arch/powerpc/platforms/pasemi/msi.c

   1 /*
   2  * Copyright 2007, Olof Johansson, PA Semi
   3  *
   4  * Based on arch/powerpc/sysdev/mpic_u3msi.c:
   5  *
   6  * Copyright 2006, Segher Boessenkool, IBM Corporation.
   7  * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; version 2 of the
  12  * License.
  13  *
  14  */
  15
  16 #include <linux/irq.h>
  17 #include <linux/msi.h>
  18 #include <asm/mpic.h>
  19 #include <asm/prom.h>
  20 #include <asm/hw_irq.h>
  21 #include <asm/ppc-pci.h>
  22 #include <asm/msi_bitmap.h>
  23
  24 #include <sysdev/mpic.h>
  25
  26 /* Allocate 16 interrupts per device, to give an alignment of 16,
  27  * since that's the size of the grouping w.r.t. affinity. If someone
  28  * needs more than 32 MSI's down the road we'll have to rethink this,
  29  * but it should be OK for now.
  30  */
  31 #define ALLOC_CHUNK 16
  32
  33 #define PASEMI_MSI_ADDR 0xfc080000
  34
  35 /* A bit ugly, can we get this from the pci_dev somehow? */
  36 static struct mpic *msi_mpic;
  37
  38
  39 static void mpic_pasemi_msi_mask_irq(struct irq_data *data)
  40 {
  41         pr_debug("mpic_pasemi_msi_mask_irq %d\n", data->irq);
  42         pci_msi_mask_irq(data);
  43         mpic_mask_irq(data);
  44 }
  45
  46 static void mpic_pasemi_msi_unmask_irq(struct irq_data *data)
  47 {
  48         pr_debug("mpic_pasemi_msi_unmask_irq %d\n", data->irq);
  49         mpic_unmask_irq(data);
  50         pci_msi_unmask_irq(data);
  51 }
  52
  53 static struct irq_chip mpic_pasemi_msi_chip = {
  54         .irq_shutdown           = mpic_pasemi_msi_mask_irq,
  55         .irq_mask               = mpic_pasemi_msi_mask_irq,
  56         .irq_unmask             = mpic_pasemi_msi_unmask_irq,
  57         .irq_eoi                = mpic_end_irq,
  58         .irq_set_type           = mpic_set_irq_type,
  59         .irq_set_affinity       = mpic_set_affinity,
  60         .name                   = "PASEMI-MSI",
  61 };
  62
  63 static void pasemi_msi_teardown_msi_irqs(struct pci_dev *pdev)
  64 {
  65         struct msi_desc *entry;
  66         irq_hw_number_t hwirq;
  67
  68         pr_debug("pasemi_msi_teardown_msi_irqs, pdev %p\n", pdev);
  69
  70         for_each_pci_msi_entry(entry, pdev) {
  71                 if (entry->irq == NO_IRQ)
  72                         continue;
  73
  74                 hwirq = virq_to_hw(entry->irq);
  75                 irq_set_msi_desc(entry->irq, NULL);
  76                 irq_dispose_mapping(entry->irq);
  77                 msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, ALLOC_CHUNK);
  78         }
  79
  80         return;
  81 }
  82
  83 static int pasemi_msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
  84 {
  85         unsigned int virq;
  86         struct msi_desc *entry;
  87         struct msi_msg msg;
  88         int hwirq;
  89
  90         if (type == PCI_CAP_ID_MSIX)
  91                 pr_debug("pasemi_msi: MSI-X untested, trying anyway\n");
  92         pr_debug("pasemi_msi_setup_msi_irqs, pdev %p nvec %d type %d\n",
  93                  pdev, nvec, type);
  94
  95         msg.address_hi = 0;
  96         msg.address_lo = PASEMI_MSI_ADDR;
  97
  98         for_each_pci_msi_entry(entry, pdev) {
  99                 /* Allocate 16 interrupts for now, since that's the grouping for
 100                  * affinity. This can be changed later if it turns out 32 is too
 101                  * few MSIs for someone, but restrictions will apply to how the
 102                  * sources can be changed independently.
 103                  */
 104                 hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap,
 105                                                 ALLOC_CHUNK);
 106                 if (hwirq < 0) {
 107                         pr_debug("pasemi_msi: failed allocating hwirq\n");
 108                         return hwirq;
 109                 }
 110
 111                 virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
 112                 if (virq == NO_IRQ) {
 113                         pr_debug("pasemi_msi: failed mapping hwirq 0x%x\n",
 114                                   hwirq);
 115                         msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq,
 116                                                ALLOC_CHUNK);
 117                         return -ENOSPC;
 118                 }
 119
 120                 /* Vector on MSI is really an offset, the hardware adds
 121                  * it to the value written at the magic address. So set
 122                  * it to 0 to remain sane.
 123                  */
 124                 mpic_set_vector(virq, 0);
 125
 126                 irq_set_msi_desc(virq, entry);
 127                 irq_set_chip(virq, &mpic_pasemi_msi_chip);
 128                 irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
 129
 130                 pr_debug("pasemi_msi: allocated virq 0x%x (hw 0x%x) " \
 131                          "addr 0x%x\n", virq, hwirq, msg.address_lo);
 132
 133                 /* Likewise, the device writes [0...511] into the target
 134                  * register to generate MSI [512...1023]
 135                  */
 136                 msg.data = hwirq-0x200;
 137                 pci_write_msi_msg(virq, &msg);
 138         }
 139
 140         return 0;
 141 }
 142
 143 int mpic_pasemi_msi_init(struct mpic *mpic)
 144 {
 145         int rc;
 146         struct pci_controller *phb;
 147
 148         if (!mpic->irqhost->of_node ||
 149             !of_device_is_compatible(mpic->irqhost->of_node,
 150                                      "pasemi,pwrficient-openpic"))
 151                 return -ENODEV;
 152
 153         rc = mpic_msi_init_allocator(mpic);
 154         if (rc) {
 155                 pr_debug("pasemi_msi: Error allocating bitmap!\n");
 156                 return rc;
 157         }
 158
 159         pr_debug("pasemi_msi: Registering PA Semi MPIC MSI callbacks\n");
 160
 161         msi_mpic = mpic;
 162         list_for_each_entry(phb, &hose_list, list_node) {
 163                 WARN_ON(phb->controller_ops.setup_msi_irqs);
 164                 phb->controller_ops.setup_msi_irqs = pasemi_msi_setup_msi_irqs;
 165                 phb->controller_ops.teardown_msi_irqs = pasemi_msi_teardown_msi_irqs;
 166         }
 167
 168         return 0;
 169 }