Re: [PATCH v2 5/5] optee: implement the RPMB subsystem interface for UFS

[Jorge Ramirez via U-Boot <u-boot@lists.u-boot-project.org>]

On 22/07/26 17:43:16, Neil Armstrong wrote:
> On 7/22/26 16:12, Jorge Ramirez wrote:
> > On 22/07/26 10:31:04, neil.armstrong@linaro.org wrote:
> > > Hi,
> > > 
> > > On 7/22/26 08:07, Jorge Ramirez-Ortiz wrote:
> > > > OP-TEE's legacy RPMB supplicant interface assumes the RPMB device is eMMC
> > > > and derives the key from an eMMC-shaped device ID, so it can never
> > > > reproduce the key Linux derives for a UFS device; secure storage on
> > > > UFS-only platforms instead needs the transport-agnostic RPMB subsystem
> > > > interface, through which the normal world describes the real RPMB device
> > > > to OP-TEE. Add a UFS backend for it so OP-TEE derives a key matching Linux
> > > > and can use RPMB secure storage on UFS, leaving the legacy eMMC path
> > > > untouched.
> > > > 
> > > > This subsystem backend currently supports UFS drives only; eMMC still uses
> > > > the legacy interface. As the legacy interface is dropped in favour of the
> > > > subsystem one, an eMMC backend should be added here so both transports are
> > > > served through a single RPMB path.
> > > > 
> > > > Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
> > > > ---
> > > >    drivers/tee/optee/Makefile               |   1 +
> > > >    drivers/tee/optee/optee_msg_supplicant.h |   8 ++
> > > >    drivers/tee/optee/optee_private.h        |  41 ++++++++
> > > >    drivers/tee/optee/rpmb.c                 | 124 +++++++++++++++++++++++
> > > 
> > > Why not rpmb_ufs ?
> > 
> > 
> > because in the future (and IMO) rpmb.c should support UFS and EMMC using
> > the new probe interface (eventually removing rpmb_legacy).
> 
> Let's see in the future, if somehow there's need for a common "new"
> and emmc only legacy some rework will be needed anyway. The eMMC RPMB
> hasn't been updated for a very long time...
> 
> Using the driver model to register an rpmb device attached to an eMMC
> or UFS controller would the cleanest way to handle that, but we're not here now.
> 
> > 
> > > 
> > > It's fine to have 2 backend implementations, the emmc is implementing the
> > > legacy optee API, just add a comment in the eMMC file about that.
> > > 
> > > Neil
> > > 
> > > >    drivers/tee/optee/supplicant.c           |   9 ++
> > > >    5 files changed, 183 insertions(+)
> > > >    create mode 100644 drivers/tee/optee/rpmb.c
> > > > 
> > > > diff --git a/drivers/tee/optee/Makefile b/drivers/tee/optee/Makefile
> > > > index 8321cf53a19..7af19834c00 100644
> > > > --- a/drivers/tee/optee/Makefile
> > > > +++ b/drivers/tee/optee/Makefile
> > > > @@ -4,3 +4,4 @@ obj-$(CONFIG_OPTEE) += core.o
> > > >    obj-y += supplicant.o
> > > >    obj-$(CONFIG_DM_I2C) += i2c.o
> > > >    obj-$(CONFIG_SUPPORT_EMMC_RPMB) += rpmb_legacy.o
> > > > +obj-$(CONFIG_SUPPORT_UFS_RPMB) += rpmb.o
> > > > diff --git a/drivers/tee/optee/optee_msg_supplicant.h b/drivers/tee/optee/optee_msg_supplicant.h
> > > > index 963cfd47824..b720d5d7b3f 100644
> > > > --- a/drivers/tee/optee/optee_msg_supplicant.h
> > > > +++ b/drivers/tee/optee/optee_msg_supplicant.h
> > > > @@ -152,6 +152,14 @@
> > > >     */
> > > >    #define OPTEE_MSG_RPC_CMD_I2C_TRANSFER 21
> > > > +#define OPTEE_MSG_RPC_CMD_RPMB_PROBE_RESET	22
> > > > +#define OPTEE_MSG_RPC_CMD_RPMB_PROBE_NEXT	23
> > > > +#define OPTEE_MSG_RPC_CMD_RPMB_FRAMES		24
> > > > +
> > > > +#define OPTEE_RPC_SHM_TYPE_APPL		0
> > > > +
> > > > +#define OPTEE_RPC_RPMB_UFS		1
