x86: irq: Support discrete PIRQ routing registers via device tree

Currently both pirq_reg_to_linkno() and pirq_linkno_to_reg() assume
consecutive PIRQ routing control registers. But this is not always
the case on some platforms. Introduce a new device tree property
intel,pirq-regmap to describe how the PIRQ routing register offset
is mapped to the link number and adjust the irq router driver to
utilize the mapping.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/irq.c

@@ -16,18 +16,75 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+/**
+ * pirq_reg_to_linkno() - Convert a PIRQ routing register offset to link number
+ *
+ * @priv:	IRQ router driver's priv data
+ * @reg:	PIRQ routing register offset from the base address
+ * @return:	PIRQ link number (0 for PIRQA, 1 for PIRQB, etc)
+ */
+static inline int pirq_reg_to_linkno(struct irq_router *priv, int reg)
+{
+	int linkno = 0;
+
+	if (priv->has_regmap) {
+		struct pirq_regmap *map = priv->regmap;
+		int i;
+
+		for (i = 0; i < priv->link_num; i++) {
+			if (reg - priv->link_base == map->offset) {
+				linkno = map->link;
+				break;
+			}
+			map++;
+		}
+	} else {
+		linkno = reg - priv->link_base;
+	}
+
+	return linkno;
+}
+
+/**
+ * pirq_linkno_to_reg() - Convert a PIRQ link number to routing register offset
+ *
+ * @priv:	IRQ router driver's priv data
+ * @linkno:	PIRQ link number (0 for PIRQA, 1 for PIRQB, etc)
+ * @return:	PIRQ routing register offset from the base address
+ */
+static inline int pirq_linkno_to_reg(struct irq_router *priv, int linkno)
+{
+	int reg = 0;
+
+	if (priv->has_regmap) {
+		struct pirq_regmap *map = priv->regmap;
+		int i;
+
+		for (i = 0; i < priv->link_num; i++) {
+			if (linkno == map->link) {
+				reg = map->offset + priv->link_base;
+				break;
+			}
+			map++;
+		}
+	} else {
+		reg = linkno + priv->link_base;
+	}
+
+	return reg;
+}
+
 bool pirq_check_irq_routed(struct udevice *dev, int link, u8 irq)
 {
 	struct irq_router *priv = dev_get_priv(dev);
 	u8 pirq;
-	int base = priv->link_base;
 
 	if (priv->config == PIRQ_VIA_PCI)
 		dm_pci_read_config8(dev->parent,
-				    pirq_linkno_to_reg(link, base), &pirq);
+				    pirq_linkno_to_reg(priv, link), &pirq);
 	else
 		pirq = readb((uintptr_t)priv->ibase +
-			     pirq_linkno_to_reg(link, base));
+			     pirq_linkno_to_reg(priv, link));
 
 	pirq &= 0xf;
 
@@ -42,13 +99,12 @@ int pirq_translate_link(struct udevice *dev, int link)
 {
 	struct irq_router *priv = dev_get_priv(dev);
 
-	return pirq_reg_to_linkno(link, priv->link_base);
+	return pirq_reg_to_linkno(priv, link);
 }
 
 void pirq_assign_irq(struct udevice *dev, int link, u8 irq)
 {
 	struct irq_router *priv = dev_get_priv(dev);
-	int base = priv->link_base;
 
 	/* IRQ# 0/1/2/8/13 are reserved */
 	if (irq < 3 || irq == 8 || irq == 13)
@@ -56,10 +112,10 @@ void pirq_assign_irq(struct udevice *dev, int link, u8 irq)
 
 	if (priv->config == PIRQ_VIA_PCI)
 		dm_pci_write_config8(dev->parent,
-				     pirq_linkno_to_reg(link, base), irq);
+				     pirq_linkno_to_reg(priv, link), irq);
 	else
 		writeb(irq, (uintptr_t)priv->ibase +
-		       pirq_linkno_to_reg(link, base));
+		       pirq_linkno_to_reg(priv, link));
 }
 
 static struct irq_info *check_dup_entry(struct irq_info *slot_base,
@@ -82,7 +138,7 @@ static inline void fill_irq_info(struct irq_router *priv, struct irq_info *slot,
 {
 	slot->bus = bus;
 	slot->devfn = (device << 3) | 0;
-	slot->irq[pin - 1].link = pirq_linkno_to_reg(pirq, priv->link_base);
+	slot->irq[pin - 1].link = pirq_linkno_to_reg(priv, pirq);
 	slot->irq[pin - 1].bitmap = priv->irq_mask;
 }
 
@@ -93,6 +149,7 @@ static int create_pirq_routing_table(struct udevice *dev)
 	int node;
 	int len, count;
 	const u32 *cell;
+	struct pirq_regmap *map;
 	struct irq_routing_table *rt;
 	struct irq_info *slot, *slot_base;
 	int irq_entries = 0;
@@ -127,6 +184,33 @@ static int create_pirq_routing_table(struct udevice *dev)
 		priv->link_num = CONFIG_MAX_PIRQ_LINKS;
 	}
 
