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         list_for_each_entry(entry, &dev->msi_list, list) {
  48                 irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
  49                 if (irq < 0) {
  50                         pr_debug("%s: Failed to allocate msi interrupt\n",
  51                                  __func__);
  52                         return irq;
  53                 }
  54
  55                 hwirq = ppc4xx_hsta_msi.irq_map[irq];
  56                 if (hwirq == NO_IRQ) {
  57                         pr_err("%s: Failed mapping irq %d\n", __func__, irq);
  58                         return -EINVAL;
  59                 }
  60
  61                 /*
  62                  * HSTA generates interrupts on writes to 128-bit aligned
  63                  * addresses.
  64                  */
  65                 addr = ppc4xx_hsta_msi.address + irq*0x10;
  66                 msg.address_hi = upper_32_bits(addr);
  67                 msg.address_lo = lower_32_bits(addr);
  68
  69                 /* Data is not used by the HSTA. */
  70                 msg.data = 0;
  71
  72                 pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
  73                          (((u64) msg.address_hi) << 32) | msg.address_lo);
  74
  75                 if (irq_set_msi_desc(hwirq, entry)) {
  76                         pr_err(
  77                         "%s: Invalid hwirq %d specified in device tree\n",
  78                         __func__, hwirq);
  79                         msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
  80                         return -EINVAL;
  81                 }
  82                 write_msi_msg(hwirq, &msg);
  83         }
  84
  85         return 0;
  86 }
  87
  88 static int hsta_find_hwirq_offset(int hwirq)
  89 {
  90         int irq;
  91
  92         /* Find the offset given the hwirq */
  93         for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
  94                 if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
  95                         return irq;
  96
  97         return -EINVAL;
  98 }
  99
 100 static void hsta_teardown_msi_irqs(struct pci_dev *dev)
 101 {
 102         struct msi_desc *entry;
 103         int irq;
 104
 105         list_for_each_entry(entry, &dev->msi_list, list) {
 106                 if (entry->irq == NO_IRQ)
 107                         continue;
 108
 109                 irq = hsta_find_hwirq_offset(entry->irq);
 110
 111                 /* entry->irq should always be in irq_map */
 112                 BUG_ON(irq < 0);
 113                 irq_set_msi_desc(entry->irq, NULL);
 114                 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
 115                 pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
 116                          entry->irq, irq);
 117         }
 118 }
 119
 120 static int hsta_msi_check_device(struct pci_dev *pdev, int nvec, int type)
 121 {
 122         /* We don't support MSI-X */
 123         if (type == PCI_CAP_ID_MSIX) {
 124                 pr_debug("%s: MSI-X not supported.\n", __func__);
 125                 return -EINVAL;
 126         }
 127
 128         return 0;
 129 }
 130
 131 static int hsta_msi_probe(struct platform_device *pdev)
 132 {
 133         struct device *dev = &pdev->dev;
 134         struct resource *mem;
 135         int irq, ret, irq_count;
 136
 137         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 138         if (IS_ERR(mem)) {
 139                 dev_err(dev, "Unable to get mmio space\n");
 140                 return -EINVAL;
 141         }
 142
 143         irq_count = of_irq_count(dev->of_node);
 144         if (!irq_count) {
 145                 dev_err(dev, "Unable to find IRQ range\n");
 146                 return -EINVAL;
 147         }
 148
 149         ppc4xx_hsta_msi.dev = dev;
 150         ppc4xx_hsta_msi.address = mem->start;
 151         ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
 152         ppc4xx_hsta_msi.irq_count = irq_count;
 153         if (IS_ERR(ppc4xx_hsta_msi.data)) {
 154                 dev_err(dev, "Unable to map memory\n");
 155                 return -ENOMEM;
 156         }
 157
 158         ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
 159         if (ret)
 160                 goto out;
 161
 162         ppc4xx_hsta_msi.irq_map = kmalloc(sizeof(int) * irq_count, GFP_KERNEL);
 163         if (IS_ERR(ppc4xx_hsta_msi.irq_map)) {
 164                 ret = -ENOMEM;
 165                 goto out1;
 166         }
 167
 168         /* Setup a mapping from irq offsets to hardware irq numbers */
 169         for (irq = 0; irq < irq_count; irq++) {
 170                 ppc4xx_hsta_msi.irq_map[irq] =
 171                         irq_of_parse_and_map(dev->of_node, irq);
 172                 if (ppc4xx_hsta_msi.irq_map[irq] == NO_IRQ) {
 173                         dev_err(dev, "Unable to map IRQ\n");
 174                         ret = -EINVAL;
 175                         goto out2;
 176                 }
 177         }
 178
 179         ppc_md.setup_msi_irqs = hsta_setup_msi_irqs;
 180         ppc_md.teardown_msi_irqs = hsta_teardown_msi_irqs;
 181         ppc_md.msi_check_device = hsta_msi_check_device;
 182         return 0;
 183
 184 out2:
 185         kfree(ppc4xx_hsta_msi.irq_map);
 186
 187 out1:
 188         msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
 189
 190 out:
 191         iounmap(ppc4xx_hsta_msi.data);
 192         return ret;
 193 }
 194
 195 static const struct of_device_id hsta_msi_ids[] = {
 196         {
 197                 .compatible = "ibm,hsta-msi",
 198         },
 199         {}
 200 };
 201
 202 static struct platform_driver hsta_msi_driver = {
 203         .probe = hsta_msi_probe,
 204         .driver = {
 205                 .name = "hsta-msi",
 206                 .owner = THIS_MODULE,
 207                 .of_match_table = hsta_msi_ids,
 208         },
 209 };
 210
 211 static int hsta_msi_init(void)
 212 {
 213         return platform_driver_register(&hsta_msi_driver);
 214 }
 215 subsys_initcall(hsta_msi_init);