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Subject[PATCH] tpm: Autodetect itpm devices
Date
Some Lenovos have TPMs that require a quirk to function correctly. This can
be autodetected by checking whether the device has a _HID of INTC0102. This
is an invalid PNPid, and as such is discarded by the pnp layer - however
it's still present in the ACPI code, so we can pull it out that way. This
means that the quirk won't be automatically applied on non-ACPI systems,
but without ACPI we don't have any way to identify the chip anyway so I
don't think that's a great concern.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
drivers/char/tpm/tpm_tis.c | 24 ++++++++++++++++++++++++
1 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 1030f84..c17a305 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -25,6 +25,7 @@
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
+#include <linux/acpi.h>
#include "tpm.h"

#define TPM_HEADER_SIZE 10
@@ -78,6 +79,26 @@ enum tis_defaults {
static LIST_HEAD(tis_chips);
static DEFINE_SPINLOCK(tis_lock);

+#ifdef CONFIG_ACPI
+static int is_itpm(struct pnp_dev *dev)
+{
+ struct acpi_device *acpi = pnp_acpi_device(dev);
+ struct acpi_hardware_id *id;
+
+ list_for_each_entry(id, &acpi->pnp.ids, list) {
+ if (!strcmp("INTC0102", id->id))
+ return 1;
+ }
+
+ return 0;
+}
+#else
+static int is_itpm(struct pnp_dev *dev)
+{
+ return 0;
+}
+#endif
+
static int check_locality(struct tpm_chip *chip, int l)
{
if ((ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
@@ -472,6 +493,9 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
"1.2 TPM (device-id 0x%X, rev-id %d)\n",
vendor >> 16, ioread8(chip->vendor.iobase + TPM_RID(0)));

+ if (is_itpm(to_pnp_dev(dev)))
+ itpm = 1;
+
if (itpm)
dev_info(dev, "Intel iTPM workaround enabled\n");

--
1.7.3.1


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