drivers/pci/host/pcie-altera-msi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Altera PCIe MSI support
   4  *
   5  * Author: Ley Foon Tan <lftan@altera.com>
   6  *
   7  * Copyright Altera Corporation (C) 2013-2015. All rights reserved
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/irqchip/chained_irq.h>
  12 #include <linux/init.h>
  13 #include <linux/msi.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/of_pci.h>
  17 #include <linux/pci.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20
  21 #define MSI_STATUS              0x0
  22 #define MSI_ERROR               0x4
  23 #define MSI_INTMASK             0x8
  24
  25 #define MAX_MSI_VECTORS         32
  26
  27 struct altera_msi {
  28         DECLARE_BITMAP(used, MAX_MSI_VECTORS);
  29         struct mutex            lock;   /* protect "used" bitmap */
  30         struct platform_device  *pdev;
  31         struct irq_domain       *msi_domain;
  32         struct irq_domain       *inner_domain;
  33         void __iomem            *csr_base;
  34         void __iomem            *vector_base;
  35         phys_addr_t             vector_phy;
  36         u32                     num_of_vectors;
  37         int                     irq;
  38 };
  39
  40 static inline void msi_writel(struct altera_msi *msi, const u32 value,
  41                               const u32 reg)
  42 {
  43         writel_relaxed(value, msi->csr_base + reg);
  44 }
  45
  46 static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
  47 {
  48         return readl_relaxed(msi->csr_base + reg);
  49 }
  50
  51 static void altera_msi_isr(struct irq_desc *desc)
  52 {
  53         struct irq_chip *chip = irq_desc_get_chip(desc);
  54         struct altera_msi *msi;
  55         unsigned long status;
  56         u32 bit;
  57         u32 virq;
  58
  59         chained_irq_enter(chip, desc);
  60         msi = irq_desc_get_handler_data(desc);
  61
  62         while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
  63                 for_each_set_bit(bit, &status, msi->num_of_vectors) {
  64                         /* Dummy read from vector to clear the interrupt */
  65                         readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
  66
  67                         virq = irq_find_mapping(msi->inner_domain, bit);
  68                         if (virq)
  69                                 generic_handle_irq(virq);
  70                         else
  71                                 dev_err(&msi->pdev->dev, "unexpected MSI\n");
  72                 }
  73         }
  74
  75         chained_irq_exit(chip, desc);
  76 }
  77
  78 static struct irq_chip altera_msi_irq_chip = {
  79         .name = "Altera PCIe MSI",
  80         .irq_mask = pci_msi_mask_irq,
  81         .irq_unmask = pci_msi_unmask_irq,
  82 };
  83
  84 static struct msi_domain_info altera_msi_domain_info = {
  85         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
  86                      MSI_FLAG_PCI_MSIX),
  87         .chip   = &altera_msi_irq_chip,
  88 };
  89
  90 static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
  91 {
  92         struct altera_msi *msi = irq_data_get_irq_chip_data(data);
  93         phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
  94
  95         msg->address_lo = lower_32_bits(addr);
  96         msg->address_hi = upper_32_bits(addr);
  97         msg->data = data->hwirq;
  98
  99         dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
 100                 (int)data->hwirq, msg->address_hi, msg->address_lo);
 101 }
 102
 103 static int altera_msi_set_affinity(struct irq_data *irq_data,
 104                                    const struct cpumask *mask, bool force)
 105 {
 106          return -EINVAL;
 107 }
 108
 109 static struct irq_chip altera_msi_bottom_irq_chip = {
 110         .name                   = "Altera MSI",
 111         .irq_compose_msi_msg    = altera_compose_msi_msg,
 112         .irq_set_affinity       = altera_msi_set_affinity,
 113 };
 114
 115 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
 116                                    unsigned int nr_irqs, void *args)
 117 {
 118         struct altera_msi *msi = domain->host_data;
 119         unsigned long bit;
 120         u32 mask;
 121
 122         WARN_ON(nr_irqs != 1);
 123         mutex_lock(&msi->lock);
 124
 125         bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
 126         if (bit >= msi->num_of_vectors) {
 127                 mutex_unlock(&msi->lock);
 128                 return -ENOSPC;
 129         }
 130
 131         set_bit(bit, msi->used);
 132
 133         mutex_unlock(&msi->lock);
 134
 135         irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
 136                             domain->host_data, handle_simple_irq,
 137                             NULL, NULL);
 138
 139         mask = msi_readl(msi, MSI_INTMASK);
 140         mask |= 1 << bit;
 141         msi_writel(msi, mask, MSI_INTMASK);
 142
 143         return 0;
 144 }
 145
 146 static void altera_irq_domain_free(struct irq_domain *domain,
