Input: atmel_mxt_ts - improve bootloader state machine handling

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>

1 files changed, 102 insertions, 86 deletions

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 85672e0233e..7a4ed198d7e 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -255,6 +255,8 @@ struct mxt_flash {
 	size_t frame_size;
 	unsigned int count;
 	unsigned int retry;
+	u8 previous;
+	bool complete;
 };
 
 /* Each client has this additional data */
@@ -648,67 +650,127 @@ static int mxt_probe_bootloader(struct mxt_data *data, bool alt_address)
 	return 0;
 }
 
-static int mxt_check_bootloader(struct mxt_data *data, unsigned int state,
-				bool wait)
+static int mxt_send_bootloader_cmd(struct mxt_data *data, bool unlock);
+
+static int mxt_write_firmware_frame(struct mxt_data *data, struct mxt_flash *f)
+{
+	f->frame = (struct mxt_fw_frame*)(f->fw->data + f->pos);
+
+	/* Take account of CRC bytes */
+	f->frame_size = __be16_to_cpu(f->frame->size) + 2U;
+
+	/* Write one frame to device */
+	return mxt_bootloader_write(data, f->fw->data + f->pos,
+				   f->frame_size);
+}
+
+static int mxt_check_bootloader(struct mxt_data *data, struct mxt_flash *f)
 {
 	struct device *dev = &data->client->dev;
-	u8 val;
+	u8 state;
 	int ret;
 
-recheck:
-	if (wait) {
+	/*
+	 * In application update mode, the interrupt
+	 * line signals state transitions. We must wait for the
+	 * CHG assertion before reading the status byte.
+	 * Once the status byte has been read, the line is deasserted.
+	 */
+	ret = mxt_wait_for_completion(data, &data->bl_completion,
+				      MXT_FW_CHG_TIMEOUT);
+	if (ret) {
 		/*
-		 * In application update mode, the interrupt
-		 * line signals state transitions. We must wait for the
-		 * CHG assertion before reading the status byte.
-		 * Once the status byte has been read, the line is deasserted.
+		 * TODO: handle -ERESTARTSYS better by terminating
+		 * fw update process before returning to userspace
+		 * by writing length 0x000 to device (iff we are in
+		 * WAITING_FRAME_DATA state).
 		 */
-		ret = mxt_wait_for_completion(data, &data->bl_completion,
-					      MXT_FW_CHG_TIMEOUT);
-		if (ret) {
-			/*
-			 * TODO: handle -ERESTARTSYS better by terminating
-			 * fw update process before returning to userspace
-			 * by writing length 0x000 to device (iff we are in
-			 * WAITING_FRAME_DATA state).
-			 */
-			dev_err(dev, "Update wait error %d\n", ret);
-			return ret;
-		}
+		dev_warn(dev, "Update wait error %d\n", ret);
 	}
 
-	ret = mxt_bootloader_read(data, &val, 1);
+	ret = mxt_bootloader_read(data, &state, 1);
 	if (ret)
 		return ret;
 
+	/* Remove don't care bits */
+	if (state & ~MXT_BOOT_STATUS_MASK)
+		state &= ~MXT_BOOT_STATUS_MASK;
+
 	switch (state) {
 	case MXT_WAITING_BOOTLOAD_CMD:
+		dev_info(dev, "Unlocking bootloader\n");
+		ret = mxt_send_bootloader_cmd(data, true);
+		if (ret)
+			return ret;
+
+		break;
+
 	case MXT_WAITING_FRAME_DATA:
-	case MXT_APP_CRC_FAIL:
-		val &= ~MXT_BOOT_STATUS_MASK;
+		if ((f->previous != MXT_WAITING_BOOTLOAD_CMD)
+		    && (f->previous != MXT_FRAME_CRC_PASS)
+		    && (f->previous != MXT_FRAME_CRC_FAIL))
+			goto unexpected;
+
+		ret = mxt_write_firmware_frame(data, f);
+		if (ret)
+			return ret;
+
 		break;
+
+	case MXT_FRAME_CRC_CHECK:
+		if (f->previous != MXT_WAITING_FRAME_DATA)
+			goto unexpected;
+		break;
+
 	case MXT_FRAME_CRC_PASS:
-		if (val == MXT_FRAME_CRC_CHECK) {
-			goto recheck;
-		} else if (val == MXT_FRAME_CRC_FAIL) {
-			dev_err(dev, "Bootloader CRC fail\n");
-			return -EINVAL;
+		if (f->previous != MXT_FRAME_CRC_CHECK)
+			goto unexpected;
+
+		/* Next frame */
+		f->retry = 0;
+		f->pos += f->frame_size;
+		f->count++;
+
+		if (f->pos >= f->fw->size) {
+			f->complete = true;
+			dev_info(dev, "Sent %u frames, %zu bytes\n",
+				f->count, f->fw->size);
+		} else if (f->count % 50 == 0) {
+			dev_dbg(dev, "Sent %u frames, %lld/%zu bytes\n",
+				f->count, f->pos, f->fw->size);
 		}
+
 		break;
+
+	case MXT_FRAME_CRC_FAIL:
+		f->retry++;
+
+		if (f->retry > 20) {
+			dev_err(dev, "Retry count exceeded\n");
+			return -EIO;
+		} else {
+			dev_dbg(dev, "Bootloader frame CRC failure\n");
+		}
+
+		/* Back off by 20ms per retry */
+		msleep(f->retry * 20);
+
+		break;
+
 	default:
 		return -EINVAL;
 	}
 
