Hi Simon,
Late versions of OP-TEE support a pseudo bus. TAs that behave as hardware blocks (e.g TPM, RNG etc) present themselves on a bus which we can scan. Unfortunately U-Boot doesn't support that yet. It's worth noting that we already have a workaround for RNG. The details are in commit 70812bb83da6 ("tee: optee: bind rng optee driver")
So let's add a list of devices based on U-Boot Kconfig options that we will scan until we properly implement the tee-bus functionality.
While at it change the behaviour of the tee core itself wrt to device binding. If some device binding fails, print a warning instead of disabling OP-TEE.
Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org Reviewed-by: Jens Wiklander jens.wiklander@linaro.org Reviewed-by: Etienne Carriere etienne.carriere@linaro.org
Changes since v3:
- Use NULL instead of a child ptr on device_bind_driver(), since it's not
really needed
- Changed the style of the optee_bus_probe[] definition to {.drv_name = xxx, .dev_name = yyy }
Changes since v2:
- Fixed typo on driver name ftpm-tee -> ftpm_tee
Changes since v1:
- remove a macro and use ARRAY_SIZE directly
drivers/tee/optee/core.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-)
[...]
Some things *are* working without a DT entry. You had similar concerns on FF-A (where you requested a DT node again) and people gave the exact same response. As long as a bus is scanable in any way, it's preferable to than adding a DT entry. Moreover this code does not prevent anyone from adding a DT entry.
To make things even worse if the TA is compiled as 'scanable' and has a DT entry, it might cause issues down the road when being probed by the kernel. So really this is just a patch that makes u-boot behave and plug in properly to the rest of the ecosystem
Calling device_bind() is supposed to be used in extremis. I don't see any scanning of an OP-TEE bus here. I just see it binding two child devices which are hard-coded in U-Boot. What am I missing?
The commit description describes the current state of U-Boot
This appears to be a Linaro binding, so you should be able to update it easily enough.
Linaro binding? The DT is governed by a spec, we commit everything upstream there. OTOH I still don't see what we need to put in there. As we discussed this is a bus that can be used to scan devices.
Thanks /Ilias
Regards, Simon