Re: [PATCH 4/5] tpm_tis_spi: Remove limitation of transfers to MAX_SPI_FRAMESIZE bytes

Christophe Ricard
2017-02-17T05:11:58Z

I am not sure i understand here, are you considering there could be
burstcount > 64 with "TCG" TPM ?

Or is this because of TIS vs PTP differences ?

To be honest, this is a little behind me now :-)

On 16/02/2017 08:08, Peter Huewe wrote:
> Limiting transfers to MAX_SPI_FRAMESIZE was not expected by the upper
> layers, as tpm_tis has no such limitation. Add a loop to hide that
> limitation.
>
> Cc: <stable@vger.kernel.org>
> Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy")
> Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
> Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
> ---
> drivers/char/tpm/tpm_tis_spi.c | 108 ++++++++++++++++++++++-------------------
> 1 file changed, 57 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
> index 16938e2253d2..b50c5b072df3 100644
> --- a/drivers/char/tpm/tpm_tis_spi.c
> +++ b/drivers/char/tpm/tpm_tis_spi.c
> @@ -61,68 +61,74 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 len,
> {
> struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
> int ret;
> - struct spi_message m;
> - struct spi_transfer spi_xfer = {
> - .tx_buf = phy->tx_buf,
> - .rx_buf = phy->rx_buf,
> - .len = 4,
> - .cs_change = 1,
> - };
> -
> - if (len > MAX_SPI_FRAMESIZE)
> - return -ENOMEM;
>
> - phy->tx_buf[0] = direction | (len - 1);
> - phy->tx_buf[1] = 0xd4;
> - phy->tx_buf[2] = addr >> 8;
> - phy->tx_buf[3] = addr;
> + spi_bus_lock(phy->spi_device->master);
>
> - spi_message_init(&m);
> - spi_message_add_tail(&spi_xfer, &m);
> + while (len) {
> + struct spi_message m;
> + struct spi_transfer spi_xfer = {
> + .tx_buf = phy->tx_buf,
> + .rx_buf = phy->rx_buf,
> + .len = 4,
> + .cs_change = 1,
> + };
> + u8 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;
> +
> + spi_message_init(&m);
> + spi_message_add_tail(&spi_xfer, &m);
> + ret = spi_sync_locked(phy->spi_device, &m);
> + if (ret < 0)
> + goto exit;
>
> - spi_bus_lock(phy->spi_device->master);
> - ret = spi_sync_locked(phy->spi_device, &m);
> - if (ret < 0)
> - goto exit;
> -
> - if ((phy->rx_buf[3] & 0x01) == 0) {
> - // handle SPI wait states
> - int i;
> -
> - phy->tx_buf[0] = 0;
> -
> - for (i = 0; i < TPM_RETRY; i++) {
> - spi_xfer.len = 1;
> - spi_message_init(&m);
> - spi_message_add_tail(&spi_xfer, &m);
> - ret = spi_sync_locked(phy->spi_device, &m);
> - if (ret < 0)
> + if ((phy->rx_buf[3] & 0x01) == 0) {
> + // handle SPI wait states
> + int i;
> +
> + phy->tx_buf[0] = 0;
> +
> + for (i = 0; i < TPM_RETRY; i++) {
> + spi_xfer.len = 1;
> + spi_message_init(&m);
> + spi_message_add_tail(&spi_xfer, &m);
> + ret = spi_sync_locked(phy->spi_device, &m);
> + if (ret < 0)
> + goto exit;
> + if (phy->rx_buf[0] & 0x01)
> + break;
> + }
> +
> + if (i == TPM_RETRY) {
> + ret = -ETIMEDOUT;
> goto exit;
> - if (phy->rx_buf[0] & 0x01)
> - break;
> + }
> }
>
> - if (i == TPM_RETRY) {
> - ret = -ETIMEDOUT;
> - goto exit;
> + spi_xfer.cs_change = 0;
> + spi_xfer.len = transfer_len;
> +
> + if (direction) {
> + spi_xfer.tx_buf = NULL;
> + spi_xfer.rx_buf = buffer;
> + } else {
> + spi_xfer.tx_buf = buffer;
> + spi_xfer.rx_buf = NULL;
> }
> - }
>
> - spi_xfer.cs_change = 0;
> - spi_xfer.len = len;
> + spi_message_init(&m);
> + spi_message_add_tail(&spi_xfer, &m);
> + ret = spi_sync_locked(phy->spi_device, &m);
> + if (ret < 0)
> + goto exit;
>
> - if (direction) {
> - spi_xfer.tx_buf = NULL;
> - spi_xfer.rx_buf = buffer;
> - } else {
> - spi_xfer.tx_buf = buffer;
> - spi_xfer.rx_buf = NULL;
> + len -= transfer_len;
> + buffer += transfer_len;
> }
>
> - spi_message_init(&m);
> - spi_message_add_tail(&spi_xfer, &m);
> - ret = spi_sync_locked(phy->spi_device, &m);
> -
> exit:
> spi_bus_unlock(phy->spi_device->master);
> return ret;