freebsd-nq/sys/sys/timepps.h
Ian Lepore 28315e27a7 Implement a mechanism for making changes in the kernel<->driver PPS
interface without breaking ABI or API compatibility with existing drivers.

The existing data structures used to communicate between the kernel and
driver portions of PPS processing contain no spare/padding fields and no
flags field or other straightforward mechanism for communicating changes
in the structures or behaviors of the code.  This makes it difficult to
MFC new features added to the PPS facility.  ABI compatibility is
important; out-of-tree drivers in module form are known to exist.  (Note
that the existing api_version field in the pps_params structure must
contain the value mandated by RFC 2783 and any RFCs that come along after.)

These changes introduce a pair of abi-version fields which are filled in
by the driver and the kernel respectively to indicate the interface
version.  The driver sets its version field before calling the new
pps_init_abi() function.  That lets the kernel know how much of the
pps_state structure is understood by the driver and it can avoid using
newer fields at the end of the structure that it knows about if the driver
is a lower version.  The kernel fills in its version field during the init
call, letting the driver know what features and data the kernel supports.

To implement the new version information in a way that is backwards
compatible with code from before these changes, the high bit of the
lightly-used 'kcmode' field is repurposed as a flag bit that indicates the
driver is aware of the abi versioning scheme.  Basically if this bit is
clear that indicates a "version 0" driver and if it is set the driver_abi
field indicates the version.

These changes also move the recently-added 'mtx' field of pps_state from
the middle to the end of the structure, and make the kernel code that uses
this field conditional on the driver being abi version 1 or higher.  It
changes the only driver currently supplying the mtx field, usb_serial, to
use pps_init_abi().

