arch/powerpc/sysdev/mpic_u3msi.c

   1 /*
   2  * Copyright 2006, Segher Boessenkool, IBM Corporation.
   3  * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; version 2 of the
   8  * License.
   9  *
  10  */
  11
  12 #include <linux/irq.h>
  13 #include <linux/bootmem.h>
  14 #include <linux/msi.h>
  15 #include <asm/mpic.h>
  16 #include <asm/prom.h>
  17 #include <asm/hw_irq.h>
  18 #include <asm/ppc-pci.h>
  19 #include <asm/msi_bitmap.h>
  20
  21 #include "mpic.h"
  22
  23 /* A bit ugly, can we get this from the pci_dev somehow? */
  24 static struct mpic *msi_mpic;
  25
  26 static void mpic_u3msi_mask_irq(unsigned int irq)
  27 {
  28         mask_msi_irq(irq);
  29         mpic_mask_irq(irq);
  30 }
  31
  32 static void mpic_u3msi_unmask_irq(unsigned int irq)
  33 {
  34         mpic_unmask_irq(irq);
  35         unmask_msi_irq(irq);
  36 }
  37
  38 static struct irq_chip mpic_u3msi_chip = {
  39         .shutdown       = mpic_u3msi_mask_irq,
  40         .mask           = mpic_u3msi_mask_irq,
  41         .unmask         = mpic_u3msi_unmask_irq,
  42         .eoi            = mpic_end_irq,
  43         .set_type       = mpic_set_irq_type,
  44         .set_affinity   = mpic_set_affinity,
  45         .name           = "MPIC-U3MSI",
  46 };
  47
  48 static u64 read_ht_magic_addr(struct pci_dev *pdev, unsigned int pos)
  49 {
  50         u8 flags;
  51         u32 tmp;
  52         u64 addr;
  53
  54         pci_read_config_byte(pdev, pos + HT_MSI_FLAGS, &flags);
  55
  56         if (flags & HT_MSI_FLAGS_FIXED)
  57                 return HT_MSI_FIXED_ADDR;
  58
  59         pci_read_config_dword(pdev, pos + HT_MSI_ADDR_LO, &tmp);
  60         addr = tmp & HT_MSI_ADDR_LO_MASK;
  61         pci_read_config_dword(pdev, pos + HT_MSI_ADDR_HI, &tmp);
  62         addr = addr | ((u64)tmp << 32);
  63
  64         return addr;
  65 }
  66
  67 static u64 find_ht_magic_addr(struct pci_dev *pdev, unsigned int hwirq)
  68 {
  69         struct pci_bus *bus;
  70         unsigned int pos;
  71
  72         for (bus = pdev->bus; bus && bus->self; bus = bus->parent) {
  73                 pos = pci_find_ht_capability(bus->self, HT_CAPTYPE_MSI_MAPPING);
  74                 if (pos)
  75                         return read_ht_magic_addr(bus->self, pos);
  76         }
  77
  78         return 0;
  79 }
  80
  81 static u64 find_u4_magic_addr(struct pci_dev *pdev, unsigned int hwirq)
  82 {
  83         struct pci_controller *hose = pci_bus_to_host(pdev->bus);
  84
  85         /* U4 PCIe MSIs need to write to the special register in
  86          * the bridge that generates interrupts. There should be
  87          * theorically a register at 0xf8005000 where you just write
  88          * the MSI number and that triggers the right interrupt, but
  89          * unfortunately, this is busted in HW, the bridge endian swaps
  90          * the value and hits the wrong nibble in the register.
  91          *
  92          * So instead we use another register set which is used normally
  93          * for converting HT interrupts to MPIC interrupts, which decodes
  94          * the interrupt number as part of the low address bits
  95          *
  96          * This will not work if we ever use more than one legacy MSI in
  97          * a block but we never do. For one MSI or multiple MSI-X where
  98          * each interrupt address can be specified separately, it works
  99          * just fine.
