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tpm_tis_spi: Use DMA-safe memory for SPI transfers

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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.

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: 0edbfea537 ("tpm/tpm_tis_spi: Add support for spi phy")
Cc: stable@vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Alexander Steffen 2017-09-11 12:26:52 +02:00 committed by Jarkko Sakkinen
parent f5357413db
commit 6b3a13173f
1 changed files with 27 additions and 18 deletions
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45
drivers/char/tpm/tpm_tis_spi.c
View File

@ -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] = (in ? 0x80 : 0) | (transfer_len - 1);
phy->tx_buf[1] = 0xd4;
phy->tx_buf[2] = addr >> 8;
phy->tx_buf[3] = addr;
phy->iobuf[0] = (in ? 0x80 : 0) | (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;
}
@ -112,8 +110,14 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
spi_xfer.cs_change = 0;
spi_xfer.len = transfer_len;
spi_xfer.delay_usecs = 5;
spi_xfer.tx_buf = out;
spi_xfer.rx_buf = in;
if (in) {
spi_xfer.tx_buf = NULL;
} else if (out) {
spi_xfer.rx_buf = NULL;
memcpy(phy->iobuf, out, transfer_len);
out += transfer_len;
}
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
@ -121,11 +125,12 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
if (ret < 0)
goto exit;
len -= transfer_len;
if (in)
if (in) {
memcpy(in, phy->iobuf, transfer_len);
in += transfer_len;
if (out)
out += transfer_len;
}
len -= transfer_len;
}
exit:
@ -191,6 +196,10 @@ 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);
}