arch/x86/acpi: Add code to generate ACPI for PS2 keyboards

Add new file to generate ACPI _DSD code for PS2 keyboards. The
following 2 device properties are generated as needed:

function-row-phymap: A list of ordered scancodes for function row.

linux,keymap: Symantically, this is an array of "scancode,keycode"
tuple entries. Each entry teaches linux the keycode corresponding
to a scancode.

Signed-off-by: Rajat Jain <rajatja@google.com>
Change-Id: I5ee05173106a125793e91c263610731543c85472
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40031
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

3 files changed, 339 insertions, 0 deletions

diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
index b28ef78adc..2d007094c7 100644
--- a/src/arch/x86/Makefile.inc
+++ b/src/arch/x86/Makefile.inc
@@ -235,6 +235,7 @@ ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpigen.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpigen_dsm.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi_device.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi_pld.c
+ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpigen_ps2_keybd.c
 ramstage-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.c
 ramstage-$(CONFIG_ACPI_BERT) += acpi_bert_storage.c
 ramstage-y += c_start.S
diff --git a/src/arch/x86/acpigen_ps2_keybd.c b/src/arch/x86/acpigen_ps2_keybd.c
new file mode 100644
index 0000000000..1573de8924
--- /dev/null
+++ b/src/arch/x86/acpigen_ps2_keybd.c
@@ -0,0 +1,297 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <arch/acpi.h>
+#include <arch/acpigen.h>
+#include <arch/acpigen_ps2_keybd.h>
+#include <console/console.h>
+#include <input-event-codes.h>
+
+#define KEYMAP(scancode, keycode) (((uint32_t)(scancode) << 16) | (keycode & 0xFFFF))
+#define SCANCODE(keymap) ((keymap >> 16) & 0xFFFF)
+
+/* Possible keymaps for function keys in the top row */
+static const uint32_t function_keymaps[] = {
+	KEYMAP(0x3b, KEY_F1),
+	KEYMAP(0x3c, KEY_F2),
+	KEYMAP(0x3d, KEY_F3),
+	KEYMAP(0x3e, KEY_F4),
+	KEYMAP(0x3f, KEY_F5),
+	KEYMAP(0x40, KEY_F6),
+	KEYMAP(0x41, KEY_F7),
+	KEYMAP(0x42, KEY_F8),
+	KEYMAP(0x43, KEY_F9),
+	KEYMAP(0x44, KEY_F10),
+	KEYMAP(0x57, KEY_F11),
+	KEYMAP(0x58, KEY_F12),
+	KEYMAP(0x59, KEY_F13),
+	KEYMAP(0x5a, KEY_F14),
+	KEYMAP(0x5b, KEY_F15),
+};
+
+/*
+ * Possible keymaps for action keys in the top row. This is a superset of
+ * possible keys. Individual keyboards will have a subset of these keys.
+ * The scancodes are true / condensed 1 byte scancodes from set-1
+ */
+static const uint32_t action_keymaps[] = {
+	[PS2_KEY_BACK] = KEYMAP(0xea, KEY_BACK),		/* e06a */
+	[PS2_KEY_FORWARD] = KEYMAP(0xe9, KEY_FORWARD),		/* e069 */
+	[PS2_KEY_REFRESH] = KEYMAP(0xe7, KEY_REFRESH),		/* e067 */
