Commit 6b3a1317 authored by Alexander Steffen's avatar Alexander Steffen Committed by Jarkko Sakkinen
Browse files

tpm_tis_spi: Use DMA-safe memory for SPI transfers 



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: 0edbfea5 ("tpm/tpm_tis_spi: Add support for spi phy")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarAlexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent f5357413

drivers/char/tpm/tpm_tis_spi.c

+27 −18
Original line number Diff line number Diff line
@@ -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);

}

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