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 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 V3: > > > > * Move back the driver model interface for the TPM RNG devices under > > drivers/rng/ directory. > > * Add a rng read function for the tpm devices which calls the > > tpm*_get_random API's. > > * Pass the TPM device pointer to the tpm*_get_random API's from the > > TPM RNG drivers as suggested by Simon. > > > > drivers/rng/Makefile | 2 ++ > > drivers/rng/tpm1_rng.c | 24 ++++++++++++++++++++++++ > > drivers/rng/tpm2_rng.c | 23 +++++++++++++++++++++++ > > include/tpm-v1.h | 4 ++-- > > include/tpm-v2.h | 4 ++-- > > lib/tpm-v1.c | 16 +++++++++------- > > lib/tpm-v2.c | 9 +++++---- > > lib/tpm_api.c | 23 +++++++++++++++++++---- > > 8 files changed, 86 insertions(+), 19 deletions(-) > > create mode 100644 drivers/rng/tpm1_rng.c > > create mode 100644 drivers/rng/tpm2_rng.c
<snip> > > +static int rng_tpm2_random_read(struct udevice *dev, void *data, size_t > > count) > > +{ > > + return tpm2_get_random(dev->parent, data, count); > > +} > > + > > +static const struct dm_rng_ops tpm2_rng_ops = { > > + .read = rng_tpm2_random_read, > > +}; > > + > > +U_BOOT_DRIVER(tpm2_rng) = { > > + .name = "tpm2-rng", > > + .id = UCLASS_RNG, > > + .ops = &tpm2_rng_ops, > > +}; > > Can't you just have one driver and have a tpm_get_random() function in > tpm_api.h ? With a call to tpm_get_random we can, yes. > > > 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); > > Do you need to change these? It would be better if the caller dealt with this. I am putting these functions in line with the RNG uclass interface which has the count parameter as a size_t data type. > > > > > /** > > * Lock data in the TPM > > diff --git a/lib/tpm-v1.c b/lib/tpm-v1.c > > index 22a769c587..4c6bc31a64 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; > > + 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..d7a23ccf7e 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; > > + 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 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) > > This is the function you should call My thinking was that the TPM drivers would use the tpm{1,2}_get_random functions directly, while tpm_get_random would be a generic API which could be called from any other module. This API would then call the driver model interface(dm_rng_read). But I see that you want this function to be called from the tpm rng driver. I have made the change in my v5. > > > { > > + 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); > > What is going on here? This code should stay the same. Why would you > go off and hunt for the device? > > > else if (tpm_is_v2(dev)) > > - return -ENOSYS; /* not implemented yet */ > > It is implemented above Yeah I know :). This is existing code which, for some reason, was not calling the tpm2_get_random function. I am fixing this now by removing this line. > > > - 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); > > ?? Don't you want to call the TPM to get the random number? I am just lost. Please see the explanation above. -sughosh