| Message ID | 20220720122926.415659-3-sughosh.ganu@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tpm: rng: Move TPM RNG functionality to driver model | expand |
On Wed, 20 Jul 2022 at 15:30, Sughosh Ganu <sughosh.ganu@linaro.org> 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.ganu@linaro.org> > --- > Changes since V6: > * Remove the changes made in tpm-v[12].c to return -EIO instead of > TPM_LIB_ERROR as suggested by Simon > > drivers/rng/Kconfig | 9 +++++++++ > drivers/rng/Makefile | 1 + > drivers/rng/tpm_rng.c | 23 +++++++++++++++++++++++ > lib/Kconfig | 1 + > lib/tpm_api.c | 6 +++--- > 5 files changed, 37 insertions(+), 3 deletions(-) > create mode 100644 drivers/rng/tpm_rng.c > > diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig > index 21a9ff0195..16143681da 100644 > --- a/drivers/rng/Kconfig > +++ b/drivers/rng/Kconfig > @@ -74,4 +74,13 @@ config RNG_SMCCC_TRNG > Enable random number generator for platforms that support Arm > SMCCC TRNG interface. > > +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. > + > endif We could probably skip the extra Kconfig and just look for a TPM. But let's leave it as is for now, it's an easy change if we ever want that > diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile > index 2494717d7c..78f61051ac 100644 > --- a/drivers/rng/Makefile > +++ b/drivers/rng/Makefile > @@ -13,3 +13,4 @@ obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o > obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o > obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o > obj-$(CONFIG_RNG_SMCCC_TRNG) += smccc_trng.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 7dd777b56a..e888c29245 100644 > --- a/lib/Kconfig > +++ b/lib/Kconfig > @@ -360,6 +360,7 @@ 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_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; > } > -- > 2.34.1 > Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig index 21a9ff0195..16143681da 100644 --- a/drivers/rng/Kconfig +++ b/drivers/rng/Kconfig @@ -74,4 +74,13 @@ config RNG_SMCCC_TRNG Enable random number generator for platforms that support Arm SMCCC TRNG interface. +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. + endif diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile index 2494717d7c..78f61051ac 100644 --- a/drivers/rng/Makefile +++ b/drivers/rng/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o obj-$(CONFIG_RNG_SMCCC_TRNG) += smccc_trng.o +obj-$(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 7dd777b56a..e888c29245 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -360,6 +360,7 @@ 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_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; }
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.ganu@linaro.org> --- Changes since V6: * Remove the changes made in tpm-v[12].c to return -EIO instead of TPM_LIB_ERROR as suggested by Simon drivers/rng/Kconfig | 9 +++++++++ drivers/rng/Makefile | 1 + drivers/rng/tpm_rng.c | 23 +++++++++++++++++++++++ lib/Kconfig | 1 + lib/tpm_api.c | 6 +++--- 5 files changed, 37 insertions(+), 3 deletions(-) create mode 100644 drivers/rng/tpm_rng.c