[PATCH v3 0/7] add tpm i2c ptp driver

[PATCH v3 0/7] add tpm i2c ptp driver

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

This patch set adds support for TPM devices that implement the I2C.
Interface defined by TCG PTP specification:
https://trustedcomputinggroup.org/wp-content/uploads/TCG_PC_Client_Platform_TPM_Profile_PTP_2.0_r1.03_v22.pdf

The driver was tested on Raspberry-Pie 3, using Nuvoton NPCT75X TPM.

Interrupts are not implemented yet, preparing it for the next patch.
This patch is based on initial work by oshri Alkoby, Alexander Steffen and Christophe Ricard

Addressed comments from:
 - Jarkko Sakkinen: https://patchwork.kernel.org/patch/11236257/
 - Rob Herring: https://patchwork.kernel.org/patch/11236253/

Changes since version 1:
-"char:tpm:Add check_data handle to tpm_tis_phy_ops in order to check data integrity"
        - Fixed and extended commit description.
        - Fixed an issue regarding handling max retries.
-"dt-bindings: tpm: Add YAML schema for TPM TIS I2C options":
        -Converted "tpm_tis_i2c.txt" to "tpm-tis-i2c.yaml".
        - Renamed "tpm_tis-i2c" to "tpm-tis-i2c".
        - Removed interrupts properties.
-"char: tpm: add tpm_tis_i2c driver"
        - Replaced "tpm_tis-i2c" with "tpm-tis-i2c" in "tpm_tis_i2c.c".


Changes since version 2:
- Added 2 new commits with improvements suggested by Benoit Houyere.
        -"Fix expected bit handling  and send all bytes in one shot without last byte in exception"
        -"Handle an exeption for TPM Firmware Update mode."
- Updated patch to latest v5.5
-"dt-bindings: tpm: Add YAML schema for TPM TIS I2C options"
        - Added "interrupts" and "crc-checksum" to properties.
        - Updated binding description and commit info.
-"char: tpm: add tpm_tis_i2c driver" (suggested by Benoit Houyere)
        - Added repeat I2C frame after NACK.
        - Checksum I2C feature activation in DTS file configuration.

Amir Mizinski (7):
  char: tpm: Make implementation of read16 read32 write32 optional
  char: tpm: Add check_data handle to tpm_tis_phy_ops in order to check
    data integrity
  char: tpm: rewrite "tpm_tis_req_canceled()"
  char: tpm: Fix expected bit handling and send all bytes in one shot
    without last byte in exception
  tpm: Handle an exception for TPM Firmware Update mode.
  dt-bindings: tpm: Add YAML schema for TPM TIS I2C options
  char: tpm: add tpm_tis_i2c driver

 .../bindings/security/tpm/tpm-tis-i2c.yaml         |  43 +++
 drivers/char/tpm/Kconfig                           |  12 +
 drivers/char/tpm/Makefile                          |   1 +
 drivers/char/tpm/tpm2-cmd.c                        |   4 +
 drivers/char/tpm/tpm_tis_core.c                    | 182 ++++++-------
 drivers/char/tpm/tpm_tis_core.h                    |  41 ++-
 drivers/char/tpm/tpm_tis_i2c.c                     | 292 +++++++++++++++++++++
 drivers/char/tpm/tpm_tis_spi.c                     |  41 ---
 include/linux/tpm.h                                |   1 +
 9 files changed, 482 insertions(+), 135 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
 create mode 100644 drivers/char/tpm/tpm_tis_i2c.c

-- 
2.7.4

[PATCH v3 1/7] char: tpm: Make implementation of read16 read32 write32 optional

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

Only tpm_tis has a faster way to access multiple bytes at once, every other
driver will just fall back to read_bytes/write_bytes. Therefore, move this
common code out of tpm_tis_spi into tpm_tis_core, so that it is
automatically used when low-level drivers do not implement the specialized
methods.

This commit is based on previous work by Alexander Steffen.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.h | 38 +++++++++++++++++++++++++++++++++++---
 drivers/char/tpm/tpm_tis_spi.c  | 41 -----------------------------------------
 2 files changed, 35 insertions(+), 44 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index 7337819..d06c65b 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -122,13 +122,35 @@ static inline int tpm_tis_read8(struct tpm_tis_data *data, u32 addr, u8 *result)
 static inline int tpm_tis_read16(struct tpm_tis_data *data, u32 addr,
 				 u16 *result)
 {
-	return data->phy_ops->read16(data, addr, result);
+	__le16 result_le;
+	int rc;
+
+	if (data->phy_ops->read16)
+		return data->phy_ops->read16(data, addr, result);
+
+	rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
+				       (u8 *)&result_le);
+	if (!rc)
+		*result = le16_to_cpu(result_le);
+
+	return rc;
 }
 
 static inline int tpm_tis_read32(struct tpm_tis_data *data, u32 addr,
 				 u32 *result)
 {
-	return data->phy_ops->read32(data, addr, result);
+	__le32 result_le;
+	int rc;
+
+	if (data->phy_ops->read32)
+		return data->phy_ops->read32(data, addr, result);
+
+	rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
+				       (u8 *)&result_le);
+	if (!rc)
+		*result = le32_to_cpu(result_le);
+
+	return rc;
 }
 
 static inline int tpm_tis_write_bytes(struct tpm_tis_data *data, u32 addr,
@@ -145,7 +167,17 @@ static inline int tpm_tis_write8(struct tpm_tis_data *data, u32 addr, u8 value)
 static inline int tpm_tis_write32(struct tpm_tis_data *data, u32 addr,
 				  u32 value)
 {
-	return data->phy_ops->write32(data, addr, value);
+	__le32 value_le;
+	int rc;
+
+	if (data->phy_ops->write32)
+		return data->phy_ops->write32(data, addr, value);
+
+	value_le = cpu_to_le32(value);
+	rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
+					(u8 *)&value_le);
+
+	return rc;
 }
 
 static inline bool is_bsw(void)
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
index d1754fd..95fef9d 100644
--- a/drivers/char/tpm/tpm_tis_spi.c
+++ b/drivers/char/tpm/tpm_tis_spi.c
@@ -152,44 +152,6 @@ static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 	return tpm_tis_spi_transfer(data, addr, len, NULL, value);
 }
 
