keyboard: Keep only scan code set 2 table and do translation for set 1.

The 8042 scan code set 1 can be directly translated from set 2, with a
256 byte table. With this change, we can always process key stroke in
scan code (set 2), and only translate in the single function
`scancode_bytes`. This is very helpful when we need to do key
processing, for example the buttons_8042 can now be simplified with only
one scan code. And is extremely helpful if we want to do dynamic
translation (i.e., to prevent something like CL:1164725).

For `make BOARD=samus', the free space is also increased from 18472 to
18656 (+184) bytes.

BUG=None
TEST=make buildall; manually installed on Eve and tested by
     running 'keyboard' factory test to make sure all key scancodes
     are not changed.
BRANCH=None

Change-Id: Ieb303d84edcd4375bbeb1ea5f032d0462bbfd250
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1166742
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

2 files changed, 87 insertions, 103 deletions

diff --git a/common/keyboard_8042.c b/common/keyboard_8042.c
index 04e00d2bb2..4b2b9a5db9 100644
--- a/common/keyboard_8042.c
+++ b/common/keyboard_8042.c
@@ -252,6 +252,11 @@ static enum scancode_set_list acting_code_set(enum scancode_set_list set)
 	return set;
 }
 
+static int is_supported_code_set(enum scancode_set_list set)
+{
+	return (set == SCANCODE_SET_1 || set == SCANCODE_SET_2);
+}
+
 /**
  * Return the make or break code bytes for the active scancode set.
  *
@@ -269,33 +274,22 @@ static void scancode_bytes(uint16_t make_code, int8_t pressed,
 
 	/* Output the make code (from table) */
 	if (make_code >= 0x0100) {
-		*len += 2;
-		scan_code[0] = make_code >> 8;
-		scan_code[1] = make_code & 0xff;
-	} else {
-		*len += 1;
-		scan_code[0] = make_code & 0xff;
+		scan_code[(*len)++] = make_code >> 8;
+		make_code &= 0xff;
 	}
 
 	switch (code_set) {
 	case SCANCODE_SET_1:
-		/* OR 0x80 for the last byte. */
-		if (!pressed) {
-			ASSERT(*len >= 1);
-			scan_code[*len - 1] |= 0x80;
-		}
+		make_code = scancode_translate_set2_to_1(make_code);
+		scan_code[(*len)++] = pressed ? make_code : (make_code | 0x80);
 		break;
 
 	case SCANCODE_SET_2:
-		/*
-		 * Insert the break byte, move back the last byte and insert a
-		 * 0xf0 byte before that.
-		 */
-		if (!pressed) {
-			ASSERT(*len >= 1);
-			scan_code[*len] = scan_code[*len - 1];
-			scan_code[*len - 1] = 0xf0;
-			*len += 1;
+		if (pressed) {
+			scan_code[(*len)++] = make_code;
+		} else {
+			scan_code[(*len)++] = 0xf0;
+			scan_code[(*len)++] = make_code;
 		}
 		break;
 	default:
@@ -316,21 +310,12 @@ static enum ec_error_list matrix_callback(int8_t row, int8_t col,
 	if (row >= KEYBOARD_ROWS || col >= KEYBOARD_COLS)
 		return EC_ERROR_INVAL;
 
+	make_code = scancode_set2[row][col];
 	if (pressed)
-		keyboard_special(scancode_set1[row][col]);
+		keyboard_special(make_code);
 
 	code_set = acting_code_set(code_set);
-
-	switch (code_set) {
-	case SCANCODE_SET_1:
-		make_code = scancode_set1[row][col];
-		break;
-
-	case SCANCODE_SET_2:
-		make_code = scancode_set2[row][col];
-		break;
-
-	default:
+	if (!is_supported_code_set(code_set)) {
 		CPRINTS("KB scancode set %d unsupported", code_set);
 		return EC_ERROR_UNIMPLEMENTED;
 	}
@@ -791,30 +776,30 @@ static void i8042_handle_from_host(void)
 static void keyboard_special(uint16_t k)
 {
 	static uint8_t s;
-	static const uint16_t a[] = {0xe048, 0xe048, 0xe050, 0xe050, 0xe04b,
-				     0xe04d, 0xe04b, 0xe04d, 0x0030, 0x001e};
+	static const uint16_t a[] = {0xe075, 0xe075, 0xe072, 0xe072, 0xe06b,
+				     0xe074, 0xe06b, 0xe074, 0x0032, 0x001c};
 #ifdef HAS_TASK_LIGHTBAR
 	/* Lightbar demo mode: keyboard can fake the battery state */
 	switch (k) {
-	case 0xe048:				/* up */
+	case 0xe075:				/* up */
 		demo_battery_level(1);
 		break;
-	case 0xe050:				/* down */
+	case 0xe072:				/* down */
 		demo_battery_level(-1);
 		break;
-	case 0xe04b:				/* left */
+	case 0xe06b:				/* left */
 		demo_is_charging(0);
 		break;
-	case 0xe04d:				/* right */
+	case 0xe074:				/* right */
 		demo_is_charging(1);
 		break;
-	case 0x0040:				/* dim */
+	case 0x000b:				/* dim */
 		demo_brightness(-1);
 		break;
-	case 0x0041:				/* bright */
+	case 0x0083:				/* bright */
 		demo_brightness(1);
 		break;
-	case 0x0014:				/* T */
+	case 0x002c:				/* T */
 		demo_tap();
 		break;
 	}
@@ -822,7 +807,7 @@ static void keyboard_special(uint16_t k)
 
