The buffers used as tx_buf/rx_buf in a SPI transfer need to be DMA-safe. This cannot be guaranteed for the buffers passed to tpm_tis_spi_read_bytes and tpm_tis_spi_write_bytes. Therefore, we need to use our own DMA-safe buffer and copy the data to/from it. A single buffer is sufficient for both tx and rx, since bytes that have already been sent are not used anymore and can safely be overwritten with the received bytes. The buffer needs to be allocated separately, to ensure that it is cacheline-aligned and not shared with other data, so that DMA can work correctly. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Alexander Steffen <Alexander.Steffen@xxxxxxxxxxxx> --- v2: Updated commit message with more explanations. drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 88fe72a..5321245 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -46,9 +46,7 @@ struct tpm_tis_spi_phy { struct tpm_tis_data priv; struct spi_device *spi_device; - - u8 tx_buf[4]; - u8 rx_buf[4]; + u8 *iobuf; }; static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data) @@ -71,14 +69,14 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, while (len) { transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE); - phy->tx_buf[0] = direction | (transfer_len - 1); - phy->tx_buf[1] = 0xd4; - phy->tx_buf[2] = addr >> 8; - phy->tx_buf[3] = addr; + phy->iobuf[0] = direction | (transfer_len - 1); + phy->iobuf[1] = 0xd4; + phy->iobuf[2] = addr >> 8; + phy->iobuf[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.tx_buf = phy->iobuf; + spi_xfer.rx_buf = phy->iobuf; spi_xfer.len = 4; spi_xfer.cs_change = 1; @@ -88,9 +86,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; - if ((phy->rx_buf[3] & 0x01) == 0) { + if ((phy->iobuf[3] & 0x01) == 0) { // handle SPI wait states - phy->tx_buf[0] = 0; + phy->iobuf[0] = 0; for (i = 0; i < TPM_RETRY; i++) { spi_xfer.len = 1; @@ -99,7 +97,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, ret = spi_sync_locked(phy->spi_device, &m); if (ret < 0) goto exit; - if (phy->rx_buf[0] & 0x01) + if (phy->iobuf[0] & 0x01) break; } @@ -115,10 +113,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (direction) { spi_xfer.tx_buf = NULL; - spi_xfer.rx_buf = buffer; } else { - spi_xfer.tx_buf = buffer; spi_xfer.rx_buf = NULL; + memcpy(phy->iobuf, buffer, transfer_len); } spi_message_init(&m); @@ -127,6 +124,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; + if (direction) + memcpy(buffer, phy->iobuf, transfer_len); + len -= transfer_len; buffer += transfer_len; } @@ -194,6 +194,10 @@ static int tpm_tis_spi_probe(struct spi_device *dev) phy->spi_device = dev; + phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + if (!phy->iobuf) + return -ENOMEM; + return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops, NULL); } -- 2.7.4