-int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
-{
-	__le16 result_le;
-	int rc;
-
-	rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
-				       (u8 *)&result_le);
-	if (!rc)
-		*result = le16_to_cpu(result_le);
-
-	return rc;
-}
-
-int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
-{
-	__le32 result_le;
-	int rc;
-
-	rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
-				       (u8 *)&result_le);
-	if (!rc)
-		*result = le32_to_cpu(result_le);
-
-	return rc;
-}
-
-int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
-{
-	__le32 value_le;
-	int rc;
-
-	value_le = cpu_to_le32(value);
-	rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
-					(u8 *)&value_le);
-
-	return rc;
-}
-
 int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
 		     int irq, const struct tpm_tis_phy_ops *phy_ops)
 {
@@ -205,9 +167,6 @@ int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 	.read_bytes = tpm_tis_spi_read_bytes,
 	.write_bytes = tpm_tis_spi_write_bytes,
-	.read16 = tpm_tis_spi_read16,
-	.read32 = tpm_tis_spi_read32,
-	.write32 = tpm_tis_spi_write32,
 };
 
 static int tpm_tis_spi_probe(struct spi_device *dev)
-- 
2.7.4

Re: [PATCH v3 1/7] char: tpm: Make implementation of read16 read32 write32 optional

[Jarkko Sakkinen]

On Mon, Feb 10, 2020 at 06:28:32PM +0200, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
> 
> Only tpm_tis has a faster way to access multiple bytes at once, every other
> driver will just fall back to read_bytes/write_bytes. Therefore, move this

Describe exactly what you mean instead of "faster way" and "multiple
bytes".

> common code out of tpm_tis_spi into tpm_tis_core, so that it is
> automatically used when low-level drivers do not implement the specialized
> methods.
> 
> This commit is based on previous work by Alexander Steffen.
> 
> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>

You are missing commas in the short summary message when you list bunch
of things.

We prefer "tpm:" instead of "char: tpm:" as the tag for this subsystem.
You are also implying that this would be something global for the TPM
driver whereas it is only scoped to tpm_tis:

Rephrase it something like:

  "tpm: tpm_tis: Make 32-bit reads and writes optional"

Please, first, take this away:

"
This commit is based on previous work by Alexander Steffen.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
"

Then, replace it with:

Co-developed-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>

/Jarkko

[PATCH v3 2/7] char: tpm: Add check_data handle to tpm_tis_phy_ops in order to check data integrity

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

In order to compute the crc over the data sent in lower layer
 (I2C for instance), tpm_tis_check_data() calls an operation (if available)
 to check data integrity. If data integrity cannot be verified, a retry
 attempt to save the sent/received data is implemented.

The current steps are done when sending a command:
    1. Host writes to TPM_STS.commandReady.
    2. Host writes command.
    3. Host checks that TPM received data is valid.
    4. If data is currupted go to step 1.

When receiving data:
    1. Host checks that TPM_STS.dataAvail is set.
    2. Host saves received data.
    3. Host checks that received data is correct.
    4. If data is currupted Host writes to TPM_STS.responseRetry and go to
        step 1.

This commit is based on previous work by Christophe Richard.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 102 +++++++++++++++++++++++++---------------
 drivers/char/tpm/tpm_tis_core.h |   3 ++
 2 files changed, 67 insertions(+), 38 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 27c6ca0..6c4f232 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -242,6 +242,15 @@ static u8 tpm_tis_status(struct tpm_chip *chip)
 	return status;
 }
 
+static bool tpm_tis_check_data(struct tpm_chip *chip, const u8 *buf, size_t len)
+{
+	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+
+	if (priv->phy_ops->check_data)
+		return priv->phy_ops->check_data(priv, buf, len);
+	return true;
+}
+
 static void tpm_tis_ready(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
@@ -308,47 +317,59 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	int size = 0;
-	int status;
+	int status, i;
 	u32 expected;
+	bool check_data = false;
 
-	if (count < TPM_HEADER_SIZE) {
-		size = -EIO;
-		goto out;
-	}
+	for (i = 0; i < TPM_RETRY; i++) {
+		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) {
-		dev_err(&chip->dev, "Unable to read header\n");
-		goto out;
-	}
+		size = recv_data(chip, buf, TPM_HEADER_SIZE);
+		/* read first 10 bytes, including tag, paramsize, and result */
+		if (size < TPM_HEADER_SIZE) {
+			dev_err(&chip->dev, "Unable to read header\n");
+			goto out;
+		}
 
-	expected = be32_to_cpu(*(__be32 *) (buf + 2));
-	if (expected > count || expected < TPM_HEADER_SIZE) {
-		size = -EIO;
-		goto out;
-	}
+		expected = be32_to_cpu(*(__be32 *) (buf + 2));
+		if (expected > count || expected < TPM_HEADER_SIZE) {
+			size = -EIO;
+			goto out;
+		}
 
-	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
-			  expected - TPM_HEADER_SIZE);
-	if (size < expected) {
-		dev_err(&chip->dev, "Unable to read remainder of result\n");
-		size = -ETIME;
-		goto out;
-	}
+		size += recv_data(chip, &buf[TPM_HEADER_SIZE],
+				  expected - TPM_HEADER_SIZE);
+		if (size < expected) {
+			dev_err(&chip->dev, "Unable to read remainder of result\n");
+			size = -ETIME;
+			goto out;
+		}
 
