viafb: allow some pll calculations

This patch allows calculating the pll multiplier within limits based
on the previous table. All available information supports that it
should be possible/sane to choose the multiplier free within some
ranges.
Storing the multiplier ranges instead of lots of pll configurations
reduces the memory needed and may as well improve the performance.
It is also expected to provide better pll values resulting in better
frequencies for the connected devices.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

drivers/video/via/hw.c

@@ -22,272 +22,80 @@
 #include <linux/via-core.h>
 #include "global.h"
 
-static struct pll_config cle266_pll_config[] = {
-	{19, 4, 0},
-	{26, 5, 0},
-	{28, 5, 0},
-	{31, 5, 0},
-	{33, 5, 0},
-	{55, 5, 0},
-	{102, 5, 0},
-	{53, 6, 0},
-	{92, 6, 0},
-	{98, 6, 0},
-	{112, 6, 0},
-	{41, 7, 0},
-	{60, 7, 0},
-	{99, 7, 0},
-	{100, 7, 0},
-	{83, 8, 0},
-	{86, 8, 0},
-	{108, 8, 0},
-	{87, 9, 0},
-	{118, 9, 0},
-	{95, 12, 0},
-	{115, 12, 0},
-	{108, 13, 0},
-	{83, 17, 0},
-	{67, 20, 0},
-	{86, 20, 0},
-	{98, 20, 0},
-	{121, 24, 0},
-	{99, 29, 0},
-	{33, 3, 1},
-	{15, 4, 1},
-	{23, 4, 1},
-	{37, 5, 1},
-	{83, 5, 1},
-	{85, 5, 1},
-	{94, 5, 1},
-	{103, 5, 1},
-	{109, 5, 1},
-	{113, 5, 1},
-	{121, 5, 1},
-	{82, 6, 1},
-	{31, 7, 1},
-	{55, 7, 1},
-	{84, 7, 1},
-	{83, 8, 1},
-	{76, 9, 1},
-	{127, 9, 1},
-	{33, 4, 2},
-	{75, 4, 2},
-	{119, 4, 2},
-	{121, 4, 2},
-	{91, 5, 2},
-	{118, 5, 2},
-	{83, 6, 2},
-	{109, 6, 2},
-	{90, 7, 2},
-	{93, 2, 3},
-	{53, 3, 3},
-	{73, 4, 3},
-	{89, 4, 3},
-	{105, 4, 3},
-	{117, 4, 3},
-	{101, 5, 3},
-	{121, 5, 3},
-	{127, 5, 3},
-	{99, 7, 3}
+static struct pll_limit cle266_pll_limits[] = {
+	{19, 19, 4, 0},
+	{26, 102, 5, 0},
+	{53, 112, 6, 0},
+	{41, 100, 7, 0},
+	{83, 108, 8, 0},
+	{87, 118, 9, 0},
+	{95, 115, 12, 0},
+	{108, 108, 13, 0},
+	{83, 83, 17, 0},
+	{67, 98, 20, 0},
+	{121, 121, 24, 0},
+	{99, 99, 29, 0},
+	{33, 33, 3, 1},
+	{15, 23, 4, 1},
+	{37, 121, 5, 1},
+	{82, 82, 6, 1},
+	{31, 84, 7, 1},
+	{83, 83, 8, 1},
+	{76, 127, 9, 1},
+	{33, 121, 4, 2},
+	{91, 118, 5, 2},
+	{83, 109, 6, 2},
+	{90, 90, 7, 2},
+	{93, 93, 2, 3},
+	{53, 53, 3, 3},
+	{73, 117, 4, 3},
+	{101, 127, 5, 3},
+	{99, 99, 7, 3}
 };
 
