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.

Signed-off-by: Alexander Steffen <alexander.stef...@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
---
 drivers/char/tpm/tpm_tis_spi.c | 34 ++++++++++++++--------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
index 05ce841..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;
-       u8 *rx_buf;
+       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;
                        }
 
@@ -117,7 +115,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, 
u32 addr, u16 len,
                        spi_xfer.tx_buf = NULL;
                } else {
                        spi_xfer.rx_buf = NULL;
-                       memcpy(phy->tx_buf, buffer, transfer_len);
+                       memcpy(phy->iobuf, buffer, transfer_len);
                }
 
                spi_message_init(&m);
@@ -127,7 +125,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, 
u32 addr, u16 len,
                        goto exit;
 
                if (direction)
-                       memcpy(buffer, phy->rx_buf, transfer_len);
+                       memcpy(buffer, phy->iobuf, transfer_len);
 
                len -= transfer_len;
                buffer += transfer_len;
@@ -196,12 +194,8 @@ static int tpm_tis_spi_probe(struct spi_device *dev)
 
        phy->spi_device = dev;
 
-       phy->tx_buf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
-       if (!phy->tx_buf)
-               return -ENOMEM;
-
-       phy->rx_buf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
-       if (!phy->rx_buf)
+       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,
-- 
2.7.4


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