linux/arch/powerpc/sysdev/mpic_pasemi_msi.c
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   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#undef DEBUG
  17
  18#include <linux/irq.h>
  19#include <linux/bootmem.h>
  20#include <linux/msi.h>
  21#include <asm/mpic.h>
  22#include <asm/prom.h>
  23#include <asm/hw_irq.h>
  24#include <asm/ppc-pci.h>
  25#include <asm/msi_bitmap.h>
  26
  27#include "mpic.h"
  28
  29/* Allocate 16 interrupts per device, to give an alignment of 16,
  30 * since that's the size of the grouping w.r.t. affinity. If someone
  31 * needs more than 32 MSI's down the road we'll have to rethink this,
  32 * but it should be OK for now.
  33 */
  34#define ALLOC_CHUNK 16
  35
  36#define PASEMI_MSI_ADDR 0xfc080000
  37
  38/* A bit ugly, can we get this from the pci_dev somehow? */
  39static struct mpic *msi_mpic;
  40
  41
  42static void mpic_pasemi_msi_mask_irq(struct irq_data *data)
  43{
  44        pr_debug("mpic_pasemi_msi_mask_irq %d\n", data->irq);
  45        mask_msi_irq(data);
  46        mpic_mask_irq(data);
  47}
  48
  49static void mpic_pasemi_msi_unmask_irq(struct irq_data *data)
  50{
  51        pr_debug("mpic_pasemi_msi_unmask_irq %d\n", data->irq);
  52        mpic_unmask_irq(data);
  53        unmask_msi_irq(data);
  54}
  55
  56static struct irq_chip mpic_pasemi_msi_chip = {
  57        .irq_shutdown           = mpic_pasemi_msi_mask_irq,
  58        .irq_mask               = mpic_pasemi_msi_mask_irq,
  59        .irq_unmask             = mpic_pasemi_msi_unmask_irq,
  60        .irq_eoi                = mpic_end_irq,
  61        .irq_set_type           = mpic_set_irq_type,
  62        .irq_set_affinity       = mpic_set_affinity,
  63        .name                   = "PASEMI-MSI",
  64};
  65
  66static int pasemi_msi_check_device(struct pci_dev *pdev, int nvec, int type)
  67{
  68        if (type == PCI_CAP_ID_MSIX)
  69                pr_debug("pasemi_msi: MSI-X untested, trying anyway\n");
  70
  71        return 0;
  72}
  73
  74static void pasemi_msi_teardown_msi_irqs(struct pci_dev *pdev)
  75{
  76        struct msi_desc *entry;
  77
  78        pr_debug("pasemi_msi_teardown_msi_irqs, pdev %p\n", pdev);
  79
  80        list_for_each_entry(entry, &pdev->msi_list, list) {
  81                if (entry->irq == NO_IRQ)
  82                        continue;
  83
  84                irq_set_msi_desc(entry->irq, NULL);
  85                msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap,
  86                                       virq_to_hw(entry->irq), ALLOC_CHUNK);
  87                irq_dispose_mapping(entry->irq);
  88        }
  89
  90        return;
  91}
  92
  93static int pasemi_msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
  94{
  95        unsigned int virq;
  96        struct msi_desc *entry;
  97        struct msi_msg msg;
  98        int hwirq;
  99
 100        pr_debug("pasemi_msi_setup_msi_irqs, pdev %p nvec %d type %d\n",
 101                 pdev, nvec, type);
 102
 103        msg.address_hi = 0;
 104        msg.address_lo = PASEMI_MSI_ADDR;
 105
 106        list_for_each_entry(entry, &pdev->msi_list, list) {
 107                /* Allocate 16 interrupts for now, since that's the grouping for
 108                 * affinity. This can be changed later if it turns out 32 is too
 109                 * few MSIs for someone, but restrictions will apply to how the
 110                 * sources can be changed independently.
 111                 */
 112                hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap,
 113                                                ALLOC_CHUNK);
 114                if (hwirq < 0) {
 115                        pr_debug("pasemi_msi: failed allocating hwirq\n");
 116                        return hwirq;
 117                }
 118
 119                virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
 120                if (virq == NO_IRQ) {
 121                        pr_debug("pasemi_msi: failed mapping hwirq 0x%x\n",
 122                                  hwirq);
 123                        msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq,
 124                                               ALLOC_CHUNK);
 125                        return -ENOSPC;
 126                }
 127
 128                /* Vector on MSI is really an offset, the hardware adds
 129                 * it to the value written at the magic address. So set
 130                 * it to 0 to remain sane.
 131                 */
 132                mpic_set_vector(virq, 0);
 133
 134                irq_set_msi_desc(virq, entry);
 135                irq_set_chip(virq, &mpic_pasemi_msi_chip);
 136                irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
 137
 138                pr_debug("pasemi_msi: allocated virq 0x%x (hw 0x%x) " \
 139                         "addr 0x%x\n", virq, hwirq, msg.address_lo);
 140
 141                /* Likewise, the device writes [0...511] into the target
 142                 * register to generate MSI [512...1023]
 143                 */
 144                msg.data = hwirq-0x200;
 145                write_msi_msg(virq, &msg);
 146        }
 147
 148        return 0;
 149}
 150
 151int mpic_pasemi_msi_init(struct mpic *mpic)
 152{
 153        int rc;
 154
 155        if (!mpic->irqhost->of_node ||
 156            !of_device_is_compatible(mpic->irqhost->of_node,
 157                                     "pasemi,pwrficient-openpic"))
 158                return -ENODEV;
 159
 160        rc = mpic_msi_init_allocator(mpic);
 161        if (rc) {
 162                pr_debug("pasemi_msi: Error allocating bitmap!\n");
 163                return rc;
 164        }
 165
 166        pr_debug("pasemi_msi: Registering PA Semi MPIC MSI callbacks\n");
 167
 168        msi_mpic = mpic;
 169        WARN_ON(ppc_md.setup_msi_irqs);
 170        ppc_md.setup_msi_irqs = pasemi_msi_setup_msi_irqs;
 171        ppc_md.teardown_msi_irqs = pasemi_msi_teardown_msi_irqs;
 172        ppc_md.msi_check_device = pasemi_msi_check_device;
 173
 174        return 0;
 175}
 176