-static struct pll_config k800_pll_config[] = {
-	{22, 2, 0},
-	{28, 3, 0},
-	{81, 3, 1},
-	{85, 3, 1},
-	{98, 3, 1},
-	{112, 3, 1},
-	{86, 4, 1},
-	{166, 4, 1},
-	{109, 5, 1},
-	{113, 5, 1},
-	{121, 5, 1},
-	{131, 5, 1},
-	{143, 5, 1},
-	{153, 5, 1},
-	{66, 3, 2},
-	{68, 3, 2},
-	{95, 3, 2},
-	{106, 3, 2},
-	{116, 3, 2},
-	{93, 4, 2},
-	{119, 4, 2},
-	{121, 4, 2},
-	{133, 4, 2},
-	{137, 4, 2},
-	{117, 5, 2},
-	{118, 5, 2},
-	{120, 5, 2},
-	{124, 5, 2},
-	{132, 5, 2},
-	{137, 5, 2},
-	{141, 5, 2},
-	{166, 5, 2},
-	{170, 5, 2},
-	{191, 5, 2},
-	{206, 5, 2},
-	{208, 5, 2},
-	{30, 2, 3},
-	{69, 3, 3},
-	{82, 3, 3},
-	{83, 3, 3},
-	{109, 3, 3},
-	{114, 3, 3},
-	{125, 3, 3},
-	{89, 4, 3},
-	{103, 4, 3},
-	{117, 4, 3},
-	{126, 4, 3},
-	{150, 4, 3},
-	{161, 4, 3},
-	{121, 5, 3},
-	{127, 5, 3},
-	{131, 5, 3},
-	{134, 5, 3},
-	{148, 5, 3},
-	{169, 5, 3},
-	{172, 5, 3},
-	{182, 5, 3},
-	{195, 5, 3},
-	{196, 5, 3},
-	{208, 5, 3},
-	{66, 2, 4},
-	{85, 3, 4},
-	{141, 4, 4},
-	{146, 4, 4},
-	{161, 4, 4},
-	{177, 5, 4}
+static struct pll_limit k800_pll_limits[] = {
+	{22, 22, 2, 0},
+	{28, 28, 3, 0},
+	{81, 112, 3, 1},
+	{86, 166, 4, 1},
+	{109, 153, 5, 1},
+	{66, 116, 3, 2},
+	{93, 137, 4, 2},
+	{117, 208, 5, 2},
+	{30, 30, 2, 3},
+	{69, 125, 3, 3},
+	{89, 161, 4, 3},
+	{121, 208, 5, 3},
+	{66, 66, 2, 4},
+	{85, 85, 3, 4},
+	{141, 161, 4, 4},
+	{177, 177, 5, 4}
 };
 
-static struct pll_config cx700_pll_config[] = {
-	{98, 3, 1},
-	{86, 4, 1},
-	{109, 5, 1},
-	{110, 5, 1},
-	{113, 5, 1},
-	{121, 5, 1},
-	{131, 5, 1},
-	{135, 5, 1},
-	{142, 5, 1},
-	{143, 5, 1},
-	{153, 5, 1},
-	{187, 5, 1},
-	{208, 5, 1},
-	{68, 2, 2},
-	{95, 3, 2},
-	{116, 3, 2},
-	{93, 4, 2},
-	{119, 4, 2},
-	{133, 4, 2},
-	{137, 4, 2},
-	{151, 4, 2},
-	{166, 4, 2},
-	{110, 5, 2},
-	{112, 5, 2},
-	{117, 5, 2},
-	{118, 5, 2},
-	{120, 5, 2},
-	{132, 5, 2},
-	{137, 5, 2},
-	{141, 5, 2},
-	{151, 5, 2},
-	{166, 5, 2},
-	{175, 5, 2},
-	{191, 5, 2},
-	{206, 5, 2},
-	{174, 7, 2},
-	{82, 3, 3},
-	{109, 3, 3},
-	{117, 4, 3},
-	{150, 4, 3},
-	{161, 4, 3},
-	{112, 5, 3},
-	{115, 5, 3},
-	{121, 5, 3},
-	{127, 5, 3},
-	{129, 5, 3},
-	{131, 5, 3},
-	{134, 5, 3},
-	{138, 5, 3},
-	{148, 5, 3},
-	{157, 5, 3},
-	{169, 5, 3},
-	{172, 5, 3},
-	{190, 5, 3},
-	{195, 5, 3},
-	{196, 5, 3},
-	{208, 5, 3},
-	{141, 5, 4},
-	{150, 5, 4},
-	{166, 5, 4},
-	{176, 5, 4},
-	{177, 5, 4},
-	{183, 5, 4},
-	{202, 5, 4}
+static struct pll_limit cx700_pll_limits[] = {
+	{98, 98, 3, 1},
+	{86, 86, 4, 1},
+	{109, 208, 5, 1},
+	{68, 68, 2, 2},
+	{95, 116, 3, 2},
+	{93, 166, 4, 2},
+	{110, 206, 5, 2},
+	{174, 174, 7, 2},
+	{82, 109, 3, 3},
+	{117, 161, 4, 3},
+	{112, 208, 5, 3},
+	{141, 202, 5, 4}
 };
 
