arch/powerpc/sysdev/mpic_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 #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? */
  39 static struct mpic *msi_mpic;
  40
  41
  42 static void mpic_pasemi_msi_mask_irq(unsigned int irq)
  43 {
  44         pr_debug("mpic_pasemi_msi_mask_irq %d\n", irq);
  45         mask_msi_irq(irq);
  46         mpic_mask_irq(irq);
  47 }
  48
  49 static void mpic_pasemi_msi_unmask_irq(unsigned int irq)
  50 {
  51         pr_debug("mpic_pasemi_msi_unmask_irq %d\n", irq);
  52         mpic_unmask_irq(irq);
  53         unmask_msi_irq(irq);
  54 }
  55
  56 static struct irq_chip mpic_pasemi_msi_chip = {
  57         .shutdown       = mpic_pasemi_msi_mask_irq,
  58         .mask           = mpic_pasemi_msi_mask_irq,
  59         .unmask         = mpic_pasemi_msi_unmask_irq,
  60         .eoi            = mpic_end_irq,
  61         .set_type       = mpic_set_irq_type,
  62         .set_affinity   = mpic_set_affinity,
  63         .name           = "PASEMI-MSI",
  64 };
  65
  66 static 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
  74 static 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                 set_irq_msi(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
  93 static 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                 set_irq_msi(virq, entry);
 135                 set_irq_chip(virq, &mpic_pasemi_msi_chip);
 136                 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
 151 int 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 }