On Mon, Jul 04, 2022 at 07:04:39PM +0530, Sughosh Ganu wrote: > 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 V5: > * Use the dev_get_parent() interface for getting the TPM device when > calling the tpm_get_random() function > > drivers/rng/Kconfig | 11 +++++++++++ > drivers/rng/Makefile | 1 + > drivers/rng/tpm_rng.c | 23 +++++++++++++++++++++++ > lib/Kconfig | 1 + > lib/tpm-v1.c | 13 +++++++------ > lib/tpm-v2.c | 6 +++--- > lib/tpm_api.c | 6 +++--- > 7 files changed, 49 insertions(+), 12 deletions(-) > create mode 100644 drivers/rng/tpm_rng.c > > diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig > index c10f7d345b..67c65311c7 100644 > --- a/drivers/rng/Kconfig > +++ b/drivers/rng/Kconfig > @@ -58,4 +58,15 @@ config RNG_IPROC200 > depends on DM_RNG > help > Enable random number generator for RPI4. > + > +config TPM_RNG > + bool "Enable random number generator on TPM device" > + depends on TPM > + default y > + help > + The TPM device has an inbuilt random number generator > + functionality. Enable random number generator on TPM > + devices.
Maybe we discussed this on a previous version, but why do we want to have this as a config option? Code size? A TPM will always be able to generate a random number. Couldn't we compile this based on an existing TPM Kconfig option? > + > + > endif > diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile > index 435b3b965a..e4ca9c4149 100644 > --- a/drivers/rng/Makefile > +++ b/drivers/rng/Makefile > @@ -11,3 +11,4 @@ obj-$(CONFIG_RNG_OPTEE) += optee_rng.o > obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o > obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o > obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o > +obj-$(CONFIG_TPM_RNG) += tpm_rng.o > diff --git a/drivers/rng/tpm_rng.c b/drivers/rng/tpm_rng.c > new file mode 100644 > index 0000000000..1a5e9e2e4b > --- /dev/null > +++ b/drivers/rng/tpm_rng.c > @@ -0,0 +1,23 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Copyright (c) 2022, Linaro Limited > + */ > + > +#include <dm.h> > +#include <rng.h> > +#include <tpm_api.h> > + > +static int rng_tpm_random_read(struct udevice *dev, void *data, size_t count) > +{ > + return tpm_get_random(dev_get_parent(dev), data, count); > +} > + > +static const struct dm_rng_ops tpm_rng_ops = { > + .read = rng_tpm_random_read, > +}; > + > +U_BOOT_DRIVER(tpm_rng) = { > + .name = "tpm-rng", > + .id = UCLASS_RNG, > + .ops = &tpm_rng_ops, > +}; > diff --git a/lib/Kconfig b/lib/Kconfig > index acc0ac081a..17efaa4c80 100644 > --- a/lib/Kconfig > +++ b/lib/Kconfig > @@ -358,6 +358,7 @@ source lib/crypt/Kconfig > config TPM > bool "Trusted Platform Module (TPM) Support" > depends on DM > + imply DM_RNG > help > This enables support for TPMs which can be used to provide security > features for your board. The TPM can be connected via LPC or I2C > diff --git a/lib/tpm-v1.c b/lib/tpm-v1.c > index 22a769c587..f7091e5bc7 100644 > --- a/lib/tpm-v1.c > +++ b/lib/tpm-v1.c > @@ -9,12 +9,13 @@ > #include <common.h> > #include <dm.h> > #include <log.h> > -#include <asm/unaligned.h> > -#include <u-boot/sha1.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 > @@ -892,19 +893,19 @@ 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; > + return -EIO; > err = tpm_sendrecv_command(dev, 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; > diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c > index 1bf627853a..abca9a14b0 100644 > --- a/lib/tpm-v2.c > +++ b/lib/tpm-v2.c > @@ -585,19 +585,19 @@ 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; > + return -EIO; > err = tpm_sendrecv_command(dev, 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; > diff --git a/lib/tpm_api.c b/lib/tpm_api.c > index 4ac4612c81..032f383ca0 100644 > --- a/lib/tpm_api.c > +++ b/lib/tpm_api.c > @@ -269,7 +269,7 @@ u32 tpm_get_random(struct udevice *dev, void *data, u32 > count) > if (tpm_is_v1(dev)) > return tpm1_get_random(dev, data, count); > else if (tpm_is_v2(dev)) > - return -ENOSYS; /* not implemented yet */ > - else > - return -ENOSYS; > + return tpm2_get_random(dev, data, count); > + > + return -ENOSYS; > } > -- > 2.25.1 > Thanks /Ilias