[PATCH v4 1/4] tpm_tis: Improve reporting of IO errors

[Ed Swierk <eswierk@skyportsystems.com>]

Mysterious TPM behavior can be difficult to track down through all the
layers of software. Add error messages for conditions that should
never happen. Also include the manufacturer ID along with other chip
data printed during init.

Signed-off-by: Ed Swierk <eswierk@skyportsystems.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm_tis.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 65f7eec..088fa86 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -299,6 +299,8 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 
 	expected = be32_to_cpu(*(__be32 *) (buf + 2));
 	if (expected > count) {
+		dev_err(chip->pdev, "Response too long (wanted %zd, got %d)\n",
+			count, expected);
 		size = -EIO;
 		goto out;
 	}
@@ -366,6 +368,8 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 				  &chip->vendor.int_queue, false);
 		status = tpm_tis_status(chip);
 		if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
+			dev_err(chip->pdev, "Chip not accepting %zd bytes\n",
+				len - count);
 			rc = -EIO;
 			goto out_err;
 		}
@@ -378,6 +382,7 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 			  &chip->vendor.int_queue, false);
 	status = tpm_tis_status(chip);
 	if ((status & TPM_STS_DATA_EXPECT) != 0) {
+		dev_err(chip->pdev, "Chip not accepting last byte\n");
 		rc = -EIO;
 		goto out_err;
 	}
@@ -689,8 +694,9 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 	vendor = ioread32(chip->vendor.iobase + TPM_DID_VID(0));
 	chip->vendor.manufacturer_id = vendor;
 
-	dev_info(dev, "%s TPM (device-id 0x%X, rev-id %d)\n",
+	dev_info(dev, "%s TPM (manufacturer-id 0x%X, device-id 0x%X, rev-id %d)\n",
 		 (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2",
+		 chip->vendor.manufacturer_id,
 		 vendor >> 16, ioread8(chip->vendor.iobase + TPM_RID(0)));
 
 	if (!itpm) {
-- 
1.9.1