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