 	if (k == a[s])
 		s++;
-	else if (k != 0xe048)
+	else if (k != 0xe075)
 		s = 0;
 	else if (s != 2)
 		s = 1;
@@ -919,7 +904,6 @@ test_mockable void keyboard_update_button(enum keyboard_button_type button,
 					  int is_pressed)
 {
 	uint8_t scan_code[MAX_SCAN_CODE_LEN];
-	uint16_t make_code;
 	uint32_t len;
 	struct button_8042_t button_8042;
 	enum scancode_set_list code_set;
@@ -932,20 +916,12 @@ test_mockable void keyboard_update_button(enum keyboard_button_type button,
 		return;
 
 	code_set = acting_code_set(scancode_set);
-	button_8042 = buttons_8042[button];
-
-	switch (code_set) {
-	case SCANCODE_SET_1:
-		make_code = button_8042.scancode_set1;
-		break;
-	case SCANCODE_SET_2:
-		make_code = button_8042.scancode_set2;
-		break;
-	default:
-		return; /* Other sets are not supported */
-	}
+	if (!is_supported_code_set(code_set))
+		return;
 
-	scancode_bytes(make_code, is_pressed, code_set, scan_code, &len);
+	button_8042 = buttons_8042[button];
+	scancode_bytes(button_8042.scancode, is_pressed, code_set, scan_code,
+		       &len);
 	ASSERT(len > 0);
 
 	if (button_8042.repeat) {
diff --git a/common/keyboard_8042_sharedlib.c b/common/keyboard_8042_sharedlib.c
index 7aba63502d..0ea4dca792 100644
--- a/common/keyboard_8042_sharedlib.c
+++ b/common/keyboard_8042_sharedlib.c
@@ -12,39 +12,11 @@
 #include "libsharedobjs.h"
 #include "util.h"
 
