tpm, tpm_tis: fix tpm_tis ACPI detection issue with TPM 2.0

commit 399235dc6e95400a1322a9999e92073bc572f0c8 upstream.

Both for FIFO and CRB interface TCG has decided to use the same HID
MSFT0101. They can be differentiated by looking at the start method from
TPM2 ACPI table. This patches makes necessary fixes to tpm_tis and
tpm_crb modules in order to correctly detect, which module should be
used.

For MSFT0101 we must use struct acpi_driver because struct pnp_driver
has a 7 character limitation.

It turned out that the root cause in b371616b8 was not correct for
https://bugzilla.kernel.org/show_bug.cgi?id=98181.

v2:

* One fixup was missing from v1: is_tpm2_fifo -> is_fifo

v3:

* Use pnp_driver for existing HIDs and acpi_driver only for MSFT0101 in
  order ensure backwards compatibility.

v4:

* Check for FIFO before doing *anything* in crb_acpi_add().
* There was return immediately after acpi_bus_unregister_driver() in
  cleanup_tis(). This caused pnp_unregister_driver() not to be called.

Reported-by: Michael Saunders <mick.saunders@gmail.com>
Reported-by: Michael Marley <michael@michaelmarley.com>
Reported-by: Jethro Beekman <kernel@jbeekman.nl>
Reported-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Michael Marley <michael@michaelmarley.com>
Tested-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (on TPM 1.2)
Reviewed-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 11 insertions, 21 deletions

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 1267322595da..2b971b3e5c1c 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -34,12 +34,6 @@ enum crb_defaults {
 	CRB_ACPI_START_INDEX = 1,
 };
 
-enum crb_start_method {
-	CRB_SM_ACPI_START = 2,
-	CRB_SM_CRB = 7,
-	CRB_SM_CRB_WITH_ACPI_START = 8,
-};
-
 struct acpi_tpm2 {
 	struct acpi_table_header hdr;
 	u16 platform_class;
@@ -220,12 +214,6 @@ static int crb_acpi_add(struct acpi_device *device)
 	u64 pa;
 	int rc;
 
-	chip = tpmm_chip_alloc(dev, &tpm_crb);
-	if (IS_ERR(chip))
-		return PTR_ERR(chip);
-
-	chip->flags = TPM_CHIP_FLAG_TPM2;
-
 	status = acpi_get_table(ACPI_SIG_TPM2, 1,
 				(struct acpi_table_header **) &buf);
 	if (ACPI_FAILURE(status)) {
@@ -233,13 +221,15 @@ static int crb_acpi_add(struct acpi_device *device)
 		return -ENODEV;
 	}
 
-	/* At least some versions of AMI BIOS have a bug that TPM2 table has
-	 * zero address for the control area and therefore we must fail.
-	*/
-	if (!buf->control_area_pa) {
-		dev_err(dev, "TPM2 ACPI table has a zero address for the control area\n");
-		return -EINVAL;
-	}
+	/* Should the FIFO driver handle this? */
+	if (buf->start_method == TPM2_START_FIFO)
+		return -ENODEV;
+
+	chip = tpmm_chip_alloc(dev, &tpm_crb);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+
+	chip->flags = TPM_CHIP_FLAG_TPM2;
 
 	if (buf->hdr.length < sizeof(struct acpi_tpm2)) {
 		dev_err(dev, "TPM2 ACPI table has wrong size");
@@ -259,11 +249,11 @@ static int crb_acpi_add(struct acpi_device *device)
 	 * report only ACPI start but in practice seems to require both
 	 * ACPI start and CRB start.
 	 */
-	if (sm == CRB_SM_CRB || sm == CRB_SM_CRB_WITH_ACPI_START ||
+	if (sm == TPM2_START_CRB || sm == TPM2_START_FIFO ||
 	    !strcmp(acpi_device_hid(device), "MSFT0101"))
 		priv->flags |= CRB_FL_CRB_START;
 
-	if (sm == CRB_SM_ACPI_START || sm == CRB_SM_CRB_WITH_ACPI_START)
+	if (sm == TPM2_START_ACPI || sm == TPM2_START_CRB_WITH_ACPI)
 		priv->flags |= CRB_FL_ACPI_START;
 
 	priv->cca = (struct crb_control_area __iomem *)