tpm: self test failure should not cause suspend to fail

The Acer Acer Veriton X4110G has a TPM device detected as:
  tpm_tis 00:0b: 1.2 TPM (device-id 0xFE, rev-id 71)

After the first S3 suspend, the following error appears during resume:
  tpm tpm0: A TPM error(38) occurred continue selftest

Any following S3 suspend attempts will now fail with this error:
  tpm tpm0: Error (38) sending savestate before suspend
  PM: Device 00:0b failed to suspend: error 38

Error 38 is TPM_ERR_INVALID_POSTINIT which means the TPM is
not in the correct state. This indicates that the platform BIOS
is not sending the usual TPM_Startup command during S3 resume.
>From this point onwards, all TPM commands will fail.

The same issue was previously reported on Foxconn 6150BK8MC and
Sony Vaio TX3.

The platform behaviour seems broken here, but we should not break
suspend/resume because of this.

When the unexpected TPM state is encountered, set a flag to skip the
affected TPM_SaveState command on later suspends.

Cc: [email protected]
Signed-off-by: Chris Chiu <[email protected]>
Signed-off-by: Daniel Drake <[email protected]>
Link: http://lkml.kernel.org/r/CAB4CAwfSCvj1cudi+MWaB5g2Z67d9DwY1o475YOZD64ma23UiQ@mail.gmail.com
Link: https://lkml.org/lkml/2011/3/28/192
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=591031
Reviewed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>

drivers/char/tpm/tpm-interface.c

@@ -1002,6 +1002,10 @@ int tpm_do_selftest(struct tpm_chip *chip)
 	loops = jiffies_to_msecs(duration) / delay_msec;
 
 	rc = tpm_continue_selftest(chip);
+	if (rc == TPM_ERR_INVALID_POSTINIT) {
+		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
+		dev_info(&chip->dev, "TPM not ready (%d)\n", rc);
+	}
 	/* This may fail if there was no TPM driver during a suspend/resume
 	 * cycle; some may return 10 (BAD_ORDINAL), others 28 (FAILEDSELFTEST)
 	 */