Patch "tpm_tis_spi: Check correct byte for wait state indicator" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

tpm_tis_spi: Check correct byte for wait state indicator

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tpm_tis_spi-check-correct-byte-for-wait-state-indicator.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Peter Huewe <[email protected]>
Date: Thu, 2 Mar 2017 13:03:13 +0000
Subject: tpm_tis_spi: Check correct byte for wait state indicator

From: Peter Huewe <[email protected]>

commit e110cc69dc2ad679d6d478df636b99b14e6fbbc9 upstream.

Wait states are signaled in the last byte received from the TPM in response to the header, not the first byte. Check rx_buf[3] instead of rx_buf[0].

---
 drivers/char/tpm/tpm_tis_spi.c |   34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

@@ -86,25 +86,25 @@ static int tpm_tis_spi_transfer(struct t
 	if (ret < 0)
 		goto exit;
 
-	phy->tx_buf[0] = 0;
+	if ((phy->rx_buf[3] & 0x01) == 0) {
+		// handle SPI wait states
+		phy->tx_buf[0] = 0;
 
-	/* According to TCG PTP specification, if there is no TPM present at
-	 * all, then the design has a weak pull-up on MISO. If a TPM is not
-	 * present, a pull-up on MISO means that the SB controller sees a 1,
-	 * and will latch in 0xFF on the read.
-	 */
-	for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {
-		spi_xfer.len = 1;
-		spi_message_init(&m);
-		spi_message_add_tail(&spi_xfer, &m);
-		ret = spi_sync_locked(phy->spi_device, &m);
-		if (ret < 0)
-			goto exit;
-	}
+		for (i = 0; i < TPM_RETRY; i++) {
+			spi_xfer.len = 1;
+			spi_message_init(&m);
+			spi_message_add_tail(&spi_xfer, &m);
+			ret = spi_sync_locked(phy->spi_device, &m);
+			if (ret < 0)
+				goto exit;
+			if (phy->rx_buf[0] & 0x01)
+				break;
+		}
 
-	if (i == TPM_RETRY) {
-		ret = -ETIMEDOUT;
-		goto exit;
+		if (i == TPM_RETRY) {
+			ret = -ETIMEDOUT;
+			goto exit;
+		}
 	}
 
 	spi_xfer.cs_change = 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/tpm_tis_spi-abort-transfer-when-too-many-wait-states-are-signaled.patch queue-4.9/tpm_tis_spi-remove-limitation-of-transfers-to-max_spi_framesize-bytes.patch queue-4.9/tpm_tis_core-choose-appropriate-timeout-for-reading-burstcount.patch queue-4.9/tpm_tis_spi-add-small-delay-after-last-transfer.patch queue-4.9/tpm_tis_spi-check-correct-byte-for-wait-state-indicator.patch queue-4.9/tpm_tis_spi-use-single-function-to-transfer-data.patch