PCHG: Support reset to firmware update mode

This patch allows a charger chip to reset to firmware update mode
(a.k.a. download mode). Actual firmware update will be added
in a separate patch.

Currently, a reset event causes the state machine to unconditionally
transition to normal mode. This patch makes the state machine check
'mode' field in the context to decide whether it transitions to
normal mode or not.

This patch also makes ctn730 driver explicitly return
PCHG_EVENT_*_ERROR while PCHG_EVENT_NONE was returned previously.

BUG=b:173235954
BRANCH=trogdor
TEST=Stylus connect, disconnect, charge events are triggered as
expected.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: I10dbd25d0b3d5284952e57d4ade2949e9594c8d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2770503

1 files changed, 59 insertions, 19 deletions

diff --git a/driver/nfc/ctn730.c b/driver/nfc/ctn730.c
index 75487fa701..6efb75efb4 100644
--- a/driver/nfc/ctn730.c
+++ b/driver/nfc/ctn730.c
@@ -56,12 +56,17 @@ static const int _detection_interval_ms = 100;
 #define WLC_CHG_CTRL_CHARGING_INFO		0b010101
 
 /* WLC_HOST_CTRL_RESET constants */
-#define WLC_HOST_CTRL_RESET_CMD_SIZE		1
-#define WLC_HOST_CTRL_RESET_RSP_SIZE		1
-#define WLC_HOST_CTRL_RESET_EVT_NORMAL_MODE	0x00
-#define WLC_HOST_CTRL_RESET_EVT_DOWNLOAD_MODE	0x01
-#define WLC_HOST_CTRL_RESET_CMD_MODE_NORMAL	0x00
-#define WLC_HOST_CTRL_RESET_CMD_MODE_DOWNLOAD	0x01
+#define WLC_HOST_CTRL_RESET_CMD_SIZE			1
+#define WLC_HOST_CTRL_RESET_RSP_SIZE			1
+#define WLC_HOST_CTRL_RESET_EVT_NORMAL_MODE		0x00
+#define WLC_HOST_CTRL_RESET_EVT_NORMAL_MODE_SIZE	3
+#define WLC_HOST_CTRL_RESET_EVT_DOWNLOAD_MODE		0x01
+#define WLC_HOST_CTRL_RESET_EVT_DOWNLOAD_MODE_SIZE	2
+#define WLC_HOST_CTRL_RESET_REASON_INTENDED		0x00
+#define WLC_HOST_CTRL_RESET_REASON_CORRUPTED		0x01
+#define WLC_HOST_CTRL_RESET_REASON_UNRECOVERABLE	0x02
+#define WLC_HOST_CTRL_RESET_CMD_MODE_NORMAL		0x00
+#define WLC_HOST_CTRL_RESET_CMD_MODE_DOWNLOAD		0x01
 
 /* WLC_CHG_CTRL_ENABLE constants */
 #define WLC_CHG_CTRL_ENABLE_CMD_SIZE		2
@@ -207,6 +212,20 @@ static const char *_text_status_code(uint8_t code)
 	}
 }
 
+static const char *_text_reset_reason(uint8_t code)
+{
+	switch (code) {
+	case WLC_HOST_CTRL_RESET_REASON_INTENDED:
+		return "intended";
+	case WLC_HOST_CTRL_RESET_REASON_CORRUPTED:
+		return "corrupted";
+	case WLC_HOST_CTRL_RESET_REASON_UNRECOVERABLE:
+		return "unrecoverable";
+	default:
+		return "unknown";
+	}
+}
+
 static int _i2c_read(int i2c_port, uint8_t *in, int in_len)
 {
 	int rv;
@@ -269,7 +288,9 @@ static int ctn730_init(struct pchg *ctx)
 	cmd->message_type = CTN730_MESSAGE_TYPE_COMMAND;
 	cmd->instruction = WLC_HOST_CTRL_RESET;
 	cmd->length = WLC_HOST_CTRL_RESET_CMD_SIZE;
-	cmd->payload[0] = WLC_HOST_CTRL_RESET_CMD_MODE_NORMAL;
+	cmd->payload[0] = ctx->mode == PCHG_MODE_NORMAL
+			? WLC_HOST_CTRL_RESET_CMD_MODE_NORMAL
+			: WLC_HOST_CTRL_RESET_CMD_MODE_DOWNLOAD;
 
