lynxpoint: Enable extra 16 IOAPIC entries for GPIO PIRQ

LynxPoint-LP has an additional 16 entries in the IOAPIC that
can be assigned to specific GPIOs when they are configured
as PIRQ.

The maximum redirection entries field in the IOAPIC needs to
be set to 0x27 when this is enabled.

Additionally specific GPIOs need to be routed to PIRQ so they
interrupt via the IOAPIC instead of the GPIO IRQ 14/15.

Change-Id: Ie587e1d203422ff6fb7fc5056d20a5ae66720991
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/56620
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/4203
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

3 files changed, 54 insertions, 0 deletions

diff --git a/src/southbridge/intel/lynxpoint/lp_gpio.c b/src/southbridge/intel/lynxpoint/lp_gpio.c
index b90e5ba4b8..7d1a28d73c 100644
--- a/src/southbridge/intel/lynxpoint/lp_gpio.c
+++ b/src/southbridge/intel/lynxpoint/lp_gpio.c
@@ -36,6 +36,35 @@ static u16 get_gpio_base(void)
 #endif
 }
 
+
+/*
+ * This function will return a number that indicates which PIRQ
+ * this GPIO maps to.  If this is not a PIRQ capable GPIO then
+ * it will return -1.  The GPIO to PIRQ mapping is not linear.
+ */
+static int lp_gpio_to_pirq(int gpio)
+{
+	switch (gpio) {
+	case 8:  return 0;	/* PIRQI */
+	case 9:  return 1;	/* PIRQJ */
+	case 10: return 2;	/* PIRQK */
+	case 13: return 3;	/* PIRQL */
+	case 14: return 4;	/* PIRQM */
+	case 45: return 5;	/* PIRQN */
+	case 46: return 6;	/* PIRQO */
+	case 47: return 7;	/* PIRQP */
+	case 48: return 8;	/* PIRQQ */
+	case 49: return 9;	/* PIRQR */
+	case 50: return 10;	/* PIRQS */
+	case 51: return 11;	/* PIRQT */
+	case 52: return 12;	/* PIRQU */
+	case 53: return 13;	/* PIRQV */
+	case 54: return 14;	/* PIRQW */
+	case 55: return 15;	/* PIRQX */
+	default: return -1;
+	};
+}
+
 void setup_pch_lp_gpios(const struct pch_lp_gpio_map map[])
 {
 	u16 gpio_base = get_gpio_base();
@@ -45,6 +74,7 @@ void setup_pch_lp_gpios(const struct pch_lp_gpio_map map[])
 	u32 irqen[3] = {0};
 	u32 reset[3] = {0};
 	u32 blink = 0;
+	u16 pirq2apic = 0;
 	int set, bit, gpio = 0;
 
 	for (config = map; config->conf0 != GPIO_LIST_END; config++, gpio++) {
@@ -67,6 +97,13 @@ void setup_pch_lp_gpios(const struct pch_lp_gpio_map map[])
 
 		if (set == 0)
 			blink |= config->blink << bit;
+
+		/* PIRQ to IO-APIC map */
+		if (config->pirq == GPIO_PIRQ_APIC_ROUTE) {
+			set = lp_gpio_to_pirq(gpio);
+			if (set >= 0)
+				pirq2apic |= 1 << set;
+		}
 	}
 
 	for (set = 0; set <= 2; set++) {
@@ -77,6 +114,7 @@ void setup_pch_lp_gpios(const struct pch_lp_gpio_map map[])
 	}
 
 	outl(blink, gpio_base + GPIO_BLINK);
+	outl(pirq2apic, gpio_base + GPIO_PIRQ_APIC_EN);
 }
 
 int get_gpio(int gpio_num)
diff --git a/src/southbridge/intel/lynxpoint/lp_gpio.h b/src/southbridge/intel/lynxpoint/lp_gpio.h
index d9927dc975..f1b2717423 100644
--- a/src/southbridge/intel/lynxpoint/lp_gpio.h
+++ b/src/southbridge/intel/lynxpoint/lp_gpio.h
@@ -93,6 +93,11 @@
 #define GPIO_RESET_PWROK	0
 #define GPIO_RESET_RSMRST	1
 
+/* pirq route to io-apic */
+
+#define GPIO_PIRQ_APIC_MASK	0
+#define GPIO_PIRQ_APIC_ROUTE	1
+
 #define LP_GPIO_END \
 	{ .conf0 = GPIO_LIST_END }
 
@@ -128,6 +133,11 @@
 	  .owner = GPIO_OWNER_GPIO, \
 	  .irqen = GPIO_IRQ_ENABLE }
 
+#define LP_GPIO_PIRQ \
+	{ .conf0 = GPIO_MODE_GPIO | GPIO_DIR_INPUT, \
+	  .owner = GPIO_OWNER_GPIO, \
+	  .pirq  = GPIO_PIRQ_APIC_ROUTE }
+
 #define LP_GPIO_OUT_HIGH \
 	{ .conf0 = GPIO_MODE_GPIO | GPIO_DIR_OUTPUT | GPO_LEVEL_HIGH, \
 	  .owner = GPIO_OWNER_GPIO, \
@@ -147,6 +157,7 @@ struct pch_lp_gpio_map {
 	u8 irqen;
 	u8 reset;
 	u8 blink;
+	u8 pirq;
 } __attribute__ ((packed));
 
 /* Configure GPIOs with mainboard provided settings */
diff --git a/src/southbridge/intel/lynxpoint/lpc.c b/src/southbridge/intel/lynxpoint/lpc.c
index 33d74f1903..ff50476a62 100644
--- a/src/southbridge/intel/lynxpoint/lpc.c
+++ b/src/southbridge/intel/lynxpoint/lpc.c
@@ -59,6 +59,11 @@ static void pch_enable_ioapic(struct device *dev)
 
 	/* affirm full set of redirection table entries ("write once") */
 	reg32 = io_apic_read(IO_APIC_ADDR, 0x01);
+	if (pch_is_lp()) {
+		/* PCH-LP has 39 redirection entries */
+		reg32 &= ~0x00ff0000;
+		reg32 |= 0x00270000;
+	}
 	io_apic_write(IO_APIC_ADDR, 0x01, reg32);
 
 	/*