hi Simon,
On Tue, 1 Mar 2022 at 20:28, Simon Glass sjg@chromium.org wrote:
Hi Sughosh,
On Mon, 28 Feb 2022 at 05:07, Sughosh Ganu sughosh.ganu@linaro.org wrote:
Currently, the TPM random number generator(RNG) functions are defined as part of the library functions under the corresponding tpm files for tpmv1 and tpmv2. Move the RNG functionality under TPM RNG drivers complying with the driver model.
Also make changes to the tpm_get_random function to have it call the TPM RNG driver functions instead of the library functions.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org
Changes since V1:
- Added existing copyrights for the rng functions taken from the tpm library routines
- Return -EIO for TPM command returning an error
- Simplify the logic in tpm_get_random based on the review comments from Ilias
drivers/rng/Makefile | 1 + drivers/rng/tpm1_rng.c | 87 ++++++++++++++++++++++++++++++++++++++++++ drivers/rng/tpm2_rng.c | 86 +++++++++++++++++++++++++++++++++++++++++ lib/tpm-v1.c | 44 --------------------- lib/tpm-v2.c | 44 --------------------- lib/tpm_api.c | 23 +++++++++-- 6 files changed, 193 insertions(+), 92 deletions(-) create mode 100644 drivers/rng/tpm1_rng.c create mode 100644 drivers/rng/tpm2_rng.c
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile index 39f7ee3f03..129cfbd006 100644 --- a/drivers/rng/Makefile +++ b/drivers/rng/Makefile @@ -10,3 +10,4 @@ obj-$(CONFIG_RNG_MSM) += msm_rng.o obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o +obj-$(CONFIG_TPM) += tpm1_rng.o tpm2_rng.o diff --git a/drivers/rng/tpm1_rng.c b/drivers/rng/tpm1_rng.c new file mode 100644 index 0000000000..7e629756b3 --- /dev/null +++ b/drivers/rng/tpm1_rng.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*
- Copyright (c) 2013 The Chromium OS Authors.
- Coypright (c) 2013 Guntermann & Drunck GmbH
- Copyright (c) 2022, Linaro Limited
- */
+#include <common.h> +#include <dm.h> +#include <rng.h> +#include <tpm-utils.h> +#include <tpm-v1.h>
+#include <linux/errno.h>
+#define TPM_HEADER_SIZE 10
+#define TPMV1_DATA_OFFSET 14
+/**
- tpm1_rng_read() - Read the random bytes from TPMv1 device
- @param dev TPMv1 RNG device
- @param data data buffer to write random bytes
- @param count number of random bytes to read from
the device
- Function to read the random bytes from the RNG pseudo device
- built into the TPMv1 device. Reads 'count' number of bytes
- from the random number generator and copies them into the
- 'data' buffer.
- Return: 0 if OK, -ve on error.
- */
+static int tpm1_rng_read(struct udevice *dev, void *data, size_t count) +{
const u8 command[14] = {0x0, 0xc1, /* TPM_TAG */0x0, 0x0, 0x0, 0xe, /* parameter size */0x0, 0x0, 0x0, 0x46, /* TPM_COMMAND_CODE */};const size_t length_offset = TPM_HEADER_SIZE;const size_t data_size_offset = TPM_HEADER_SIZE;const size_t data_offset = TPMV1_DATA_OFFSET;u8 buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];size_t response_length = sizeof(response);u32 data_size;u8 *out = data;The current model is that all TPM calls are set up in lib/tpm and I don't think we should change it. You should be able to move these functions into lib/tpm and add your random_read function to tpm_api.h
I moved these functions under separate drivers as I thought that looked cleaner as against exporting the driver interface in tpm-v{1,2}.c. If you strongly feel that these should remain under lib/tpm, I will make the change. But I believe you do not have a problem with exporting these rng functions as part of the driver model. We do need that so that the EFI_RNG_PROTOCOL can use these for getting the random bytes.
-sughosh
Regards, Simon