Nuttx currently has 2 types of sleep interfaces:
1. Signal-scheduled sleep: nxsig_sleep() / nxsig_usleep() / nxsig_nanosleep()
Weaknesses:
a. Signal-dependent: The signal-scheduled sleep method is bound to the signal framework, while some driver sleep operations do not depend on signals.
b. Timespec conversion: Signal-scheduled sleep involves timespec conversion, which has a significant impact on performance.
2. Busy sleep: up_mdelay() / up_udelay()
Weaknesses:
a. Does not actively trigger scheduling, occupy the CPU loading.
3. New interfaces: Scheduled sleep: nxsched_sleep() / nxsched_usleep() / nxsched_msleep() / nxsched_ticksleep()
Strengths:
a. Does not depend on the signal framework.
b. Tick-based, without additional computational overhead.
Currently, the Nuttx driver framework extensively uses nxsig_* interfaces. However, the driver does not need to rely on signals or timespec conversion.
Therefore, a new set of APIs is added to reduce dependencies on other modules.
(This PR also aims to make signals optional, further reducing the code size of Nuttx.)
Signed-off-by: chao an <anchao.archer@bytedance.com>
This commit simplifies sending errors back to OP-TEE and avoids
code duplication when handling errno values.
Signed-off-by: Theodore Karatapanis <tkaratapanis@census-labs.com>
This commit expands RPC support for the OP-TEE driver using 2 files:
1) drivers/misc/optee_rpc.c
* Add support for RPCs that can be handled directly by the kernel.
* Can delegate RPC handling to optee_supplicant.c for RPCs that
need userspace interaction.
2) drivers/misc/optee_supplicant.c
* Enable communication between the userspace TEE supplicant and the
kernel driver.
Additional changes were needed to the following files:
1) drivers/misc/optee.c
* Add ioctls used SOLELY by the userspace TEE supplicant.
* Register /dev/teepriv0 if the supplicant is enabled in Kconfig
* Add OPTEE_ROLE_CA and OPTEE_ROLE_SUPPLICANT conditionals to
differentiate paths, between a normal Client Application (CA)
and the TEE supplicant.
* Change some functions from static to "public" to reuse them
in other C files.
* Adjust optee_to/from_msg_param() to work with RPCs.
2) drivers/misc/optee_smc.c
* Call the RPC handler from optee_rpc.c
3) drivers/misc/optee_msg.h
* Add definition needed for RPCs
4) drivers/misc/tee.h
* Add ioctl definitions
* Add TEE_SHM_SUPP flag, checked when unregistering supplicant
memory.
5) Documentation/guides/optee.rs
* Add documentation for RPCs and the supplicant.
6) drivers/misc/{CMakeLists.txt, Make.defs}
* Account for the new files.
7) drivers/misc/Kconfig
* Add DEV_OPTEE_SUPPLICANT option to enable/disable the supplicant
driver.
Signed-off-by: Theodore Karatapanis <tkaratapanis@census-labs.com>
