The TPM device has a builtin random number generator(RNG)
functionality. Expose the RNG functions of the TPM device to the
driver model so that they can be used by the EFI_RNG_PROTOCOL if the
protocol is installed.
Also change the function arguments and return type of the random
number functions to comply with the driver model api.
Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org>
---
Changes since V2:
* Export the existing tpm*_get_random functions to the driver model
instead of moving them to the drivers/rng/ directory.
include/tpm-v1.h | 4 ++--
include/tpm-v2.h | 4 ++--
lib/tpm-v1.c | 28 ++++++++++++++++++++--------
lib/tpm-v2.c | 21 ++++++++++++++++-----
lib/tpm_api.c | 23 +++++++++++++++++++----
5 files changed, 59 insertions(+), 21 deletions(-)
diff --git a/include/tpm-v1.h b/include/tpm-v1.h
index 33d53fb695..d2ff8b446d 100644
--- a/include/tpm-v1.h
+++ b/include/tpm-v1.h
@@ -555,9 +555,9 @@ u32 tpm1_find_key_sha1(struct udevice *dev, const u8
auth[20],
* @param dev TPM device
* @param data output buffer for the random bytes
* @param count size of output buffer
- * Return: return code of the operation
+ * Return: 0 if OK, -ve on error
*/
-u32 tpm1_get_random(struct udevice *dev, void *data, u32 count);
+int tpm1_get_random(struct udevice *dev, void *data, size_t count);
/**
* tpm_finalise_physical_presence() - Finalise physical presence
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index e79c90b939..4fb1e7a948 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -619,9 +619,9 @@ u32 tpm2_pcr_setauthvalue(struct udevice *dev, const char
*pw,
* @param data output buffer for the random bytes
* @param count size of output buffer
*
- * Return: return code of the operation
+ * Return: 0 if OK, -ve on error
*/
-u32 tpm2_get_random(struct udevice *dev, void *data, u32 count);
+int tpm2_get_random(struct udevice *dev, void *data, size_t count);
/**
* Lock data in the TPM
diff --git a/lib/tpm-v1.c b/lib/tpm-v1.c
index 22a769c587..57bb4a39cb 100644
--- a/lib/tpm-v1.c
+++ b/lib/tpm-v1.c
@@ -9,12 +9,14 @@
#include <common.h>
#include <dm.h>
#include <log.h>
-#include <asm/unaligned.h>
-#include <u-boot/sha1.h>
+#include <rng.h>
#include <tpm-common.h>
#include <tpm-v1.h>
#include "tpm-utils.h"
+#include <asm/unaligned.h>
+#include <u-boot/sha1.h>
+
#ifdef CONFIG_TPM_AUTH_SESSIONS
#ifndef CONFIG_SHA1
@@ -869,7 +871,7 @@ u32 tpm1_find_key_sha1(struct udevice *dev, const u8
auth[20],
#endif /* CONFIG_TPM_AUTH_SESSIONS */
-u32 tpm1_get_random(struct udevice *dev, void *data, u32 count)
+int tpm1_get_random(struct udevice *dev, void *data, size_t count)
{
const u8 command[14] = {
0x0, 0xc1, /* TPM_TAG */
@@ -892,19 +894,19 @@ u32 tpm1_get_random(struct udevice *dev, void *data, u32
count)
if (pack_byte_string(buf, sizeof(buf), "sd",
0, command, sizeof(command),
length_offset, this_bytes))
- return TPM_LIB_ERROR;
- err = tpm_sendrecv_command(dev, buf, response,
+ return -EIO;
+ err = tpm_sendrecv_command(dev->parent, buf, response,
&response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "d",
data_size_offset, &data_size))
- return TPM_LIB_ERROR;
+ return -EIO;
if (data_size > count)