Reviewed by:	hselasky@
2015-05-04 17:59:39 +00:00

267 lines
6.4 KiB
C

/*-
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* Copyright (c) 2011 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by Julien Ridoux at the University
* of Melbourne under sponsorship from the FreeBSD Foundation.
*
* $FreeBSD$
*
* The is a FreeBSD version of the RFC 2783 API for Pulse Per Second
* timing interfaces.
*/
#ifndef _SYS_TIMEPPS_H_
#define _SYS_TIMEPPS_H_
#include <sys/_ffcounter.h>
#include <sys/ioccom.h>
#include <sys/time.h>
#define PPS_API_VERS_1 1
typedef int pps_handle_t;
typedef unsigned pps_seq_t;
typedef struct ntp_fp {
unsigned int integral;
unsigned int fractional;
} ntp_fp_t;
typedef union pps_timeu {
struct timespec tspec;
ntp_fp_t ntpfp;
unsigned long longpad[3];
} pps_timeu_t;
typedef struct {
pps_seq_t assert_sequence; /* assert event seq # */
pps_seq_t clear_sequence; /* clear event seq # */
pps_timeu_t assert_tu;
pps_timeu_t clear_tu;
int current_mode; /* current mode bits */
} pps_info_t;
typedef struct {
pps_seq_t assert_sequence; /* assert event seq # */
pps_seq_t clear_sequence; /* clear event seq # */
pps_timeu_t assert_tu;
pps_timeu_t clear_tu;
ffcounter assert_ffcount; /* ffcounter on assert event */
ffcounter clear_ffcount; /* ffcounter on clear event */
int current_mode; /* current mode bits */
} pps_info_ffc_t;
#define assert_timestamp assert_tu.tspec
#define clear_timestamp clear_tu.tspec
#define assert_timestamp_ntpfp assert_tu.ntpfp
#define clear_timestamp_ntpfp clear_tu.ntpfp
typedef struct {
int api_version; /* API version # */
int mode; /* mode bits */
pps_timeu_t assert_off_tu;
pps_timeu_t clear_off_tu;
} pps_params_t;
#define assert_offset assert_off_tu.tspec
#define clear_offset clear_off_tu.tspec
#define assert_offset_ntpfp assert_off_tu.ntpfp
#define clear_offset_ntpfp clear_off_tu.ntpfp
#define PPS_CAPTUREASSERT 0x01
#define PPS_CAPTURECLEAR 0x02
#define PPS_CAPTUREBOTH 0x03
#define PPS_OFFSETASSERT 0x10
#define PPS_OFFSETCLEAR 0x20
#define PPS_ECHOASSERT 0x40
#define PPS_ECHOCLEAR 0x80
#define PPS_CANWAIT 0x100
#define PPS_CANPOLL 0x200
#define PPS_TSFMT_TSPEC 0x1000
#define PPS_TSFMT_NTPFP 0x2000
#define PPS_TSCLK_FBCK 0x10000
#define PPS_TSCLK_FFWD 0x20000
#define PPS_TSCLK_MASK 0x30000
#define PPS_KC_HARDPPS 0
#define PPS_KC_HARDPPS_PLL 1
#define PPS_KC_HARDPPS_FLL 2
struct pps_fetch_args {
int tsformat;
pps_info_t pps_info_buf;
struct timespec timeout;
};
struct pps_fetch_ffc_args {
int tsformat;
pps_info_ffc_t pps_info_buf_ffc;
struct timespec timeout;
};
struct pps_kcbind_args {
int kernel_consumer;
int edge;
int tsformat;
};
#define PPS_IOC_CREATE _IO('1', 1)
#define PPS_IOC_DESTROY _IO('1', 2)
#define PPS_IOC_SETPARAMS _IOW('1', 3, pps_params_t)
#define PPS_IOC_GETPARAMS _IOR('1', 4, pps_params_t)
#define PPS_IOC_GETCAP _IOR('1', 5, int)
#define PPS_IOC_FETCH _IOWR('1', 6, struct pps_fetch_args)
#define PPS_IOC_KCBIND _IOW('1', 7, struct pps_kcbind_args)
#define PPS_IOC_FETCH_FFCOUNTER _IOWR('1', 8, struct pps_fetch_ffc_args)
#ifdef _KERNEL
struct mtx;
#define KCMODE_EDGEMASK 0x03
#define KCMODE_ABIFLAG 0x80000000 /* Internal use: abi-aware driver. */
#define PPS_ABI_VERSION 1
#define PPSFLAG_MTX_SPIN 0x01 /* Driver mtx is MTX_SPIN type. */
struct pps_state {
/* Capture information. */
struct timehands *capth;
struct fftimehands *capffth;
unsigned capgen;
unsigned capcount;
/* State information. */
pps_params_t ppsparam;
pps_info_t ppsinfo;
pps_info_ffc_t ppsinfo_ffc;
int kcmode;
int ppscap;
struct timecounter *ppstc;
unsigned ppscount[3];
/*
* The following fields are valid if the driver calls pps_init_abi().
*/
uint16_t driver_abi; /* Driver sets before pps_init_abi(). */
uint16_t kernel_abi; /* Kernel sets during pps_init_abi(). */
struct mtx *driver_mtx; /* Optional, valid if non-NULL. */
uint32_t flags;
};
void pps_capture(struct pps_state *pps);
void pps_event(struct pps_state *pps, int event);
void pps_init(struct pps_state *pps);
void pps_init_abi(struct pps_state *pps);
int pps_ioctl(unsigned long cmd, caddr_t data, struct pps_state *pps);
void hardpps(struct timespec *tsp, long nsec);
#else /* !_KERNEL */
static __inline int
time_pps_create(int filedes, pps_handle_t *handle)
{
int error;
*handle = -1;
error = ioctl(filedes, PPS_IOC_CREATE, 0);
if (error < 0)
return (-1);
*handle = filedes;
return (0);
}
static __inline int
time_pps_destroy(pps_handle_t handle)
{
return (ioctl(handle, PPS_IOC_DESTROY, 0));
}
static __inline int
time_pps_setparams(pps_handle_t handle, const pps_params_t *ppsparams)
{
return (ioctl(handle, PPS_IOC_SETPARAMS, ppsparams));
}
static __inline int
time_pps_getparams(pps_handle_t handle, pps_params_t *ppsparams)
{
return (ioctl(handle, PPS_IOC_GETPARAMS, ppsparams));
}
static __inline int
time_pps_getcap(pps_handle_t handle, int *mode)
{
return (ioctl(handle, PPS_IOC_GETCAP, mode));
}
static __inline int
time_pps_fetch(pps_handle_t handle, const int tsformat,
pps_info_t *ppsinfobuf, const struct timespec *timeout)
{
int error;
struct pps_fetch_args arg;
arg.tsformat = tsformat;
if (timeout == NULL) {
arg.timeout.tv_sec = -1;
arg.timeout.tv_nsec = -1;
} else
arg.timeout = *timeout;
error = ioctl(handle, PPS_IOC_FETCH, &arg);
*ppsinfobuf = arg.pps_info_buf;
return (error);
}
static __inline int
time_pps_fetch_ffc(pps_handle_t handle, const int tsformat,
pps_info_ffc_t *ppsinfobuf, const struct timespec *timeout)
{
struct pps_fetch_ffc_args arg;
int error;
arg.tsformat = tsformat;
if (timeout == NULL) {
arg.timeout.tv_sec = -1;
arg.timeout.tv_nsec = -1;
} else {
arg.timeout = *timeout;
}
error = ioctl(handle, PPS_IOC_FETCH_FFCOUNTER, &arg);
*ppsinfobuf = arg.pps_info_buf_ffc;
return (error);
}
static __inline int
time_pps_kcbind(pps_handle_t handle, const int kernel_consumer,
const int edge, const int tsformat)
{
struct pps_kcbind_args arg;
arg.kernel_consumer = kernel_consumer;
arg.edge = edge;
arg.tsformat = tsformat;
return (ioctl(handle, PPS_IOC_KCBIND, &arg));
}
#endif /* KERNEL */
#endif /* !_SYS_TIMEPPS_H_ */