 	/* TODO: Run 1 sec timeout timer. */
 	rv = _send_command(ctx, cmd);
@@ -327,26 +348,36 @@ static int _process_payload_response(struct pchg *ctx, struct ctn730_msg *res)
 
 	switch (res->instruction) {
 	case WLC_HOST_CTRL_RESET:
-		if (len != WLC_HOST_CTRL_RESET_RSP_SIZE
-				|| buf[0] != WLC_HOST_STATUS_OK)
+		if (len != WLC_HOST_CTRL_RESET_RSP_SIZE)
 			return EC_ERROR_UNKNOWN;
+		if (buf[0] != WLC_HOST_STATUS_OK)
+			ctx->event = PCHG_EVENT_OTHER_ERROR;
 		break;
 	case WLC_CHG_CTRL_ENABLE:
-		if (len != WLC_CHG_CTRL_ENABLE_RSP_SIZE
-				|| buf[0] != WLC_HOST_STATUS_OK)
+		if (len != WLC_CHG_CTRL_ENABLE_RSP_SIZE)
 			return EC_ERROR_UNKNOWN;
-		ctx->event = PCHG_EVENT_ENABLED;
+		if (buf[0] != WLC_HOST_STATUS_OK)
+			ctx->event = PCHG_EVENT_OTHER_ERROR;
+		else
+			ctx->event = PCHG_EVENT_ENABLED;
 		break;
 	case WLC_CHG_CTRL_DISABLE:
-		if (len != WLC_CHG_CTRL_DISABLE_RSP_SIZE
-				|| buf[0] != WLC_HOST_STATUS_OK)
+		if (len != WLC_CHG_CTRL_DISABLE_RSP_SIZE)
 			return EC_ERROR_UNKNOWN;
+		if (buf[0] != WLC_HOST_STATUS_OK)
+			ctx->event = PCHG_EVENT_OTHER_ERROR;
+		else
+			ctx->event = PCHG_EVENT_DISABLED;
 		break;
 	case WLC_CHG_CTRL_CHARGING_INFO:
-		if (len != WLC_CHG_CTRL_CHARGING_INFO_RSP_SIZE
-				|| buf[0] != WLC_HOST_STATUS_OK)
+		if (len != WLC_CHG_CTRL_CHARGING_INFO_RSP_SIZE)
 			return EC_ERROR_UNKNOWN;
-		ctx->battery_percent = buf[1];
+		if (buf[0] != WLC_HOST_STATUS_OK) {
+			ctx->event = PCHG_EVENT_OTHER_ERROR;
+		} else {
+			ctx->battery_percent = buf[1];
+			ctx->event = PCHG_EVENT_CHARGE_UPDATE;
+		}
 		break;
 	default:
 		CPRINTS("Received unknown response (%d)", res->instruction);
@@ -374,16 +405,25 @@ static int _process_payload_event(struct pchg *ctx, struct ctn730_msg *res)
 	if (IS_ENABLED(CTN730_DEBUG))
 		CPRINTS("Payload: %ph", HEX_BUF(buf, len));
 
+	ctx->event = PCHG_EVENT_NONE;
+
 	switch (res->instruction) {
 	case WLC_HOST_CTRL_RESET:
 		if (buf[0] == WLC_HOST_CTRL_RESET_EVT_NORMAL_MODE) {
-			ctx->event = PCHG_EVENT_INITIALIZED;
+			if (len != WLC_HOST_CTRL_RESET_EVT_NORMAL_MODE_SIZE)
+				return EC_ERROR_INVAL;
+			ctx->event = PCHG_EVENT_IN_NORMAL;
+			CPRINTS("Normal Mode (FW=0x%02x.%02x)", buf[1], buf[2]);
 			/*
 			 * ctn730 isn't immediately ready for i2c write after
 			 * normal mode initialization (b:178096436).
 			 */
 			msleep(5);
 		} else if (buf[0] == WLC_HOST_CTRL_RESET_EVT_DOWNLOAD_MODE) {
+			if (len != WLC_HOST_CTRL_RESET_EVT_DOWNLOAD_MODE_SIZE)
+				return EC_ERROR_INVAL;
+			CPRINTS("Download Mode (%s)",
+				_text_reset_reason(buf[1]));
 			ctx->event = PCHG_EVENT_RESET;
 		} else {
 			return EC_ERROR_INVAL;
@@ -481,7 +521,7 @@ static int ctn730_get_soc(struct pchg *ctx)
 	if (rv)
 		return rv;
 
-	return EC_SUCCESS;
+	return EC_SUCCESS_IN_PROGRESS;
 }
 
 /**