ref: 5ff1d749f42b1c145d30248c3f157a2b5b5eaebe
parent: 65bf18d655db88faed69fdbc13a342500cef328a
author: glenda <glenda@kingship>
date: Sat Jun 8 21:49:29 EDT 2024
rtc fs
--- /dev/null
+++ b/rtc7940fs.c
@@ -1,0 +1,279 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+
+#define CTL "/dev/i2c1/i2c.6f.ctl"
+#define DATA "/dev/i2c1/i2c.6f.data"
+
+enum {+ /* registers */
+ Seconds= 0,
+ Minutes= 1,
+ Hours= 2,
+ Weekday= 3,
+ Mday= 4,
+ Month= 5,
+ Year= 6,
+ Nbcd= 7,
+
+ /* Hours register may be in 12-hour or 24-hour mode */
+ Twelvehr= 0x40,
+ Pm= 0x20,
+
+ Start= 0x80,
+ Vbaten= 0x08,
+};
+
+typedef struct Rtc Rtc;
+
+struct Rtc
+{+ int sec;
+ int min;
+ int hour;
+ int mday;
+ int mon;
+ int year;
+};
+
+#define SEC2MIN 60L
+#define SEC2HOUR (60L*SEC2MIN)
+#define SEC2DAY (24L*SEC2HOUR)
+
+/*
+ * days per month plus days/year
+ */
+static int dmsize[] =
+{+ 365, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+static int ldmsize[] =
+{+ 366, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+/*
+ * return the days/month for the given year
+ */
+static int*
+yrsize(int y)
+{+ if((y%4) == 0 && ((y%100) != 0 || (y%400) == 0))
+ return ldmsize;
+ else
+ return dmsize;
+}
+
+/*
+ * compute seconds since Jan 1 1970
+ */
+static ulong
+rtc2sec(Rtc *rtc)
+{+ ulong secs;
+ int i;
+ int *d2m;
+
+ secs = 0;
+
+ /*
+ * seconds per year
+ */
+ for(i = 1970; i < rtc->year; i++){+ d2m = yrsize(i);
+ secs += d2m[0] * SEC2DAY;
+ }
+
+ /*
+ * seconds per month
+ */
+ d2m = yrsize(rtc->year);
+ for(i = 1; i < rtc->mon; i++)
+ secs += d2m[i] * SEC2DAY;
+
+ secs += (rtc->mday-1) * SEC2DAY;
+ secs += rtc->hour * SEC2HOUR;
+ secs += rtc->min * SEC2MIN;
+ secs += rtc->sec;
+
+ return secs;
+}
+
+/*
+ * compute rtc from seconds since Jan 1 1970
+ */
+static void
+sec2rtc(ulong secs, Rtc *rtc)
+{+ int d;
+ long hms, day;
+ int *d2m;
+
+ /*
+ * break initial number into days
+ */
+ hms = secs % SEC2DAY;
+ day = secs / SEC2DAY;
+ if(hms < 0) {+ hms += SEC2DAY;
+ day -= 1;
+ }
+
+ /*
+ * generate hours:minutes:seconds
+ */
+ rtc->sec = hms % 60;
+ d = hms / 60;
+ rtc->min = d % 60;
+ d /= 60;
+ rtc->hour = d;
+
+ /*
+ * year number
+ */
+ if(day >= 0)
+ for(d = 1970; day >= *yrsize(d); d++)
+ day -= *yrsize(d);
+ else
+ for (d = 1970; day < 0; d--)
+ day += *yrsize(d-1);
+ rtc->year = d;
+
+ /*
+ * generate month
+ */
+ d2m = yrsize(rtc->year);
+ for(d = 1; day >= d2m[d]; d++)
+ day -= d2m[d];
+ rtc->mday = day + 1;
+ rtc->mon = d;
+
+ return;
+}
+
+void
+ctl(char *s)
+{+ int fd = open(CTL, OWRITE);
+ if (fd < 0)
+ sysfatal("open");+ write(fd, s, strlen(s));
+ close(fd);
+}
+
+static int
+bcd(int n)
+{+ return (n & 0xF) + (10 * (n >> 4));
+}
+
+void
+fsread(Req *r)
+{+ int fd;
+ uchar clk[Nbcd];
+ Rtc rtc;
+ char buf[256];
+ ulong t;
+
+ clk[0] = 0;
+
+ if ((int)(r->fid->file->aux) == 173) {+ fd = open(DATA, ORDWR);
+ if (fd < 0)
+ sysfatal("open");+ write(fd, clk, 1);
+ read(fd, clk, Nbcd);
+ close(fd);
+
+ rtc.sec = bcd(clk[Seconds] & 0x7F);
+ rtc.min = bcd(clk[Minutes] & 0x7F);
+ rtc.hour = bcd(clk[Hours] & 0x3F);
+ if(clk[Hours] & Twelvehr){+ rtc.hour = bcd(clk[Hours] & 0x1F);
+ if(clk[Hours] & Pm)
+ rtc.hour += 12;
+ }
+ rtc.mday = bcd(clk[Mday] & 0x3F);
+ rtc.mon = bcd(clk[Month] & 0x1F);
+ rtc.year = bcd(clk[Year]);
+
+ if(rtc.year < 70)
+ rtc.year += 2000;
+ else
+ rtc.year += 1900;
+
+ t = rtc2sec(&rtc);
+ snprint(buf, 256, "%12d", t);
+ readstr(r, buf);
+ respond(r, nil);
+ } else {+ respond(r, "Egreg");
+ }
+}
+
+#define PUTBCD(n,o) bcdclock[1+o] = (n % 10) | (((n / 10) % 10)<<4)
+
+void
+fswrite(Req *r)
+{+ Rtc rtc;
+ ulong secs;
+ uchar bcdclock[1+Nbcd];
+ char *p, *ep;
+ int fd;
+
+ if ((int)(r->fid->file->aux) == 173) {+ p = r->ifcall.data;
+ ep = p + r->ifcall.count;
+
+ while(p < ep)
+ if (*p >= '0' && *p <= '9')
+ break;
+ else
+ p++;
+
+ secs = strtoul(p, 0, 0);
+ sec2rtc(secs, &rtc);
+ PUTBCD(rtc.sec, Seconds);
+ PUTBCD(rtc.min, Minutes); /* forces 24 hour mode */
+ PUTBCD(rtc.hour, Hours);
+ PUTBCD(0, Weekday); /* hope no other OS uses this */
+ PUTBCD(rtc.mday, Mday);
+ PUTBCD(rtc.mon, Month);
+ PUTBCD(rtc.year, Year);
+
+ bcdclock[0] = 0;
+
+ bcdclock[1+Seconds] |= Start;
+ bcdclock[1+Weekday] |= Vbaten;
+
+ fd = open(DATA, OWRITE);
+ if (fd < 0)
+ sysfatal("open");+ write(fd, bcdclock, 1+Nbcd);
+ close(fd);
+
+ respond(r, nil);
+ } else {+ respond(r, "Egreg");
+ }
+}
+
+Srv fs = {+.read = fsread,
+.write = fswrite,
+};
+
+void
+main()
+{+ ctl("size 10");+ ctl("subaddress 0");+
+ fs.tree = alloctree("rtcfs", "rtcfs", DMDIR|0555, nil);+ createfile(fs.tree->root, "rtc", "rtcfs", 0666, (void*)173);
+ postmountsrv(&fs, nil, "/dev", MBEFORE);
+}