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tpm_i2c_nuvoton: handle errors after checking the tpm fifo status
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The functions tpm_is_expecting() and tpm_is_data_avail() ignore the
errors returned by the tpm-i2c interface.

This adds code to handle erros after checking the tpm fifo status. The
tpm_is_expecting() and tpm_is_data_avail() functions are replaced by
tpm_wait_for_fifo_status().

Fixes: 56ad053
Signed-off-by: Claudio Carvalho <cclaudio@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
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@stewartsmith
Claudio Carvalho authored and stewartsmith committed Nov 29, 2016
1 parent 71b8822 commit 454d0be
Showing 1 changed file with 86 additions and 66 deletions.
152 changes: 86 additions & 66 deletions libstb/drivers/tpm_i2c_nuvoton.c
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Expand Up @@ -77,30 +77,6 @@ static bool tpm_check_status(uint8_t status, uint8_t mask, uint8_t expected)
return ((status & mask) == expected);
}

static int tpm_read_sts_reg_valid(uint8_t* value)
{
int polls, rc;

for(polls=0; polls<=MAX_STSVALID_POLLS; polls++) {
rc = tpm_status_read_byte(TPM_STS, value);
if (rc < 0)
return rc;
if (tpm_check_status(*value, TPM_STS_VALID, TPM_STS_VALID))
return 0;
/* Wait TPM STS register be settled */
time_wait_ms(5);
}
value = 0;
/**
* @fwts-label TPMValidBitTimeout
* @fwts-advice The valid bit of the tpm status register is taking
* longer to be settled. Either the wait time needs to be increased
* or the TPM device is not functional.
*/
prlog(PR_ERR, "TPM: valid bit not settled. Timeout.\n");
return STB_TPM_TIMEOUT;
}

static int tpm_wait_for_command_ready(void)
{
int rc, delay;
Expand Down Expand Up @@ -168,39 +144,59 @@ static int tpm_set_command_ready(void)
return STB_TPM_TIMEOUT;
}

static bool tpm_is_expecting(int* rc)
static int tpm_wait_for_fifo_status(uint8_t mask, uint8_t expected)
{
uint8_t value = 0;
*rc = tpm_read_sts_reg_valid(&value);
if (*rc < 0)
return false;
if (tpm_check_status(value, TPM_STS_EXPECT, TPM_STS_EXPECT))
return true;
return false;
}
int retries, rc;
uint8_t status;

static bool tpm_is_data_avail(int* rc)
{
uint8_t value = 0;

*rc = tpm_read_sts_reg_valid(&value);
if (*rc < 0)
return false;
if (tpm_check_status(value, TPM_STS_DATA_AVAIL, TPM_STS_DATA_AVAIL))
return true;
return false;
for(retries = 0; retries <= MAX_STSVALID_POLLS; retries++) {
rc = tpm_status_read_byte(TPM_STS, &status);
if (rc < 0) {
/**
* @fwts-label TPMReadFifoStatus
* @fwts-advice Either the tpm device or the tpm-i2c
* interface doesn't seem to be working properly. Check
* the return code (rc) for further details.
*/
prlog(PR_ERR, "NUVOTON: fail to read fifo status: "
"mask %x, expected %x, rc=%d\n", mask, expected,
rc);
return STB_DRIVER_ERROR;
}
if (tpm_check_status(status, mask, expected))
return 0;
/* Wait TPM STS register be settled */
time_wait_ms(5);
}
return STB_TPM_TIMEOUT;
}

static int tpm_poll_for_data_avail(void)
static int tpm_wait_for_data_avail(void)
{
int delay, rc;
uint8_t status;

for (delay = 0; delay < TPM_TIMEOUT_A;
delay += TPM_TIMEOUT_INTERVAL) {
if (tpm_is_data_avail(&rc)) {

