arch/x86/lib/pirq_routing.c

   1 /*
   2  * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
   3  *
   4  * Part of this file is ported from coreboot src/arch/x86/boot/pirq_routing.c
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <pci.h>
  11 #include <asm/pci.h>
  12 #include <asm/pirq_routing.h>
  13 #include <asm/tables.h>
  14
  15 static bool irq_already_routed[16];
  16
  17 static u8 pirq_get_next_free_irq(u8 *pirq, u16 bitmap)
  18 {
  19         int i, link;
  20         u8 irq = 0;
  21
  22         /* IRQ sharing starts from IRQ#3 */
  23         for (i = 3; i < 16; i++) {
  24                 /* Can we assign this IRQ? */
  25                 if (!((bitmap >> i) & 1))
  26                         continue;
  27
  28                 /* We can, now let's assume we can use this IRQ */
  29                 irq = i;
  30
  31                 /* Have we already routed it? */
  32                 if (irq_already_routed[irq])
  33                         continue;
  34
  35                 for (link = 0; link < CONFIG_MAX_PIRQ_LINKS; link++) {
  36                         if (pirq_check_irq_routed(link, irq)) {
  37                                 irq_already_routed[irq] = true;
  38                                 break;
  39                         }
  40                 }
  41
  42                 /* If it's not yet routed, use it */
  43                 if (!irq_already_routed[irq]) {
  44                         irq_already_routed[irq] = true;
  45                         break;
  46                 }
  47
  48                 /* But if it was already routed, try the next one */
  49         }
  50
  51         /* Now we get our IRQ */
  52         return irq;
  53 }
  54
  55 void pirq_route_irqs(struct irq_info *irq, int num)
  56 {
  57         unsigned char irq_slot[MAX_INTX_ENTRIES];
  58         unsigned char pirq[CONFIG_MAX_PIRQ_LINKS];
  59         int i, intx;
  60
  61         memset(pirq, 0, CONFIG_MAX_PIRQ_LINKS);
  62
  63         /* Set PCI IRQs */
  64         for (i = 0; i < num; i++) {
  65                 debug("PIRQ Entry %d Dev: %d.%x.%d\n", i,
  66                       irq->bus, irq->devfn >> 3, irq->devfn & 7);
  67
  68                 for (intx = 0; intx < MAX_INTX_ENTRIES; intx++) {
  69                         int link = irq->irq[intx].link;
  70                         int bitmap = irq->irq[intx].bitmap;
  71                         int irq = 0;
  72
  73                         debug("INT%c link: %x bitmap: %x ",
  74                               'A' + intx, link, bitmap);
  75
  76                         if (!bitmap || !link) {
  77                                 debug("not routed\n");
  78                                 irq_slot[intx] = irq;
  79                                 continue;
  80                         }
  81
  82                         /* translate link value to link number */
  83                         link = pirq_translate_link(link);
  84
  85                         /* yet not routed */
  86                         if (!pirq[link]) {
  87                                 irq = pirq_get_next_free_irq(pirq, bitmap);
  88                                 pirq[link] = irq;
  89                         } else {
  90                                 irq = pirq[link];
  91                         }
  92
  93                         debug("IRQ: %d\n", irq);
  94                         irq_slot[intx] = irq;
  95
  96                         /* Assign IRQ in the interrupt router */
  97                         pirq_assign_irq(link, irq);
  98                 }
  99
 100                 /* Bus, device, slots IRQs for {A,B,C,D} */
 101                 pci_assign_irqs(irq->bus, irq->devfn >> 3, irq->devfn & 7,
 102                                 irq_slot);
 103
 104                 irq++;
 105         }
 106
 107         for (i = 0; i < CONFIG_MAX_PIRQ_LINKS; i++)
 108                 debug("PIRQ%c: %d\n", 'A' + i, pirq[i]);
 109 }
 110
 111 u32 copy_pirq_routing_table(u32 addr, struct irq_routing_table *rt)
 112 {
 113         struct irq_routing_table *rom_rt;
 114
 115         /* Fix up the table checksum */
 116         rt->checksum = table_compute_checksum(rt, rt->size);
 117
 118         /* Align the table to be 16 byte aligned */
 119         addr = ALIGN(addr, 16);
 120
 121         debug("Copying Interrupt Routing Table to 0x%x\n", addr);
 122         memcpy((void *)addr, rt, rt->size);
 123
 124         /*
 125          * We do the sanity check here against the copied table after memcpy,
 126          * as something might go wrong after the memcpy, which is normally
 127          * due to the F segment decode is not turned on to systeam RAM.
 128          */
 129         rom_rt = (struct irq_routing_table *)addr;
 130         if (rom_rt->signature != PIRQ_SIGNATURE ||
 131             rom_rt->version != PIRQ_VERSION || rom_rt->size % 16) {
 132                 printf("Interrupt Routing Table not valid\n");
 133                 return addr;
 134         }
 135
 136         return addr + rt->size;
 137 }