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

Peter Huewe
2017-02-16T16:09:12Z

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;
--
2.7.4