 100          */
 101         if (of_device_is_compatible(hose->dn, "u4-pcie") ||
 102             of_device_is_compatible(hose->dn, "U4-pcie"))
 103                 return 0xf8004000 | (hwirq << 4);
 104
 105         return 0;
 106 }
 107
 108 static int u3msi_msi_check_device(struct pci_dev *pdev, int nvec, int type)
 109 {
 110         if (type == PCI_CAP_ID_MSIX)
 111                 pr_debug("u3msi: MSI-X untested, trying anyway.\n");
 112
 113         /* If we can't find a magic address then MSI ain't gonna work */
 114         if (find_ht_magic_addr(pdev, 0) == 0 &&
 115             find_u4_magic_addr(pdev, 0) == 0) {
 116                 pr_debug("u3msi: no magic address found for %s\n",
 117                          pci_name(pdev));
 118                 return -ENXIO;
 119         }
 120
 121         return 0;
 122 }
 123
 124 static void u3msi_teardown_msi_irqs(struct pci_dev *pdev)
 125 {
 126         struct msi_desc *entry;
 127
 128         list_for_each_entry(entry, &pdev->msi_list, list) {
 129                 if (entry->irq == NO_IRQ)
 130                         continue;
 131
 132                 set_irq_msi(entry->irq, NULL);
 133                 msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap,
 134                                        virq_to_hw(entry->irq), 1);
 135                 irq_dispose_mapping(entry->irq);
 136         }
 137
 138         return;
 139 }
 140
 141 static int u3msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 142 {
 143         unsigned int virq;
 144         struct msi_desc *entry;
 145         struct msi_msg msg;
 146         u64 addr;
 147         int hwirq;
 148
 149         list_for_each_entry(entry, &pdev->msi_list, list) {
 150                 hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap, 1);
 151                 if (hwirq < 0) {
 152                         pr_debug("u3msi: failed allocating hwirq\n");
 153                         return hwirq;
 154                 }
 155
 156                 addr = find_ht_magic_addr(pdev, hwirq);
 157                 if (addr == 0)
 158                         addr = find_u4_magic_addr(pdev, hwirq);
 159                 msg.address_lo = addr & 0xFFFFFFFF;
 160                 msg.address_hi = addr >> 32;
 161
 162                 virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
 163                 if (virq == NO_IRQ) {
 164                         pr_debug("u3msi: failed mapping hwirq 0x%x\n", hwirq);
 165                         msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
 166                         return -ENOSPC;
 167                 }
 168
 169                 set_irq_msi(virq, entry);
 170                 set_irq_chip(virq, &mpic_u3msi_chip);
 171                 set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
 172
 173                 pr_debug("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
 174                           virq, hwirq, (unsigned long)addr);
 175
 176                 printk("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
 177                           virq, hwirq, (unsigned long)addr);
 178                 msg.data = hwirq;
 179                 write_msi_msg(virq, &msg);
 180
 181                 hwirq++;
 182         }
 183
 184         return 0;
 185 }
 186
 187 int mpic_u3msi_init(struct mpic *mpic)
 188 {
 189         int rc;
 190
 191         rc = mpic_msi_init_allocator(mpic);
 192         if (rc) {
 193                 pr_debug("u3msi: Error allocating bitmap!\n");
 194                 return rc;
 195         }
 196
 197         pr_debug("u3msi: Registering MPIC U3 MSI callbacks.\n");
 198
 199         BUG_ON(msi_mpic);
 200         msi_mpic = mpic;
 201
 202         WARN_ON(ppc_md.setup_msi_irqs);
 203         ppc_md.setup_msi_irqs = u3msi_setup_msi_irqs;
 204         ppc_md.teardown_msi_irqs = u3msi_teardown_msi_irqs;
 205         ppc_md.msi_check_device = u3msi_msi_check_device;
 206
 207         return 0;
 208 }