drivers/irqchip/irq-ls-scfg-msi.c

   1 /*
   2  * Freescale SCFG MSI(-X) support
   3  *
   4  * Copyright (C) 2016 Freescale Semiconductor.
   5  *
   6  * Author: Minghuan Lian <Minghuan.Lian@nxp.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/msi.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irq.h>
  18 #include <linux/irqchip/chained_irq.h>
  19 #include <linux/irqdomain.h>
  20 #include <linux/of_pci.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/spinlock.h>
  23
  24 #define MSI_MAX_IRQS    32
  25 #define MSI_IBS_SHIFT   3
  26 #define MSIR            4
  27
  28 struct ls_scfg_msi {
  29         spinlock_t              lock;
  30         struct platform_device  *pdev;
  31         struct irq_domain       *parent;
  32         struct irq_domain       *msi_domain;
  33         void __iomem            *regs;
  34         phys_addr_t             msiir_addr;
  35         int                     irq;
  36         DECLARE_BITMAP(used, MSI_MAX_IRQS);
  37 };
  38
  39 static struct irq_chip ls_scfg_msi_irq_chip = {
  40         .name = "MSI",
  41         .irq_mask       = pci_msi_mask_irq,
  42         .irq_unmask     = pci_msi_unmask_irq,
  43 };
  44
  45 static struct msi_domain_info ls_scfg_msi_domain_info = {
  46         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS |
  47                    MSI_FLAG_USE_DEF_CHIP_OPS |
  48                    MSI_FLAG_PCI_MSIX),
  49         .chip   = &ls_scfg_msi_irq_chip,
  50 };
  51
  52 static void ls_scfg_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
  53 {
  54         struct ls_scfg_msi *msi_data = irq_data_get_irq_chip_data(data);
  55
  56         msg->address_hi = upper_32_bits(msi_data->msiir_addr);
  57         msg->address_lo = lower_32_bits(msi_data->msiir_addr);
  58         msg->data = data->hwirq << MSI_IBS_SHIFT;
  59 }
  60
  61 static int ls_scfg_msi_set_affinity(struct irq_data *irq_data,
  62                                     const struct cpumask *mask, bool force)
  63 {
  64         return -EINVAL;
  65 }
  66
  67 static struct irq_chip ls_scfg_msi_parent_chip = {
  68         .name                   = "SCFG",
  69         .irq_compose_msi_msg    = ls_scfg_msi_compose_msg,
  70         .irq_set_affinity       = ls_scfg_msi_set_affinity,
  71 };
  72
  73 static int ls_scfg_msi_domain_irq_alloc(struct irq_domain *domain,
  74                                         unsigned int virq,
  75                                         unsigned int nr_irqs,
  76                                         void *args)
  77 {
  78         struct ls_scfg_msi *msi_data = domain->host_data;
  79         int pos, err = 0;
  80
  81         WARN_ON(nr_irqs != 1);
  82
  83         spin_lock(&msi_data->lock);
  84         pos = find_first_zero_bit(msi_data->used, MSI_MAX_IRQS);
  85         if (pos < MSI_MAX_IRQS)
  86                 __set_bit(pos, msi_data->used);
  87         else
  88                 err = -ENOSPC;
  89         spin_unlock(&msi_data->lock);
  90
  91         if (err)
  92                 return err;
  93
  94         irq_domain_set_info(domain, virq, pos,
  95                             &ls_scfg_msi_parent_chip, msi_data,
  96                             handle_simple_irq, NULL, NULL);
  97
  98         return 0;
  99 }
 100
 101 static void ls_scfg_msi_domain_irq_free(struct irq_domain *domain,
 102                                    unsigned int virq, unsigned int nr_irqs)
 103 {
 104         struct irq_data *d = irq_domain_get_irq_data(domain, virq);
 105         struct ls_scfg_msi *msi_data = irq_data_get_irq_chip_data(d);
 106         int pos;
 107
 108         pos = d->hwirq;
 109         if (pos < 0 || pos >= MSI_MAX_IRQS) {
 110                 pr_err("failed to teardown msi. Invalid hwirq %d\n", pos);
 111                 return;
 112         }
 113
 114         spin_lock(&msi_data->lock);
 115         __clear_bit(pos, msi_data->used);
 116         spin_unlock(&msi_data->lock);
 117 }
 118
 119 static const struct irq_domain_ops ls_scfg_msi_domain_ops = {
 120         .alloc  = ls_scfg_msi_domain_irq_alloc,
 121         .free   = ls_scfg_msi_domain_irq_free,
 122 };
 123
 124 static void ls_scfg_msi_irq_handler(struct irq_desc *desc)
 125 {
