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dongjiuzhu1
1c643b5cc3
This patch implements POSIX-compliant CLOCKFD support, enabling user
applications to access dynamic PTP clocks through file descriptors
combined with clock_gettime() and clock_settime() system calls.
Key changes include:
1. CLOCKFD macro support:
- Added CLOCKFD() macro in include/nuttx/clock.h
- Allows encoding file descriptor into clockid_t: CLOCKFD(fd)
- Enables accessing PTP clocks via: clock_gettime(CLOCKFD(fd), &ts)
2. clock_gettime() enhancements:
- Modified sched/clock/clock_gettime.c to detect CLOCKFD clockids
- Extracts file descriptor from clockid using CLOCKFD_TO_FD()
- Validates file descriptor and calls file_ioctl() with PTP_CLOCK_GETTIME
- Falls back to standard clock handling for non-CLOCKFD clockids
3. clock_settime() enhancements:
- Modified sched/clock/clock_settime.c to support CLOCKFD clockids
- Extracts file descriptor and validates accessibility
- Issues PTP_CLOCK_SETTIME ioctl to underlying PTP clock device
- Maintains backward compatibility with standard POSIX clocks
4. File descriptor validation:
- Checks file descriptor validity using fs_getfilep()
- Ensures proper reference counting with fs_putfilep()
- Returns appropriate error codes (EINVAL, EBADF) on failures
5. Integration with PTP clock framework:
- Seamlessly integrates with PTP clock driver's ioctl interface
- Enables standard POSIX clock API usage for dynamic PTP clocks
- No changes required to existing applications using standard clocks
Usage example:
int fd = open("/dev/ptp0", O_RDONLY);
struct timespec ts;
clock_gettime(CLOCKFD(fd), &ts); /* Get PTP clock time */
clock_settime(CLOCKFD(fd), &ts); /* Set PTP clock time */
close(fd);
This implementation follows the Linux kernel's PTP clock model, providing
a familiar interface for developers working with PTP hardware.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>