TPM: Issue TPM_STARTUP at driver load if the TPM has not been started

The TPM will respond to TPM_GET_CAP with TPM_ERR_INVALID_POSTINIT if
TPM_STARTUP has not been issued. Detect this and automatically
issue TPM_STARTUP.

This is for embedded applications where the kernel is the first thing
to touch the TPM.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Peter Huewe <peter.huewe@infineon.com>
Reviewed-by: Peter Huewe <peter.huewe@infineon.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

2 files changed, 46 insertions, 4 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 0a08af031a57..023dfbaffe73 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -451,7 +451,7 @@ static ssize_t transmit_cmd(struct tpm_chip *chip, struct tpm_cmd_t *cmd,
                 return -EFAULT;
 
         err = be32_to_cpu(cmd->header.out.return_code);
-        if (err != 0)
+        if (err != 0 && desc)
                 dev_err(chip->dev, "A TPM error (%d) occurred %s\n", err, desc);
 
         return err;
@@ -511,6 +511,25 @@ void tpm_gen_interrupt(struct tpm_chip *chip)
 }
 EXPORT_SYMBOL_GPL(tpm_gen_interrupt);
 
+#define TPM_ORD_STARTUP cpu_to_be32(153)
+#define TPM_ST_CLEAR cpu_to_be16(1)
+#define TPM_ST_STATE cpu_to_be16(2)
+#define TPM_ST_DEACTIVATED cpu_to_be16(3)
+static const struct tpm_input_header tpm_startup_header = {
+        .tag = TPM_TAG_RQU_COMMAND,
+        .length = cpu_to_be32(12),
+        .ordinal = TPM_ORD_STARTUP
+};
+
+static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
+{
+        struct tpm_cmd_t start_cmd;
+        start_cmd.header.in = tpm_startup_header;
+        start_cmd.params.startup_in.startup_type = startup_type;
+        return transmit_cmd(chip, &start_cmd, TPM_INTERNAL_RESULT_SIZE,
+                            "attempting to start the TPM");
+}
+
 int tpm_get_timeouts(struct tpm_chip *chip)
 {
         struct tpm_cmd_t tpm_cmd;
@@ -524,11 +543,28 @@ int tpm_get_timeouts(struct tpm_chip *chip)
         tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
         tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
         tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;
+        rc = transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, NULL);
 
-        rc = transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
-                        "attempting to determine the timeouts");
-        if (rc)
+        if (rc == TPM_ERR_INVALID_POSTINIT) {
+                /* The TPM is not started, we are the first to talk to it.
+                   Execute a startup command. */
+                dev_info(chip->dev, "Issuing TPM_STARTUP");
+                if (tpm_startup(chip, TPM_ST_CLEAR))
+                        return rc;
+
+                tpm_cmd.header.in = tpm_getcap_header;
+                tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
+                tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
+                tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;
+                rc = transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
+                                  NULL);
+        }
+        if (rc) {
+                dev_err(chip->dev,
+                        "A TPM error (%zd) occurred attempting to determine the timeouts\n",
+                        rc);
                 goto duration;
+        }
 
         if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 ||
             be32_to_cpu(tpm_cmd.header.out.length)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 8ef7649a50aa..8971b128500b 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -47,6 +47,7 @@ enum tpm_addr {
 #define TPM_WARN_DOING_SELFTEST 0x802
 #define TPM_ERR_DEACTIVATED     0x6
 #define TPM_ERR_DISABLED        0x7
+#define TPM_ERR_INVALID_POSTINIT 38
 
 #define TPM_HEADER_SIZE         10
 extern ssize_t tpm_show_pubek(struct device *, struct device_attribute *attr,
@@ -291,6 +292,10 @@ struct tpm_getrandom_in {
         __be32 num_bytes;
 }__attribute__((packed));
 
+struct tpm_startup_in {
+        __be16  startup_type;
+} __packed;
+
 typedef union {
         struct  tpm_getcap_params_out getcap_out;
         struct  tpm_readpubek_params_out readpubek_out;
@@ -301,6 +306,7 @@ typedef union {
         struct  tpm_pcrextend_in pcrextend_in;
         struct  tpm_getrandom_in getrandom_in;
         struct  tpm_getrandom_out getrandom_out;
+        struct tpm_startup_in startup_in;
 } tpm_cmd_params;
 
 struct tpm_cmd_t {