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Commit f848f214 authored by Peter Huewe's avatar Peter Huewe Committed by Jarkko Sakkinen
Browse files

tpm_tis_spi: Use single function to transfer data 



The algorithm for sending data to the TPM is mostly identical to the
algorithm for receiving data from the TPM, so a single function is
sufficient to handle both cases.

This is a prequisite for all the other fixes, so we don't have to fix
everything twice (send/receive)

v2: u16 instead of u8 for the length.
Cc: <stable@vger.kernel.org>
Fixes: 0edbfea5 ("tpm/tpm_tis_spi: Add support for spi phy")
Signed-off-by: default avatarAlexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: default avatarPeter Huewe <peter.huewe@infineon.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: default avatarBenoit Houyere <benoit.houyere@st.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent 095fc30c

drivers/char/tpm/tpm_tis_spi.c

+24 −63
Original line number Diff line number Diff line
@@ -47,8 +47,8 @@ struct tpm_tis_spi_phy { 
	struct tpm_tis_data priv;

	struct spi_device *spi_device;



	u8 tx_buf[MAX_SPI_FRAMESIZE + 4];

	u8 rx_buf[MAX_SPI_FRAMESIZE + 4];

	u8 tx_buf[4];

	u8 rx_buf[4];

};



static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
@@ -56,8 +56,8 @@ static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *da 
	return container_of(data, struct tpm_tis_spi_phy, priv);

}



static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,

				  u16 len, u8 *result)

static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,

				u8 *buffer, u8 direction)

{

	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);

	int ret, i;
@@ -66,17 +66,17 @@ static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, 
		.tx_buf = phy->tx_buf,

		.rx_buf = phy->rx_buf,

		.len = 4,

		.cs_change = 1,

	};



	if (len > MAX_SPI_FRAMESIZE)

		return -ENOMEM;



	phy->tx_buf[0] = 0x80 | (len - 1);

	phy->tx_buf[0] = direction | (len - 1);

	phy->tx_buf[1] = 0xd4;

	phy->tx_buf[2] = (addr >> 8)  & 0xFF;

	phy->tx_buf[3] = addr	      & 0xFF;

	phy->tx_buf[2] = addr >> 8;

	phy->tx_buf[3] = addr;



	spi_xfer.cs_change = 1;

	spi_message_init(&m);

	spi_message_add_tail(&spi_xfer, &m);
@@ -85,7 +85,7 @@ static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, 
	if (ret < 0)

		goto exit;



	memset(phy->tx_buf, 0, len);

	phy->tx_buf[0] = 0;



	/* According to TCG PTP specification, if there is no TPM present at

	 * all, then the design has a weak pull-up on MISO. If a TPM is not
@@ -103,7 +103,14 @@ static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, 


	spi_xfer.cs_change = 0;

	spi_xfer.len = len;

	spi_xfer.rx_buf = result;



	if (direction) {

		spi_xfer.tx_buf = NULL;

		spi_xfer.rx_buf = buffer;

	} else {

		spi_xfer.tx_buf = buffer;

		spi_xfer.rx_buf = NULL;

	}



	spi_message_init(&m);

	spi_message_add_tail(&spi_xfer, &m);
@@ -114,62 +121,16 @@ static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, 
	return ret;

}



static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,

				   u16 len, u8 *value)

static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,

				  u16 len, u8 *result)

{

	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);

	int ret, i;

	struct spi_message m;

	struct spi_transfer spi_xfer = {

		.tx_buf = phy->tx_buf,

		.rx_buf = phy->rx_buf,

		.len = 4,

	};



	if (len > MAX_SPI_FRAMESIZE)

		return -ENOMEM;



	phy->tx_buf[0] = len - 1;

	phy->tx_buf[1] = 0xd4;

	phy->tx_buf[2] = (addr >> 8)  & 0xFF;

	phy->tx_buf[3] = addr         & 0xFF;



	spi_xfer.cs_change = 1;

	spi_message_init(&m);

	spi_message_add_tail(&spi_xfer, &m);



	spi_bus_lock(phy->spi_device->master);

	ret = spi_sync_locked(phy->spi_device, &m);

	if (ret < 0)

		goto exit;



	memset(phy->tx_buf, 0, len);



	/* According to TCG PTP specification, if there is no TPM present at

	 * all, then the design has a weak pull-up on MISO. If a TPM is not

	 * present, a pull-up on MISO means that the SB controller sees a 1,

	 * and will latch in 0xFF on the read.

	 */

	for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {

		spi_xfer.len = 1;

		spi_message_init(&m);

		spi_message_add_tail(&spi_xfer, &m);

		ret = spi_sync_locked(phy->spi_device, &m);

		if (ret < 0)

			goto exit;

	return tpm_tis_spi_transfer(data, addr, len, result, 0x80);

}



	spi_xfer.len = len;

	spi_xfer.tx_buf = value;

	spi_xfer.cs_change = 0;

	spi_xfer.tx_buf = value;

	spi_message_init(&m);

	spi_message_add_tail(&spi_xfer, &m);

	ret = spi_sync_locked(phy->spi_device, &m);



exit:

	spi_bus_unlock(phy->spi_device->master);

	return ret;

static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,

				   u16 len, u8 *value)

{

	return tpm_tis_spi_transfer(data, addr, len, value, 0);

}



static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)