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From: Ross Philipson <ross.philipson@oracle.com>
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Subject: [PATCH v9 16/19] tpm: Add ability to set the preferred locality the TPM chip uses
Date: Thu, 30 May 2024 18:03:28 -0700
Message-Id: <20240531010331.134441-17-ross.philipson@oracle.com>
In-Reply-To: <20240531010331.134441-1-ross.philipson@oracle.com>
References: <20240531010331.134441-1-ross.philipson@oracle.com>
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Curently the locality is hard coded to 0 but for DRTM support, access
is needed to localities 1 through 4.

Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
 drivers/char/tpm/tpm-chip.c      | 24 +++++++++++++++++++++++-
 drivers/char/tpm/tpm-interface.c | 15 +++++++++++++++
 drivers/char/tpm/tpm.h           |  1 +
 include/linux/tpm.h              |  4 ++++
 4 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 854546000c92..73eac54d61fb 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -44,7 +44,7 @@ static int tpm_request_locality(struct tpm_chip *chip)
 	if (!chip->ops->request_locality)
 		return 0;
 
-	rc = chip->ops->request_locality(chip, 0);
+	rc = chip->ops->request_locality(chip, chip->pref_locality);
 	if (rc < 0)
 		return rc;
 
@@ -143,6 +143,27 @@ void tpm_chip_stop(struct tpm_chip *chip)
 }
 EXPORT_SYMBOL_GPL(tpm_chip_stop);
 
+/**
+ * tpm_chip_preferred_locality() - set the TPM chip preferred locality to open
+ * @chip:	a TPM chip to use
+ * @locality:   the preferred locality
+ *
+ * Return:
+ * * true      - Preferred locality set
+ * * false     - Invalid locality specified
+ */
+bool tpm_chip_preferred_locality(struct tpm_chip *chip, int locality)
+{
+	if (locality < 0 || locality >=TPM_MAX_LOCALITY)
+		return false;
+
+	mutex_lock(&chip->tpm_mutex);
+	chip->pref_locality = locality;
+	mutex_unlock(&chip->tpm_mutex);
+	return true;
+}
+EXPORT_SYMBOL_GPL(tpm_chip_preferred_locality);
+
 /**
  * tpm_try_get_ops() - Get a ref to the tpm_chip
  * @chip: Chip to ref
@@ -374,6 +395,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	}
 
 	chip->locality = -1;
+	chip->pref_locality = 0;
 	return chip;
 
 out:
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5da134f12c9a..35f14ccecf0e 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -274,6 +274,21 @@ int tpm_is_tpm2(struct tpm_chip *chip)
 }
 EXPORT_SYMBOL_GPL(tpm_is_tpm2);
 
+/**
+ * tpm_preferred_locality() - set the TPM chip preferred locality to open
+ * @chip:	a TPM chip to use
+ * @locality:   the preferred locality
+ *
+ * Return:
+ * * true      - Preferred locality set
+ * * false     - Invalid locality specified
+ */
+bool tpm_preferred_locality(struct tpm_chip *chip, int locality)
+{
+	return tpm_chip_preferred_locality(chip, locality);
+}
+EXPORT_SYMBOL_GPL(tpm_preferred_locality);
+
 /**
  * tpm_pcr_read - read a PCR value from SHA1 bank
  * @chip:	a &struct tpm_chip instance, %NULL for the default chip
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 6b8b9956ba69..be465422d3fa 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -267,6 +267,7 @@ static inline void tpm_msleep(unsigned int delay_msec)
 int tpm_chip_bootstrap(struct tpm_chip *chip);
 int tpm_chip_start(struct tpm_chip *chip);
 void tpm_chip_stop(struct tpm_chip *chip);
+bool tpm_chip_preferred_locality(struct tpm_chip *chip, int locality);
 struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
 
 struct tpm_chip *tpm_chip_alloc(struct device *dev,
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 363f7078c3a9..935a3457d7c8 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -219,6 +219,9 @@ struct tpm_chip {
 	u8 null_ec_key_y[EC_PT_SZ];
 	struct tpm2_auth *auth;
 #endif
+
+	/* preferred locality - default 0 */
+	int pref_locality;
 };
 
 #define TPM_HEADER_SIZE		10
@@ -461,6 +464,7 @@ static inline u32 tpm2_rc_value(u32 rc)
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
 extern int tpm_is_tpm2(struct tpm_chip *chip);
+extern bool tpm_preferred_locality(struct tpm_chip *chip, int locality);
 extern __must_check int tpm_try_get_ops(struct tpm_chip *chip);
 extern void tpm_put_ops(struct tpm_chip *chip);
 extern ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
-- 
2.39.3