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

Peter Huewe
2017-02-17T07:20:18Z

Am 17. Februar 2017 06:11:53 MEZ schrieb Christophe Ricard <christophe.ricard@gmail.com>:
>I am not sure i understand here, are you considering there could be
>burstcount > 64 with "TCG" TPM ?
>
With the current upstream version, any command larger with a response of more than 64 byte is broken, since the splitting loop went missing during the merge.
At least with our tpms that's the case.
(I think we are signalling a higher burstcount value than 64, which is allowed)

>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;

--
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