 126         struct ls_scfg_msi *msi_data = irq_desc_get_handler_data(desc);
 127         unsigned long val;
 128         int pos, virq;
 129
 130         chained_irq_enter(irq_desc_get_chip(desc), desc);
 131
 132         val = ioread32be(msi_data->regs + MSIR);
 133         for_each_set_bit(pos, &val, MSI_MAX_IRQS) {
 134                 virq = irq_find_mapping(msi_data->parent, (31 - pos));
 135                 if (virq)
 136                         generic_handle_irq(virq);
 137         }
 138
 139         chained_irq_exit(irq_desc_get_chip(desc), desc);
 140 }
 141
 142 static int ls_scfg_msi_domains_init(struct ls_scfg_msi *msi_data)
 143 {
 144         /* Initialize MSI domain parent */
 145         msi_data->parent = irq_domain_add_linear(NULL,
 146                                                  MSI_MAX_IRQS,
 147                                                  &ls_scfg_msi_domain_ops,
 148                                                  msi_data);
 149         if (!msi_data->parent) {
 150                 dev_err(&msi_data->pdev->dev, "failed to create IRQ domain\n");
 151                 return -ENOMEM;
 152         }
 153
 154         msi_data->msi_domain = pci_msi_create_irq_domain(
 155                                 of_node_to_fwnode(msi_data->pdev->dev.of_node),
 156                                 &ls_scfg_msi_domain_info,
 157                                 msi_data->parent);
 158         if (!msi_data->msi_domain) {
 159                 dev_err(&msi_data->pdev->dev, "failed to create MSI domain\n");
 160                 irq_domain_remove(msi_data->parent);
 161                 return -ENOMEM;
 162         }
 163
 164         return 0;
 165 }
 166
 167 static int ls_scfg_msi_probe(struct platform_device *pdev)
 168 {
 169         struct ls_scfg_msi *msi_data;
 170         struct resource *res;
 171         int ret;
 172
 173         msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data), GFP_KERNEL);
 174         if (!msi_data)
 175                 return -ENOMEM;
 176
 177         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 178         msi_data->regs = devm_ioremap_resource(&pdev->dev, res);
 179         if (IS_ERR(msi_data->regs)) {
 180                 dev_err(&pdev->dev, "failed to initialize 'regs'\n");
 181                 return PTR_ERR(msi_data->regs);
 182         }
 183         msi_data->msiir_addr = res->start;
 184
 185         msi_data->irq = platform_get_irq(pdev, 0);
 186         if (msi_data->irq <= 0) {
 187                 dev_err(&pdev->dev, "failed to get MSI irq\n");
 188                 return -ENODEV;
 189         }
 190
 191         msi_data->pdev = pdev;
 192         spin_lock_init(&msi_data->lock);
 193
 194         ret = ls_scfg_msi_domains_init(msi_data);
 195         if (ret)
 196                 return ret;
 197
 198         irq_set_chained_handler_and_data(msi_data->irq,
 199                                          ls_scfg_msi_irq_handler,
 200                                          msi_data);
 201
 202         platform_set_drvdata(pdev, msi_data);
 203
 204         return 0;
 205 }
 206
 207 static int ls_scfg_msi_remove(struct platform_device *pdev)
 208 {
 209         struct ls_scfg_msi *msi_data = platform_get_drvdata(pdev);
 210
 211         irq_set_chained_handler_and_data(msi_data->irq, NULL, NULL);
 212
 213         irq_domain_remove(msi_data->msi_domain);
 214         irq_domain_remove(msi_data->parent);
 215
 216         platform_set_drvdata(pdev, NULL);
 217
 218         return 0;
 219 }
 220
 221 static const struct of_device_id ls_scfg_msi_id[] = {
 222         { .compatible = "fsl,1s1021a-msi", },
 223         { .compatible = "fsl,1s1043a-msi", },
 224         {},
 225 };
 226
 227 static struct platform_driver ls_scfg_msi_driver = {
 228         .driver = {
 229                 .name = "ls-scfg-msi",
 230                 .of_match_table = ls_scfg_msi_id,
 231         },
 232         .probe = ls_scfg_msi_probe,
 233         .remove = ls_scfg_msi_remove,
 234 };
 235
 236 module_platform_driver(ls_scfg_msi_driver);
 237
 238 MODULE_AUTHOR("Minghuan Lian <Minghuan.Lian@nxp.com>");
 239 MODULE_DESCRIPTION("Freescale Layerscape SCFG MSI controller driver");
 240 MODULE_LICENSE("GPL v2");