- return TPM_LIB_ERROR;
+ return -EIO;
if (unpack_byte_string(response, response_length, "s",
data_offset, out, data_size))
- return TPM_LIB_ERROR;
+ return -EIO;
count -= data_size;
out += data_size;
@@ -912,3 +914,13 @@ u32 tpm1_get_random(struct udevice *dev, void *data, u32
count)
return 0;
}
+
+static const struct dm_rng_ops tpm1_rng_ops = {
+ .read = tpm1_get_random,
+};
+
+U_BOOT_DRIVER(tpm1_rng) = {
+ .name = "tpm1-rng",
+ .id = UCLASS_RNG,
+ .ops = &tpm1_rng_ops,
+};
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 1bf627853a..18f64f0886 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -6,6 +6,7 @@
#include <common.h>
#include <dm.h>
+#include <rng.h>
#include <tpm-common.h>
#include <tpm-v2.h>
#include <linux/bitops.h>
@@ -562,7 +563,7 @@ u32 tpm2_pcr_setauthvalue(struct udevice *dev, const char
*pw,
return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
}
-u32 tpm2_get_random(struct udevice *dev, void *data, u32 count)
+int tpm2_get_random(struct udevice *dev, void *data, size_t count)
{
const u8 command_v2[10] = {
tpm_u16(TPM2_ST_NO_SESSIONS),
@@ -585,19 +586,19 @@ u32 tpm2_get_random(struct udevice *dev, void *data, u32
count)
if (pack_byte_string(buf, sizeof(buf), "sw",
0, command_v2, sizeof(command_v2),
sizeof(command_v2), this_bytes))
- return TPM_LIB_ERROR;
- err = tpm_sendrecv_command(dev, buf, response,
+ return -EIO;
+ err = tpm_sendrecv_command(dev->parent, buf, response,
&response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "w",
data_size_offset, &data_size))
- return TPM_LIB_ERROR;
+ return -EIO;
if (data_size > this_bytes)
return TPM_LIB_ERROR;
if (unpack_byte_string(response, response_length, "s",
data_offset, out, data_size))
- return TPM_LIB_ERROR;
+ return -EIO;
count -= data_size;
out += data_size;
@@ -669,3 +670,13 @@ u32 tpm2_submit_command(struct udevice *dev, const u8
*sendbuf,
{
return tpm_sendrecv_command(dev, sendbuf, recvbuf, recv_size);
}
+
+static const struct dm_rng_ops tpm2_rng_ops = {
+ .read = tpm2_get_random,
+};
+
+U_BOOT_DRIVER(tpm2_rng) = {
+ .name = "tpm2-rng",
+ .id = UCLASS_RNG,
+ .ops = &tpm2_rng_ops,
+};
diff --git a/lib/tpm_api.c b/lib/tpm_api.c
index da48058abe..3584fda98c 100644
--- a/lib/tpm_api.c
+++ b/lib/tpm_api.c
@@ -6,6 +6,7 @@
#include <common.h>
#include <dm.h>
#include <log.h>
+#include <rng.h>
#include <tpm_api.h>
#include <tpm-v1.h>
#include <tpm-v2.h>
@@ -265,12 +266,26 @@ u32 tpm_get_permissions(struct udevice *dev, u32 index,
u32 *perm)
return -ENOSYS;
}
+#if CONFIG_IS_ENABLED(DM_RNG)
int tpm_get_random(struct udevice *dev, void *data, u32 count)
{
+ int ret = -ENOSYS;
+ struct udevice *rng_dev;
+
if (tpm_is_v1(dev))
- return tpm1_get_random(dev, data, count);
+ ret = uclass_get_device_by_driver(UCLASS_RNG,
+ DM_DRIVER_GET(tpm1_rng),
+ &rng_dev);
else if (tpm_is_v2(dev))
- return -ENOSYS; /* not implemented yet */
- else
- return -ENOSYS;
+ ret = uclass_get_device_by_driver(UCLASS_RNG,
+ DM_DRIVER_GET(tpm1_rng),
+ &rng_dev);
+
+ if (ret) {
+ log_err("Getting tpm rng device failed\n");
+ return ret;
+ }
+
+ return dm_rng_read(rng_dev, data, (size_t)count);
}
+#endif /* DM_RNG */
--
2.25.1
