Messages in this thread | | | Date | Mon, 23 Jul 2007 18:04:02 +0200 | From | Rodolfo Giometti <> | Subject | Re: [PATCH] LinuxPPS - definitive version |
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On Mon, Jul 23, 2007 at 02:35:16PM +0100, David Woodhouse wrote: > > s/Documentaion/Documentation/ in the last line of Documentation/pps/pps.txt
Fixed.
> Please feed it to scripts/checkpatch.pl -- you can ignore all the > warnings about lines greater than 80 characters, and the complete crap > about "declaring multiple variables together should be avoided", but > some of what it points out is valid. Including the one about 'volatile'
Ok, I'll do it.
> -- your explanation lacked credibility. If you really need 'volatile' > then put it at the places you actually need it; not the declaration of > the structure.
About this debate, please, take a look at the pps_event() function:
void pps_event(int source, int event, void *data) { struct timespec __ts; struct pps_ktime ts;
/* First of all we get the time stamp... */ getnstimeofday(&__ts);
/* ... and translate it to PPS time data struct */ ts.sec = __ts.tv_sec; ts.nsec = __ts.tv_nsec;
if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0 ) { pps_err("unknow event (%x) for source %d", event, source); return; }
/* We wish not using locks at all into this function... a possible * solution is to check the "info" field against the pointer to * "dummy_info". * If "info" points to "dummy_info" we can return doing nothing since, * even if a new PPS source is registered by another CPU we can * safely not register current event. * If "info" points to a valid PPS source's info data we can continue * without problem since, even if current PPS source is deregistered * by another CPU, we still continue writing data into a valid area * (dummy_info). */ if (pps_source[source].info == &dummy_info) return;
/* Must call the echo function? */ if ((pps_source[source].params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) pps_source[source].info->echo(source, event, data);
/* Check the event */ pps_source[source].current_mode = pps_source[source].params.mode; if (event & PPS_CAPTUREASSERT) { /* We have to add an offset? */ if (pps_source[source].params.mode & PPS_OFFSETASSERT) pps_add_offset(&ts, &pps_source[source].params.assert_off_tu);
/* Save the time stamp */ pps_source[source].assert_tu = ts; pps_source[source].assert_sequence++; pps_dbg("capture assert seq #%u for source %d", pps_source[source].assert_sequence, source); } if (event & PPS_CAPTURECLEAR) { /* We have to add an offset? */ if (pps_source[source].params.mode & PPS_OFFSETCLEAR) pps_add_offset(&ts, &pps_source[source].params.clear_off_tu);
/* Save the time stamp */ pps_source[source].clear_tu = ts; pps_source[source].clear_sequence++; pps_dbg("capture clear seq #%u for source %d", pps_source[source].clear_sequence, source); }
pps_source[source].go = ~0; wake_up_interruptible(&pps_source[source].queue); }
The problems should arise at:
if (pps_source[source].info == &dummy_info) return;
but as explained into the comment there should be no problems at all...
About "where" to put the "volatile" attribute I don't understand what you mean... such attribute is needed (IMHO) for "assert_sequence"&C, where should I put it? :-o > You've also reverted to structures which vary between 32-bit and 64-bit > userspace, because they use 'long' and 'struct timespec', but you > haven't provided the compat_* routines which are then necessary.
As already suggested I used fixed size variables. See the new struct "struct pps_ktime".
> +typedef int pps_handle_t; /* represents a PPS source */ > +typedef unsigned long pps_seq_t; /* sequence number */ > +typedef struct ntp_fp ntp_fp_t; /* NTP-compatible time stamp */ > +typedef union pps_timeu pps_timeu_t; /* generic data type to represent time s > tamps */ > +typedef struct pps_info pps_info_t; > +typedef struct pps_params pps_params_t; > > Don't do this for the structures. It's dubious enough for the integer > types.
Such code is for userland since RFC2783 requires such types... I moved all userland code into Documentation/pps/timepps.h which can be used by userland programs whose require RFC compatibility.
I'll post a new patch ASAP.
Ciao,
Rodolfo
--
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