-/* The standard Chrome OS keyboard matrix table. */
-#ifdef CONFIG_KEYBOARD_SCANCODE_MUTABLE
-uint16_t scancode_set1[KEYBOARD_ROWS][KEYBOARD_COLS] = {
-#else
-SHAREDLIB(const uint16_t scancode_set1[KEYBOARD_ROWS][KEYBOARD_COLS] = {
+/* The standard Chrome OS keyboard matrix table in scan code set 2. */
+#ifndef CONFIG_KEYBOARD_SCANCODE_MUTABLE
+SHAREDLIB(const
 #endif
-	{0x0000, 0xe05b, 0x003b, 0x0030, 0x0044, 0x0073, 0x0031, 0x0000, 0x000d,
-	 0x0000, 0xe038, 0x0000, 0x0000},
-	{0x0000, 0x0001, 0x003e, 0x0022, 0x0041, 0x0000, 0x0023, 0x0000, 0x0028,
-	 0x0043, 0x0000, 0x000e, 0x0079},
-	{0x001d, 0x000f, 0x003d, 0x0014, 0x0040, 0x001b, 0x0015, 0x0056, 0x001a,
-	 0x0042, 0x007d, 0x0000, 0x0000},
-	{0xe05b, 0x0029, 0x003c, 0x0006, 0x003f, 0x0000, 0x0007, 0x0000, 0x000c,
-	 0x005d, 0x0000, 0x002b, 0x007b},
-	{0xe01d, 0x001e, 0x0020, 0x0021, 0x001f, 0x0025, 0x0024, 0x0000, 0x0027,
-	 0x0026, 0x002b, 0x001c, 0x0000},
-	{0xe058, 0x002c, 0x002e, 0x002f, 0x002d, 0x0033, 0x0032, 0x002a, 0x0035,
-	 0x0034, 0x0000, 0x0039, 0x0000},
-	{0x0000, 0x0002, 0x0004, 0x0005, 0x0003, 0x0009, 0x0008, 0x0000, 0x000b,
-	 0x000a, 0x0038, 0xe050, 0xe04d},
-	{0x0000, 0x0010, 0x0012, 0x0013, 0x0011, 0x0017, 0x0016, 0x0036, 0x0019,
-	 0x0018, 0x0000, 0xe048, 0xe04b},
-#ifdef CONFIG_KEYBOARD_SCANCODE_MUTABLE
-};
-#else
-});
-#endif
-
-#ifdef CONFIG_KEYBOARD_SCANCODE_MUTABLE
 uint16_t scancode_set2[KEYBOARD_ROWS][KEYBOARD_COLS] = {
-#else
-SHAREDLIB(uint16_t const scancode_set2[KEYBOARD_ROWS][KEYBOARD_COLS] = {
-#endif
 	{0x0000, 0xe01f, 0x0005, 0x0032, 0x0009, 0x0051, 0x0031, 0x0000, 0x0055,
 	 0x0000, 0xe011, 0x0000, 0x0000},
 	{0x0000, 0x0076, 0x000c, 0x0034, 0x0083, 0x0000, 0x0033, 0x0000, 0x0052,
@@ -61,27 +33,63 @@ SHAREDLIB(uint16_t const scancode_set2[KEYBOARD_ROWS][KEYBOARD_COLS] = {
 	 0x0046, 0x0011, 0xe072, 0xe074},
 	{0x0000, 0x0015, 0x0024, 0x002d, 0x001d, 0x0043, 0x003c, 0x0059, 0x004d,
 	 0x0044, 0x0000, 0xe075, 0xe06b},
-#ifdef CONFIG_KEYBOARD_SCANCODE_MUTABLE
-};
-#else
-});
+}
+#ifndef CONFIG_KEYBOARD_SCANCODE_MUTABLE
+)
 #endif
+;
+
+/*
+ * The translation table from scan code set 2 to set 1.
+ * Ref: http://kbd-project.org/docs/scancodes/scancodes-10.html#ss10.3
+ * To reduce space, we only keep the translation for 0~127,
+ * so a real translation need to do 0x83=>0x41 explicitly (
+ * see scancode_translate_set2_to_1 below).
+ */
+SHAREDLIB(const uint8_t scancode_translate_table[128] = {
+	0xff, 0x43, 0x41, 0x3f, 0x3d, 0x3b, 0x3c, 0x58,
+	0x64, 0x44, 0x42, 0x40, 0x3e, 0x0f, 0x29, 0x59,
+	0x65, 0x38, 0x2a, 0x70, 0x1d, 0x10, 0x02, 0x5a,
+	0x66, 0x71, 0x2c, 0x1f, 0x1e, 0x11, 0x03, 0x5b,
+	0x67, 0x2e, 0x2d, 0x20, 0x12, 0x05, 0x04, 0x5c,
+	0x68, 0x39, 0x2f, 0x21, 0x14, 0x13, 0x06, 0x5d,
+	0x69, 0x31, 0x30, 0x23, 0x22, 0x15, 0x07, 0x5e,
+	0x6a, 0x72, 0x32, 0x24, 0x16, 0x08, 0x09, 0x5f,
+	0x6b, 0x33, 0x25, 0x17, 0x18, 0x0b, 0x0a, 0x60,
+	0x6c, 0x34, 0x35, 0x26, 0x27, 0x19, 0x0c, 0x61,
+	0x6d, 0x73, 0x28, 0x74, 0x1a, 0x0d, 0x62, 0x6e,
+	0x3a, 0x36, 0x1c, 0x1b, 0x75, 0x2b, 0x63, 0x76,
+	0x55, 0x56, 0x77, 0x78, 0x79, 0x7a, 0x0e, 0x7b,
+	0x7c, 0x4f, 0x7d, 0x4b, 0x47, 0x7e, 0x7f, 0x6f,
+	0x52, 0x53, 0x50, 0x4c, 0x4d, 0x48, 0x01, 0x45,
+	0x57, 0x4e, 0x51, 0x4a, 0x37, 0x49, 0x46, 0x54,
+});
+
+uint8_t scancode_translate_set2_to_1(uint8_t code)
+{
+	if (code & 0x80) {
+		if (code == 0x83)
+			return 0x41;
+		return code;
+	}
+	return scancode_translate_table[code];
+}
 
 /*
- * Button scancodes.
+ * Button scancodes in code set 2.
  * Must be in the same order as defined in keyboard_button_type.
  */
 SHAREDLIB(const struct button_8042_t buttons_8042[] = {
-	{0xe05e, 0xe037, 0}, /* Power */
-	{0xe02e, 0xe021, 1}, /* Volume Down */
-	{0xe030, 0xe032, 1}, /* Volume Up */
-	{0x0002, 0x0016, 1}, /* 1 */
-	{0x0003, 0x001e, 1}, /* 2 */
-	{0x0004, 0x0026, 1}, /* 3 */
-	{0x0005, 0x0025, 1}, /* 4 */
-	{0x0006, 0x002e, 1}, /* 5 */
-	{0x0007, 0x0036, 1}, /* 6 */
-	{0x0008, 0x003d, 1}, /* 7 */
-	{0x0009, 0x003e, 1}, /* 8 */
+	{0xe037, 0}, /* Power */
+	{0xe021, 1}, /* Volume Down */
+	{0xe032, 1}, /* Volume Up */
+	{0x0016, 1}, /* 1 */
+	{0x001e, 1}, /* 2 */
+	{0x0026, 1}, /* 3 */
+	{0x0025, 1}, /* 4 */
+	{0x002e, 1}, /* 5 */
+	{0x0036, 1}, /* 6 */
+	{0x003d, 1}, /* 7 */
+	{0x003e, 1}, /* 8 */
 });
 BUILD_ASSERT(ARRAY_SIZE(buttons_8042) == KEYBOARD_BUTTON_COUNT);