x86: Support platform PIRQ routing
On x86 boards, platform chipset receives up to four different
interrupt signals from PCI devices (INTA/B/C/D), which in turn
will be routed to chipset internal PIRQ lines then routed to
8259 PIC finally if configuring the whole system to work under
the so-called PIC mode (in contrast to symmetric IO mode which
uses IOAPIC).
We add two major APIs to aid this, one for routing PIRQ and the
other one for generating a PIRQ routing table.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/lib/pirq_routing.c b/arch/x86/lib/pirq_routing.c
new file mode 100644
index 0000000..5a2591a
--- /dev/null
+++ b/arch/x86/lib/pirq_routing.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * Part of this file is ported from coreboot src/arch/x86/boot/pirq_routing.c
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <pci.h>
+#include <asm/pci.h>
+#include <asm/pirq_routing.h>
+#include <asm/tables.h>
+
+static bool irq_already_routed[16];
+
+static u8 pirq_get_next_free_irq(u8 *pirq, u16 bitmap)
+{
+ int i, link;
+ u8 irq = 0;
+
+ /* IRQ sharing starts from IRQ#3 */
+ for (i = 3; i < 16; i++) {
+ /* Can we assign this IRQ? */
+ if (!((bitmap >> i) & 1))
+ continue;
+
+ /* We can, now let's assume we can use this IRQ */
+ irq = i;
+
+ /* Have we already routed it? */
+ if (irq_already_routed[irq])
+ continue;
+
+ for (link = 0; link < CONFIG_MAX_PIRQ_LINKS; link++) {
+ if (pirq_check_irq_routed(link, irq)) {
+ irq_already_routed[irq] = true;
+ break;
+ }
+ }
+
+ /* If it's not yet routed, use it */
+ if (!irq_already_routed[irq]) {
+ irq_already_routed[irq] = true;
+ break;
+ }
+
+ /* But if it was already routed, try the next one */
+ }
+
+ /* Now we get our IRQ */
+ return irq;
+}
+
+void pirq_route_irqs(struct irq_info *irq, int num)
+{
+ unsigned char irq_slot[MAX_INTX_ENTRIES];
+ unsigned char pirq[CONFIG_MAX_PIRQ_LINKS];
+ int i, intx;
+
+ memset(pirq, 0, CONFIG_MAX_PIRQ_LINKS);
+
+ /* Set PCI IRQs */
+ for (i = 0; i < num; i++) {
+ debug("PIRQ Entry %d Dev: %d.%x.%d\n", i,
+ irq->bus, irq->devfn >> 3, irq->devfn & 7);
+
+ for (intx = 0; intx < MAX_INTX_ENTRIES; intx++) {
+ int link = irq->irq[intx].link;
+ int bitmap = irq->irq[intx].bitmap;
+ int irq = 0;
+
+ debug("INT%c link: %x bitmap: %x ",
+ 'A' + intx, link, bitmap);
+
+ if (!bitmap || !link) {
+ debug("not routed\n");
+ irq_slot[intx] = irq;
+ continue;
+ }
+
+ /* translate link value to link number */
+ link = pirq_translate_link(link);
+
+ /* yet not routed */
+ if (!pirq[link]) {
+ irq = pirq_get_next_free_irq(pirq, bitmap);
+ pirq[link] = irq;
+ } else {
+ irq = pirq[link];
+ }
+
+ debug("IRQ: %d\n", irq);
+ irq_slot[intx] = irq;
+
+ /* Assign IRQ in the interrupt router */
+ pirq_assign_irq(link, irq);
+ }
+
+ /* Bus, device, slots IRQs for {A,B,C,D} */
+ pci_assign_irqs(irq->bus, irq->devfn >> 3, irq->devfn & 7,
+ irq_slot);
+
+ irq++;
+ }
+
+ for (i = 0; i < CONFIG_MAX_PIRQ_LINKS; i++)
+ debug("PIRQ%c: %d\n", 'A' + i, pirq[i]);
+}
+
+u32 copy_pirq_routing_table(u32 addr, struct irq_routing_table *rt)
+{
+ if (rt->signature != PIRQ_SIGNATURE || rt->version != PIRQ_VERSION ||
+ rt->size % 16) {
+ debug("Interrupt Routing Table not valid\n");
+ return addr;
+ }
+
+ /* Fix up the table checksum */
+ rt->checksum = table_compute_checksum(rt, rt->size);
+
+ /* Align the table to be 16 byte aligned */
+ addr = ALIGN(addr, 16);
+
+ debug("Copying Interrupt Routing Table to 0x%x\n", addr);
+ memcpy((void *)addr, rt, rt->size);
+
+ return addr + rt->size;
+}