[Skiboot] [PATCH v2 13/31] libstb/drivers/tpm_i2c_nuvoton.c: check command ready

[Claudio Carvalho]

On 10/05/2016 01:50 AM, Stewart Smith wrote:
> Claudio Carvalho <cclaudio at linux.vnet.ibm.com> writes:
>> This adds the 1/5 step performed by the TPM I2C Nuvoton driver to
>> transmit a command to the TPM device. In this step the driver
>> checks if the TPM device is ready to receive a new command.
>>
>> Signed-off-by: Claudio Carvalho <cclaudio at linux.vnet.ibm.com>
>> ---
>>  libstb/drivers/Makefile.inc      |   2 +-
>>  libstb/drivers/tpm_i2c_nuvoton.c | 134 +++++++++++++++++++++++++++++++++++++++
>>  libstb/status_codes.h            |   3 +
>>  3 files changed, 138 insertions(+), 1 deletion(-)
>>  create mode 100644 libstb/drivers/tpm_i2c_nuvoton.c
>>
>> diff --git a/libstb/drivers/Makefile.inc b/libstb/drivers/Makefile.inc
>> index f0f3d70..2817378 100644
>> --- a/libstb/drivers/Makefile.inc
>> +++ b/libstb/drivers/Makefile.inc
>> @@ -4,7 +4,7 @@ DRIVERS_DIR = libstb/drivers
>>  
>>  SUBDIRS += $(DRIVERS_DIR)
>>  
>> -DRIVERS_SRCS = romcode.c tpm_i2c_interface.c
>> +DRIVERS_SRCS = romcode.c tpm_i2c_interface.c tpm_i2c_nuvoton.c
>>  DRIVERS_OBJS = $(DRIVERS_SRCS:%.c=%.o)
>>  DRIVERS = $(DRIVERS_DIR)/built-in.o
>>  
>> diff --git a/libstb/drivers/tpm_i2c_nuvoton.c b/libstb/drivers/tpm_i2c_nuvoton.c
>> new file mode 100644
>> index 0000000..ead0f15
>> --- /dev/null
>> +++ b/libstb/drivers/tpm_i2c_nuvoton.c
>> @@ -0,0 +1,134 @@
>> +/* Copyright 2013-2016 IBM Corp.
>> + *
>> + * Licensed under the Apache License, Version 2.0 (the "License");
>> + * you may not use this file except in compliance with the License.
>> + * You may obtain a copy of the License at
>> + *
>> + *      http://www.apache.org/licenses/LICENSE-2.0
>> + *
>> + * Unless required by applicable law or agreed to in writing, software
>> + * distributed under the License is distributed on an "AS IS" BASIS,
>> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
>> + * implied.
>> + * See the License for the specific language governing permissions and
>> + * limitations under the License.
>> + */
>> +
>> +/****************************************************************************
>> + * THIS DRIVER WAS DEVELOPED BASED ON:
>> + * https://github.com/open-power/hostboot/blob/master-p8/src/usr/i2c/tpmdd.C
>> + ****************************************************************************/
>> +
>> +#include <timebase.h>
>> +#include <skiboot.h>
>> +#include <i2c.h>
>> +#include "../status_codes.h"
>> +#include "../tpm_chip.h"
>> +#include "tpm_i2c_interface.h"
>> +
>> +//#define DBG(fmt, ...) prlog(PR_DEBUG, fmt, ##__VA_ARGS__)
>> +#define DBG(fmt, ...)
>> +
>> +/*
>> + * Timings between various states or transitions within the interface protocol
>> + * as defined in the TCG PC Client Platform TPM Profile specification, Revision
>> + * 00.43.
>> + */
>> +#define TCG_PTP_TIMEOUT_B	2000
>> +
>> +/* I2C interface offsets */
>> +#define NUVOTON_TPM_STS			0x00
>> +
>> +/* Bit masks for the TPM STATUS register */
>> +#define TCG_PTP_STS_COMMAND_READY	0x40
>> +
>> +/* TPM Driver values */
>> +#define TPM_TIMEOUT_INTERVAL	10
>> +
>> +static struct tpm_dev *tpm_device = NULL;
>> +
>> +static int tpm_status_write_byte(uint8_t byte)
>> +{
>> +	uint8_t value = byte;
>> +	return tpm_i2c_request_send(tpm_device->bus_id, tpm_device->xscom_base,
>> +				    SMBUS_WRITE, NUVOTON_TPM_STS, 1, &value,
>> +				    sizeof(value));
>> +}
>> +
>> +static bool tpm_is_command_ready(int* rc)
>> +{
>> +	uint8_t value = 0;
>> +	*rc = tpm_i2c_request_send(tpm_device->bus_id, tpm_device->xscom_base,
>> +				   SMBUS_READ, NUVOTON_TPM_STS, 1, &value,
>> +				   sizeof(value));
>> +	if (*rc == 0  &&
>> +	   ((value & TCG_PTP_STS_COMMAND_READY) == TCG_PTP_STS_COMMAND_READY)){
>> +		DBG("---- TPM is command ready\n");
>> +		return true;
>> +	}
>> +	return false;
>> +}
>> +
>> +static int tpm_poll_for_command_ready(void)
>> +{
>> +	int rc, polls, delay;
>> +	/*
>> +	 * The first write to command ready may just abort an
>> +	 * outstanding command, so we poll twice
>> +	 */
>> +	for (polls=0; polls<2; polls++) {
>> +		rc = tpm_status_write_byte(TCG_PTP_STS_COMMAND_READY);
>> +		if (rc < 0) {
>> +			return rc;
>> +		}
>> +		for (delay = 0; delay < TCG_PTP_TIMEOUT_B;
>> +		     delay += TPM_TIMEOUT_INTERVAL) {
>> +			if (tpm_is_command_ready(&rc))
>> +				return rc;
>> +			time_wait_ms(TPM_TIMEOUT_INTERVAL);
>> +		}
>> +		DBG("--- Command ready polling, delay %d/%d\n",
>> +		    delay, TCG_PTP_TIMEOUT_B);
>> +	}
>> +	/**
>> +	 * @fwts-label TPMCommandReadyBitTimeout
>> +	 * @fwts-advice The command ready bit of the tpm status register is
>> +	 * taking longer to be settled. Either the wait time need to be
>> +	 * increased or the TPM device is not functional.
>> +	 */
>> +	prlog(PR_ERR, "TPM: command ready polling timeout\n");
>> +	return STB_TPM_TIMEOUT;
>> +}
>> +
>> +static int tpm_transmit(struct tpm_dev *dev, uint8_t* buf, size_t cmdlen,
>> +			size_t* buflen)
> 
> Unused parameters buf, cmdlen, buflen  cause build to fail:
> 
> as does defining tpm_transit without using it.
> 
> I'm thinking that the individual commits for the nouvoton driver can
> just be squashed into a single commit.
> 

I compiled each patch individually, but without issuing
skiboot-dirclean. That's why I did not catch this error. Sorry.

I splitted the Nuvoton driver into smaller patches just help on the
review process. I am OK if you want to squash the six commits into a
single one.