rc = tpm_status_read_byte(TPM_STS, &status);
if (rc < 0) {
/**
* @fwts-label TPMReadDataAvail
* @fwts-advice Either the tpm device or the tpm-i2c
* interface doesn't seem to be working properly. Check
* the return code (rc) for further details.
*/
prlog(PR_ERR, "NUVOTON: fail to read sts.dataAvail, "
"rc=%d\n", rc);
return STB_DRIVER_ERROR;
}
if (tpm_check_status(status,
TPM_STS_VALID | TPM_STS_DATA_AVAIL,
TPM_STS_VALID | TPM_STS_DATA_AVAIL)) {
DBG("---- read FIFO. Data available. delay=%d/%d\n",
delay, TPM_TIMEOUT_A);
return rc;
return 0;
}
time_wait_ms(TPM_TIMEOUT_INTERVAL);
}
Expand All @@ -210,7 +206,7 @@ static int tpm_poll_for_data_avail(void)
* longer to be settled. Either the wait time need to be increased or
* the TPM device is not functional.
*/
prlog(PR_ERR, "TPM: read FIFO. Polling timeout, delay=%d/%d\n",
prlog(PR_ERR, "NUVOTON: timeout on sts.dataAvail, delay=%d/%d\n",
delay, TPM_TIMEOUT_A);
return STB_TPM_TIMEOUT;
}
Expand Down Expand Up @@ -291,14 +287,19 @@ static int tpm_write_fifo(uint8_t* buf, size_t buflen)
if (rc < 0)
return rc;

if (!tpm_is_expecting(&rc)) {
rc = tpm_wait_for_fifo_status(TPM_STS_VALID | TPM_STS_EXPECT,
TPM_STS_VALID | TPM_STS_EXPECT);
if (rc == STB_DRIVER_ERROR)
return rc;
if (rc == STB_TPM_TIMEOUT) {
/**
* @fwts-label TPMWriteFifoOverflow1
* @fwts-label TPMWriteFifoNotExpecting
* @fwts-advice The write to the TPM FIFO overflowed,
* the TPM is not expecting more data. This indicates a bug
* in the TPM device driver.
* the TPM is not expecting more data. This indicates a
* bug in the TPM device driver.
*/
prlog(PR_ERR, "TPM: write FIFO overflow1\n");
prlog(PR_ERR, "NUVOTON: write FIFO overflow, not expecting "
"more data\n");
return STB_TPM_OVERFLOW;
}
} while (curByte < length);
Expand All @@ -318,20 +319,34 @@ static int tpm_write_fifo(uint8_t* buf, size_t buflen)
DBG("%s write FIFO sent last byte, rc=%d\n",
(rc) ? "!!!!" : "----", TPM_TIMEOUT_D, rc);

if (rc < 0) {
/**
* @fwts-label TPMWriteFifo
* @fwts-advice The tpm-i2c interface doesn't seem to be
* working properly. Check the return code (rc) for
* further details.
*/
prlog(PR_ERR, "NUVOTON: fail to write fifo (last byte), "
"curByte=%zd, rc=%d\n", curByte, rc);
return STB_DRIVER_ERROR;
}
rc = tpm_wait_for_fifo_status(TPM_STS_VALID | TPM_STS_EXPECT,
TPM_STS_VALID | TPM_STS_EXPECT);
if (rc == STB_DRIVER_ERROR)
return rc;
if (rc == 0) {
if (tpm_is_expecting(&rc)) {
/**
* @fwts-label TPMWriteFifoOverflow2
* @fwts-advice The write to the TPM FIFO overflowed.
* It is expecting more data even though we think we
* are done. This indicates a bug in the TPM device
* driver.
*/
prlog(PR_ERR, "TPM: write FIFO overflow2\n");
return STB_TPM_OVERFLOW;
}
/**
* @fwts-label TPMWriteFifoExpecting
* @fwts-advice The write to the TPM FIFO overflowed.
* It is expecting more data even though we think we
* are done. This indicates a bug in the TPM device
* driver.
*/
prlog(PR_ERR, "TPM: write FIFO overflow, expecting "
"more data\n");
return STB_TPM_OVERFLOW;
}
return rc;
return 0;
}

static int tpm_read_fifo(uint8_t* buf, size_t* buflen)
Expand All @@ -341,7 +356,7 @@ static int tpm_read_fifo(uint8_t* buf, size_t* buflen)
uint8_t* bytePtr = (uint8_t*)buf;
uint8_t* curBytePtr = NULL;

rc = tpm_poll_for_data_avail();
rc = tpm_wait_for_data_avail();
if (rc < 0)
goto error;

Expand Down Expand Up @@ -377,7 +392,12 @@ static int tpm_read_fifo(uint8_t* buf, size_t* buflen)
(rc) ? "!!!!" : "----", curByte, rc);
if (rc < 0)
goto error;
} while (tpm_is_data_avail(&rc));
rc = tpm_wait_for_fifo_status(
TPM_STS_VALID | TPM_STS_DATA_AVAIL,
TPM_STS_VALID | TPM_STS_DATA_AVAIL);
if (rc == STB_DRIVER_ERROR)
goto error;
} while (rc == 0);

*buflen = curByte;
return 0;
Expand Down

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