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path: root/drivers/char/tpm
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Diffstat (limited to 'drivers/char/tpm')
-rw-r--r--drivers/char/tpm/tpm_tis.c77
1 files changed, 73 insertions, 4 deletions
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 47517e49d2be..ed97cfed30ea 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -306,11 +306,10 @@ MODULE_PARM_DESC(itpm, "Force iTPM workarounds (found on some Lenovo laptops)");
* tpm.c can skip polling for the data to be available as the interrupt is
* waited for here
*/
-static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
+static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
{
int rc, status, burstcnt;
size_t count = 0;
- u32 ordinal;
if (request_locality(chip, 0) < 0)
return -EBUSY;
@@ -345,8 +344,7 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
/* write last byte */
iowrite8(buf[count],
- chip->vendor.iobase +
- TPM_DATA_FIFO(chip->vendor.locality));
+ chip->vendor.iobase + TPM_DATA_FIFO(chip->vendor.locality));
wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
&chip->vendor.int_queue);
status = tpm_tis_status(chip);
@@ -355,6 +353,28 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
goto out_err;
}
+ return 0;
+
+out_err:
+ tpm_tis_ready(chip);
+ release_locality(chip, chip->vendor.locality, 0);
+ return rc;
+}
+
+/*
+ * If interrupts are used (signaled by an irq set in the vendor structure)
+ * tpm.c can skip polling for the data to be available as the interrupt is
+ * waited for here
+ */
+static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
+{
+ int rc;
+ u32 ordinal;
+
+ rc = tpm_tis_send_data(chip, buf, len);
+ if (rc < 0)
+ return rc;
+
/* go and do it */
iowrite8(TPM_STS_GO,
chip->vendor.iobase + TPM_STS(chip->vendor.locality));
@@ -376,6 +396,47 @@ out_err:
return rc;
}
+/*
+ * Early probing for iTPM with STS_DATA_EXPECT flaw.
+ * Try sending command without itpm flag set and if that
+ * fails, repeat with itpm flag set.
+ */
+static int probe_itpm(struct tpm_chip *chip)
+{
+ int rc = 0;
+ u8 cmd_getticks[] = {
+ 0x00, 0xc1, 0x00, 0x00, 0x00, 0x0a,
+ 0x00, 0x00, 0x00, 0xf1
+ };
+ size_t len = sizeof(cmd_getticks);
+ int rem_itpm = itpm;
+
+ itpm = 0;
+
+ rc = tpm_tis_send_data(chip, cmd_getticks, len);
+ if (rc == 0)
+ goto out;
+
+ tpm_tis_ready(chip);
+ release_locality(chip, chip->vendor.locality, 0);
+
+ itpm = 1;
+
+ rc = tpm_tis_send_data(chip, cmd_getticks, len);
+ if (rc == 0) {
+ dev_info(chip->dev, "Detected an iTPM.\n");
+ rc = 1;
+ } else
+ rc = -EFAULT;
+
+out:
+ itpm = rem_itpm;
+ tpm_tis_ready(chip);
+ release_locality(chip, chip->vendor.locality, 0);
+
+ return rc;
+}
+
static const struct file_operations tis_ops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
@@ -515,6 +576,14 @@ 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 (!itpm) {
+ itpm = probe_itpm(chip);
+ if (itpm < 0) {
+ rc = -ENODEV;
+ goto out_err;
+ }
+ }
+
if (itpm)
dev_info(dev, "Intel iTPM workaround enabled\n");