, 0x17, 0x05, 0x12, 0x14, 0x18, 0x15, 0x09,
+	0x0f, 0x10, 0x1b, 0x1d, '\n', 0xff, 0x01, 0x13,	/* 0x10 - 0x1f */
+	0x04, 0x06, 0x08, 0x09, 0x0a, 0x0b, 0x0c, ';',
+	'\'', '~', 0x00, 0x1c, 0x1a, 0x18, 0x03, 0x16,	/* 0x20 - 0x2f */
+	0x02, 0x0e, 0x0d, '<', '>', '?', 0xff, 0xff,
+	0xff, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,	/* 0x30 - 0x3f */
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, '7',
+	'8', '9', '-', '4', '5', '6', '+', '1',		/* 0x40 - 0x4f */
+	'2', '3', '0', '.', 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,	/* 0x50 - 0x5F */
+	'\r', 0xff, 0xff
+};
+
+
+int input_queue_ascii(struct input_config *config, int ch)
+{
+	if (config->fifo_in + 1 == INPUT_BUFFER_LEN) {
+		if (!config->fifo_out)
+			return -1; /* buffer full */
+		else
+			config->fifo_in = 0;
+	} else {
+		if (config->fifo_in + 1 == config->fifo_out)
+			return -1; /* buffer full */
+		config->fifo_in++;
+	}
+	config->fifo[config->fifo_in] = (uchar)ch;
+
+	return 0;
+}
+
+int input_tstc(struct input_config *config)
+{
+	if (config->fifo_in == config->fifo_out && config->read_keys) {
+		if (!(*config->read_keys)(config))
+			return 0;
+	}
+	return config->fifo_in != config->fifo_out;
+}
+
+int input_getc(struct input_config *config)
+{
+	int err = 0;
+
+	while (config->fifo_in == config->fifo_out) {
+		if (config->read_keys)
+			err = (*config->read_keys)(config);
+		if (err)
+			return -1;
+	}
+
+	if (++config->fifo_out == INPUT_BUFFER_LEN)
+		config->fifo_out = 0;
+
+	return config->fifo[config->fifo_out];
+}
+
+/**
+ * Process a modifier/special key press or release and decide which key
+ * translation array should be used as a result.
+ *
+ * TODO: Should keep track of modifier press/release
+ *
+ * @param config	Input state
+ * @param key		Key code to process
+ * @param release	0 if a press, 1 if a release
+ * @return pointer to keycode->ascii translation table that should be used
+ */
+static struct input_key_xlate *process_modifier(struct input_config *config,
+						int key, int release)
+{
+	struct input_key_xlate *table;
+	int flip = -1;
+	int i;
+
+	/* Start with the main table, and see what modifiers change it */
+	assert(config->num_tables > 0);
+	table = &config->table[0];
+	for (i = 1; i < config->num_tables; i++) {
+		struct input_key_xlate *tab = &config->table[i];
+
+		if (key == tab->left_keycode || key == tab->right_keycode)
+			table = tab;
+	}
+
+	/* Handle the lighted keys */
+	if (!release) {
+		switch (key) {
+		case KEY_SCROLLLOCK:
+			flip = FLAG_SCROLL_LOCK;
+			break;
+		case KEY_NUMLOCK:
+			flip = FLAG_NUM_LOCK;
+			break;
+		case KEY_CAPSLOCK:
+			flip = FLAG_CAPS_LOCK;
+			break;
+		}
+	}
+
+	if (flip != -1) {
+		int leds = 0;
+
+		config->leds ^= flip;
+		if (config->flags & FLAG_NUM_LOCK)
+			leds |= INPUT_LED_NUM;
+		if (config->flags & FLAG_CAPS_LOCK)
+			leds |= INPUT_LED_CAPS;
+		if (config->flags & FLAG_SCROLL_LOCK)
+			leds |= INPUT_LED_SCROLL;
+		config->leds = leds;
+	}
+
+	return table;
+}
+
+/**
+ * Search an int array for a key value
+ *
+ * @param array	Array to search
+ * @param count	Number of elements in array
+ * @param key	Key value to find
+ * @return element where value was first found, -1 if none
+ */
+static int array_search(int *array, int count, int key)
+{
+	int i;
+
+	for (i = 0; i < count; i++) {
+		if (array[i] == key)
+			return i;
+	}
+
+	return -1;
+}
+
+/**
+ * Sort an array so that those elements that exist in the ordering are
+ * first in the array, and in the same order as the ordering. The algorithm
+ * is O(count * ocount) and designed for small arrays.
