arch/powerpc/sysdev/ppc4xx_hsta_msi.c

   1 /*
   2  * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for
   3  * generation of the interrupt.
   4  *
   5  * Copyright © 2013 Alistair Popple <alistair@popple.id.au> IBM Corporation
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/msi.h>
  16 #include <linux/of.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/pci.h>
  19 #include <linux/semaphore.h>
  20 #include <asm/msi_bitmap.h>
  21 #include <asm/ppc-pci.h>
  22
  23 struct ppc4xx_hsta_msi {
  24         struct device *dev;
  25
  26         /* The ioremapped HSTA MSI IO space */
  27         u32 __iomem *data;
  28
  29         /* Physical address of HSTA MSI IO space */
  30         u64 address;
  31         struct msi_bitmap bmp;
  32
  33         /* An array mapping offsets to hardware IRQs */
  34         int *irq_map;
  35
  36         /* Number of hwirqs supported */
  37         int irq_count;
  38 };
  39 static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
  40
  41 static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  42 {
  43         struct msi_msg msg;
  44         struct msi_desc *entry;
  45         int irq, hwirq;
  46         u64 addr;
  47
  48         /* We don't support MSI-X */
  49         if (type == PCI_CAP_ID_MSIX) {
  50                 pr_debug("%s: MSI-X not supported.\n", __func__);
  51                 return -EINVAL;
  52         }
  53
  54         for_each_pci_msi_entry(entry, dev) {
  55                 irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
  56                 if (irq < 0) {
  57                         pr_debug("%s: Failed to allocate msi interrupt\n",
  58                                  __func__);
  59                         return irq;
  60                 }
  61
  62                 hwirq = ppc4xx_hsta_msi.irq_map[irq];
  63                 if (!hwirq) {
  64                         pr_err("%s: Failed mapping irq %d\n", __func__, irq);
  65                         return -EINVAL;
  66                 }
  67
  68                 /*
  69                  * HSTA generates interrupts on writes to 128-bit aligned
  70                  * addresses.
  71                  */
  72                 addr = ppc4xx_hsta_msi.address + irq*0x10;
  73                 msg.address_hi = upper_32_bits(addr);
  74                 msg.address_lo = lower_32_bits(addr);
  75
  76                 /* Data is not used by the HSTA. */
  77                 msg.data = 0;
  78
  79                 pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
  80                          (((u64) msg.address_hi) << 32) | msg.address_lo);
  81
  82                 if (irq_set_msi_desc(hwirq, entry)) {
  83                         pr_err(
  84                         "%s: Invalid hwirq %d specified in device tree\n",
  85                         __func__, hwirq);
  86                         msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
  87                         return -EINVAL;
  88                 }
  89                 pci_write_msi_msg(hwirq, &msg);
  90         }
  91
  92         return 0;
  93 }
  94
  95 static int hsta_find_hwirq_offset(int hwirq)
  96 {
  97         int irq;
  98
  99         /* Find the offset given the hwirq */
 100         for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
 101                 if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
 102                         return irq;
 103
 104         return -EINVAL;
 105 }
 106
 107 static void hsta_teardown_msi_irqs(struct pci_dev *dev)
 108 {
 109         struct msi_desc *entry;
 110         int irq;
 111
 112         for_each_pci_msi_entry(entry, dev) {
 113                 if (!entry->irq)
 114                         continue;
 115
 116                 irq = hsta_find_hwirq_offset(entry->irq);
 117
 118                 /* entry->irq should always be in irq_map */
 119                 BUG_ON(irq < 0);
 120                 irq_set_msi_desc(entry->irq, NULL);
 121                 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
 122                 pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
 123                          entry->irq, irq);
 124         }
 125 }
 126
 127 static int hsta_msi_probe(struct platform_device *pdev)
 128 {
 129         struct device *dev = &pdev->dev;
 130         struct resource *mem;
 131         int irq, ret, irq_count;
 132         struct pci_controller *phb;
 133
 134         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 135         if (!mem) {
 136                 dev_err(dev, "Unable to get mmio space\n");
 137                 return -EINVAL;
 138         }
 139
 140         irq_count = of_irq_count(dev->of_node);
 141         if (!irq_count) {
 142                 dev_err(dev, "Unable to find IRQ range\n");
 143                 return -EINVAL;
 144         }
 145
 146         ppc4xx_hsta_msi.dev = dev;
 147         ppc4xx_hsta_msi.address = mem->start;
 148         ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
 149         ppc4xx_hsta_msi.irq_count = irq_count;
 150         if (!ppc4xx_hsta_msi.data) {
 151                 dev_err(dev, "Unable to map memory\n");
 152                 return -ENOMEM;
 153         }
 154
 155         ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
 156         if (ret)
 157                 goto out;
 158
 159         ppc4xx_hsta_msi.irq_map = kmalloc(sizeof(int) * irq_count, GFP_KERNEL);
 160         if (!ppc4xx_hsta_msi.irq_map) {
 161                 ret = -ENOMEM;
 162                 goto out1;
 163         }
 164
 165         /* Setup a mapping from irq offsets to hardware irq numbers */
 166         for (irq = 0; irq < irq_count; irq++) {
 167                 ppc4xx_hsta_msi.irq_map[irq] =
 168                         irq_of_parse_and_map(dev->of_node, irq);
 169                 if (!ppc4xx_hsta_msi.irq_map[irq]) {
 170                         dev_err(dev, "Unable to map IRQ\n");
 171                         ret = -EINVAL;
 172                         goto out2;
 173                 }
 174         }
 175
 176         list_for_each_entry(phb, &hose_list, list_node) {
 177                 phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs;
 178                 phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs;
 179         }
 180         return 0;
 181
 182 out2:
 183         kfree(ppc4xx_hsta_msi.irq_map);
 184
 185 out1:
 186         msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
 187
 188 out:
 189         iounmap(ppc4xx_hsta_msi.data);
 190         return ret;
 191 }
 192
 193 static const struct of_device_id hsta_msi_ids[] = {
 194         {
 195                 .compatible = "ibm,hsta-msi",
 196         },
 197         {}
 198 };
 199
 200 static struct platform_driver hsta_msi_driver = {
 201         .probe = hsta_msi_probe,
 202         .driver = {
 203                 .name = "hsta-msi",
 204                 .of_match_table = hsta_msi_ids,
 205         },
 206 };
 207
 208 static int hsta_msi_init(void)
 209 {
 210         return platform_driver_register(&hsta_msi_driver);
 211 }
 212 subsys_initcall(hsta_msi_init);