From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH v3 2/2] tpm_tis_spi: Use a single buffer for SPI transfers Date: Fri, 25 Aug 2017 19:39:50 +0300 Message-ID: <20170825163950.bakf66k665nsbl3a@linux.intel.com> References: <20170824082745.9372-1-Alexander.Steffen@infineon.com> <20170824082745.9372-3-Alexander.Steffen@infineon.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20170824082745.9372-3-Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Alexander Steffen Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net On Thu, Aug 24, 2017 at 10:27:45AM +0200, Alexander Steffen wrote: > 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 > --- > 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 > Reviewed-by: Jarkko Sakkinen /Jarkko ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot