autoport/bd82x6x.go: Improve gpio.c generation

This generates better gpio.c files where structs are initialised as
static to be able to drop some entries since those would be
initialised as 0.
This makes these files less cluttered since only relevant things are
shown:
* GPIO direction, level, invert, blink depend on GPIO mode
* GPIO level is read only on input
* GPIO invert is only valid on input
* only show when GPIO are inverted, blinking, reset by RSMRST#

Change-Id: I83382d38a4a3b7ed11b8e7077cc5fbe154e261a7
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/19508
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/util/autoport/bd82x6x.go b/util/autoport/bd82x6x.go
index e23262c..ee7e207 100644
--- a/util/autoport/bd82x6x.go
+++ b/util/autoport/bd82x6x.go
@@ -11,7 +11,7 @@
 }
 
 func (b bd82x6x) writeGPIOSet(ctx Context, sb *os.File,
-	val uint32, set uint, partno int) {
+	val uint32, set uint, partno int, constraint uint32) {
 
 	max := uint(32)
 	if set == 3 {
@@ -28,22 +28,24 @@
 	}
 
 	for i := uint(0); i < max; i++ {
-		fmt.Fprintf(sb, "	.gpio%d = %s,\n",
-			(set-1)*32+i,
-			bits[partno][(val>>i)&1])
+		if ((constraint>>i)&1 == 1) {
+			fmt.Fprintf(sb, "	.gpio%d = %s,\n",
+				(set-1)*32+i,
+				bits[partno][(val>>i)&1])
+		}
 	}
 }
 
 func (b bd82x6x) GPIO(ctx Context, inteltool InteltoolData) {
+	var constraint uint32
 	gpio := Create(ctx, "gpio.c")
 	defer gpio.Close()
 
 	AddROMStageFile("gpio.c", "")
 
-	gpio.WriteString(`#include <southbridge/intel/common/gpio.h>
-`)
+	gpio.WriteString("#include <southbridge/intel/common/gpio.h>\n\n")
 
-	adresses := [3][6]int{
+	addresses := [3][6]int{
 		{0x00, 0x04, 0x0c, 0x60, 0x2c, 0x18},
 		{0x30, 0x34, 0x38, 0x64, -1, -1},
 		{0x40, 0x44, 0x48, 0x68, -1, -1},
@@ -51,14 +53,37 @@
 
 	for set := 1; set <= 3; set++ {
 		for partno, part := range []string{"mode", "direction", "level", "reset", "invert", "blink"} {
-			addr := adresses[set-1][partno]
+			addr := addresses[set-1][partno]
 			if addr < 0 {
 				continue
 			}
-			fmt.Fprintf(gpio, "const struct pch_gpio_set%d pch_gpio_set%d_%s = {\n",
+			fmt.Fprintf(gpio, "static const struct pch_gpio_set%d pch_gpio_set%d_%s = {\n",
 				set, set, part)
 
-			b.writeGPIOSet(ctx, gpio, inteltool.GPIO[uint16(addr)], uint(set), partno)
+			constraint = 0xffffffff
+			switch part {
+			case "direction":
+				/* Ignored on native mode */
+				constraint = inteltool.GPIO[uint16(addresses[set-1][0])]
+			case "level":
+				/* Level doesn't matter for input */
+				constraint = inteltool.GPIO[uint16(addresses[set-1][0])]
+				constraint &^= inteltool.GPIO[uint16(addresses[set-1][1])]
+			case "reset":
+				/* Only show reset */
+				constraint = inteltool.GPIO[uint16(addresses[set-1][3])]
+			case "invert":
+				/* Only on input and only show inverted GPIO */
+				constraint = inteltool.GPIO[uint16(addresses[set-1][0])]
+				constraint &= inteltool.GPIO[uint16(addresses[set-1][1])]
+				constraint &= inteltool.GPIO[uint16(addresses[set-1][4])]
+			case "blink":
+				/* Only on output and only show blinking GPIO */
+				constraint = inteltool.GPIO[uint16(addresses[set-1][0])]
+				constraint &^= inteltool.GPIO[uint16(addresses[set-1][1])]
+				constraint &= inteltool.GPIO[uint16(addresses[set-1][5])]
+			}
+			b.writeGPIOSet(ctx, gpio, inteltool.GPIO[uint16(addr)], uint(set), partno, constraint)
 			gpio.WriteString("};\n\n")
 		}
 	}