From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Steffen Subject: [PATCH RESEND v3 2/2] tpm_tis_spi: Use a single buffer for SPI transfers Date: Thu, 31 Aug 2017 18:58:19 +0200 Message-ID: <20170831165819.13544-3-Alexander.Steffen@infineon.com> References: <20170831165819.13544-1-Alexander.Steffen@infineon.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <20170831165819.13544-1-Alexander.Steffen@infineon.com> Sender: owner-linux-security-module@vger.kernel.org To: jarkko.sakkinen@linux.intel.com, tpmdd-devel@lists.sourceforge.net, benoit.houyere@st.com Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Alexander Steffen List-Id: tpmdd-devel@lists.sourceforge.net 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 Reviewed-by: Jarkko Sakkinen --- 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