-static struct pll_config vx855_pll_config[] = {
-	{86, 4, 1},
-	{108, 5, 1},
-	{110, 5, 1},
-	{113, 5, 1},
-	{121, 5, 1},
-	{131, 5, 1},
-	{135, 5, 1},
-	{142, 5, 1},
-	{143, 5, 1},
-	{153, 5, 1},
-	{164, 5, 1},
-	{187, 5, 1},
-	{208, 5, 1},
-	{110, 5, 2},
-	{112, 5, 2},
-	{117, 5, 2},
-	{118, 5, 2},
-	{124, 5, 2},
-	{132, 5, 2},
-	{137, 5, 2},
-	{141, 5, 2},
-	{149, 5, 2},
-	{151, 5, 2},
-	{159, 5, 2},
-	{166, 5, 2},
-	{167, 5, 2},
-	{172, 5, 2},
-	{189, 5, 2},
-	{191, 5, 2},
-	{194, 5, 2},
-	{206, 5, 2},
-	{208, 5, 2},
-	{83, 3, 3},
-	{88, 3, 3},
-	{109, 3, 3},
-	{112, 3, 3},
-	{103, 4, 3},
-	{105, 4, 3},
-	{161, 4, 3},
-	{112, 5, 3},
-	{115, 5, 3},
-	{121, 5, 3},
-	{127, 5, 3},
-	{134, 5, 3},
-	{137, 5, 3},
-	{148, 5, 3},
-	{157, 5, 3},
-	{169, 5, 3},
-	{172, 5, 3},
-	{182, 5, 3},
-	{191, 5, 3},
-	{195, 5, 3},
-	{209, 5, 3},
-	{142, 4, 4},
-	{146, 4, 4},
-	{161, 4, 4},
-	{141, 5, 4},
-	{150, 5, 4},
-	{165, 5, 4},
-	{176, 5, 4}
+static struct pll_limit vx855_pll_limits[] = {
+	{86, 86, 4, 1},
+	{108, 208, 5, 1},
+	{110, 208, 5, 2},
+	{83, 112, 3, 3},
+	{103, 161, 4, 3},
+	{112, 209, 5, 3},
+	{142, 161, 4, 4},
+	{141, 176, 5, 4}
 };
 
 /* according to VIA Technologies these values are based on experiment */
@@ -1633,17 +1441,34 @@ static inline u32 get_pll_output_frequency(u32 ref_freq, struct pll_config pll)
 	return get_pll_internal_frequency(ref_freq, pll)>>pll.rshift;
 }
 
