hi Simon, On Sat, 12 Mar 2022 at 08:14, Simon Glass <s...@chromium.org> wrote: > > Hi Sughosh, > > On Wed, 9 Mar 2022 at 05:28, Sughosh Ganu <sughosh.g...@linaro.org> wrote: > > > > The TPM device comes with the random number generator(RNG) > > functionality which is built into the TPM device. Add logic to add the > > RNG child device in the TPM uclass post probe callback. > > > > The RNG device can then be used to pass a set of random bytes to the > > linux kernel, need for address space randomisation through the > > EFI_RNG_PROTOCOL interface. > > > > Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org> > > --- > > > > Changes since V3: > > > > * Build the RNG child addition only for the u-boot proper stage using > > the CONFIG_{SPL,TPL}_BUILD guards instead of CONFIG_TPM config which > > gets included in all stages. > > * Remove the child_pre_probe callback which was starting the TPM > > device based on review from Simon. > > > > drivers/tpm/tpm-uclass.c | 40 ++++++++++++++++++++++++++++++++++++---- > > lib/Kconfig | 1 + > > 2 files changed, 37 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/tpm/tpm-uclass.c b/drivers/tpm/tpm-uclass.c > > index f67fe1019b..241ed01e68 100644 > > --- a/drivers/tpm/tpm-uclass.c > > +++ b/drivers/tpm/tpm-uclass.c > > @@ -11,10 +11,16 @@ > > #include <log.h> > > #include <linux/delay.h> > > #include <linux/unaligned/be_byteshift.h> > > +#include <tpm_api.h> > > #include <tpm-v1.h> > > #include <tpm-v2.h> > > #include "tpm_internal.h" > > > > +#include <dm/lists.h> > > + > > +#define TPM_RNG1_DRV_NAME "tpm1-rng" > > +#define TPM_RNG2_DRV_NAME "tpm2-rng" > > + > > int tpm_open(struct udevice *dev) > > { > > struct tpm_ops *ops = tpm_get_ops(dev); > > @@ -136,12 +142,38 @@ int tpm_xfer(struct udevice *dev, const uint8_t > > *sendbuf, size_t send_size, > > return 0; > > } > > > > +#if !IS_ENABLED(CONFIG_SPL_BUILD) && !IS_ENABLED(CONFIG_TPL_BUILD) > > Drop that
Okay. Btw, putting the check for the config symbol as you suggest below does add some size to the SPL/TPL code. But that is theoretical, since we currently do not enable CONFIG_{SPL,TPL}_TPM. > > > +static int tpm_uclass_post_probe(struct udevice *dev) > > +{ > > + int ret; > > + const char *drv = tpm_is_v1(dev) ? > > + TPM_RNG1_DRV_NAME : TPM_RNG2_DRV_NAME; > > + struct udevice *child; > > + > > if (CONFIG_IS_ENABLED(TPM_RNG)) { Okay > > > + ret = device_bind_driver(dev, drv, "tpm-rng0", &child); > > + if (ret == -ENOENT) { > > + log_err("No driver configured for tpm-rng device\n"); > > That is a lot of code size for the string that will likely never > happen. You can use > > > + return 0; > > You should report the error. > > > + } > > + > > + if (ret) { > > + log_err("Unable to bind rng driver with the tpm-rng > > device\n"); > > You might want to use > > return log_msg_ret("bind", ret) > > since it doesn't add to code since unless you turn on CONFIG_LOG_ERROR_RETURN Okay. -sughosh > > > + return ret; > > + } > > + > > + return 0; > > +} > > +#endif /* !CONFIG_SPL_BUILD && !CONFIG_TPL_BUILD */ > > + > > UCLASS_DRIVER(tpm) = { > > - .id = UCLASS_TPM, > > - .name = "tpm", > > - .flags = DM_UC_FLAG_SEQ_ALIAS, > > + .id = UCLASS_TPM, > > + .name = "tpm", > > + .flags = DM_UC_FLAG_SEQ_ALIAS, > > #if CONFIG_IS_ENABLED(OF_REAL) > > - .post_bind = dm_scan_fdt_dev, > > + .post_bind = dm_scan_fdt_dev, > > +#endif > > +#if !IS_ENABLED(CONFIG_SPL_BUILD) && !IS_ENABLED(CONFIG_TPL_BUILD) > > Drop that and do it in the function as above > > > + .post_probe = tpm_uclass_post_probe, > > #endif > > .per_device_auto = sizeof(struct tpm_chip_priv), > > }; > > diff --git a/lib/Kconfig b/lib/Kconfig > > index 3c6fa99b1a..0f05c97afc 100644 > > --- a/lib/Kconfig > > +++ b/lib/Kconfig > > @@ -341,6 +341,7 @@ source lib/crypt/Kconfig > > config TPM > > bool "Trusted Platform Module (TPM) Support" > > depends on DM > > + select DM_RNG > > imply might be better, so boards can disable it. > > > 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 > > -- > > 2.25.1 > > > > Regards, > Simon