+	[PS2_KEY_FULLSCREEN] = KEYMAP(0x91, KEY_FULL_SCREEN),	/* e011 */
+	[PS2_KEY_OVERVIEW] = KEYMAP(0x92, KEY_SCALE),		/* e012 */
+	[PS2_KEY_VOL_MUTE] = KEYMAP(0xa0, KEY_MUTE),		/* e020 */
+	[PS2_KEY_VOL_DOWN] = KEYMAP(0xae, KEY_VOLUMEDOWN),	/* e02e */
+	[PS2_KEY_VOL_UP] = KEYMAP(0xb0, KEY_VOLUMEUP),		/* e030 */
+	[PS2_KEY_PLAY_PAUSE] = KEYMAP(0x9a, KEY_PLAYPAUSE),	/* e01a */
+	[PS2_KEY_NEXT_TRACK] = KEYMAP(0x99, KEY_NEXTSONG),	/* e019 */
+	[PS2_KEY_PREV_TRACK] = KEYMAP(0x90, KEY_PREVIOUSSONG),	/* e010 */
+	[PS2_KEY_SNAPSHOT] = KEYMAP(0x93, KEY_SYSRQ),		/* e013 */
+	[PS2_KEY_BRIGHTNESS_DOWN] = KEYMAP(0x94, KEY_BRIGHTNESSDOWN),/* e014 */
+	[PS2_KEY_BRIGHTNESS_UP] = KEYMAP(0x95, KEY_BRIGHTNESSUP),    /* e015 */
+	[PS2_KEY_KBD_BKLIGHT_DOWN] = KEYMAP(0x97, KEY_KBDILLUMDOWN), /* e017 */
+	[PS2_KEY_KBD_BKLIGHT_UP] = KEYMAP(0x98, KEY_KBDILLUMUP),     /* e018 */
+	[PS2_KEY_PRIVACY_SCRN_TOGGLE] = KEYMAP(0x96,		     /* e016 */
+					  KEY_PRIVACY_SCREEN_TOGGLE),
+};
+
+/* Keymap for numeric keypad keys */
+static uint32_t numeric_keypad_keymaps[] = {
+	/* Row-0 */
+	KEYMAP(0xc9, KEY_PAGEUP),
+	KEYMAP(0xd1, KEY_PAGEDOWN),
+	KEYMAP(0xc7, KEY_HOME),
+	KEYMAP(0xcf, KEY_END),
+	/* Row-1 */
+	KEYMAP(0xd3, KEY_DELETE),
+	KEYMAP(0xb5, KEY_KPSLASH),
+	KEYMAP(0x37, KEY_KPASTERISK),
+	KEYMAP(0x4a, KEY_KPMINUS),
+	/* Row-2 */
+	KEYMAP(0x47, KEY_KP7),
+	KEYMAP(0x48, KEY_KP8),
+	KEYMAP(0x49, KEY_KP9),
+	KEYMAP(0x4e, KEY_KPPLUS),
+	/* Row-3 */
+	KEYMAP(0x4b, KEY_KP4),
+	KEYMAP(0x4c, KEY_KP5),
+	KEYMAP(0x4d, KEY_KP6),
+	/* Row-4 */
+	KEYMAP(0x4f, KEY_KP1),
+	KEYMAP(0x50, KEY_KP2),
+	KEYMAP(0x51, KEY_KP3),
+	KEYMAP(0x9c, KEY_KPENTER),
+	/* Row-5 */
+	KEYMAP(0x52, KEY_KP0),
+	KEYMAP(0x53, KEY_KPDOT),
+};
+
+/*
+ * Keymap for rest of non-top-row keys. This is a superset of all the possible
+ * keys that any chromeos keyboards can have.
+ */
+static uint32_t rest_of_keymaps[] = {
+	/* Row-0 */
+	KEYMAP(0x01, KEY_ESC),
+	/* Row-1 */
+	KEYMAP(0x29, KEY_GRAVE),
+	KEYMAP(0x02, KEY_1),
+	KEYMAP(0x03, KEY_2),
+	KEYMAP(0x04, KEY_3),
+	KEYMAP(0x05, KEY_4),
+	KEYMAP(0x06, KEY_5),
+	KEYMAP(0x07, KEY_6),
+	KEYMAP(0x08, KEY_7),
+	KEYMAP(0x09, KEY_8),
+	KEYMAP(0x0a, KEY_9),
+	KEYMAP(0x0b, KEY_0),
+	KEYMAP(0x0c, KEY_MINUS),
+	KEYMAP(0x0d, KEY_EQUAL),
+	KEYMAP(0x0e, KEY_BACKSPACE),
+	/* Row-2 */
+	KEYMAP(0x0f, KEY_TAB),
+	KEYMAP(0x10, KEY_Q),
+	KEYMAP(0x11, KEY_W),
+	KEYMAP(0x12, KEY_E),
+	KEYMAP(0x13, KEY_R),
+	KEYMAP(0x14, KEY_T),
+	KEYMAP(0x15, KEY_Y),
+	KEYMAP(0x16, KEY_U),
+	KEYMAP(0x17, KEY_I),
+	KEYMAP(0x18, KEY_O),
+	KEYMAP(0x19, KEY_P),
+	KEYMAP(0x1a, KEY_LEFTBRACE),
+	KEYMAP(0x1b, KEY_RIGHTBRACE),
+	KEYMAP(0x2b, KEY_BACKSLASH),
+	/* Row-3 */
+	KEYMAP(0xdb, KEY_LEFTMETA),
+	KEYMAP(0x1e, KEY_A),
+	KEYMAP(0x1f, KEY_S),
+	KEYMAP(0x20, KEY_D),
+	KEYMAP(0x21, KEY_F),
+	KEYMAP(0x22, KEY_G),