-static struct pll_config get_pll_config(struct pll_config *config, int size,
+static struct pll_config get_pll_config(struct pll_limit *limits, int size,
 	int clk)
 {
-	struct pll_config best = config[0];
+	struct pll_config cur, up, down, best = {0, 1, 0};
 	const u32 f0 = 14318180; /* X1 frequency */
-	int i;
-
-	for (i = 1; i < size; i++) {
-		if (abs(get_pll_output_frequency(f0, config[i]) - clk)
-			< abs(get_pll_output_frequency(f0, best) - clk))
-			best = config[i];
+	int i, f;
+
+	for (i = 0; i < size; i++) {
+		cur.rshift = limits[i].rshift;
+		cur.divisor = limits[i].divisor;
+		cur.multiplier = clk / ((f0 / cur.divisor)>>cur.rshift);
+		f = abs(get_pll_output_frequency(f0, cur) - clk);
+		up = down = cur;
+		up.multiplier++;
+		down.multiplier--;
+		if (abs(get_pll_output_frequency(f0, up) - clk) < f)
+			cur = up;
+		else if (abs(get_pll_output_frequency(f0, down) - clk) < f)
+			cur = down;
+
+		if (cur.multiplier < limits[i].multiplier_min)
+			cur.multiplier = limits[i].multiplier_min;
+		else if (cur.multiplier > limits[i].multiplier_max)
+			cur.multiplier = limits[i].multiplier_max;
+
+		f = abs(get_pll_output_frequency(f0, cur) - clk);
+		if (f < abs(get_pll_output_frequency(f0, best) - clk))
+			best = cur;
 	}
 
 	return best;
@@ -1656,14 +1481,14 @@ u32 viafb_get_clk_value(int clk)
 	switch (viaparinfo->chip_info->gfx_chip_name) {
 	case UNICHROME_CLE266:
 	case UNICHROME_K400:
-		value = cle266_encode_pll(get_pll_config(cle266_pll_config,
-			ARRAY_SIZE(cle266_pll_config), clk));
+		value = cle266_encode_pll(get_pll_config(cle266_pll_limits,
+			ARRAY_SIZE(cle266_pll_limits), clk));
 		break;
 	case UNICHROME_K800:
 	case UNICHROME_PM800:
 	case UNICHROME_CN700:
-		value = k800_encode_pll(get_pll_config(k800_pll_config,
-			ARRAY_SIZE(k800_pll_config), clk));
+		value = k800_encode_pll(get_pll_config(k800_pll_limits,
+			ARRAY_SIZE(k800_pll_limits), clk));
 		break;
 	case UNICHROME_CX700:
 	case UNICHROME_CN750:
@@ -1671,13 +1496,13 @@ u32 viafb_get_clk_value(int clk)
 	case UNICHROME_P4M890:
 	case UNICHROME_P4M900:
 	case UNICHROME_VX800:
-		value = k800_encode_pll(get_pll_config(cx700_pll_config,
-			ARRAY_SIZE(cx700_pll_config), clk));
+		value = k800_encode_pll(get_pll_config(cx700_pll_limits,
+			ARRAY_SIZE(cx700_pll_limits), clk));
 		break;
 	case UNICHROME_VX855:
 	case UNICHROME_VX900:
-		value = vx855_encode_pll(get_pll_config(vx855_pll_config,
-			ARRAY_SIZE(vx855_pll_config), clk));
+		value = vx855_encode_pll(get_pll_config(vx855_pll_limits,
+			ARRAY_SIZE(vx855_pll_limits), clk));
 		break;
 	}
 

drivers/video/via/hw.h

@@ -738,12 +738,11 @@ struct pll_config {
 	u8 rshift;
 };
 
-struct pll_map {
-	u32 clk;
-	struct pll_config cle266_pll;
-	struct pll_config k800_pll;
-	struct pll_config cx700_pll;
-	struct pll_config vx855_pll;
+struct pll_limit {
+	u16 multiplier_min;
+	u16 multiplier_max;
+	u8 divisor;
+	u8 rshift;
 };
 
 struct rgbLUT {