static int sbefifo_read_response()

in fsi-sbefifo.c [540:622]

• 50 lines of code
• 11 McCabe index (conditional complexity)

static int sbefifo_read_response(struct sbefifo *sbefifo, struct iov_iter *response)
{
	struct device *dev = &sbefifo->fsi_dev->dev;
	u32 status, eot_set;
	unsigned long timeout;
	bool overflow = false;
	__be32 data;
	size_t len;
	int rc;

	dev_vdbg(dev, "reading response, buflen = %zd\n", iov_iter_count(response));

	timeout = msecs_to_jiffies(SBEFIFO_TIMEOUT_START_RSP);
	for (;;) {
		/* Grab FIFO status (this will handle parity errors) */
		rc = sbefifo_wait(sbefifo, false, &status, timeout);
		if (rc < 0)
			return rc;
		timeout = msecs_to_jiffies(SBEFIFO_TIMEOUT_IN_RSP);

		/* Decode status */
		len = sbefifo_populated(status);
		eot_set = sbefifo_eot_set(status);

		dev_vdbg(dev, "  chunk size %zd eot_set=0x%x\n", len, eot_set);

		/* Go through the chunk */
		while(len--) {
			/* Read the data */
			rc = sbefifo_down_read(sbefifo, &data);
			if (rc < 0)
				return rc;

			/* Was it an EOT ? */
			if (eot_set & 0x80) {
				/*
				 * There should be nothing else in the FIFO,
				 * if there is, mark broken, this will force
				 * a reset on next use, but don't fail the
				 * command.
				 */
				if (len) {
					dev_warn(dev, "FIFO read hit"
						 " EOT with still %zd data\n",
						 len);
					sbefifo->broken = true;
				}

				/* We are done */
				rc = sbefifo_regw(sbefifo,
						  SBEFIFO_DOWN | SBEFIFO_EOT_ACK, 0);

				/*
				 * If that write fail, still complete the request but mark
				 * the fifo as broken for subsequent reset (not much else
				 * we can do here).
				 */
				if (rc) {
					dev_err(dev, "FSI error %d ack'ing EOT\n", rc);
					sbefifo->broken = true;
				}

				/* Tell whether we overflowed */
				return overflow ? -EOVERFLOW : 0;
			}

			/* Store it if there is room */
			if (iov_iter_count(response) >= sizeof(__be32)) {
				if (copy_to_iter(&data, sizeof(__be32), response) < sizeof(__be32))
					return -EFAULT;
			} else {
				dev_vdbg(dev, "Response overflowed !\n");

				overflow = true;
			}

			/* Next EOT bit */
			eot_set <<= 1;
		}
	}
	/* Shouldn't happen */
	return -EIO;
}