+	KEYMAP(0x23, KEY_H),
+	KEYMAP(0x24, KEY_J),
+	KEYMAP(0x25, KEY_K),
+	KEYMAP(0x26, KEY_L),
+	KEYMAP(0x27, KEY_SEMICOLON),
+	KEYMAP(0x28, KEY_APOSTROPHE),
+	KEYMAP(0x1c, KEY_ENTER),
+	/* Row-4 */
+	KEYMAP(0x2a, KEY_LEFTSHIFT),
+	KEYMAP(0x2c, KEY_Z),
+	KEYMAP(0x2d, KEY_X),
+	KEYMAP(0x2e, KEY_C),
+	KEYMAP(0x2f, KEY_V),
+	KEYMAP(0x30, KEY_B),
+	KEYMAP(0x31, KEY_N),
+	KEYMAP(0x32, KEY_M),
+	KEYMAP(0x33, KEY_COMMA),
+	KEYMAP(0x34, KEY_DOT),
+	KEYMAP(0x35, KEY_SLASH),
+	KEYMAP(0x36, KEY_RIGHTSHIFT),
+	/* Row-5 */
+	KEYMAP(0x1d, KEY_LEFTCTRL),
+	KEYMAP(0x38, KEY_LEFTALT),
+	KEYMAP(0x39, KEY_SPACE),
+	KEYMAP(0xb8, KEY_RIGHTALT),
+	KEYMAP(0x9d, KEY_RIGHTCTRL),
+	/* Arrow keys */
+	KEYMAP(0xcb, KEY_LEFT),
+	KEYMAP(0xd0, KEY_DOWN),
+	KEYMAP(0xcd, KEY_RIGHT),
+	KEYMAP(0xc8, KEY_UP),
+};
+
+static void ssdt_generate_physmap(struct acpi_dp *dp, uint8_t num_top_row_keys,
+				  enum ps2_action_key action_keys[])
+{
+	struct acpi_dp *dp_array;
+	enum ps2_action_key key;
+	uint32_t keymap, i;
+
+	dp_array = acpi_dp_new_table("function-row-physmap");
+	if (!dp_array) {
+		printk(BIOS_ERR, "PS2K: couldn't write function-row-physmap\n");
+		return;
+	}
+
+	printk(BIOS_INFO, "PS2K: Physmap: [");
+	for (i = 0; i < num_top_row_keys; i++) {
+		key = action_keys[i];
+		if (key && key < ARRAY_SIZE(action_keymaps)) {
+			keymap = action_keymaps[key];
+		} else {
+			keymap = 0;
+			printk(BIOS_ERR,
+			       "PS2K: invalid top-action-key-%u: %u(skipped)\n",
+			       i, key);
+		}
+		acpi_dp_add_integer(dp_array, NULL, SCANCODE(keymap));
+		printk(BIOS_INFO, " %X", SCANCODE(keymap));
+	}
+
+	printk(BIOS_INFO, " ]\n");
+	acpi_dp_add_array(dp, dp_array);
+}
+
+static void ssdt_generate_keymap(struct acpi_dp *dp, uint8_t num_top_row_keys,
+				 enum ps2_action_key action_keys[],
+				 bool can_send_function_keys,
+				 bool has_numeric_keypad,
+				 bool has_scrnlock_key)
+{
+	struct acpi_dp *dp_array;
+	enum ps2_action_key key;
+	uint32_t keymap;
+	unsigned int i, total = 0;
+
+	dp_array = acpi_dp_new_table("linux,keymap");
+	if (!dp_array) {
+		printk(BIOS_ERR, "PS2K: couldn't write linux,keymap\n");
+		return;
+	}
+
+	/* Write out keymap for top row action keys */
+	for (i = 0; i < num_top_row_keys; i++) {
+		key = action_keys[i];
+		if (!key || key >= ARRAY_SIZE(action_keymaps)) {
+			printk(BIOS_ERR,
+			       "PS2K: invalid top-action-key-%u: %u\n", i, key);
+			continue;
+		}
+		keymap = action_keymaps[key];
+		acpi_dp_add_integer(dp_array, NULL, keymap);
+		total++;
+	}
+
+	/* Write out keymap for function keys, if keyboard can send them */
+	if (can_send_function_keys) {
+		for (i = 0; i < num_top_row_keys; i++) {
+			keymap = function_keymaps[i];
+			acpi_dp_add_integer(dp_array, NULL, keymap);
+		}
+
+		total += num_top_row_keys;
+	}
+
