[PATCH V3 2/2] cmd: tpm: add a subcommand device

[Philippe Reynes]

The command tpm (and tpm2) search the tpm and use it.
On sandbox, there are two tpm (tpm 1.x and tpm 2.0).
So the command tpm and tpm2 are always executed with
the first tpm (tpm 1.x), and the command tpm2 always
fails.

This add a subcommand device to command tpm and
command tpm2. Then the command tpm and tpm2 use
the device selected with the subcommand device.

To be compatible with previous behaviour, if the
subcommand device is not used before a tpm (or tpm2)
command, the device 0 is selected.

Signed-off-by: Philippe Reynes <philippe.reynes at softathome.com>
---
 cmd/tpm-common.c     | 77 +++++++++++++++++++++++++++++++++++++++++++++++++---
 cmd/tpm-user-utils.h |  1 +
 cmd/tpm-v1.c         |  3 ++
 cmd/tpm-v2.c         |  3 ++
 4 files changed, 80 insertions(+), 4 deletions(-)

Changelog:
v3:
- no change
v2:
- use helper for tpm device (idea from Miquel)
- don't set tpm in the look (feedback from Miquel)
- add a comment to explain the backward code (feedback from Miquel)

diff --git a/cmd/tpm-common.c b/cmd/tpm-common.c
index 38900fb..42882b1 100644
--- a/cmd/tpm-common.c
+++ b/cmd/tpm-common.c
@@ -12,6 +12,8 @@
 #include <tpm-common.h>
 #include "tpm-user-utils.h"
 
+static struct udevice *tpm_dev;
+
 /**
  * Print a byte string in hexdecimal format, 16-bytes per line.
  *
@@ -231,19 +233,86 @@ int type_string_write_vars(const char *type_str, u8 *data,
 	return 0;
 }
 
+static int tpm_show_device(void)
+{
+	struct udevice *dev;
+	char buf[80];
+	int n = 0, rc;
+
+	for_each_tpm_device(dev) {
+		rc = tpm_get_desc(dev, buf, sizeof(buf));
+		if (rc < 0)
+			printf("device %d: can't get info\n", n);
+		else
+			printf("device %d: %s\n", n, buf);
+
+		n++;
+	};
+
+	return 0;
+}
+
+static int tpm_set_device(unsigned long num)
+{
+	struct udevice *dev;
+	unsigned long n = 0;
+	int rc = CMD_RET_FAILURE;
+
+	for_each_tpm_device(dev) {
+		if (n == num) {
+			rc = 0;
+			break;
+		}
+
+		n++;
+	}
+
+	if (!rc)
+		tpm_dev = dev;
+
+	return rc;
+}
+
 int get_tpm(struct udevice **devp)
 {
 	int rc;
 
-	rc = uclass_first_device_err(UCLASS_TPM, devp);
-	if (rc) {
-		printf("Could not find TPM (ret=%d)\n", rc);
-		return CMD_RET_FAILURE;
+	/*
+	 * To keep a backward compatibility with previous code,
+	 * if a tpm device is not explicitly set, we set the first one.
+	 */
+	if (!tpm_dev) {
+		rc = tpm_set_device(0);
+		if (rc) {
+			printf("Couldn't set TPM 0 (rc = %d)\n", rc);
+			return CMD_RET_FAILURE;
+		}
 	}
 
+	if (devp)
+		*devp = tpm_dev;
+
 	return 0;
 }
 
+int do_tpm_device(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
+{
+	unsigned long num;
+	int rc;
+
+	if (argc == 2) {
+		num = simple_strtoul(argv[1], NULL, 10);
+
+		rc = tpm_set_device(num);
+		if (rc)
+			printf("Couldn't set TPM %lu (rc = %d)\n", num, rc);
+	} else {
+		rc = tpm_show_device();
+	}
+
+	return rc;
+}
+
 int do_tpm_info(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 {
 	struct udevice *dev;
diff --git a/cmd/tpm-user-utils.h b/cmd/tpm-user-utils.h
index 8ce9861..a851d9c 100644
--- a/cmd/tpm-user-utils.h
+++ b/cmd/tpm-user-utils.h
@@ -17,6 +17,7 @@ int type_string_pack(const char *type_str, char * const values[], u8 *data);
 int type_string_write_vars(const char *type_str, u8 *data, char * const vars[]);
 int get_tpm(struct udevice **devp);
 
+int do_tpm_device(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]);
 int do_tpm_init(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]);
 int do_tpm_info(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]);
 int do_tpm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
diff --git a/cmd/tpm-v1.c b/cmd/tpm-v1.c
index 2807331..bc34e06 100644
--- a/cmd/tpm-v1.c
+++ b/cmd/tpm-v1.c
@@ -645,6 +645,7 @@ TPM_COMMAND_NO_ARG(tpm_physical_enable)
 TPM_COMMAND_NO_ARG(tpm_physical_disable)
 
 static cmd_tbl_t tpm1_commands[] = {
+	U_BOOT_CMD_MKENT(device, 0, 1, do_tpm_device, "", ""),
 	U_BOOT_CMD_MKENT(info, 0, 1, do_tpm_info, "", ""),
 	U_BOOT_CMD_MKENT(init, 0, 1, do_tpm_init, "", ""),
 	U_BOOT_CMD_MKENT(startup, 0, 1,
@@ -721,6 +722,8 @@ U_BOOT_CMD(tpm, CONFIG_SYS_MAXARGS, 1, do_tpm,
 "cmd args...\n"
 "    - Issue TPM command <cmd> with arguments <args...>.\n"
 "Admin Startup and State Commands:\n"
+"  device [num device]\n"
+"    - Show all devices or set the specified device\n"
 "  info - Show information about the TPM\n"
 "  init\n"
 "    - Put TPM into a state where it waits for 'startup' command.\n"
diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index 459a955..0cd3982 100644
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -354,6 +354,7 @@ static int do_tpm_pcr_setauthvalue(cmd_tbl_t *cmdtp, int flag,
 }
 
 static cmd_tbl_t tpm2_commands[] = {
+	U_BOOT_CMD_MKENT(device, 0, 1, do_tpm_device, "", ""),
 	U_BOOT_CMD_MKENT(info, 0, 1, do_tpm_info, "", ""),
 	U_BOOT_CMD_MKENT(init, 0, 1, do_tpm_init, "", ""),
 	U_BOOT_CMD_MKENT(startup, 0, 1, do_tpm2_startup, "", ""),
@@ -381,6 +382,8 @@ cmd_tbl_t *get_tpm2_commands(unsigned int *size)
 U_BOOT_CMD(tpm2, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command",
 "<command> [<arguments>]\n"
 "\n"
+"device [num device]\n"
+"    Show all devices or set the specified device\n"
 "info\n"
 "    Show information about the TPM.\n"
 "init\n"
-- 
2.7.4