Add tpm i2c ptp driver

From: Amir Mizinski <[email protected]>

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

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

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 exception 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.
Addressed comments from:
- Rob Herring: https://lore.kernel.org/patchwork/patch/1161287/

Changes since version 3:
- Updated patch to latest v5.6
- Updated commits headlines and development credit format by Jarkko Sakkinen suggestion -"tpm: tpm_tis: Make implementation of read16 read32 write32 optional"
- Updated commit description.
-"dt-bindings: tpm: Add YAML schema for TPM TIS I2C options"
- Fixed 'make dt_binding_check' errors on YAML file.
- Removed interrupts from required and examples since there is no use for them in current patch.
Addressed comments from:
- Jarkko Sakkinen: https://lore.kernel.org/patchwork/patch/1192101/
- Rob Herring: https://lore.kernel.org/patchwork/patch/1192099/

Changes since version 4:
-"tpm: tpm_tis: Make implementation of read16 read32 write32 optional"
-Added a "Reviewed-by" tag:
-"tpm: tpm_tis: Add check_data handle to tpm_tis_phy_ops in order to check data integrity"
-Fixed credit typos.
-"tpm: tpm_tis: rewrite "tpm_tis_req_canceled()""
-Added fixes tag and removed changes for STM.
-"tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception"
-Fixed typos, edited description to be clearer, and added a "Suggested-by" tag.
-"tpm: Handle an exception for TPM Firmware Update mode."
-Added a "Suggested-by" tag.
-"dt-bindings: tpm: Add YAML schema for TPM TIS I2C options"
-Fixed 'make dt_binding_check' errors.
-"tpm: tpm_tis: add tpm_tis_i2c driver"
-Added tested-by tag by Eddie James.
-Fixed indent in Kconfig file.
-Fixed 'MODULE_DESCRIPTION'.
Addressed comments from:
- Jarkko Sakkinen: https://patchwork.kernel.org/patch/11467645/

                https://patchwork.kernel.org/patch/11467655/
                https://patchwork.kernel.org/patch/11467643/
                https://patchwork.kernel.org/patch/11467659/
                https://patchwork.kernel.org/patch/11467651/

- Rob Herring: https://patchwork.kernel.org/patch/11467653/
- Randy Dunlap: https://patchwork.kernel.org/patch/11467651/
- Eddie James: https://lore.kernel.org/patchwork/patch/1192104/

Changes since version 5:
-"tpm: tpm_tis: Add check_data handle to tpm_tis_phy_ops"
-Updated short description and fixed long description to be more clear.
Addressed comments from:
- Jarkko Sakkinen: https://lkml.org/lkml/2020/4/6/748

Changes since version 6:
-"tpm: tpm_tis: Make implementation of read16, read32 and write32 optional"
-Fixed short description.
-fixed long description proofreading issues.
-"tpm: tpm_tis: Add check_data handle to tpm_tis_phy_ops"
-Fixed long description by Jarkko comments and proofreading issues. -Replaced "check_data" with verify_data_integrity". -New line before return statement.
-"tpm: tpm_tis: rewrite "tpm_tis_req_canceled()"
-Fixed line over 80 characters.
-fixed long description proofreading issues.
-" tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot"
-fixed long description proofreading issues.
-"dt-bindings: tpm: Add YAML schema for TPM TIS I2C option"
-Replaced "tpm-tis-i2c@2e" with "tpm_tis@2e".
-Fixed CRC_Checksum description.
-"tpm: tpm_tis: add tpm_tis_i2c driver"
-Replaced "depends on CRC_CCIT" with "select CRC_CCIT". -Added tested-by tag by Joel Stanley.
-Fixed checkpatch.pl warnings.
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1221336/
        https://lore.kernel.org/patchwork/patch/1221337/
        https://lore.kernel.org/patchwork/patch/1221339/
 - Joel Stanley:
        https://lore.kernel.org/patchwork/patch/1220543/
 - Rob Herring:
        https://lore.kernel.org/patchwork/patch/1221334/

