From: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Alexander Steffen
<Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
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 [thread overview]
Message-ID: <20170825163950.bakf66k665nsbl3a@linux.intel.com> (raw)
In-Reply-To: <20170824082745.9372-3-Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
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 <Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
> ---
> 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.sakkine-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
/Jarkko
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next prev parent reply other threads:[~2017-08-25 16:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-24 8:27 [PATCH v3 0/2] tpm_tis_spi: Use DMA-safe memory Alexander Steffen
[not found] ` <20170824082745.9372-1-Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
2017-08-24 8:27 ` [PATCH v3 1/2] tpm_tis_spi: Use DMA-safe memory for SPI transfers Alexander Steffen
2017-08-25 16:39 ` Jarkko Sakkinen
2017-08-24 8:27 ` [PATCH v3 2/2] tpm_tis_spi: Use a single buffer " Alexander Steffen
[not found] ` <20170824082745.9372-3-Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
2017-08-25 16:39 ` Jarkko Sakkinen [this message]
2017-08-26 11:22 ` [PATCH v3 0/2] tpm_tis_spi: Use DMA-safe memory Jarkko Sakkinen
[not found] ` <20170826112259.ypwtqbwakyfdqkzo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-08-29 12:14 ` Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w
[not found] ` <9aea582eccbe4655b5de487dacf7c745-nFblLGNE8XKJSz+rYg/bSJowlv4uC7bZ@public.gmane.org>
2017-08-30 8:42 ` Benoit HOUYERE
[not found] ` <fe81962beaec4c6fa21ea90df0f01560-tklXXlf0F76qZDvoWP1BVkEOCMrvLtNR@public.gmane.org>
2017-08-31 12:34 ` Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w
2017-08-30 10:08 ` Jarkko Sakkinen
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