Import sources from 2011-03-30 iso image

1 files changed, 108 insertions, 0 deletions

diff --git a/sys/src/cmd/aux/vga/tvp3026clock.c b/sys/src/cmd/aux/vga/tvp3026clock.c
new file mode 100755
index 000000000..787e6ae48
--- /dev/null
+++ b/sys/src/cmd/aux/vga/tvp3026clock.c
@@ -0,0 +1,108 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+#include "pci.h"
+#include "vga.h"
+
+#define SCALE(f)	((f)/10)		/* could be /10 */
+
+static void
+init(Vga* vga, Ctlr* ctlr)
+{
+	int f, k;
+	ulong fmin, fvco, m, n, p, q;
+	double z;
+
+	if(ctlr->flag & Finit)
+		return;
+
+	if(vga->f[0] == 0)
+		vga->f[0] = vga->mode->frequency;
+	vga->misc &= ~0x0C;
+	if(vga->f[0] == VgaFreq0){
+		/* nothing to do */;
+	}
+	else if(vga->f[0] == VgaFreq1)
+		vga->misc |= 0x04;
+	else
+		vga->misc |= 0x0C;
+
+	/*
+	 * Look for values of n, d and p that give
+	 * the least error for
+	 *	Fvco = 8*RefFreq*(65-m)/(65-n)
+	 *	Fpll = Fvco/2**p
+	 * N and m are 6 bits, p is 2 bits. Constraints:
+	 *	110MHz <= Fvco <= 250MHz
+	 *	40 <= n <= 62
+	 *	 1 <= m <= 62
+	 *	 0 <= p <=  3
+	 * Should try to minimise n, m.
+	 *
+	 * There's nothing like brute force and ignorance.
+	 */
+	fmin = vga->f[0];
+	vga->m[0] = 0x15;
+	vga->n[0] = 0x18;
+	vga->p[0] = 3;
+	for(m = 62; m > 0; m--){
+		for(n = 62; n >= 40; n--){
+			fvco = 8*SCALE(RefFreq)*(65-m)/(65-n);
+			if(fvco < SCALE(110000000) || fvco > SCALE(250000000))
+				continue;
+			for(p = 0; p < 4; p++){
+				f = SCALE(vga->f[0]) - (fvco>>p);
+				if(f < 0)
+					f = -f;
+				if(f < fmin){
+					fmin = f;
+					vga->m[0] = m;
+					vga->n[0] = n;
+					vga->p[0] = p;
+				}
+			}
+		}
+	}
+
+	/*
+	 * Now the loop clock:
+	 * 	m is fixed;
+	 *	calculate n;
+	 *	set z to the lower bound (110MHz) and calculate p and q.
+	 */
+	vga->m[1] = 61;
+	if(ctlr->flag & Uenhanced)
+		k = 64/8;
+	else
+		k = 8/8;
+	n = 65 - 4*k;
+	fvco = (8*RefFreq*(65-vga->m[0]))/(65-vga->n[0]);
+	vga->f[1] = fvco;
+	z = 110.0*(65-n)/(4*(fvco/1000000.0)*k);
+	if(z <= 16){
+		for(p = 0; p < 4; p++){
+			if(1<<(p+1) > z)
+				break;
+		}
+		q = 0;
+	}
+	else{
+		p = 3;
+		q = (z - 16)/16 + 1;
+	}
+	vga->n[1] = n;
+	vga->p[1] = p;
+	vga->q[1] = q;
+
+	ctlr->flag |= Finit;
+}
+
+Ctlr tvp3026clock = {
+	"tvp3026clock",			/* name */
+	0,				/* snarf */
+	0,				/* options */
+	init,				/* init */
+	0,				/* load */
+	0,				/* dump */
+};