+ *
+ * TODO: Move this to common / lib?
+ *
+ * @param dest		Array with elements to sort, also destination array
+ * @param count		Number of elements to sort
+ * @param order		Array containing ordering elements
+ * @param ocount	Number of ordering elements
+ * @return number of elements in dest that are in order (these will be at the
+ *	start of dest).
+ */
+static int sort_array_by_ordering(int *dest, int count, int *order,
+				   int ocount)
+{
+	int temp[count];
+	int dest_count;
+	int same;	/* number of elements which are the same */
+	int i;
+
+	/* setup output items, copy items to be sorted into our temp area */
+	memcpy(temp, dest, count * sizeof(*dest));
+	dest_count = 0;
+
+	/* work through the ordering, move over the elements we agree on */
+	for (i = 0; i < ocount; i++) {
+		if (array_search(temp, count, order[i]) != -1)
+			dest[dest_count++] = order[i];
+	}
+	same = dest_count;
+
+	/* now move over the elements that are not in the ordering */
+	for (i = 0; i < count; i++) {
+		if (array_search(order, ocount, temp[i]) == -1)
+			dest[dest_count++] = temp[i];
+	}
+	assert(dest_count == count);
+	return same;
+}
+
+/**
+ * Check a list of key codes against the previous key scan
+ *
+ * Given a list of new key codes, we check how many of these are the same
+ * as last time.
+ *
+ * @param config	Input state
+ * @param keycode	List of key codes to examine
+ * @param num_keycodes	Number of key codes
+ * @param same		Returns number of key codes which are the same
+ */
+static int input_check_keycodes(struct input_config *config,
+			   int keycode[], int num_keycodes, int *same)
+{
+	/* Select the 'plain' xlate table to start with */
+	if (!config->num_tables) {
+		debug("%s: No xlate tables: cannot decode keys\n", __func__);
+		return -1;
+	}
+
+	/* sort the keycodes into the same order as the previous ones */
+	*same = sort_array_by_ordering(keycode, num_keycodes,
+			config->prev_keycodes, config->num_prev_keycodes);
+
+	memcpy(config->prev_keycodes, keycode, num_keycodes * sizeof(int));
+	config->num_prev_keycodes = num_keycodes;
+
+	return *same != num_keycodes;
+}
+
+/**
+ * Convert a list of key codes into ASCII
+ *
+ * You must call input_check_keycodes() before this. It turns the keycode
+ * list into a list of ASCII characters which are ready to send to the
+ * input layer.
+ *
+ * Characters which were seen last time do not generate fresh ASCII output.
+ *
+ * @param config	Input state
+ * @param keycode	List of key codes to examine
+ * @param num_keycodes	Number of key codes
+ * @param same		Number of key codes which are the same
+ */
+static int input_keycodes_to_ascii(struct input_config *config,
+		int keycode[], int num_keycodes, char output_ch[], int same)
+{
+	struct input_key_xlate *table;
+	int ch_count;
+	int i;
+
+	table = &config->table[0];
+
+	/* deal with modifiers first */
+	for (i = 0; i < num_keycodes; i++) {
+		int key = keycode[i] & KEY_MASK;
+
+		if (key >= table->num_entries || table->xlate[key] == 0xff) {
+			table = process_modifier(config, key,
+					keycode[i] & KEY_RELEASE);
+		}
+	}
+
+	/* now find normal keys */
+	for (i = ch_count = 0; i < num_keycodes; i++) {
+		int key = keycode[i];
+
+		if (key < table->num_entries && i >= same) {
+			int ch = table->xlate[key];
+
+			/* If a normal key with an ASCII value, add it! */
+			if (ch != 0xff)
+				output_ch[ch_count++] = (uchar)ch;
+		}
+	}
+
+	/* ok, so return keys */
+	return ch_count;
+}
+
+int input_send_keycodes(struct input_config *config,
+			int keycode[], int num_keycodes)
+{
+	char ch[num_keycodes];
+	int count, i, same = 0;
+	int is_repeat = 0;
+	unsigned delay_ms;
+
+	config->modifiers = 0;
+	if (!input_check_keycodes(config, keycode, num_keycodes, &same)) {
+		/*
+		 * Same as last time - is it time for another repeat?
