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Diffstat (limited to 'drivers/char/tpm')
-rw-r--r--drivers/char/tpm/tpm_tis_core.c37
-rw-r--r--drivers/char/tpm/tpm_tis_core.h1
2 files changed, 30 insertions, 8 deletions
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 469e4cd7fb4a..52e2dc7a9f81 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -340,7 +340,7 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
return size;
}
-static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+static int tpm_tis_try_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
int size = 0;
@@ -348,11 +348,6 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
u32 expected;
int rc;
- if (count < TPM_HEADER_SIZE) {
- size = -EIO;
- goto out;
- }
-
size = recv_data(chip, buf, TPM_HEADER_SIZE);
/* read first 10 bytes, including tag, paramsize, and result */
if (size < TPM_HEADER_SIZE) {
@@ -385,7 +380,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
goto out;
}
status = tpm_tis_status(chip);
- if (status & TPM_STS_DATA_AVAIL) { /* retry? */
+ if (status & TPM_STS_DATA_AVAIL) {
dev_err(&chip->dev, "Error left over data\n");
size = -EIO;
goto out;
@@ -399,10 +394,36 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
}
out:
- tpm_tis_ready(chip);
return size;
}
+static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+ struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+ unsigned int try;
+ int rc = 0;
+
+ if (count < TPM_HEADER_SIZE)
+ return -EIO;
+
+ for (try = 0; try < TPM_RETRY; try++) {
+ rc = tpm_tis_try_recv(chip, buf, count);
+
+ if (rc == -EIO)
+ /* Data transfer errors, indicated by EIO, can be
+ * recovered by rereading the response.
+ */
+ tpm_tis_write8(priv, TPM_STS(priv->locality),
+ TPM_STS_RESPONSE_RETRY);
+ else
+ break;
+ }
+
+ tpm_tis_ready(chip);
+
+ 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
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index b1a169d7d1ca..13e99cf65efe 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -34,6 +34,7 @@ enum tis_status {
TPM_STS_GO = 0x20,
TPM_STS_DATA_AVAIL = 0x10,
TPM_STS_DATA_EXPECT = 0x08,
+ TPM_STS_RESPONSE_RETRY = 0x02,
TPM_STS_READ_ZERO = 0x23, /* bits that must be zero on read */
};