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