+		 * TODO(sjg@chromium.org) We drop repeats here and since
+		 * the caller may not call in again for a while, our
+		 * auto-repeat speed is not quite correct. We should
+		 * insert another character if we later realise that we
+		 * have missed a repeat slot.
+		 */
+		is_repeat = (int)get_timer(config->next_repeat_ms) >= 0;
+		if (!is_repeat)
+			return 0;
+	}
+
+	count = input_keycodes_to_ascii(config, keycode, num_keycodes,
+					ch, is_repeat ? 0 : same);
+	for (i = 0; i < count; i++)
+		input_queue_ascii(config, ch[i]);
+	delay_ms = is_repeat ?
+			config->repeat_rate_ms :
+			config->repeat_delay_ms;
+
+	config->next_repeat_ms = get_timer(0) + delay_ms;
+	return 0;
+}
+
+int input_add_table(struct input_config *config, int left_keycode,
+		    int right_keycode, const uchar *xlate, int num_entries)
+{
+	struct input_key_xlate *table;
+
+	if (config->num_tables == INPUT_MAX_MODIFIERS) {
+		debug("%s: Too many modifier tables\n", __func__);
+		return -1;
+	}
+
+	table = &config->table[config->num_tables++];
+	table->left_keycode = left_keycode;
+	table->right_keycode = right_keycode;
+	table->xlate = xlate;
+	table->num_entries = num_entries;
+
+	return 0;
+}
+
+int input_init(struct input_config *config, int leds, int repeat_delay_ms,
+	       int repeat_rate_ms)
+{
+	memset(config, '\0', sizeof(*config));
+	config->leds = leds;
+	config->repeat_delay_ms = repeat_delay_ms;
+	config->repeat_rate_ms = repeat_rate_ms;
+	if (input_add_table(config, -1, -1,
+			kbd_plain_xlate, ARRAY_SIZE(kbd_plain_xlate)) ||
+		input_add_table(config, KEY_LEFTSHIFT, KEY_RIGHTSHIFT,
+			kbd_shift_xlate, ARRAY_SIZE(kbd_shift_xlate)) ||
+		input_add_table(config, KEY_LEFTCTRL, KEY_RIGHTCTRL,
+			kbd_ctrl_xlate, ARRAY_SIZE(kbd_ctrl_xlate))) {
+		debug("%s: Could not add modifier tables\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int input_stdio_register(struct stdio_dev *dev)
+{
+	int error;
+
+	error = stdio_register(dev);
+
+	/* check if this is the standard input device */
+	if (!error && strcmp(getenv("stdin"), dev->name) == 0) {
+		/* reassign the console */
+		if (OVERWRITE_CONSOLE ||
+				console_assign(stdin, dev->name))
+			return -1;
+	}
+
+	return 0;
+}
diff --git a/include/input.h b/include/input.h
new file mode 100644
index 0000000..31b1ef9
--- /dev/null
+++ b/include/input.h
@@ -0,0 +1,147 @@
+/*
+ * Keyboard input helper functions (too small to be called a layer)
+ *
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _INPUT_H
+#define _INPUT_H
+
+enum {
+	INPUT_MAX_MODIFIERS	= 4,
+	INPUT_BUFFER_LEN	= 16,
+};
+
+enum {
+	/* Keyboard LEDs */
+	INPUT_LED_SCROLL	= 1 << 0,
+	INPUT_LED_CAPS		= 1 << 1,
+	INPUT_LED_NUM		= 1 << 2,
+};
+
+/*
+ * This table translates key codes to ASCII. Most of the entries are ASCII
+ * codes, but entries after KEY_FIRST_MOD indicate that this key is a
+ * modifier key, like shift, ctrl. KEY_FIRST_MOD + MOD_SHIFT is the shift
+ * key, for example.
