[PATCH v3 3/3] tpm_crb: request and relinquish locality 0

[Jarkko Sakkinen]

Request and relinquish locality for the driver use in order to be a
better citizen in a multi locality environment like TXT.

Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
---
 drivers/char/tpm/tpm_crb.c | 73 ++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 64 insertions(+), 9 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 853bd7b..96f661a 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -34,6 +34,15 @@ enum crb_defaults {
        CRB_ACPI_START_INDEX = 1,
 };
 
+enum crb_loc_ctrl {
+       CRB_LOC_CTRL_REQUEST_ACCESS     = BIT(0),
+       CRB_LOC_CTRL_RELINQUISH         = BIT(1),
+};
+
+enum crb_loc_state {
+       CRB_LOC_STATE_LOC_ASSIGNED      = BIT(1),
+};
+
 enum crb_ctrl_req {
        CRB_CTRL_REQ_CMD_READY  = BIT(0),
        CRB_CTRL_REQ_GO_IDLE    = BIT(1),
@@ -165,13 +174,42 @@ static int __maybe_unused crb_cmd_ready(struct device 
*dev,
                                 CRB_CTRL_REQ_CMD_READY /* mask */,
                                 0, /* value */
                                 TPM2_TIMEOUT_C)) {
-               dev_warn(dev, "cmdReady timed out\n");
+               dev_warn(dev, "TPM_CRB_CTRL_REQ_x.cmdReady timed out\n");
+               return -ETIME;
+       }
+
+       return 0;
+}
+
+static int crb_request_locality(struct tpm_chip *chip)
+{
+       struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+       if (!priv->regs_h)
+               return 0;
+
+       iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
+       if (!crb_wait_for_reg_32(&priv->regs_h->loc_state,
+                                CRB_LOC_STATE_LOC_ASSIGNED, /* mask */
+                                CRB_LOC_STATE_LOC_ASSIGNED, /* value */
+                                TPM2_TIMEOUT_C)) {
+               dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed 
out\n");
                return -ETIME;
        }
 
        return 0;
 }
 
+static void crb_relinquish_locality(struct tpm_chip *chip)
+{
+       struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+       if (!priv->regs_h)
+               return;
+
+       iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
+}
+
 static u8 crb_status(struct tpm_chip *chip)
 {
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
@@ -188,23 +226,33 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, 
size_t count)
 {
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
        unsigned int expected;
+       int rc;
 
        /* sanity check */
        if (count < 6)
                return -EIO;
 
-       if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
-               return -EIO;
+       rc = crb_request_locality(chip);
+       if (rc)
+               return rc;
+
+       if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR) {
+               rc = -EIO;
+               goto out;
+       }
 
        memcpy_fromio(buf, priv->rsp, 6);
        expected = be32_to_cpup((__be32 *) &buf[2]);
-
-       if (expected > count)
-               return -EIO;
+       if (expected > count) {
+               rc = -EIO;
+               goto out;
+       }
 
        memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 
-       return expected;
+out:
+       crb_relinquish_locality(chip);
+       return rc ? rc : expected;
 }
 
 static int crb_do_acpi_start(struct tpm_chip *chip)
@@ -227,7 +275,11 @@ static int crb_do_acpi_start(struct tpm_chip *chip)
 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 {
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
-       int rc = 0;
+       int rc;
+
+       rc = crb_request_locality(chip);
+       if (rc)
+               return rc;
 
        /* Zero the cancel register so that the next command will not get
         * canceled.
@@ -237,7 +289,8 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t 
len)
        if (len > priv->cmd_size) {
                dev_err(&chip->dev, "invalid command count value %zd %d\n",
                        len, priv->cmd_size);
-               return -E2BIG;
+               rc = -E2BIG;
+               goto out;
        }
 
        memcpy_toio(priv->cmd, buf, len);
@@ -251,6 +304,8 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t 
len)
        if (priv->flags & CRB_FL_ACPI_START)
                rc = crb_do_acpi_start(chip);
 
+out:
+       crb_relinquish_locality(chip);
        return rc;
 }
 
-- 
2.9.3