+	/* Write out keymap for numeric keypad, if the keyboard has it */
+	if (has_numeric_keypad) {
+		for (i = 0; i < ARRAY_SIZE(numeric_keypad_keymaps); i++) {
+			keymap = numeric_keypad_keymaps[i];
+			acpi_dp_add_integer(dp_array, NULL, keymap);
+		}
+
+		total += ARRAY_SIZE(numeric_keypad_keymaps);
+	}
+
+	/* Provide keymap for screenlock only if it is present */
+	if (has_scrnlock_key) {
+		acpi_dp_add_integer(dp_array, NULL, KEYMAP(0x5d, KEY_SLEEP));
+		total++;
+	}
+
+	/* Write out keymap for rest of keys */
+	for (i = 0; i < ARRAY_SIZE(rest_of_keymaps); i++) {
+		keymap = rest_of_keymaps[i];
+		acpi_dp_add_integer(dp_array, NULL, keymap);
+	}
+
+	total += ARRAY_SIZE(rest_of_keymaps);
+	printk(BIOS_INFO, "PS2K: Passing %u keymaps to kernel\n", total);
+
+	acpi_dp_add_array(dp, dp_array);
+}
+
+void acpigen_ps2_keyboard_dsd(const char *scope, uint8_t num_top_row_keys,
+			      enum ps2_action_key action_keys[],
+			      bool can_send_function_keys,
+			      bool has_numeric_keypad,
+			      bool has_scrnlock_key)
+{
+	struct acpi_dp *dsd;
+
+	if (!scope ||
+	    num_top_row_keys < PS2_MIN_TOP_ROW_KEYS ||
+	    num_top_row_keys > PS2_MAX_TOP_ROW_KEYS) {
+		printk(BIOS_ERR, "PS2K: %s: invalid args\n", __func__);
+		return;
+	}
+
+	dsd = acpi_dp_new_table("_DSD");
+	if (!dsd) {
+		printk(BIOS_ERR, "PS2K: couldn't write _DSD\n");
+		return;
+	}
+
+	acpigen_write_scope(scope);
+	ssdt_generate_physmap(dsd, num_top_row_keys, action_keys);
+	ssdt_generate_keymap(dsd, num_top_row_keys, action_keys,
+			     can_send_function_keys, has_numeric_keypad,
+			     has_scrnlock_key);
+	acpi_dp_write(dsd);
+	acpigen_pop_len(); /* Scope */
+}
diff --git a/src/arch/x86/include/arch/acpigen_ps2_keybd.h b/src/arch/x86/include/arch/acpigen_ps2_keybd.h
new file mode 100644
index 0000000000..c0228bca16
--- /dev/null
+++ b/src/arch/x86/include/arch/acpigen_ps2_keybd.h
@@ -0,0 +1,41 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef __ACPIGEN_PS2_KEYBD_H__
+#define __ACPIGEN_PS2_KEYBD_H__
+
+#include <types.h>
+
+enum ps2_action_key {
+	PS2_KEY_ABSENT = 0,
+	PS2_KEY_BACK,
+	PS2_KEY_FORWARD,
+	PS2_KEY_REFRESH,
+	PS2_KEY_FULLSCREEN,
+	PS2_KEY_OVERVIEW,
+	PS2_KEY_BRIGHTNESS_DOWN,
+	PS2_KEY_BRIGHTNESS_UP,
+	PS2_KEY_VOL_MUTE,
+	PS2_KEY_VOL_DOWN,
+	PS2_KEY_VOL_UP,
+	PS2_KEY_SNAPSHOT,
+	PS2_KEY_PRIVACY_SCRN_TOGGLE,
+	PS2_KEY_KBD_BKLIGHT_DOWN,
+	PS2_KEY_KBD_BKLIGHT_UP,
+	PS2_KEY_PLAY_PAUSE,
+	PS2_KEY_NEXT_TRACK,
+	PS2_KEY_PREV_TRACK,
+};
+
+#define PS2_MIN_TOP_ROW_KEYS		10
+#define PS2_MAX_TOP_ROW_KEYS		15
+
+void acpigen_ps2_keyboard_dsd(const char *scope, uint8_t num_top_row_keys,
+			      enum ps2_action_key action_keys[],
+			      bool can_send_function_keys,
+			      bool has_numeric_keypad, bool has_scrnlock_key);
+
+#endif /* __ACPIGEN_PS2_KEYBD_H__ */