+ */
+struct input_key_xlate {
+	/* keycode of the modifiers which select this table, -1 if none */
+	int left_keycode;
+	int right_keycode;
+	const uchar *xlate;	/* keycode to ASCII table */
+	int num_entries;	/* number of entries in this table */
+};
+
+struct input_config {
+	uchar fifo[INPUT_BUFFER_LEN];
+	int fifo_in, fifo_out;
+
+	/* Which modifiers are active (1 bit for each MOD_... value) */
+	uchar modifiers;
+	uchar flags;		/* active state keys (FLAGS_...) */
+	uchar leds;		/* active LEDS (INPUT_LED_...) */
+	uchar num_tables;	/* number of modifier tables */
+	int prev_keycodes[INPUT_BUFFER_LEN];	/* keys held last time */
+	int num_prev_keycodes;	/* number of prev keys */
+	struct input_key_xlate table[INPUT_MAX_MODIFIERS];
+
+	/**
+	 * Function the input helper calls to scan the keyboard
+	 *
+	 * @param config	Input state
+	 * @return 0 if no keys read, otherwise number of keys read, or 1 if
+	 *		unknown
+	 */
+	int (*read_keys)(struct input_config *config);
+	unsigned int next_repeat_ms;	/* Next time we repeat a key */
+	unsigned int repeat_delay_ms;	/* Time before autorepeat starts */
+	unsigned int repeat_rate_ms;	/* Autorepeat rate in ms */
+};
+
+struct stdio_dev;
+
+/**
+ * Convert a list of key codes into ASCII and send them
+ *
+ * @param config	Input state
+ * @param keycode	List of key codes to examine
+ * @param num_keycodes	Number of key codes
+ */
+int input_send_keycodes(struct input_config *config, int keycode[], int count);
+
+/**
+ * Add a new key translation table to the input
+ *
+ * @param config	Input state
+ * @param left_keycode	Key to hold to get into this table
+ * @param right_keycode	Another key to hold to get into this table
+ * @param xlate		Conversion table from key codes to ASCII
+ * @param num_entries	Number of entries in xlate table
+ */
+int input_add_table(struct input_config *config, int left_keycode,
+		    int right_keycode, const uchar *xlate, int num_entries);
+
+/**
+ * Test if keys are available to be read
+ *
+ * @param config	Input state
+ * @return 0 if no keys available, 1 if keys are available
+ */
+int input_tstc(struct input_config *config);
+
+/**
+ * Read a key
+ *
+ * TODO: U-Boot wants 0 for no key, but Ctrl-@ is a valid key...
+ *
+ * @param config	Input state
+ * @return key, or 0 if no key, or -1 if error
+ */
+int input_getc(struct input_config *config);
+
+/**
+ * Register a new device with stdio and switch to it if wanted
+ *
+ * @param dev	Pointer to device
+ * @return 0 if ok, -1 on error
+ */
+int input_stdio_register(struct stdio_dev *dev);
+
+/**
+ * Set up the input handler with basic key maps.
+ *
+ * @param config	Input state
+ * @param leds		Initial LED value (INPUT_LED_ mask), 0 suggested
+ * @param repeat_delay_ms	Delay before key auto-repeat starts (in ms)
+ * @param repeat_rate_ms	Delay between successive key repeats (in ms)
+ * @return 0 if ok, -1 on error
+ */
+int input_init(struct input_config *config, int leds, int repeat_delay_ms,
+	       int repeat_rate_ms);
+
+#ifdef CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
+extern int overwrite_console(void);
+#define OVERWRITE_CONSOLE overwrite_console()
+#else
+#define OVERWRITE_CONSOLE 0
+#endif /* CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE */
+
+#endif