ACPI, PCI, irq: remove interrupt count restriction

Code currently supports 256 maximum interrupts at this moment. The patch is
reconfiguring the penalty array as a dynamic list to remove this
limitation.

A new penalty linklist has been added for all other interrupts greater than
16. If an IRQ is not found in the link list, an IRQ info structure will be
dynamically allocated on the first access and will be placed on the list
for further reuse. The list will grow by the number of supported interrupts
in the ACPI table rather than having a 256 hard limitation.
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/pci_link.c

@@ -4,6 +4,7 @@
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
+ *  Copyright (c) 2015, The Linux Foundation. All rights reserved.
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
@@ -437,7 +438,6 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
  * enabled system.
  */
 
-#define ACPI_MAX_IRQS		256
 #define ACPI_MAX_ISA_IRQ	16
 
 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
@@ -447,7 +447,7 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
 
-static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
+static int acpi_irq_isa_penalty[ACPI_MAX_ISA_IRQ] = {
 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
@@ -464,9 +464,68 @@ static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
 	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
 	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
-	/* >IRQ15 */
 };
 
+struct irq_penalty_info {
+	int irq;
+	int penalty;
+	struct list_head node;
+};
+
+static LIST_HEAD(acpi_irq_penalty_list);
+
+static int acpi_irq_get_penalty(int irq)
+{
+	struct irq_penalty_info *irq_info;
+
+	if (irq < ACPI_MAX_ISA_IRQ)
+		return acpi_irq_isa_penalty[irq];
+
+	list_for_each_entry(irq_info, &acpi_irq_penalty_list, node) {
+		if (irq_info->irq == irq)
+			return irq_info->penalty;
+	}
+
+	return 0;
+}
+
+static int acpi_irq_set_penalty(int irq, int new_penalty)
+{
+	struct irq_penalty_info *irq_info;
+
+	/* see if this is a ISA IRQ */
+	if (irq < ACPI_MAX_ISA_IRQ) {
+		acpi_irq_isa_penalty[irq] = new_penalty;
+		return 0;
+	}
+
+	/* next, try to locate from the dynamic list */
+	list_for_each_entry(irq_info, &acpi_irq_penalty_list, node) {
+		if (irq_info->irq == irq) {
+			irq_info->penalty  = new_penalty;
+			return 0;
+		}
+	}
+
+	/* nope, let's allocate a slot for this IRQ */
+	irq_info = kzalloc(sizeof(*irq_info), GFP_KERNEL);
+	if (!irq_info)
+		return -ENOMEM;
+
+	irq_info->irq = irq;
+	irq_info->penalty = new_penalty;
+	list_add_tail(&irq_info->node, &acpi_irq_penalty_list);
+
+	return 0;
+}
+
+static void acpi_irq_add_penalty(int irq, int penalty)
+{
+	int curpen = acpi_irq_get_penalty(irq);
+
+	acpi_irq_set_penalty(irq, curpen + penalty);
+}
+
 int __init acpi_irq_penalty_init(void)
 {
 	struct acpi_pci_link *link;
@@ -487,15 +546,16 @@ int __init acpi_irq_penalty_init(void)
 			    link->irq.possible_count;
 
 			for (i = 0; i < link->irq.possible_count; i++) {
-				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
-					acpi_irq_penalty[link->irq.
-							 possible[i]] +=
-					    penalty;
+				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ) {
+					int irqpos = link->irq.possible[i];
+
+					acpi_irq_add_penalty(irqpos, penalty);
+				}
 			}
 
 		} else if (link->irq.active) {
-			acpi_irq_penalty[link->irq.active] +=
-			    PIRQ_PENALTY_PCI_POSSIBLE;
+			acpi_irq_add_penalty(link->irq.active,
+					     PIRQ_PENALTY_PCI_POSSIBLE);
 		}
 	}
 
@@ -547,12 +607,12 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 		 * the use of IRQs 9, 10, 11, and >15.
 		 */
 		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
-			if (acpi_irq_penalty[irq] >
-			    acpi_irq_penalty[link->irq.possible[i]])
+			if (acpi_irq_get_penalty(irq) >
+			    acpi_irq_get_penalty(link->irq.possible[i]))
 				irq = link->irq.possible[i];
 		}
 	}
-	if (acpi_irq_penalty[irq] >= PIRQ_PENALTY_ISA_ALWAYS) {
+	if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
 		printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
 			    "Try pci=noacpi or acpi=off\n",
 			    acpi_device_name(link->device),
@@ -568,7 +628,8 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 			    acpi_device_bid(link->device));
 		return -ENODEV;
 	} else {
-		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
+		acpi_irq_add_penalty(link->irq.active, PIRQ_PENALTY_PCI_USING);
+
 		printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
 		       acpi_device_name(link->device),
 		       acpi_device_bid(link->device), link->irq.active);
@@ -778,7 +839,7 @@ static void acpi_pci_link_remove(struct acpi_device *device)
 }
 
 /*
- * modify acpi_irq_penalty[] from cmdline
+ * modify penalty from cmdline
  */
 static int __init acpi_irq_penalty_update(char *str, int used)
 {
@@ -796,13 +857,10 @@ static int __init acpi_irq_penalty_update(char *str, int used)
 		if (irq < 0)
 			continue;
 
-		if (irq >= ARRAY_SIZE(acpi_irq_penalty))
-			continue;
-
 		if (used)
-			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
+			acpi_irq_add_penalty(irq, PIRQ_PENALTY_ISA_USED);
 		else
-			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
+			acpi_irq_set_penalty(irq, PIRQ_PENALTY_PCI_AVAILABLE);
 
 		if (retval != 2)	/* no next number */
 			break;
@@ -819,18 +877,23 @@ static int __init acpi_irq_penalty_update(char *str, int used)
  */
 void acpi_penalize_isa_irq(int irq, int active)
 {
-	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
+	int penalty;
+
+	if (irq < 0)
+		return;
+
 	if (active)
-			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
+		penalty = PIRQ_PENALTY_ISA_USED;
 	else
-			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
-	}
+		penalty = PIRQ_PENALTY_PCI_USING;
+
+	acpi_irq_add_penalty(irq, penalty);
 }
 
 bool acpi_isa_irq_available(int irq)
 {
-	return irq >= 0 && (irq >= ARRAY_SIZE(acpi_irq_penalty) ||
-			    acpi_irq_penalty[irq] < PIRQ_PENALTY_ISA_ALWAYS);
+	return irq >= 0 &&
+		(acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
 }
 
 /*
@@ -840,13 +903,18 @@ bool acpi_isa_irq_available(int irq)
  */
 void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
 {
-	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
+	int penalty;
+
+	if (irq < 0)
+		return;
+
 	if (trigger != ACPI_MADT_TRIGGER_LEVEL ||
 	    polarity != ACPI_MADT_POLARITY_ACTIVE_LOW)
-			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_ALWAYS;
+		penalty = PIRQ_PENALTY_ISA_ALWAYS;
 	else
-			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
-	}
+		penalty = PIRQ_PENALTY_PCI_USING;
+
+	acpi_irq_add_penalty(irq, penalty);
 }
 
 /*