> > > > +
> > > >    /*
> > > >     * Was OPTEE_MSG_RPC_CMD_SQL_FS, which isn't supported any longer
> > > >     */
> > > > diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
> > > > index 1f07a27ee4b..2888257aefe 100644
> > > > --- a/drivers/tee/optee/optee_private.h
> > > > +++ b/drivers/tee/optee/optee_private.h
> > > > @@ -9,6 +9,17 @@
> > > >    #include <tee.h>
> > > >    #include <log.h>
> > > > +#ifdef CONFIG_SUPPORT_UFS_RPMB
> > > > +/**
> > > > + * struct optee_private - OP-TEE driver private data
> > > > + * @rpmb_next_region:	next UFS RPMB region to report on PROBE_NEXT
> > > > + * @rpmb_cur_region:	UFS RPMB region selected by the last PROBE_NEXT
> > > > + */
> > > > +struct optee_private {
> > > > +	unsigned int rpmb_next_region;
> > > > +	unsigned int rpmb_cur_region;
> > > > +};
> > > > +#else
> > > >    /**
> > > >     * struct optee_private - OP-TEE driver private data
> > > >     * @rpmb_mmc:		mmc device for the RPMB partition
> > > > @@ -22,6 +33,7 @@ struct optee_private {
> > > >    	int rpmb_dev_id;
> > > >    	int rpmb_original_part;
> > > >    };
> > > > +#endif
> > > >    struct optee_msg_arg;
> > > > @@ -60,6 +72,35 @@ static inline void optee_suppl_rpmb_release(struct udevice *dev)
> > > >    }
> > > >    #endif
> > > > +#ifdef CONFIG_SUPPORT_UFS_RPMB
> > > > +void optee_suppl_cmd_rpmb_probe_reset(struct udevice *dev,
> > > > +				      struct optee_msg_arg *arg);
> > > > +
> > > > +void optee_suppl_cmd_rpmb_probe_next(struct udevice *dev,
> > > > +				     struct optee_msg_arg *arg);
> > > > +
> > > > +void optee_suppl_cmd_rpmb_frames(struct udevice *dev,
> > > > +				 struct optee_msg_arg *arg);
> > > > +#else
> > > > +static inline void optee_suppl_cmd_rpmb_probe_reset(struct udevice *dev,
> > > > +						    struct optee_msg_arg *arg)
> > > > +{
> > > > +	arg->ret = TEE_ERROR_NOT_IMPLEMENTED;
> > > > +}
> > > > +
> > > > +static inline void optee_suppl_cmd_rpmb_probe_next(struct udevice *dev,
> > > > +						   struct optee_msg_arg *arg)
> > > > +{
> > > > +	arg->ret = TEE_ERROR_NOT_IMPLEMENTED;
> > > > +}
> > > > +
> > > > +static inline void optee_suppl_cmd_rpmb_frames(struct udevice *dev,
> > > > +					       struct optee_msg_arg *arg)
> > > > +{
> > > > +	arg->ret = TEE_ERROR_NOT_IMPLEMENTED;
> > > > +}
> > > > +#endif
> > > > +
> > > >    #ifdef CONFIG_DM_I2C
> > > >    /**
> > > >     * optee_suppl_cmd_i2c_transfer() - route I2C requests to an I2C chip
> > > > diff --git a/drivers/tee/optee/rpmb.c b/drivers/tee/optee/rpmb.c
> > > > new file mode 100644
> > > > index 00000000000..9c3e0f031ad
> > > > --- /dev/null
> > > > +++ b/drivers/tee/optee/rpmb.c
> > > > @@ -0,0 +1,124 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +
> > > > +#include <dm.h>
> > > > +#include <tee.h>
> > > > +#include <ufs.h>
> > > > +
> > > > +#include "optee_msg.h"
> > > > +#include "optee_msg_supplicant.h"
> > > > +#include "optee_private.h"
> > > > +
> > > > +#define UFS_RPMB_CONTROLLER	0
> > > 
> > > Can this be a config option instead which defaults to 0 ?
> > 
> > um, I dont think so - this assumes there is only one controller. If there
> > are more than one, we would need a mechanism to select which one from
> > the enumerated values (maybe a DT alias (ie ufs-rpmb ?) I think the binding order
> > changes as we enable/disable devices)
> 
> It could collide with other SCSI devices like SATA devices over PCIe.
> 
> Usually we try not to hardcode the devices ids.


right...shall I go ahead with a DT alias approach?