+	cell = fdt_getprop(blob, node, "intel,pirq-regmap", &len);
+	if (cell) {
+		if (len % sizeof(struct pirq_regmap))
+			return -EINVAL;
+
+		count = len / sizeof(struct pirq_regmap);
+		if (count < priv->link_num) {
+			printf("Number of pirq-regmap entires is wrong\n");
+			return -EINVAL;
+		}
+
+		count = priv->link_num;
+		priv->regmap = calloc(count, sizeof(struct pirq_regmap));
+		if (!priv->regmap)
+			return -ENOMEM;
+
+		priv->has_regmap = true;
+		map = priv->regmap;
+		for (i = 0; i < count; i++) {
+			map->link = fdt_addr_to_cpu(cell[0]);
+			map->offset = fdt_addr_to_cpu(cell[1]);
+
+			cell += sizeof(struct pirq_regmap) / sizeof(u32);
+			map++;
+		}
+	}
+
 	priv->irq_mask = fdtdec_get_int(blob, node,
 					"intel,pirq-mask", PIRQ_BITMAP);
 
@@ -209,7 +293,7 @@ static int create_pirq_routing_table(struct udevice *dev)
 				 * routing information in the device tree.
 				 */
 				if (slot->irq[pr.pin - 1].link !=
-				    pirq_linkno_to_reg(pr.pirq, priv->link_base))
+				    pirq_linkno_to_reg(priv, pr.pirq))
 					debug("WARNING: Inconsistent PIRQ routing information\n");
 				continue;
 			}

arch/x86/include/asm/irq.h

@@ -22,6 +22,11 @@ enum pirq_config {
 	PIRQ_VIA_IBASE
 };
 
+struct pirq_regmap {
+	int link;
+	int offset;
+};
+
 /**
  * Intel interrupt router control block
  *
@@ -30,6 +35,7 @@ enum pirq_config {
  * @config:	PIRQ_VIA_PCI or PIRQ_VIA_IBASE
  * @link_base:	link value base number
  * @link_num:	number of PIRQ links supported
+ * @has_regmap:	has mapping table between PIRQ link and routing register offset
  * @irq_mask:	IRQ mask reprenting the 16 IRQs in 8259, bit N is 1 means
  *		IRQ N is available to be routed
  * @lb_bdf:	irq router's PCI bus/device/function number encoding
@@ -41,6 +47,8 @@ struct irq_router {
 	int config;
 	u32 link_base;
 	int link_num;
+	bool has_regmap;
+	struct pirq_regmap *regmap;
 	u16 irq_mask;
 	u32 bdf;
 	u32 ibase;
@@ -54,30 +62,6 @@ struct pirq_routing {
 	int pirq;
 };
 
-/**
- * pirq_reg_to_linkno() - Convert a PIRQ routing register offset to link number
- *
- * @reg:	PIRQ routing register offset from the base address
- * @base:	PIRQ routing register block base address
- * @return:	PIRQ link number (0 for PIRQA, 1 for PIRQB, etc)
- */
-static inline int pirq_reg_to_linkno(int reg, int base)
-{
-	return reg - base;
-}
-
-/**
- * pirq_linkno_to_reg() - Convert a PIRQ link number to routing register offset
- *
- * @linkno:	PIRQ link number (0 for PIRQA, 1 for PIRQB, etc)
- * @base:	PIRQ routing register block base address
- * @return:	PIRQ routing register offset from the base address
- */
-static inline int pirq_linkno_to_reg(int linkno, int base)
-{
-	return linkno + base;
-}
-
 #define PIRQ_BITMAP		0xdef8
 
 #endif /* _ARCH_IRQ_H_ */

doc/device-tree-bindings/misc/intel,irq-router.txt

@@ -22,6 +22,12 @@ Required properties :
 - intel,pirq-link : Specifies the PIRQ link information with two cells. The
     first cell is the register offset that controls the first PIRQ link routing.
     The second cell is the total number of PIRQ links the router supports.
+- intel,pirq-regmap : Specifies PIRQ routing register offset of all PIRQ links,
+    encoded as 2 cells a group for each link. The first cell is the PIRQ link
+    number (0 for PIRQA, 1 for PIRQB, etc). The second cell is the PIRQ routing
+    register offset from the interrupt router's base address. If this property
+    is omitted, it indicates a consecutive register offset from the first PIRQ
+    link, as specified by the first cell of intel,pirq-link.
 - intel,pirq-mask : Specifies the IRQ mask representing the 16 IRQs in the
     8259 PIC. Bit N is 1 means IRQ N is available to be routed.
 - intel,pirq-routing : Specifies all PCI devices' IRQ routing information,