On Mon, Feb 28, 2022 at 05:11:24PM -0700, Simon Glass wrote:
> Add a vendor-specific TPM2 command for this and implement it for Cr50.
>
> Signed-off-by: Simon Glass <s...@chromium.org>
> ---
>
> drivers/tpm/cr50_i2c.c | 117 +++++++++++++++++++++++++++++++++++++++++
> include/tpm-v2.h | 54 +++++++++++++++++++
> lib/tpm-v2.c | 24 +++++++++
> 3 files changed, 195 insertions(+)
>
> diff --git a/drivers/tpm/cr50_i2c.c b/drivers/tpm/cr50_i2c.c
> index f8c3087894..dabf617be0 100644
> --- a/drivers/tpm/cr50_i2c.c
> +++ b/drivers/tpm/cr50_i2c.c
> @@ -13,11 +13,13 @@
> #include <irq.h>
> #include <log.h>
> #include <spl.h>
> +#include <tpm-common.h>
> #include <tpm-v2.h>
> #include <acpi/acpigen.h>
> #include <acpi/acpi_device.h>
> #include <asm/gpio.h>
> #include <asm/io.h>
> +#include <asm/unaligned.h>
> #include <linux/delay.h>
> #include <dm/acpi.h>
>
> @@ -54,6 +56,41 @@ struct cr50_priv {
> bool use_irq;
> };
>
> +/*
> + * The below structure represents the body of the response to the 'report tpm
> + * state' vendor command.
> + *
> + * It is transferred over the wire, so it needs to be
> serialized/deserialized,
> + * and it is likely to change, so its contents must be versioned.
> + */
> +#define TPM_STATE_VERSION 1
> +struct tpm_vendor_state {
> + u32 version;
> + /*
> + * The following three fields are set by the TPM in case of an assert.
> + * There is no other processing than setting the source code line
> + * number, error code and the first 4 characters of the function name.
> + *
> + * We don't expect this happening, but it is included in the report
> + * just in case.
> + */
> + u32 fail_line; /* s_failLIne */
> + u32 fail_code; /* s_failCode */
> + char func_name[4]; /* s_failFunction, limited to 4 chars */
> +
> + /*
> + * The following two fields are the current time filtered value of the
> + * 'failed tries' TPM counter, and the maximum allowed value of the
> + * counter.
> + *
> + * failed_tries == max_tries is the definition of the TPM lockout
> + * condition.
> + */
> + u32 failed_tries; /* gp.failedTries */
> + u32 max_tries; /* gp.maxTries */
> + /* The below fields are present in version 2 and above */
> +};
> +
> /* Wait for interrupt to indicate TPM is ready */
> static int cr50_i2c_wait_tpm_ready(struct udevice *dev)
> {
> @@ -573,6 +610,85 @@ static int cr50_i2c_get_desc(struct udevice *dev, char
> *buf, int size)
> return len;
> }
>
> +static int stringify_state(char *buf, int len, char *str, size_t max_size)
> +{
> + struct tpm_vendor_state state;
> + size_t text_size = 0;
> +
> + state.version = get_unaligned_be32(buf +
> + offsetof(struct tpm_vendor_state, version));
> + state.fail_line = get_unaligned_be32(buf +
> + offsetof(struct tpm_vendor_state, fail_line));
> + state.fail_code = get_unaligned_be32(buf +
> + offsetof(struct tpm_vendor_state, fail_code));
> + memcpy(state.func_name,
> + buf + offsetof(struct tpm_vendor_state, func_name),
> + sizeof(state.func_name));
> + state.failed_tries = get_unaligned_be32(buf +
> + offsetof(struct tpm_vendor_state, failed_tries));
> + state.max_tries = get_unaligned_be32(buf +
> + offsetof(struct tpm_vendor_state, max_tries));
> +
> + text_size += snprintf(str + text_size, max_size - text_size,
> + "v=%d", state.version);
> + if (text_size >= max_size)
> + return -ENOSPC;
> +
> + if (state.version > TPM_STATE_VERSION)
> + text_size += snprintf(str + text_size,
> + max_size - text_size,
> + " not fully supported\n");
> + if (text_size >= max_size)
> + return -ENOSPC;
> +
> + if (state.version == 0)
> + return -EINVAL; /* This should never happen */
> +
> + text_size += snprintf(str + text_size,
> + max_size - text_size,
> + " failed_tries=%d max_tries=%d\n",
> + state.failed_tries, state.max_tries);
> + if (text_size >= max_size)
> + return -ENOSPC;
> +
> + if (state.fail_line) {
> + /* make sure function name is zero terminated. */
> + char func_name[sizeof(state.func_name) + 1];
> +
> + memcpy(func_name, state.func_name, sizeof(state.func_name));
> + func_name[sizeof(state.func_name)] = '\0';
> +
> + text_size += snprintf(str + text_size,
> + max_size - text_size,
> + "tpm failed: f %s line %d code %d",
> + func_name,
> + state.fail_line,
> + state.fail_code);
> + if (text_size >= max_size)
> + return -ENOSPC;
> + }
> +
> + return 0;
> +}
Is this error state described in the TCG TIS specs ? If so we should plug
this into the generic TPM API and the driver should only define
cr50_i2c_report_state() etc
> +
> +static int cr50_i2c_report_state(struct udevice *dev, char *str, int str_max)
> +{
> + char buf[50];
> + int buf_size = sizeof(buf);
> + int ret;
> +
> + ret = tpm2_cr50_report_state(dev, buf, &buf_size);
> + if (ret)
> + return ret;
> +
> + /* TPM responded as expected */
> + ret = stringify_state(buf, buf_size, str, str_max);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
[...]
Thanks
/Ilias
