touchpad_st: embed FTB header in unpacked TP FW

To make it easier to decide if full panel initialization is required,
we put the original FTB header in the beginning of unpacked TP FW.
touchpad_update_write will clear CX data if CX version will be
different.

CQ-DEPEND=CL:*697971
BRANCH=nocturne
BUG=b:117203130
TEST=manual on whiskers
Signed-off-by: Wei-Han Chen <stimim@chromium.org>

Change-Id: I60351783b8c015fcb23431811c156bfca8d15b67
Reviewed-on: https://chromium-review.googlesource.com/1267876
Commit-Ready: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

1 files changed, 31 insertions, 29 deletions

diff --git a/driver/touchpad_st.c b/driver/touchpad_st.c
index 9cfb461d47..d4c7aaa22b 100644
--- a/driver/touchpad_st.c
+++ b/driver/touchpad_st.c
@@ -898,12 +898,15 @@ static int wait_for_flash_ready(uint8_t type)
 	return retry >= 0 ? ret : EC_ERROR_TIMEOUT;
 }
 
-static int erase_flash(void)
+static int erase_flash(int full_init_required)
 {
 	int ret;
 
-	/* Erase everything, except CX */
-	ret = write_hwreg_cmd32(0x20000128, 0xFFFFFF83);
+	if (full_init_required)
+		ret = write_hwreg_cmd32(0x20000128, 0xFFFFFFFF);
+	else
+		/* Erase everything, except CX */
+		ret = write_hwreg_cmd32(0x20000128, 0xFFFFFF83);
 	if (ret)
 		return ret;
 	ret = write_hwreg_cmd8(0x2000006B, 0x00);
@@ -915,7 +918,7 @@ static int erase_flash(void)
 	return wait_for_flash_ready(0x6A);
 }
 
-static int st_tp_prepare_for_update(void)
+static int st_tp_prepare_for_update(int full_init_required)
 {
 	/* hold m3 */
 	write_hwreg_cmd8(0x20000024, 0x01);
@@ -923,7 +926,7 @@ static int st_tp_prepare_for_update(void)
 	write_hwreg_cmd8(0x20000025, 0x20);
 	/* unlock flash erase */
 	write_hwreg_cmd8(0x200000DE, 0x03);
-	erase_flash();
+	erase_flash(full_init_required);
 
 	return EC_SUCCESS;
 }
@@ -1079,32 +1082,15 @@ static int st_tp_panel_init(int full)
 		ST_TP_CMD_WRITE_SYSTEM_COMMAND, 0x00, 0x02
 	};
 	int ret, retry;
-	uint8_t old_cx_version;
-	uint8_t new_cx_version;
 
 	if (tp_control & (TP_CONTROL_INIT | TP_CONTROL_INIT_FULL))
 		return EC_ERROR_BUSY;
 
-	if (full == -1) /* not specified */
-		old_cx_version = get_cx_version(
-				system_info.release_info & 0xFF);
-
 	st_tp_stop_scan();
 	ret = st_tp_reset();
 	if (ret)
 		return ret;
 
-	if (full == -1) { /* not specified */
-		/*
-		 * On boot, ST firmware will load system info to host data
-		 * memory, So we don't need to reload it.
-		 */
-		st_tp_read_system_info(0);
-		new_cx_version = get_cx_version(
-				system_info.release_info & 0xFF);
-		full = old_cx_version != new_cx_version;
-	}
-
 	if (full) {  /* should perform full panel initialization */
 		tx_buf[2] = 0x3;
 		tp_control = TP_CONTROL_INIT_FULL;
@@ -1144,34 +1130,50 @@ static int st_tp_panel_init(int full)
  */
 int touchpad_update_write(int offset, int size, const uint8_t *data)
 {
-	int ret;
+	static int full_init_required;
+	int ret, flash_offset;
 
 	CPRINTS("%s %08x %d", __func__, offset, size);
 	if (offset == 0) {
+		const struct st_tp_fw_header_t *header;
+		uint8_t old_cx_version;
+		uint8_t new_cx_version;
+
+		header = (const struct st_tp_fw_header_t *)data;
+		if (header->signature != 0xAA55AA55)
+			return EC_ERROR_INVAL;
+
+		old_cx_version = get_cx_version(system_info.release_info);
+		new_cx_version = get_cx_version(header->release_info);
+
+		full_init_required = old_cx_version != new_cx_version;
+
 		/* stop scanning, interrupt, etc... */
 		st_tp_stop_scan();
 
-		ret = st_tp_prepare_for_update();
+		ret = st_tp_prepare_for_update(full_init_required);
 		if (ret)
 			return ret;
+		return EC_SUCCESS;
 	}
 
-	if (offset % ST_TP_DMA_CHUNK_SIZE)
+	flash_offset = offset - CONFIG_UPDATE_PDU_SIZE;
+	if (flash_offset % ST_TP_DMA_CHUNK_SIZE)
 		return EC_ERROR_INVAL;
 
-	if (offset >= ST_TP_FLASH_OFFSET_CX &&
-	    offset < ST_TP_FLASH_OFFSET_CONFIG)
+	if (flash_offset >= ST_TP_FLASH_OFFSET_CX &&
+	    flash_offset < ST_TP_FLASH_OFFSET_CONFIG)
 		/* don't update CX section */
 		return EC_SUCCESS;
 
-	ret = st_tp_write_flash(offset, size, data);
+	ret = st_tp_write_flash(flash_offset, size, data);
 	if (ret)
 		return ret;
 
 	if (offset + size == CONFIG_TOUCHPAD_VIRTUAL_SIZE) {
 		CPRINTS("%s: End update, wait for reset.", __func__);
 
-		return st_tp_panel_init(-1);
+		return st_tp_panel_init(full_init_required);
 	}
 
 	return EC_SUCCESS;