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(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
  49 static 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
  56 static 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
  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         irq_hw_number_t hwirq;
  78
  79         pr_debug("pasemi_msi_teardown_msi_irqs, pdev %p\n", pdev);
  80
  81         list_for_each_entry(entry, &pdev->msi_list, list) {
  82                 if (entry->irq == NO_IRQ)
  83                         continue;
  84
  85                 hwirq = virq_to_hw(entry->irq);
  86                 irq_set_msi_desc(entry->irq, NULL);
  87                 irq_dispose_mapping(entry->irq);
  88                 msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap,
  89                                        hwirq, ALLOC_CHUNK);
  90         }
  91
  92         return;
  93 }
  94
  95 static int pasemi_msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
  96 {
  97         unsigned int virq;
  98         struct msi_desc *entry;
  99         struct msi_msg msg;
 100         int hwirq;
 101
 102         pr_debug("pasemi_msi_setup_msi_irqs, pdev %p nvec %d type %d\n",
 103                  pdev, nvec, type);
 104
 105         msg.address_hi = 0;
 106         msg.address_lo = PASEMI_MSI_ADDR;
 107
 108         list_for_each_entry(entry, &pdev->msi_list, list) {
 109                 /* Allocate 16 interrupts for now, since that's the grouping for
 110                  * affinity. This can be changed later if it turns out 32 is too
 111                  * few MSIs for someone, but restrictions will apply to how the
 112                  * sources can be changed independently.
 113                  */
 114                 hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap,
 115                                                 ALLOC_CHUNK);
 116                 if (hwirq < 0) {
 117                         pr_debug("pasemi_msi: failed allocating hwirq\n");
 118                         return hwirq;
 119                 }
 120
 121                 virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
 122                 if (virq == NO_IRQ) {
 123                         pr_debug("pasemi_msi: failed mapping hwirq 0x%x\n",
 124                                   hwirq);
 125                         msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq,
 126                                                ALLOC_CHUNK);
 127                         return -ENOSPC;
 128                 }
 129
 130                 /* Vector on MSI is really an offset, the hardware adds
 131                  * it to the value written at the magic address. So set
 132                  * it to 0 to remain sane.
 133                  */
 134                 mpic_set_vector(virq, 0);
 135
 136                 irq_set_msi_desc(virq, entry);
 137                 irq_set_chip(virq, &mpic_pasemi_msi_chip);
 138                 irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING);
 139
 140                 pr_debug("pasemi_msi: allocated virq 0x%x (hw 0x%x) " \
 141                          "addr 0x%x\n", virq, hwirq, msg.address_lo);
 142
 143                 /* Likewise, the device writes [0...511] into the target
 144                  * register to generate MSI [512...1023]
 145                  */
 146                 msg.data = hwirq-0x200;
 147                 write_msi_msg(virq, &msg);
 148         }
 149
 150         return 0;
 151 }
 152
 153 int mpic_pasemi_msi_init(struct mpic *mpic)
 154 {
 155         int rc;
 156
 157         if (!mpic->irqhost->of_node ||
 158             !of_device_is_compatible(mpic->irqhost->of_node,
 159                                      "pasemi,pwrficient-openpic"))
 160                 return -ENODEV;
 161
 162         rc = mpic_msi_init_allocator(mpic);
 163         if (rc) {
 164                 pr_debug("pasemi_msi: Error allocating bitmap!\n");
 165                 return rc;
 166         }
 167
 168         pr_debug("pasemi_msi: Registering PA Semi MPIC MSI callbacks\n");
 169
 170         msi_mpic = mpic;
 171         WARN_ON(ppc_md.setup_msi_irqs);
 172         ppc_md.setup_msi_irqs = pasemi_msi_setup_msi_irqs;
 173         ppc_md.teardown_msi_irqs = pasemi_msi_teardown_msi_irqs;
 174         ppc_md.msi_check_device = pasemi_msi_check_device;
 175
 176         return 0;
 177 }