-	if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
-				&priv->int_queue, false) < 0) {
-		size = -ETIME;
-		goto out;
+		if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
+				      &priv->int_queue, false) < 0) {
+			size = -ETIME;
+			goto out;
+		}
+
+		status = tpm_tis_status(chip);
+		if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
+			dev_err(&chip->dev, "Error left over data\n");
+			size = -EIO;
+			goto out;
+		}
+
+		check_data = tpm_tis_check_data(chip, buf, size);
+		if (!check_data)
+			tpm_tis_write8(priv, TPM_STS(priv->locality),
+				       TPM_STS_RESPONSE_RETRY);
+		else
+			break;
 	}
-	status = tpm_tis_status(chip);
-	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
-		dev_err(&chip->dev, "Error left over data\n");
+	if (!check_data)
 		size = -EIO;
-		goto out;
-	}
-
 out:
 	tpm_tis_ready(chip);
 	return size;
@@ -453,14 +474,19 @@ static void disable_interrupts(struct tpm_chip *chip)
 static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	int rc;
+	int rc, i;
 	u32 ordinal;
 	unsigned long dur;
+	bool data_valid = false;
 
-	rc = tpm_tis_send_data(chip, buf, len);
-	if (rc < 0)
-		return rc;
-
+	for (i = 0; i < TPM_RETRY && !data_valid; i++) {
+		rc = tpm_tis_send_data(chip, buf, len);
+		if (rc < 0)
+			return rc;
+		data_valid = tpm_tis_check_data(chip, buf, len);
+	}
+	if (!data_valid)
+		return -EIO;
 	/* go and do it */
 	rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
 	if (rc < 0)
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index d06c65b..486c2e9 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,
 };
 
 enum tis_int_flags {
@@ -106,6 +107,8 @@ struct tpm_tis_phy_ops {
 	int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result);
 	int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result);
 	int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src);
+	bool (*check_data)(struct tpm_tis_data *data, const u8 *buf,
+			   size_t len);
 };
 
 static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr,
-- 
2.7.4

[PATCH v3 3/7] char: tpm: rewrite "tpm_tis_req_canceled()"

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

Using this function while read/write data resulted in aborted operation.
After investigating according to TCG TPM Profile (PTP) Specifications, i
 found cancel should happen only if TPM_STS.commandReady bit is lit and
 couldn't find a case when the current condition is valid.
Also only cmdReady bit need to be compared instead of the full lower status
 register byte.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 6c4f232..18b9dc4 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -710,17 +710,7 @@ static int probe_itpm(struct tpm_chip *chip)
 
 static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
 {
-	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-
-	switch (priv->manufacturer_id) {
-	case TPM_VID_WINBOND:
-		return ((status == TPM_STS_VALID) ||
-			(status == (TPM_STS_VALID | TPM_STS_COMMAND_READY)));
-	case TPM_VID_STM:
-		return (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY));
-	default:
-		return (status == TPM_STS_COMMAND_READY);
-	}
+	return ((status & TPM_STS_COMMAND_READY) == TPM_STS_COMMAND_READY);
 }
 
 static irqreturn_t tis_int_handler(int dummy, void *dev_id)
-- 
2.7.4

[PATCH v3 4/7] char: tpm: Fix expected bit handling and send all bytes in one shot without last byte in exception

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

Today, actual implementation for send massage is not correct. We check and
 loop only on TPM_STS.stsValid bit and next we single check TPM_STS.expect
 bit value.
TPM_STS.expected bit shall be checked in the same time of
 TPM_STS.stsValid, and should be repeated until timeout_A.
To aquire that, "wait_for_tpm_stat" function is modified to
 "wait_for_tpm_stat_result". this function read regulary status register
 and check bit defined by "mask" to reach value defined in "mask_result"
 (that way a bit in mask can be checked if reached 1 or 0).

Respectively, to send message as defined in
 TCG_DesignPrinciples_TPM2p0Driver_vp24_pubrev.pdf, all bytes should be
 sent in one shot instead of sending last byte in exception.

This improvment was suggested by Benoit Houyere.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 72 ++++++++++++++++-------------------------
 1 file changed, 28 insertions(+), 44 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 18b9dc4..c8f4cf8 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -44,9 +44,10 @@ static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
 	return false;
 }
 
-static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
-		unsigned long timeout, wait_queue_head_t *queue,
-		bool check_cancel)
+static int wait_for_tpm_stat_result(struct tpm_chip *chip, u8 mask,
+				    u8 mask_result, unsigned long timeout,
+				    wait_queue_head_t *queue,
+				    bool check_cancel)
 {
 	unsigned long stop;
 	long rc;
@@ -55,7 +56,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
 
 	/* check current status */
 	status = chip->ops->status(chip);
-	if ((status & mask) == mask)
+	if ((status & mask) == mask_result)
 		return 0;
 
 	stop = jiffies + timeout;
@@ -83,7 +84,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
 			usleep_range(TPM_TIMEOUT_USECS_MIN,
 				     TPM_TIMEOUT_USECS_MAX);
 			status = chip->ops->status(chip);
-			if ((status & mask) == mask)
+			if ((status & mask) == mask_result)
 				return 0;
 		} while (time_before(jiffies, stop));
 	}
@@ -290,10 +291,11 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 	int size = 0, burstcnt, rc;
 
 	while (size < count) {
-		rc = wait_for_tpm_stat(chip,
-				 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
-				 chip->timeout_c,
-				 &priv->read_queue, true);
+		rc = wait_for_tpm_stat_result(chip,
+					TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+					TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+					chip->timeout_c,
+					&priv->read_queue, true);
 		if (rc < 0)
 			return rc;
 		burstcnt = get_burstcount(chip);
@@ -348,8 +350,9 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 			goto out;
 		}
 
