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(struct irq_data *data)
  27 {
  28         mask_msi_irq(data);
  29         mpic_mask_irq(data);
  30 }
  31
  32 static void mpic_u3msi_unmask_irq(struct irq_data *data)
  33 {
  34         mpic_unmask_irq(data);
  35         unmask_msi_irq(data);
  36 }
  37
  38 static struct irq_chip mpic_u3msi_chip = {
  39         .irq_shutdown           = mpic_u3msi_mask_irq,
  40         .irq_mask               = mpic_u3msi_mask_irq,
  41         .irq_unmask             = mpic_u3msi_unmask_irq,
  42         .irq_eoi                = mpic_end_irq,
  43         .irq_set_type           = mpic_set_irq_type,
  44         .irq_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         irq_hw_number_t hwirq;
 128
 129         list_for_each_entry(entry, &pdev->msi_list, list) {
 130                 if (entry->irq == NO_IRQ)
 131                         continue;
 132
 133                 hwirq = virq_to_hw(entry->irq);
 134                 irq_set_msi_desc(entry->irq, NULL);
 135                 irq_dispose_mapping(entry->irq);
 136                 msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
 137         }
 138
 139         return;
 140 }
 141
 142 static int u3msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 143 {
 144         unsigned int virq;
 145         struct msi_desc *entry;
 146         struct msi_msg msg;
 147         u64 addr;
 148         int hwirq;
 149
 150         list_for_each_entry(entry, &pdev->msi_list, list) {
 151                 hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap, 1);
 152                 if (hwirq < 0) {
 153                         pr_debug("u3msi: failed allocating hwirq\n");
 154                         return hwirq;
 155                 }
 156
 157                 addr = find_ht_magic_addr(pdev, hwirq);
 158                 if (addr == 0)
 159                         addr = find_u4_magic_addr(pdev, hwirq);
 160                 msg.address_lo = addr & 0xFFFFFFFF;
 161                 msg.address_hi = addr >> 32;
 162
 163                 virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
 164                 if (virq == NO_IRQ) {
 165                         pr_debug("u3msi: failed mapping hwirq 0x%x\n", hwirq);
 166                         msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
 167                         return -ENOSPC;
 168                 }
 169
 170                 irq_set_msi_desc(virq, entry);
 171                 irq_set_chip(virq, &mpic_u3msi_chip);
 172                 irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
 173
 174                 pr_debug("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
 175                           virq, hwirq, (unsigned long)addr);
 176
 177                 printk("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n",
 178                           virq, hwirq, (unsigned long)addr);
 179                 msg.data = hwirq;
 180                 write_msi_msg(virq, &msg);
 181
 182                 hwirq++;
 183         }
 184
 185         return 0;
 186 }
 187
 188 int mpic_u3msi_init(struct mpic *mpic)
 189 {
 190         int rc;
 191
 192         rc = mpic_msi_init_allocator(mpic);
 193         if (rc) {
 194                 pr_debug("u3msi: Error allocating bitmap!\n");
 195                 return rc;
 196         }
 197
 198         pr_debug("u3msi: Registering MPIC U3 MSI callbacks.\n");
 199
 200         BUG_ON(msi_mpic);
 201         msi_mpic = mpic;
 202
 203         WARN_ON(ppc_md.setup_msi_irqs);
 204         ppc_md.setup_msi_irqs = u3msi_setup_msi_irqs;
 205         ppc_md.teardown_msi_irqs = u3msi_teardown_msi_irqs;
 206         ppc_md.msi_check_device = u3msi_msi_check_device;
 207
 208         return 0;
 209 }