tpm: introduce tpm_chip_start() and tpm_chip_stop()

Encapsulate power gating and locality functionality to tpm_chip_start()
and tpm_chip_stop() in order to clean up the branching mess in
tpm_transmit().

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>

3 files changed, 116 insertions, 81 deletions

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 157505b0f755..ed673c7216a0 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -37,6 +37,117 @@ struct class *tpm_class;
 struct class *tpmrm_class;
 dev_t tpm_devt;
 
+static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
+{
+        int rc;
+
+        if (flags & TPM_TRANSMIT_NESTED)
+                return 0;
+
+        if (!chip->ops->request_locality)
+                return 0;
+
+        rc = chip->ops->request_locality(chip, 0);
+        if (rc < 0)
+                return rc;
+
+        chip->locality = rc;
+        return 0;
+}
+
+static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
+{
+        int rc;
+
+        if (flags & TPM_TRANSMIT_NESTED)
+                return;
+
+        if (!chip->ops->relinquish_locality)
+                return;
+
+        rc = chip->ops->relinquish_locality(chip, chip->locality);
+        if (rc)
+                dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
+
+        chip->locality = -1;
+}
+
+static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
+{
+        if (flags & TPM_TRANSMIT_NESTED)
+                return 0;
+
+        if (!chip->ops->cmd_ready)
+                return 0;
+
+        return chip->ops->cmd_ready(chip);
+}
+
+static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
+{
+        if (flags & TPM_TRANSMIT_NESTED)
+                return 0;
+
+        if (!chip->ops->go_idle)
+                return 0;
+
+        return chip->ops->go_idle(chip);
+}
+
+/**
+ * tpm_chip_start() - power on the TPM
+ * @chip:       a TPM chip to use
+ * @flags:      TPM transmit flags
+ *
+ * Return:
+ * * The response length        - OK
+ * * -errno                     - A system error
+ */
+int tpm_chip_start(struct tpm_chip *chip, unsigned int flags)
+{
+        int ret;
+
+        if (chip->ops->clk_enable)
+                chip->ops->clk_enable(chip, true);
+
+        if (chip->locality == -1) {
+                ret = tpm_request_locality(chip, flags);
+                if (ret) {
+                        chip->ops->clk_enable(chip, false);
+                        return ret;
+                }
+        }
+
+        ret = tpm_cmd_ready(chip, flags);
+        if (ret) {
+                tpm_relinquish_locality(chip, flags);
+                if (chip->ops->clk_enable)
+                        chip->ops->clk_enable(chip, false);
+                return ret;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(tpm_chip_start);
+
+/**
+ * tpm_chip_stop() - power off the TPM
+ * @chip:       a TPM chip to use
+ * @flags:      TPM transmit flags
+ *
+ * Return:
+ * * The response length        - OK
+ * * -errno                     - A system error
+ */
+void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags)
+{
+        tpm_go_idle(chip, flags);
+        tpm_relinquish_locality(chip, flags);
+        if (chip->ops->clk_enable)
+                chip->ops->clk_enable(chip, false);
+}
+EXPORT_SYMBOL_GPL(tpm_chip_stop);
+
 /**
  * tpm_try_get_ops() - Get a ref to the tpm_chip
  * @chip: Chip to ref
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 54a15f59e175..038a4767d9d6 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -62,64 +62,6 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
 }
 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
 
-static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
-{
-        int rc;
-
-        if (flags & TPM_TRANSMIT_NESTED)
-                return 0;
-
-        if (!chip->ops->request_locality)
-                return 0;
-
-        rc = chip->ops->request_locality(chip, 0);
-        if (rc < 0)
-                return rc;
-
-        chip->locality = rc;
-
-        return 0;
-}
-
-static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
-{
-        int rc;
-
-        if (flags & TPM_TRANSMIT_NESTED)
-                return;
-
-        if (!chip->ops->relinquish_locality)
-                return;
-
-        rc = chip->ops->relinquish_locality(chip, chip->locality);
-        if (rc)
-                dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
-
-        chip->locality = -1;
-}
-
-static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
-{
-        if (flags & TPM_TRANSMIT_NESTED)
-                return 0;
-
-        if (!chip->ops->cmd_ready)
-                return 0;
-
-        return chip->ops->cmd_ready(chip);
-}
-
-static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
-{
-        if (flags & TPM_TRANSMIT_NESTED)
-                return 0;
-
-        if (!chip->ops->go_idle)
-                return 0;
-
-        return chip->ops->go_idle(chip);
-}
-
 static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz,
                                 unsigned int flags)
 {
@@ -221,7 +163,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
         /* space for header and handles */
         u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
         unsigned int delay_msec = TPM2_DURATION_SHORT;
-        bool has_locality = false;
         u32 rc = 0;
         ssize_t ret;
         const size_t save_size = min(sizeof(save), bufsiz);
@@ -236,32 +177,13 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
         memcpy(save, buf, save_size);
 
         for (;;) {
-                if (chip->ops->clk_enable != NULL)
-                        chip->ops->clk_enable(chip, true);
-
-                if (chip->locality == -1) {
-                        ret = tpm_request_locality(chip, flags);
-                        if (ret)
-                                goto out_locality;
-                        has_locality = true;
-                }
-
-                ret = tpm_cmd_ready(chip, flags);
+                ret = tpm_chip_start(chip, flags);
                 if (ret)
-                        goto out_locality;
+                        return ret;
 
                 ret = tpm_try_transmit(chip, buf, bufsiz, flags);
 
-                /* This may fail but do not override ret. */
-                tpm_go_idle(chip, flags);
-
-out_locality:
-                if (has_locality)
-                        tpm_relinquish_locality(chip, flags);
-
-                if (chip->ops->clk_enable != NULL)
-                        chip->ops->clk_enable(chip, false);
-
+                tpm_chip_stop(chip, flags);
                 if (ret < 0)
                         break;
                 rc = be32_to_cpu(header->return_code);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 18ef432a3fde..2d6d934f1c8b 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -523,6 +523,8 @@ static inline void tpm_msleep(unsigned int delay_msec)
                      delay_msec * 1000);
 };
 
+int tpm_chip_start(struct tpm_chip *chip, unsigned int flags);
+void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags);
 struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
 __must_check int tpm_try_get_ops(struct tpm_chip *chip);
 void tpm_put_ops(struct tpm_chip *chip);