 147                                    unsigned int virq, unsigned int nr_irqs)
 148 {
 149         struct irq_data *d = irq_domain_get_irq_data(domain, virq);
 150         struct altera_msi *msi = irq_data_get_irq_chip_data(d);
 151         u32 mask;
 152
 153         mutex_lock(&msi->lock);
 154
 155         if (!test_bit(d->hwirq, msi->used)) {
 156                 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
 157                         d->hwirq);
 158         } else {
 159                 __clear_bit(d->hwirq, msi->used);
 160                 mask = msi_readl(msi, MSI_INTMASK);
 161                 mask &= ~(1 << d->hwirq);
 162                 msi_writel(msi, mask, MSI_INTMASK);
 163         }
 164
 165         mutex_unlock(&msi->lock);
 166 }
 167
 168 static const struct irq_domain_ops msi_domain_ops = {
 169         .alloc  = altera_irq_domain_alloc,
 170         .free   = altera_irq_domain_free,
 171 };
 172
 173 static int altera_allocate_domains(struct altera_msi *msi)
 174 {
 175         struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
 176
 177         msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
 178                                              &msi_domain_ops, msi);
 179         if (!msi->inner_domain) {
 180                 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
 181                 return -ENOMEM;
 182         }
 183
 184         msi->msi_domain = pci_msi_create_irq_domain(fwnode,
 185                                 &altera_msi_domain_info, msi->inner_domain);
 186         if (!msi->msi_domain) {
 187                 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
 188                 irq_domain_remove(msi->inner_domain);
 189                 return -ENOMEM;
 190         }
 191
 192         return 0;
 193 }
 194
 195 static void altera_free_domains(struct altera_msi *msi)
 196 {
 197         irq_domain_remove(msi->msi_domain);
 198         irq_domain_remove(msi->inner_domain);
 199 }
 200
 201 static int altera_msi_remove(struct platform_device *pdev)
 202 {
 203         struct altera_msi *msi = platform_get_drvdata(pdev);
 204
 205         msi_writel(msi, 0, MSI_INTMASK);
 206         irq_set_chained_handler(msi->irq, NULL);
 207         irq_set_handler_data(msi->irq, NULL);
 208
 209         altera_free_domains(msi);
 210
 211         platform_set_drvdata(pdev, NULL);
 212         return 0;
 213 }
 214
 215 static int altera_msi_probe(struct platform_device *pdev)
 216 {
 217         struct altera_msi *msi;
 218         struct device_node *np = pdev->dev.of_node;
 219         struct resource *res;
 220         int ret;
 221
 222         msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
 223                            GFP_KERNEL);
 224         if (!msi)
 225                 return -ENOMEM;
 226
 227         mutex_init(&msi->lock);
 228         msi->pdev = pdev;
 229
 230         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
 231         msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
 232         if (IS_ERR(msi->csr_base)) {
 233                 dev_err(&pdev->dev, "failed to map csr memory\n");
 234                 return PTR_ERR(msi->csr_base);
 235         }
 236
 237         res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 238                                            "vector_slave");
 239         msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
 240         if (IS_ERR(msi->vector_base)) {
 241                 dev_err(&pdev->dev, "failed to map vector_slave memory\n");
 242                 return PTR_ERR(msi->vector_base);
 243         }
 244
 245         msi->vector_phy = res->start;
 246
 247         if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
 248                 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
 249                 return -EINVAL;
 250         }
 251
 252         ret = altera_allocate_domains(msi);
 253         if (ret)
 254                 return ret;
 255
 256         msi->irq = platform_get_irq(pdev, 0);
 257         if (msi->irq < 0) {
 258                 dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
 259                 ret = msi->irq;
 260                 goto err;
 261         }
 262
 263         irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
 264         platform_set_drvdata(pdev, msi);
 265
 266         return 0;
 267
 268 err:
 269         altera_msi_remove(pdev);
 270         return ret;
 271 }
 272
 273 static const struct of_device_id altera_msi_of_match[] = {
 274         { .compatible = "altr,msi-1.0", NULL },
 275         { },
 276 };
 277
 278 static struct platform_driver altera_msi_driver = {
 279         .driver = {
 280                 .name = "altera-msi",
 281                 .of_match_table = altera_msi_of_match,
 282         },
 283         .probe = altera_msi_probe,
 284         .remove = altera_msi_remove,
 285 };
 286
 287 static int __init altera_msi_init(void)
 288 {
 289         return platform_driver_register(&altera_msi_driver);
 290 }
 291 subsys_initcall(altera_msi_init);