diff options
Diffstat (limited to 'drivers/char/tpm/tpm_tis_spi.c')
-rw-r--r-- | drivers/char/tpm/tpm_tis_spi.c | 160 |
1 files changed, 68 insertions, 92 deletions
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 5292e5768a7e..88fe72ae967f 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) @@ -56,122 +56,98 @@ 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; + int ret = 0; + int i; struct spi_message m; - struct spi_transfer spi_xfer = { - .tx_buf = phy->tx_buf, - .rx_buf = phy->rx_buf, - .len = 4, - }; + struct spi_transfer spi_xfer; + u8 transfer_len; - if (len > MAX_SPI_FRAMESIZE) - return -ENOMEM; + spi_bus_lock(phy->spi_device->master); - phy->tx_buf[0] = 0x80 | (len - 1); - phy->tx_buf[1] = 0xd4; - phy->tx_buf[2] = (addr >> 8) & 0xFF; - phy->tx_buf[3] = addr & 0xFF; + while (len) { + transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE); - spi_xfer.cs_change = 1; - spi_message_init(&m); - spi_message_add_tail(&spi_xfer, &m); + phy->tx_buf[0] = direction | (transfer_len - 1); + phy->tx_buf[1] = 0xd4; + phy->tx_buf[2] = addr >> 8; + phy->tx_buf[3] = addr; + + memset(&spi_xfer, 0, sizeof(spi_xfer)); + spi_xfer.tx_buf = phy->tx_buf; + spi_xfer.rx_buf = phy->rx_buf; + spi_xfer.len = 4; + spi_xfer.cs_change = 1; - 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.cs_change = 0; - spi_xfer.len = len; - spi_xfer.rx_buf = result; - - 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) -{ - 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); + if ((phy->rx_buf[3] & 0x01) == 0) { + // handle SPI wait states + phy->tx_buf[0] = 0; + + for (i = 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; + if (phy->rx_buf[0] & 0x01) + break; + } + + if (i == TPM_RETRY) { + ret = -ETIMEDOUT; + goto exit; + } + } + + spi_xfer.cs_change = 0; + spi_xfer.len = transfer_len; + spi_xfer.delay_usecs = 5; + + if (direction) { + spi_xfer.tx_buf = NULL; + spi_xfer.rx_buf = buffer; + } else { + spi_xfer.tx_buf = buffer; + spi_xfer.rx_buf = NULL; + } - 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); + len -= transfer_len; + buffer += transfer_len; + } exit: spi_bus_unlock(phy->spi_device->master); 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) +{ + 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) { int rc; |