Changes since version 7:
- Added a new commit with improvements suggested by Benoit Houyere. -"tpm: tpm_tis: verify TPM_STS register is valid after locality request"
-"tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()""
-Fixed Hash for Fixes tag.
-"tpm: Add YAML schema for TPM TIS I2C options"
-Added a compatible string specific to the nuvoton npct75x chip.
-"tpm: tpm_tis: add tpm_tis_i2c driver"
-added a compatible string according to yaml file.
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1231524/
 - Rob Herring:
        https://lore.kernel.org/patchwork/patch/1231526/

Changes since version 8:
- "tpm: tpm_tis: Make implementation of read16, read32 and write32 optional"
-Fixed a compile error conflicting CR50
- "tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception" -Moved commit backwards from 4/8 to 2/8 for a better flow with new data integrity check design
- "tpm: tpm_tis: Add retry in case of protocol failure or data integrity (on I2C only) failure." -Renamed from "tpm: tpm_tis: Add check_data handle to tpm_tis_phy_ops"
-Redesign and added a retry for additional error cases.
- "tpm: Add YAML schema for TPM TIS I2C options"
-Fixed Dual-license new binding
-Removed "oneOf"
-Fixed tpm_tis@2e to tpm@2e
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1240728/
        https://lore.kernel.org/patchwork/patch/1240736/
 - Rob Herring:
        https://lore.kernel.org/patchwork/patch/1240733/

Changes since version 9:
- "tpm: Make read{16, 32}() and write32() in tpm_tis_phy_ops optional"
-Fixed short description
- "tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception" -Canceled wait_for_tpm_stat() function renaming.
-Fixed long description
- "tpm: Add YAML schema for TPM TIS I2C options"
-Added a reviewed-by tag.
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1247163/
        https://lore.kernel.org/patchwork/patch/1247164/
 - Rob Herring:
        https://lore.kernel.org/patchwork/patch/1247161/

Changes since version 10:
- "tpm: Make read{16, 32}() and write32() in tpm_tis_phy_ops optional"
-Added a Reviewed-by and Tested-by tags
- "tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception" -Renamed "mask_result" parameter with "stat"
- "tpm: tpm_tis: Add retry in case of protocol failure or data integrity (on I2C only) failure." -Edited long description.
-Modified tpm_tis_recv() to __tpm_tis_recv() and Introduced a new tpm_tis_recv() function
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1252428/
        https://lore.kernel.org/patchwork/patch/1252422/
        https://lore.kernel.org/patchwork/patch/1252424/

Changes since version 11:
- "tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception" -Added a "Reviewed-by" tag
-Renamed 'wait_for_tpm_stat()' function with 'tpm_tis_wait_for_stat()'
- "tpm: tpm_tis: Add retry in case of protocol failure."
-Removed data integrity check and created a new commit for it.
-Edited short and long description.
- "tpm: tpm_tis: Add verify_data_integrity handle to tpm_tis_phy_ops"
-This is a new commit.
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1258107/
        https://lore.kernel.org/patchwork/patch/1258110/

Changes since version 12:

- Moved "tpm: Add YAML schema for TPM TIS I2C options" to end of patch.
- Removed two commits to be resubmited on later patch:
- "tpm: tpm_tis: Add retry in case of protocol failure."
- "tpm: tpm_tis: Add verify_data_integrity handle to tpm_tis_phy_ops"
- "tpm: tpm_tis: add tpm_tis_i2c driver"
- Removed verify data integrity (Checksum) functuality from i2c driver.
- Edited Long Description.
- Updated header comment for tpm_tis_i2c.c
Addressed comments from:
- Jarkko Sakkinen:

        https://lore.kernel.org/patchwork/patch/1263805/
        https://lore.kernel.org/patchwork/patch/1263813/

Changes since version 13:

- Edited description of commits 1-6 by Jarkko comments.
- "tpm: Add YAML schema for TPM TIS I2C options"
- Fixed YAML compilation error of missing "additionalProperties" field
Addressed comments from:
- Jarkko Sakkinen:

        https://lkml.org/lkml/2021/8/26/546
        https://lkml.org/lkml/2021/8/26/548
	https://lkml.org/lkml/2021/8/26/550
	https://lkml.org/lkml/2021/8/26/551
	https://lkml.org/lkml/2021/8/26/552
	https://lkml.org/lkml/2021/8/26/553
	https://lkml.org/lkml/2021/8/26/555
 - Rob Herring:
	https://lkml.org/lkml/2021/8/26/427

