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>

2 files changed, 431 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;
+}