From f848f2143ae42dc0918400039257a893835254d1 Mon Sep 17 00:00:00 2001 From: Peter Huewe Date: Thu, 2 Mar 2017 13:03:11 +0000 Subject: [PATCH] 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: Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen Signed-off-by: Peter Huewe Reviewed-by: Jarkko Sakkinen Tested-by: Benoit Houyere Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_tis_spi.c | 87 ++++++++++------------------------ 1 file changed, 24 insertions(+), 63 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 5292e5768a7e..062799e04f04 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -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 @@ exit: return ret; } +static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, + u16 len, u8 *result) +{ + return tpm_tis_spi_transfer(data, addr, len, result, 0x80); +} + static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len, u8 *value) { - 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; - } - - 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; + 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)