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");