Amir Mizinski (7):
tpm: Make read{16, 32}() and write32() in tpm_tis_phy_ops optional
tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot
without last byte in exception
tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()"
tpm: Handle an exception for TPM Firmware Update mode.
tpm: tpm_tis: verify TPM_STS register is valid after locality request
tpm: tpm_tis: add tpm_tis_i2c driver
\tpm: Add YAML schema for TPM TIS I2C options

 .../bindings/security/tpm/tpm-tis-i2c.yaml         |  52 +++++
 drivers/char/tpm/Kconfig                           |  12 ++
 drivers/char/tpm/Makefile                          |   1 +
 drivers/char/tpm/tpm2-cmd.c                        |   4 +
 drivers/char/tpm/tpm_tis_core.c                    |  84 ++++----
 drivers/char/tpm/tpm_tis_core.h                    |  38 +++-
 drivers/char/tpm/tpm_tis_i2c.c                     | 227 +++++++++++++++++++++
 drivers/char/tpm/tpm_tis_spi.h                     |   4 -
 drivers/char/tpm/tpm_tis_spi_cr50.c                |   3 -
 drivers/char/tpm/tpm_tis_spi_main.c                |  41 ----
 include/linux/tpm.h                                |   1 +
 11 files changed, 367 insertions(+), 100 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

From: Amir Mizinski <[email protected]>

Only tpm_tis can use memory-mapped I/O, which is truly mapped into the kernel's memory space. Therefore, using ioread16/ioread32/iowrite32 turns into a straightforward pointer dereference.
Some drivers, such as tpm_tis_spi, require more complicated operations to read more than one byte at a time and, as a result, will revert to read_bytes/write_bytes.
Therefore, re-implement tpm_tis_{read, write}_{16, 32}, so that they check if implementations for {read, write}_{16, 32} in tpm_tis_phys_ops exist; if they do not exist, then revert to {read, write}_bytes().

---
 drivers/char/tpm/tpm_tis_core.h     | 38 +++++++++++++++++++++++++++++++---
 drivers/char/tpm/tpm_tis_spi.h      |  4 ----
 drivers/char/tpm/tpm_tis_spi_cr50.c |  3 ---
 drivers/char/tpm/tpm_tis_spi_main.c | 41 -------------------------------------
 4 files changed, 35 insertions(+), 51 deletions(-)

index b2a3c6c..e8fad0e 100644
@@ -124,13 +124,35 @@ 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,

@@ -147,7 +169,17 @@ 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)

index bba7397..d0f66f6 100644
@@ -31,10 +31,6 @@ extern int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
 extern int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
 				u8 *in, const u8 *out);
 
-extern int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result);
-extern int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result);
-extern int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value);
-
 #ifdef CONFIG_TCG_TIS_SPI_CR50
 extern int cr50_spi_probe(struct spi_device *spi);
 #else

index ea759af..9af6f84 100644
@@ -220,9 +220,6 @@ static int tpm_tis_spi_cr50_write_bytes(struct tpm_tis_data *data, u32 addr,
 static const struct tpm_tis_phy_ops tpm_spi_cr50_phy_ops = {
 	.read_bytes = tpm_tis_spi_cr50_read_bytes,
 	.write_bytes = tpm_tis_spi_cr50_write_bytes,
-	.read16 = tpm_tis_spi_read16,
-	.read32 = tpm_tis_spi_read32,
-	.write32 = tpm_tis_spi_write32,
 };
 
 static void cr50_print_fw_version(struct tpm_tis_data *data)

2.7.4

This is otherwise good but lacks explanation why this makes sense, other than somewhat obvious benefit of having less calbacks, which BTW should be stated explicitly in the commit message too.

You must answer what is your by doing this change, e.g. what you are unable to do, if the callbacks are removed (just an example).

I get the change, but motivation to do it needs to be there.

/Jarkko

From: Amir Mizinski <[email protected]>

Detected an incorrect implementation of the send command. Currently, the driver polls the TPM_STS.stsValid field until TRUE; then it reads TPM_STS register again to verify only that TPM_STS.expect field is FALSE (i.e., it ignores TPM_STS.stsValid).
Since TPM_STS.stsValid represents the TPM_STS.expect validity, both fields fields should be checked in the same TPM_STS register read value.

This fix modifies the signature of 'wait_for_tpm_stat()', adding an additional "mask_result" parameter to its call and renaming it to 'tpm_tis_wait_for_stat()' for better alignment with other naming. 'tpm_tis_wait_for_stat()' is now polling the TPM_STS with a mask and waits for the value in mask_result. The fix adds the ability to check if certain TPM_STS bits have been cleared.

This change is also aligned to verifying the CRC on I2C TPM. The CRC verification should be done after the TPM_STS.expect field is cleared (TPM received all expected command bytes and set the calculated CRC value in the register).

In addition, the send command was changed to comply with TCG_DesignPrinciples_TPM2p0Driver_vp24_pubrev.pdf as follows:
- send all command bytes in one loop
- remove special handling of the last byte

---
 drivers/char/tpm/tpm_tis_core.c | 70 +++++++++++++++--------------------------
 1 file changed, 26 insertions(+), 44 deletions(-)

index 69579ef..b34e59b 100644
@@ -44,9 +44,9 @@ 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 tpm_tis_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 stat,
+				 unsigned long timeout,
+				 wait_queue_head_t *queue, bool check_cancel)
 {
 	unsigned long stop;
 	long rc;

@@ -55,7 +55,7 @@ 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) == stat)
 		return 0;
 
 	stop = jiffies + timeout;

@@ -83,7 +83,7 @@ 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) == stat)
 				return 0;
 		} while (time_before(jiffies, stop));
 	}

@@ -259,10 +259,11 @@ 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 = tpm_tis_wait_for_stat(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);

@@ -315,8 +316,9 @@ 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 (tpm_tis_wait_for_stat(chip, TPM_STS_VALID, TPM_STS_VALID,
+				  chip->timeout_c, &priv->int_queue,
+				  false) < 0) {
 		size = -ETIME;
 		goto out;
 	}

@@ -342,61 +344,40 @@ 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 (tpm_tis_wait_for_stat(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 (tpm_tis_wait_for_stat(chip, TPM_STS_VALID | TPM_STS_DATA_EXPECT,
+				  TPM_STS_VALID, chip->timeout_a,
+				  &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;
 

@@ -451,9 +432,10 @@ 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 (tpm_tis_wait_for_stat(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

Use imprative form, e.g. "Modify the signature...".

What does it mean when you "align to verifying"?

I don't think the rename is important enough to be done, and it definitely should not be melded into another patch.

/Jarkko

From: Amir Mizinski <[email protected]>

tpm_tis_req_canceled() function is used to check if the caller requested to abort the current operation. It was found that in some cases tpm_tis_req_canceled() wrongly returned true.
Since a cancel request sets the TPM_STS.commandReady field to TRUE, the tpm_tis_req_canceled() function should check only the TPM_STS.commandReady field value.
The case for TPM_VID_WINBOND is wrong and was therefore removed.

Also, the default comparison is wrong. Only cmdReady bit needs to be compared instead of the full lower status register byte.

---
 drivers/char/tpm/tpm_tis_core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

index b34e59b..4145758 100644
@@ -650,13 +650,11 @@ 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);
 	}
 }
 

2.7.4

From: Amir Mizinski <[email protected]>

Add a condition to enable communication with the TPM while the TPM is in firmware update mode.
In such a case if power was cut during the TPM firmware update, the driver should ignore the "selftest" command return code (TPM2_RC_UPGRADE or TPM2_RC_COMMAND_CODE) and skip the rest of the TPM initialization sequence.

---
 drivers/char/tpm/tpm2-cmd.c | 4 ++++
 include/linux/tpm.h         | 1 +
 2 files changed, 5 insertions(+)

index a25815a..c2b541d 100644
@@ -729,6 +729,10 @@ 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;
 

index aa11fe3..c5bf934 100644
@@ -207,6 +207,7 @@ 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

From: Amir Mizinski <[email protected]>

This issue could occur when the TPM does not update TPM_STS register after a locality request (TPM_STS Initial value = 0xFF) and a TPM_STS register read occurs in the tpm_tis_status(chip) function call.

When a call to tpm_tis_send_data() function is made after a request_locality() call, the condition
("if ((status & TPM_STS_COMMAND_READY) == 0)") is checked. At this moment if the status value is 0xFF, then it is considered, wrongly, in “ready” state (by checking only one bit). However, at this moment the TPM is, in fact, in "Idle" state and remains in "Idle" state because "tpm_tis_ready(chip);" was not executed.
Waiting for the condition TPM_STS.tpmGo == 0, will ensure that the TPM status register has the correct value.

---
 drivers/char/tpm/tpm_tis_core.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

index 4145758..d527c43 100644
@@ -177,8 +177,14 @@ static int request_locality(struct tpm_chip *chip, int l)
 	} else {
 		/* wait for burstcount */
 		do {
-			if (check_locality(chip, l))
+			if (check_locality(chip, l)) {
+				if (tpm_tis_wait_for_stat(chip, TPM_STS_GO, 0,
+							  chip->timeout_c,
+							  &priv->int_queue,
+							  false) < 0)
+					return -ETIME;
 				return l;
+			}
 			tpm_msleep(TPM_TIMEOUT);
 		} while (time_before(jiffies, stop));
 	}

2.7.4

From: Amir Mizinski <[email protected]>

I2C support for TPM devices on the TIS interface is currently available only as a proprietary driver implementation for each TPM vendor. This patch implements the infrastructure for a TCG-compliant TPM TIS I2C driver with the functionality required to communicate with a TPM device over I2C according to the "TCG PC Client PTP Interface Specification" and "Device Driver Design Principles for TPM 2.0"

References:
[1] "TCG PC Client Platform TPM Profile(PTP) Interface Specification for TPM 2.0" Version 01.03 Revision 22 at:
https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
[2] "TCG PC Client Device Driver Design Principles for TPM 2.0" Version 1.0 Revision 27 at:
https://trustedcomputinggroup.org/resource/tcg-pc-client-device-driver-design-principles-for-tpm-2-0/

---
 drivers/char/tpm/Kconfig       |  12 +++
 drivers/char/tpm/Makefile      |   1 +
 drivers/char/tpm/tpm_tis_i2c.c | 227 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 240 insertions(+)
 create mode 100644 drivers/char/tpm/tpm_tis_i2c.c

index 4308f9c..1395968 100644
@@ -86,6 +86,18 @@ config TCG_TIS_SYNQUACER
 	  To compile this driver as a module, choose  M here;
 	  the module will be called tpm_tis_synquacer.
 
+config TCG_TIS_I2C
+	tristate "TPM I2C Interface Specification"
+	depends on I2C
+	select CRC_CCITT
+	select TCG_TIS_CORE
+	help
+	  If you have a TPM security chip, compliant with the TCG TPM PTP 
+	  (I2C interface) specification and connected to an I2C bus master,
+	  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_CR50
 	tristate "TPM Interface Specification 2.0 Interface (I2C - CR50)"
 	depends on I2C

index 66d39ea..0222b1d 100644
@@ -29,6 +29,7 @@ tpm_tis_spi-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o
 
 obj-$(CONFIG_TCG_TIS_I2C_CR50) += tpm_tis_i2c_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

2.7.4

From: Amir Mizinski <[email protected]>

Add a YAML schema to support tpm tis i2c related 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.

---
 .../bindings/security/tpm/tpm-tis-i2c.yaml         | 52 ++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml

new file mode 100644
index 0000000..217ba8e
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%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 <[email protected]>
+
+description:
+  Device Tree Bindings for I2C based Trusted Platform Module(TPM).
+
+properties:
+  compatible:
+    items:
+      - enum:
+          # Nuvoton's Trusted Platform Module (TPM) (NPCT75x)
+          - nuvoton,npct75x
+      - const: tcg,tpm-tis-i2c
+
+  reg:
+    maxItems: 1
+
+  interrupt:
+    maxItems: 1
+
+  crc-checksum:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      Set this flag to enable CRC checksum.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      tpm@2e {
+        compatible = "nuvoton,npct75x", "tcg,tpm-tis-i2c";
+        reg = <0x2e>;
+        crc-checksum;
+      };
+    };
+...

2.7.4