-		if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
-				      &priv->int_queue, false) < 0) {
+		if (wait_for_tpm_stat_result(chip, TPM_STS_VALID,
+					     TPM_STS_VALID, chip->timeout_c,
+					     &priv->int_queue, false) < 0) {
 			size = -ETIME;
 			goto out;
 		}
@@ -385,61 +388,40 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	int rc, status, burstcnt;
 	size_t count = 0;
-	bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
 
 	status = tpm_tis_status(chip);
 	if ((status & TPM_STS_COMMAND_READY) == 0) {
 		tpm_tis_ready(chip);
-		if (wait_for_tpm_stat
-		    (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
-		     &priv->int_queue, false) < 0) {
+		if (wait_for_tpm_stat_result(chip, TPM_STS_COMMAND_READY,
+					     TPM_STS_COMMAND_READY,
+					     chip->timeout_b,
+					     &priv->int_queue, false) < 0) {
 			rc = -ETIME;
 			goto out_err;
 		}
 	}
 
-	while (count < len - 1) {
+	while (count < len) {
 		burstcnt = get_burstcount(chip);
 		if (burstcnt < 0) {
 			dev_err(&chip->dev, "Unable to read burstcount\n");
 			rc = burstcnt;
 			goto out_err;
 		}
-		burstcnt = min_t(int, burstcnt, len - count - 1);
+		burstcnt = min_t(int, burstcnt, len - count);
 		rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
 					 burstcnt, buf + count);
 		if (rc < 0)
 			goto out_err;
 
 		count += burstcnt;
-
-		if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
-					&priv->int_queue, false) < 0) {
-			rc = -ETIME;
-			goto out_err;
-		}
-		status = tpm_tis_status(chip);
-		if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
-			rc = -EIO;
-			goto out_err;
-		}
 	}
-
-	/* write last byte */
-	rc = tpm_tis_write8(priv, TPM_DATA_FIFO(priv->locality), buf[count]);
-	if (rc < 0)
-		goto out_err;
-
-	if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
-				&priv->int_queue, false) < 0) {
+	if (wait_for_tpm_stat_result(chip, TPM_STS_VALID | TPM_STS_DATA_EXPECT,
+				     TPM_STS_VALID, chip->timeout_c,
+				     &priv->int_queue, false) < 0) {
 		rc = -ETIME;
 		goto out_err;
 	}
-	status = tpm_tis_status(chip);
-	if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) {
-		rc = -EIO;
-		goto out_err;
-	}
 
 	return 0;
 
@@ -496,9 +478,11 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
 		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 
 		dur = tpm_calc_ordinal_duration(chip, ordinal);
-		if (wait_for_tpm_stat
-		    (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID, dur,
-		     &priv->read_queue, false) < 0) {
+		if (wait_for_tpm_stat_result(chip,
+					     TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+					     TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+					     dur,
+					     &priv->read_queue, false) < 0) {
 			rc = -ETIME;
 			goto out_err;
 		}
-- 
2.7.4

[PATCH v3 5/7] tpm: Handle an exception for TPM Firmware Update mode.

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

An extra precaution for TPM Firmware Update Mode.
 For example if TPM power was cut while in Firmware update, platform
 should ignore selftest failure and skip TPM initialization sequence.

This improvment was suggested by Benoit Houyere.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm2-cmd.c | 4 ++++
 include/linux/tpm.h         | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 13696de..997b11e 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -725,6 +725,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
 		goto out;
 
 	rc = tpm2_do_selftest(chip);
+
+	if ((rc == TPM2_RC_UPGRADE) || (rc == TPM2_RC_COMMAND_CODE))
+		return 0;
+
 	if (rc && rc != TPM2_RC_INITIALIZE)
 		goto out;
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 03e9b18..5a2e031 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -199,6 +199,7 @@ enum tpm2_return_codes {
 	TPM2_RC_INITIALIZE	= 0x0100, /* RC_VER1 */
 	TPM2_RC_FAILURE		= 0x0101,
 	TPM2_RC_DISABLED	= 0x0120,
+	TPM2_RC_UPGRADE         = 0x012D,
 	TPM2_RC_COMMAND_CODE    = 0x0143,
 	TPM2_RC_TESTING		= 0x090A, /* RC_WARN */
 	TPM2_RC_REFERENCE_H0	= 0x0910,
-- 
2.7.4

[PATCH v3 6/7] dt-bindings: tpm: Add YAML schema for TPM TIS I2C options

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

Added a YAML schema to support tpm tis i2c realted dt-bindings for the I2c
 PTP based physical layer.

This patch adds the documentation for corresponding device tree bindings of
 I2C based Physical TPM.
Refer to the 'I2C Interface Definition' section in
 'TCG PC Client PlatformTPMProfile(PTP) Specification' publication
 for specification.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 .../bindings/security/tpm/tpm-tis-i2c.yaml         | 43 ++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml

diff --git a/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml b/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
new file mode 100644
index 0000000..ca16b59
--- /dev/null
+++ b/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/security/tpm/tpm-tis-i2c.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: I2C PTP based TPM Device Tree Bindings
+
+maintainers:
+  - Amir Mizinski <amirmizi6@gmail.com>
+
+description:
+  Device Tree Bindings for I2C based Trusted Platform Module(TPM).
+
+properties:
+  compatible:
+    contains:
+      const: tcg,tpm-tis-i2c
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  crc-checksum:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      CRC checksum enable.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+examples:
+  - |
+    tpm-tis-i2c: tpm-tis-i2c@2e {
+       compatible = "tcg,tpm-tis-i2c";
+       reg = <0x2e>;
+       interrupts = <&gpio 24 GPIO_ACTIVE_HIGH>;
+       crc-checksum;
+    };
-- 
2.7.4

Re: [PATCH v3 6/7] dt-bindings: tpm: Add YAML schema for TPM TIS I2C options

[Rob Herring]

On Mon, 10 Feb 2020 18:28:37 +0200, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
> 
> Added a YAML schema to support tpm tis i2c realted dt-bindings for the I2c
>  PTP based physical layer.
> 
> This patch adds the documentation for corresponding device tree bindings of
>  I2C based Physical TPM.
> Refer to the 'I2C Interface Definition' section in
>  'TCG PC Client PlatformTPMProfile(PTP) Specification' publication
>  for specification.
> 
> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
> ---
>  .../bindings/security/tpm/tpm-tis-i2c.yaml         | 43 ++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

Documentation/devicetree/bindings/display/simple-framebuffer.example.dts:21.16-37.11: Warning (chosen_node_is_root): /example-0/chosen: chosen node must be at root node
Error: Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.example.dts:17.12-13 syntax error
FATAL ERROR: Unable to parse input tree
scripts/Makefile.lib:300: recipe for target 'Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.example.dt.yaml' failed
make[1]: *** [Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.example.dt.yaml] Error 1
Makefile:1263: recipe for target 'dt_binding_check' failed
make: *** [dt_binding_check] Error 2

See https://patchwork.ozlabs.org/patch/1235916
Please check and re-submit.

[PATCH v3 7/7] char: tpm: add tpm_tis_i2c driver

[amirmizi6]

From: Amir Mizinski <amirmizi6@gmail.com>

Implements the functionality needed to communicate with an I2C TPM
according to the TCG TPM I2C Interface Specification.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/Kconfig       |  12 ++
 drivers/char/tpm/Makefile      |   1 +
 drivers/char/tpm/tpm_tis_i2c.c | 292 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/char/tpm/tpm_tis_i2c.c

diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index aacdeed..b482bbf 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -74,6 +74,18 @@ config TCG_TIS_SPI_CR50
 	  If you have a H1 secure module running Cr50 firmware on SPI bus,
 	  say Yes and it will be accessible from within Linux.
 
+config TCG_TIS_I2C
+	tristate "TPM I2C Interface Specification"
+	depends on I2C
+	 depends on CRC_CCITT
+	select TCG_TIS_CORE
+	---help---
+	  If you have a TPM security chip which is connected to a regular
+	  I2C master (i.e. most embedded platforms) that is compliant with the
+	  TCG TPM I2C Interface Specification say Yes and it will be accessible from
+	  within Linux. To compile this driver as a module, choose  M here;
+	  the module will be called tpm_tis_i2c.
+
 config TCG_TIS_I2C_ATMEL
 	tristate "TPM Interface Specification 1.2 Interface (I2C - Atmel)"
 	depends on I2C
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 5a0d99d..5c9a31d 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_TCG_TIS) += tpm_tis.o
 obj-$(CONFIG_TCG_TIS_SPI) += tpm_tis_spi_mod.o
 tpm_tis_spi_mod-y := tpm_tis_spi.o
 tpm_tis_spi_mod-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o
+obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
 obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
 obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
 obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
new file mode 100644
index 0000000..c10ec7e
--- /dev/null
+++ b/drivers/char/tpm/tpm_tis_i2c.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014-2019 Nuvoton Technology corporation
+ *
+ * TPM TIS I2C
+ *
+ * TPM TIS I2C Device Driver Interface for devices that implement the TPM I2C
+ * Interface defined by TCG PC Client Platform TPM Profile (PTP) Specification
+ * Revision 01.03 v22 at www.trustedcomputinggroup.org
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/acpi.h>
+#include <linux/freezer.h>
+#include <linux/crc-ccitt.h>
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/tpm.h>
+#include "tpm.h"
+#include "tpm_tis_core.h"
+
+#define TPM_LOC_SEL                    0x04
+#define TPM_I2C_INTERFACE_CAPABILITY   0x30
+#define TPM_I2C_DEVICE_ADDRESS         0x38
+#define TPM_DATA_CSUM_ENABLE           0x40
+#define TPM_DATA_CSUM                  0x44
+#define TPM_I2C_DID_VID                        0x48
+#define TPM_I2C_RID                    0x4C
+
+//#define I2C_IS_TPM2 1
+
+struct tpm_tis_i2c_phy {
+	struct tpm_tis_data priv;
+	struct i2c_client *i2c_client;
+	bool data_csum;
+	u8 *iobuf;
+};
+
+static inline struct tpm_tis_i2c_phy *to_tpm_tis_i2c_phy(struct tpm_tis_data *data)
+{
+	return container_of(data, struct tpm_tis_i2c_phy, priv);
+}
+
+static u8 address_to_register(u32 addr)
+{
+	addr &= 0xFFF;
+
+	switch (addr) {
+		// adapt register addresses that have changed compared to
+		// older TIS versions
+	case TPM_ACCESS(0):
+		return 0x04;
+	case TPM_LOC_SEL:
+		return 0x00;
+	case TPM_DID_VID(0):
+		return 0x48;
+	case TPM_RID(0):
+		return 0x4C;
+	default:
+		return addr;
+	}
+}
+
+static int tpm_tis_i2c_read_bytes(struct tpm_tis_data *data, u32 addr,
+				  u16 len, u8 *result)
+{
+	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+	int ret = 0;
+	int i = 0;
+	u8 reg = address_to_register(addr);
+	struct i2c_msg msgs[] = {
+		{
+			.addr = phy->i2c_client->addr,
+			.len = sizeof(reg),
+			.buf = &reg,
+		},
+		{
+			.addr = phy->i2c_client->addr,
+			.len = len,
+			.buf = result,
+			.flags = I2C_M_RD,
+		},
+	};
+
+	do {
+		ret = i2c_transfer(phy->i2c_client->adapter, msgs,
+				   ARRAY_SIZE(msgs));
+		usleep_range(250, 300); // wait default GUARD_TIME of 250µs
+
+	} while (ret < 0 && i++ < TPM_RETRY);
+
+	if (ret < 0)
+		return ret;
+
+
+	return 0;
+}
+
+static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr,
+				   u16 len, const u8 *value)
+{
+	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+	int ret = 0;
+	int i = 0;
+
+	if (phy->iobuf) {
+		if (len > TPM_BUFSIZE - 1)
+			return -EIO;
+
+		phy->iobuf[0] = address_to_register(addr);
+		memcpy(phy->iobuf + 1, value, len);
+
+		{
+			struct i2c_msg msgs[] = {
+				{
+					.addr = phy->i2c_client->addr,
+					.len = len + 1,
+					.buf = phy->iobuf,
+				},
+			};
+
+			do {
+				ret = i2c_transfer(phy->i2c_client->adapter,
+						   msgs, ARRAY_SIZE(msgs));
+				// wait default GUARD_TIME of 250µs
+				usleep_range(250, 300);
+			} while (ret < 0 && i++ < TPM_RETRY);
+		}
+	} else {
+		u8 reg = address_to_register(addr);
+
+		struct i2c_msg msgs[] = {
+			{
+				.addr = phy->i2c_client->addr,
+				.len = sizeof(reg),
+				.buf = &reg,
+			},
+			{
+				.addr = phy->i2c_client->addr,
+				.len = len,
+				.buf = (u8 *)value,
+				.flags = I2C_M_NOSTART,
+			},
+		};
+		do {
+			ret = i2c_transfer(phy->i2c_client->adapter, msgs,
+					   ARRAY_SIZE(msgs));
+			// wait default GUARD_TIME of 250µs
+			usleep_range(250, 300);
+		} while (ret < 0 && i++ < TPM_RETRY);
+	}
+
+	if (ret < 0)
+		return ret;
+
+
+	return 0;
+}
+
+static bool tpm_tis_i2c_check_data(struct tpm_tis_data *data,
+				   const u8 *buf, size_t len)
+{
+	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+	u16 crc, crc_tpm;
+	int rc;
+
+	if (phy->data_csum) {
+		crc = crc_ccitt(0x0000, buf, len);
+		rc = tpm_tis_read16(data, TPM_DATA_CSUM, &crc_tpm);
+		if (rc < 0)
+			return false;
+
+		crc_tpm = be16_to_cpu(crc_tpm);
+		return crc == crc_tpm;
+	}
+
+	return true;
+}
+
+static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
+
+static int csum_state_store(struct tpm_tis_data *data, u8 new_state)
+{
+	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
+	u8 cur_state;
+	int rc;
+
+	rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_DATA_CSUM_ENABLE,
+				     1, &new_state);
+	if (rc < 0)
+		return rc;
+
+	rc = tpm_tis_i2c_read_bytes(&phy->priv, TPM_DATA_CSUM_ENABLE,
+				    1, &cur_state);
+	if (rc < 0)
+		return rc;
+
+	if (new_state == cur_state)
+		phy->data_csum = (bool)new_state;
+
+	return rc;
+}
+
+static const struct tpm_tis_phy_ops tpm_i2c_phy_ops = {
+	.read_bytes = tpm_tis_i2c_read_bytes,
+	.write_bytes = tpm_tis_i2c_write_bytes,
+	.check_data = tpm_tis_i2c_check_data,
+};
+
+static int tpm_tis_i2c_probe(struct i2c_client *dev,
+			     const struct i2c_device_id *id)
+{
+	struct tpm_tis_i2c_phy *phy;
+	int rc;
+	int CRC_Checksum = 0;
+	const u8 loc_init = 0;
+	struct device_node *np;
+
+	phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_i2c_phy),
+			   GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	phy->i2c_client = dev;
+
+	if (!i2c_check_functionality(dev->adapter, I2C_FUNC_NOSTART)) {
+		phy->iobuf = devm_kmalloc(&dev->dev, TPM_BUFSIZE, GFP_KERNEL);
+		if (!phy->iobuf)
+			return -ENOMEM;
+	}
+
+	// select locality 0 (the driver will access only via locality 0)
+	rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_LOC_SEL, 1, &loc_init);
+	if (rc < 0)
+		return rc;
+
+	// set CRC checksum calculation enable
+	np = dev->dev.of_node;
+	if (of_property_read_bool(np, "crc-checksum"))
+		CRC_Checksum = 1;
+
+	rc = csum_state_store(&phy->priv, CRC_Checksum);
+	if (rc < 0)
+		return rc;
+
+	return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_i2c_phy_ops,
+					NULL);
+}
+
+static const struct i2c_device_id tpm_tis_i2c_id[] = {
+	{"tpm_tis_i2c", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_id);
+
+static const struct of_device_id of_tis_i2c_match[] = {
+	{ .compatible = "tcg,tpm-tis-i2c", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_tis_i2c_match);
+
+static const struct acpi_device_id acpi_tis_i2c_match[] = {
+	{"SMO0768", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_tis_i2c_match);
+
+static struct i2c_driver tpm_tis_i2c_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "tpm_tis_i2c",
+		.pm = &tpm_tis_pm,
+		.of_match_table = of_match_ptr(of_tis_i2c_match),
+		.acpi_match_table = ACPI_PTR(acpi_tis_i2c_match),
+	},
+	.probe = tpm_tis_i2c_probe,
+	.id_table = tpm_tis_i2c_id,
+};
+
+module_i2c_driver(tpm_tis_i2c_driver);
+
+MODULE_DESCRIPTION("TPM Driver for native I2C access");
+MODULE_LICENSE("GPL");
-- 
2.7.4

Re: [PATCH v3 7/7] char: tpm: add tpm_tis_i2c driver

[Eddie James]

On 2/10/20 10:28 AM, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
>
> Implements the functionality needed to communicate with an I2C TPM
> according to the TCG TPM I2C Interface Specification.


Hi,

I tested this driver (and really the whole series) on a system running 
the NPCT75X connected over I2C. Worked just fine. Thanks!


Tested-by: Eddie James <eajames@linux.ibm.com>


>
> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
> ---
>   drivers/char/tpm/Kconfig       |  12 ++
>   drivers/char/tpm/Makefile      |   1 +
>   drivers/char/tpm/tpm_tis_i2c.c | 292 +++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 305 insertions(+)
>   create mode 100644 drivers/char/tpm/tpm_tis_i2c.c
>
> diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
> index aacdeed..b482bbf 100644
> --- a/drivers/char/tpm/Kconfig
> +++ b/drivers/char/tpm/Kconfig
> @@ -74,6 +74,18 @@ config TCG_TIS_SPI_CR50
>   	  If you have a H1 secure module running Cr50 firmware on SPI bus,
>   	  say Yes and it will be accessible from within Linux.
>   
> +config TCG_TIS_I2C
> +	tristate "TPM I2C Interface Specification"
> +	depends on I2C
> +	 depends on CRC_CCITT
> +	select TCG_TIS_CORE
> +	---help---
> +	  If you have a TPM security chip which is connected to a regular
> +	  I2C master (i.e. most embedded platforms) that is compliant with the
> +	  TCG TPM I2C Interface Specification say Yes and it will be accessible from
> +	  within Linux. To compile this driver as a module, choose  M here;
> +	  the module will be called tpm_tis_i2c.
> +
>   config TCG_TIS_I2C_ATMEL
>   	tristate "TPM Interface Specification 1.2 Interface (I2C - Atmel)"
>   	depends on I2C
> diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
> index 5a0d99d..5c9a31d 100644
> --- a/drivers/char/tpm/Makefile
> +++ b/drivers/char/tpm/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_TCG_TIS) += tpm_tis.o
>   obj-$(CONFIG_TCG_TIS_SPI) += tpm_tis_spi_mod.o
>   tpm_tis_spi_mod-y := tpm_tis_spi.o
>   tpm_tis_spi_mod-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o
> +obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
>   obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
>   obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
>   obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
> diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
> new file mode 100644
> index 0000000..c10ec7e
> --- /dev/null
> +++ b/drivers/char/tpm/tpm_tis_i2c.c
> @@ -0,0 +1,292 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2014-2019 Nuvoton Technology corporation
> + *
> + * TPM TIS I2C
> + *
> + * TPM TIS I2C Device Driver Interface for devices that implement the TPM I2C
> + * Interface defined by TCG PC Client Platform TPM Profile (PTP) Specification
> + * Revision 01.03 v22 at www.trustedcomputinggroup.org
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/slab.h>
> +#include <linux/interrupt.h>
> +#include <linux/wait.h>
> +#include <linux/acpi.h>
> +#include <linux/freezer.h>
> +#include <linux/crc-ccitt.h>
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/gpio.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_gpio.h>
> +#include <linux/tpm.h>
> +#include "tpm.h"
> +#include "tpm_tis_core.h"
> +
> +#define TPM_LOC_SEL                    0x04
> +#define TPM_I2C_INTERFACE_CAPABILITY   0x30
> +#define TPM_I2C_DEVICE_ADDRESS         0x38
> +#define TPM_DATA_CSUM_ENABLE           0x40
> +#define TPM_DATA_CSUM                  0x44
> +#define TPM_I2C_DID_VID                        0x48
> +#define TPM_I2C_RID                    0x4C
> +
> +//#define I2C_IS_TPM2 1
> +
> +struct tpm_tis_i2c_phy {
> +	struct tpm_tis_data priv;
> +	struct i2c_client *i2c_client;
> +	bool data_csum;
> +	u8 *iobuf;
> +};
> +
> +static inline struct tpm_tis_i2c_phy *to_tpm_tis_i2c_phy(struct tpm_tis_data *data)
> +{
> +	return container_of(data, struct tpm_tis_i2c_phy, priv);
> +}
> +
> +static u8 address_to_register(u32 addr)
> +{
> +	addr &= 0xFFF;
> +
> +	switch (addr) {
> +		// adapt register addresses that have changed compared to
> +		// older TIS versions
> +	case TPM_ACCESS(0):
> +		return 0x04;
> +	case TPM_LOC_SEL:
> +		return 0x00;
> +	case TPM_DID_VID(0):
> +		return 0x48;
> +	case TPM_RID(0):
> +		return 0x4C;
> +	default:
> +		return addr;
> +	}
> +}
> +
> +static int tpm_tis_i2c_read_bytes(struct tpm_tis_data *data, u32 addr,
> +				  u16 len, u8 *result)
> +{
> +	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
> +	int ret = 0;
> +	int i = 0;
> +	u8 reg = address_to_register(addr);
> +	struct i2c_msg msgs[] = {
> +		{
> +			.addr = phy->i2c_client->addr,
> +			.len = sizeof(reg),
> +			.buf = &reg,
> +		},
> +		{
> +			.addr = phy->i2c_client->addr,
> +			.len = len,
> +			.buf = result,
> +			.flags = I2C_M_RD,
> +		},
> +	};
> +
> +	do {
> +		ret = i2c_transfer(phy->i2c_client->adapter, msgs,
> +				   ARRAY_SIZE(msgs));
> +		usleep_range(250, 300); // wait default GUARD_TIME of 250µs
> +
> +	} while (ret < 0 && i++ < TPM_RETRY);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +
> +	return 0;
> +}
> +
> +static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr,
> +				   u16 len, const u8 *value)
> +{
> +	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
> +	int ret = 0;
> +	int i = 0;
> +
> +	if (phy->iobuf) {
> +		if (len > TPM_BUFSIZE - 1)
> +			return -EIO;
> +
> +		phy->iobuf[0] = address_to_register(addr);
> +		memcpy(phy->iobuf + 1, value, len);
> +
> +		{
> +			struct i2c_msg msgs[] = {
> +				{
> +					.addr = phy->i2c_client->addr,
> +					.len = len + 1,
> +					.buf = phy->iobuf,
> +				},
> +			};
> +
> +			do {
> +				ret = i2c_transfer(phy->i2c_client->adapter,
> +						   msgs, ARRAY_SIZE(msgs));
> +				// wait default GUARD_TIME of 250µs
> +				usleep_range(250, 300);
> +			} while (ret < 0 && i++ < TPM_RETRY);
> +		}
> +	} else {
> +		u8 reg = address_to_register(addr);
> +
> +		struct i2c_msg msgs[] = {
> +			{
> +				.addr = phy->i2c_client->addr,
> +				.len = sizeof(reg),
> +				.buf = &reg,
> +			},
> +			{
> +				.addr = phy->i2c_client->addr,
> +				.len = len,
> +				.buf = (u8 *)value,
> +				.flags = I2C_M_NOSTART,
> +			},
> +		};
> +		do {
> +			ret = i2c_transfer(phy->i2c_client->adapter, msgs,
> +					   ARRAY_SIZE(msgs));
> +			// wait default GUARD_TIME of 250µs
> +			usleep_range(250, 300);
> +		} while (ret < 0 && i++ < TPM_RETRY);
> +	}
> +
> +	if (ret < 0)
> +		return ret;
> +
> +
> +	return 0;
> +}
> +
> +static bool tpm_tis_i2c_check_data(struct tpm_tis_data *data,
> +				   const u8 *buf, size_t len)
> +{
> +	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
> +	u16 crc, crc_tpm;
> +	int rc;
> +
> +	if (phy->data_csum) {
> +		crc = crc_ccitt(0x0000, buf, len);
> +		rc = tpm_tis_read16(data, TPM_DATA_CSUM, &crc_tpm);
> +		if (rc < 0)
> +			return false;
> +
> +		crc_tpm = be16_to_cpu(crc_tpm);
> +		return crc == crc_tpm;
> +	}
> +
> +	return true;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
> +
> +static int csum_state_store(struct tpm_tis_data *data, u8 new_state)
> +{
> +	struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data);
> +	u8 cur_state;
> +	int rc;
> +
> +	rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_DATA_CSUM_ENABLE,
> +				     1, &new_state);
> +	if (rc < 0)
> +		return rc;
> +
> +	rc = tpm_tis_i2c_read_bytes(&phy->priv, TPM_DATA_CSUM_ENABLE,
> +				    1, &cur_state);
> +	if (rc < 0)
> +		return rc;
> +
> +	if (new_state == cur_state)
> +		phy->data_csum = (bool)new_state;
> +
> +	return rc;
> +}
> +
> +static const struct tpm_tis_phy_ops tpm_i2c_phy_ops = {
> +	.read_bytes = tpm_tis_i2c_read_bytes,
> +	.write_bytes = tpm_tis_i2c_write_bytes,
> +	.check_data = tpm_tis_i2c_check_data,
> +};
> +
> +static int tpm_tis_i2c_probe(struct i2c_client *dev,
> +			     const struct i2c_device_id *id)
> +{
> +	struct tpm_tis_i2c_phy *phy;
> +	int rc;
> +	int CRC_Checksum = 0;
> +	const u8 loc_init = 0;
> +	struct device_node *np;
> +
> +	phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_i2c_phy),
> +			   GFP_KERNEL);
> +	if (!phy)
> +		return -ENOMEM;
> +
> +	phy->i2c_client = dev;
> +
> +	if (!i2c_check_functionality(dev->adapter, I2C_FUNC_NOSTART)) {
> +		phy->iobuf = devm_kmalloc(&dev->dev, TPM_BUFSIZE, GFP_KERNEL);
> +		if (!phy->iobuf)
> +			return -ENOMEM;
> +	}
> +
> +	// select locality 0 (the driver will access only via locality 0)
> +	rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_LOC_SEL, 1, &loc_init);
> +	if (rc < 0)
> +		return rc;
> +
> +	// set CRC checksum calculation enable
> +	np = dev->dev.of_node;
> +	if (of_property_read_bool(np, "crc-checksum"))
> +		CRC_Checksum = 1;
> +
> +	rc = csum_state_store(&phy->priv, CRC_Checksum);
> +	if (rc < 0)
> +		return rc;
> +
> +	return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_i2c_phy_ops,
> +					NULL);
> +}
> +
> +static const struct i2c_device_id tpm_tis_i2c_id[] = {
> +	{"tpm_tis_i2c", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_id);
> +
> +static const struct of_device_id of_tis_i2c_match[] = {
> +	{ .compatible = "tcg,tpm-tis-i2c", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, of_tis_i2c_match);
> +
> +static const struct acpi_device_id acpi_tis_i2c_match[] = {
> +	{"SMO0768", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(acpi, acpi_tis_i2c_match);
> +
> +static struct i2c_driver tpm_tis_i2c_driver = {
> +	.driver = {
> +		.owner = THIS_MODULE,
> +		.name = "tpm_tis_i2c",
> +		.pm = &tpm_tis_pm,
> +		.of_match_table = of_match_ptr(of_tis_i2c_match),
> +		.acpi_match_table = ACPI_PTR(acpi_tis_i2c_match),
> +	},
> +	.probe = tpm_tis_i2c_probe,
> +	.id_table = tpm_tis_i2c_id,
> +};
> +
> +module_i2c_driver(tpm_tis_i2c_driver);
> +
> +MODULE_DESCRIPTION("TPM Driver for native I2C access");
> +MODULE_LICENSE("GPL");