-	if (val != state) {
-		dev_err(dev, "Invalid bootloader state %02X != %02X\n",
-			val, state);
-		return -EINVAL;
-	}
+	f->previous = state;
 
 	return 0;
+
+unexpected:
+	dev_err(dev, "Unexpected state transition\n");
+	return -EINVAL;
 }
 
-static int mxt_send_bootloader_cmd(struct mxt_data *data, bool unlock)
+int mxt_send_bootloader_cmd(struct mxt_data *data, bool unlock)
 {
 	int ret;
 	u8 buf[2];
@@ -2950,57 +3012,13 @@ static int mxt_load_fw(struct device *dev)
 	if (ret)
 		goto release_firmware;
 
-	ret = mxt_check_bootloader(data, MXT_WAITING_BOOTLOAD_CMD, false);
-	if (ret) {
-		/* Bootloader may still be unlocked from previous attempt */
-		ret = mxt_check_bootloader(data, MXT_WAITING_FRAME_DATA, false);
-		if (ret)
-			goto disable_irq;
-	} else {
-		dev_info(dev, "Unlocking bootloader\n");
-
-		/* Unlock bootloader */
-		ret = mxt_send_bootloader_cmd(data, true);
+	while (true) {
+		ret = mxt_check_bootloader(data, &f);
 		if (ret)
-			goto disable_irq;
-	}
-
-	while (f.pos < f.fw->size) {
-		f.frame = (struct mxt_fw_frame*)(f.fw->data + f.pos);
-
-		ret = mxt_check_bootloader(data, MXT_WAITING_FRAME_DATA, true);
-		if (ret)
-			goto disable_irq;
-
-		/* Take account of CRC bytes */
-		f.frame_size = __be16_to_cpu(f.frame->size) + 2U;
-
-		/* Write one frame to device */
-		ret = mxt_bootloader_write(data, f.fw->data + f.pos,
-					   f.frame_size);
-		if (ret)
-			goto disable_irq;
-
-		ret = mxt_check_bootloader(data, MXT_FRAME_CRC_PASS, true);
-		if (ret) {
-			f.retry++;
-
-			/* Back off by 20ms per retry */
-			msleep(f.retry * 20);
-
-			if (f.retry > 20) {
-				dev_err(dev, "Retry count exceeded\n");
-				goto disable_irq;
-			}
-		} else {
-			f.retry = 0;
-			f.pos += f.frame_size;
-			f.count++;
-		}
+			return ret;
 
-		if (f.count % 50 == 0)
-			dev_dbg(dev, "Sent %u frames, %lld/%zu bytes\n",
-				f.count, f.pos, f.fw->size);
+		if (f.complete)
+			break;
 	}
 
 	/* Wait for flash. */
@@ -3009,7 +3027,6 @@ static int mxt_load_fw(struct device *dev)
 	if (ret)
 		goto disable_irq;
 
-	dev_dbg(dev, "Sent %u frames, %lld bytes\n", f.count, f.pos);
 
 	/*
 	 * Wait for device to reset. Some bootloader versions do not assert
@@ -3019,7 +3036,6 @@ static int mxt_load_fw(struct device *dev)
 	mxt_wait_for_completion(data, &data->bl_completion, MXT_FW_RESET_TIME);
 
 	data->in_bootloader = false;
-
 disable_irq:
 	disable_irq(data->irq);
 release_firmware: