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

   1 /*
   2  * Copyright Altera Corporation (C) 2013-2015. All rights reserved
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/interrupt.h>
  18 #include <linux/irqchip/chained_irq.h>
  19 #include <linux/module.h>
  20 #include <linux/msi.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_irq.h>
  23 #include <linux/of_pci.h>
  24 #include <linux/pci.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/slab.h>
  27
  28 #define MSI_STATUS              0x0
  29 #define MSI_ERROR               0x4
  30 #define MSI_INTMASK             0x8
  31
  32 #define MAX_MSI_VECTORS         32
  33
  34 struct altera_msi {
  35         DECLARE_BITMAP(used, MAX_MSI_VECTORS);
  36         struct mutex            lock;   /* protect "used" bitmap */
  37         struct platform_device  *pdev;
  38         struct irq_domain       *msi_domain;
  39         struct irq_domain       *inner_domain;
  40         void __iomem            *csr_base;
  41         void __iomem            *vector_base;
  42         phys_addr_t             vector_phy;
  43         u32                     num_of_vectors;
  44         int                     irq;
  45 };
  46
  47 static inline void msi_writel(struct altera_msi *msi, const u32 value,
  48                               const u32 reg)
  49 {
  50         writel_relaxed(value, msi->csr_base + reg);
  51 }
  52
  53 static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
  54 {
  55         return readl_relaxed(msi->csr_base + reg);
  56 }
  57
  58 static void altera_msi_isr(struct irq_desc *desc)
  59 {
  60         struct irq_chip *chip = irq_desc_get_chip(desc);
  61         struct altera_msi *msi;
  62         unsigned long status;
  63         u32 num_of_vectors;
  64         u32 bit;
  65         u32 virq;
  66
  67         chained_irq_enter(chip, desc);
  68         msi = irq_desc_get_handler_data(desc);
  69         num_of_vectors = msi->num_of_vectors;
  70
  71         while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
  72                 for_each_set_bit(bit, &status, msi->num_of_vectors) {
  73                         /* Dummy read from vector to clear the interrupt */
  74                         readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
  75
  76                         virq = irq_find_mapping(msi->inner_domain, bit);
  77                         if (virq)
  78                                 generic_handle_irq(virq);
  79                         else
  80                                 dev_err(&msi->pdev->dev, "unexpected MSI\n");
  81                 }
  82         }
  83
  84         chained_irq_exit(chip, desc);
  85 }
  86
  87 static struct irq_chip altera_msi_irq_chip = {
  88         .name = "Altera PCIe MSI",
  89         .irq_mask = pci_msi_mask_irq,
  90         .irq_unmask = pci_msi_unmask_irq,
  91 };
  92
  93 static struct msi_domain_info altera_msi_domain_info = {
  94         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
  95                      MSI_FLAG_PCI_MSIX),
  96         .chip   = &altera_msi_irq_chip,
  97 };
  98
  99 static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 100 {
 101         struct altera_msi *msi = irq_data_get_irq_chip_data(data);
 102         phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
 103
 104         msg->address_lo = lower_32_bits(addr);
 105         msg->address_hi = upper_32_bits(addr);
 106         msg->data = data->hwirq;
 107
 108         dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
 109                 (int)data->hwirq, msg->address_hi, msg->address_lo);
 110 }
 111
 112 static int altera_msi_set_affinity(struct irq_data *irq_data,
 113                                    const struct cpumask *mask, bool force)
 114 {
 115          return -EINVAL;
 116 }
 117
 118 static struct irq_chip altera_msi_bottom_irq_chip = {
 119         .name                   = "Altera MSI",
 120         .irq_compose_msi_msg    = altera_compose_msi_msg,
 121         .irq_set_affinity       = altera_msi_set_affinity,
 122 };
 123
 124 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
 125                                    unsigned int nr_irqs, void *args)
 126 {
 127         struct altera_msi *msi = domain->host_data;
 128         unsigned long bit;
 129         u32 mask;
 130
 131         WARN_ON(nr_irqs != 1);
 132         mutex_lock(&msi->lock);
 133
 134         bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
 135         if (bit >= msi->num_of_vectors) {
 136                 mutex_unlock(&msi->lock);
 137                 return -ENOSPC;
 138         }
 139
 140         set_bit(bit, msi->used);
 141
 142         mutex_unlock(&msi->lock);
 143
 144         irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
 145                             domain->host_data, handle_simple_irq,
 146                             NULL, NULL);
 147
 148         mask = msi_readl(msi, MSI_INTMASK);
 149         mask |= 1 << bit;
 150         msi_writel(msi, mask, MSI_INTMASK);
 151
 152         return 0;
 153 }
 154
 155 static void altera_irq_domain_free(struct irq_domain *domain,
 156                                    unsigned int virq, unsigned int nr_irqs)
 157 {
 158         struct irq_data *d = irq_domain_get_irq_data(domain, virq);
 159         struct altera_msi *msi = irq_data_get_irq_chip_data(d);
 160         u32 mask;
 161
 162         mutex_lock(&msi->lock);
 163
 164         if (!test_bit(d->hwirq, msi->used)) {
 165                 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
 166                         d->hwirq);
 167         } else {
 168                 __clear_bit(d->hwirq, msi->used);
 169                 mask = msi_readl(msi, MSI_INTMASK);
 170                 mask &= ~(1 << d->hwirq);
 171                 msi_writel(msi, mask, MSI_INTMASK);
 172         }
 173
 174         mutex_unlock(&msi->lock);
 175 }
 176
 177 static const struct irq_domain_ops msi_domain_ops = {
 178         .alloc  = altera_irq_domain_alloc,
 179         .free   = altera_irq_domain_free,
 180 };
 181
 182 static int altera_allocate_domains(struct altera_msi *msi)
 183 {
 184         struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
 185
 186         msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
 187                                              &msi_domain_ops, msi);
 188         if (!msi->inner_domain) {
 189                 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
 190                 return -ENOMEM;
 191         }
 192
 193         msi->msi_domain = pci_msi_create_irq_domain(fwnode,
 194                                 &altera_msi_domain_info, msi->inner_domain);
 195         if (!msi->msi_domain) {
 196                 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
 197                 irq_domain_remove(msi->inner_domain);
 198                 return -ENOMEM;
 199         }
 200
 201         return 0;
 202 }
 203
 204 static void altera_free_domains(struct altera_msi *msi)
 205 {
 206         irq_domain_remove(msi->msi_domain);
 207         irq_domain_remove(msi->inner_domain);
 208 }
 209
 210 static int altera_msi_remove(struct platform_device *pdev)
 211 {
 212         struct altera_msi *msi = platform_get_drvdata(pdev);
 213
 214         msi_writel(msi, 0, MSI_INTMASK);
 215         irq_set_chained_handler(msi->irq, NULL);
 216         irq_set_handler_data(msi->irq, NULL);
 217
 218         altera_free_domains(msi);
 219
 220         platform_set_drvdata(pdev, NULL);
 221         return 0;
 222 }
 223
 224 static int altera_msi_probe(struct platform_device *pdev)
 225 {
 226         struct altera_msi *msi;
 227         struct device_node *np = pdev->dev.of_node;
 228         struct resource *res;
 229         int ret;
 230
 231         msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
 232                            GFP_KERNEL);
 233         if (!msi)
 234                 return -ENOMEM;
 235
 236         mutex_init(&msi->lock);
 237         msi->pdev = pdev;
 238
 239         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
 240         if (!res) {
 241                 dev_err(&pdev->dev, "no csr memory resource defined\n");
 242                 return -ENODEV;
 243         }
 244
 245         msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
 246         if (IS_ERR(msi->csr_base)) {
 247                 dev_err(&pdev->dev, "failed to map csr memory\n");
 248                 return PTR_ERR(msi->csr_base);
 249         }
 250
 251         res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 252                                            "vector_slave");
 253         if (!res) {
 254                 dev_err(&pdev->dev, "no vector_slave memory resource defined\n");
 255                 return -ENODEV;
 256         }
 257
 258         msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
 259         if (IS_ERR(msi->vector_base)) {
 260                 dev_err(&pdev->dev, "failed to map vector_slave memory\n");
 261                 return PTR_ERR(msi->vector_base);
 262         }
 263
 264         msi->vector_phy = res->start;
 265
 266         if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
 267                 dev_err(&pdev->dev, "failed to parse the number of vectors\n");
 268                 return -EINVAL;
 269         }
 270
 271         ret = altera_allocate_domains(msi);
 272         if (ret)
 273                 return ret;
 274
 275         msi->irq = platform_get_irq(pdev, 0);
 276         if (msi->irq <= 0) {
 277                 dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
 278                 ret = -ENODEV;
 279                 goto err;
 280         }
 281
 282         irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
 283         platform_set_drvdata(pdev, msi);
 284
 285         return 0;
 286
 287 err:
 288         altera_msi_remove(pdev);
 289         return ret;
 290 }
 291
 292 static const struct of_device_id altera_msi_of_match[] = {
 293         { .compatible = "altr,msi-1.0", NULL },
 294         { },
 295 };
 296
 297 static struct platform_driver altera_msi_driver = {
 298         .driver = {
 299                 .name = "altera-msi",
 300                 .of_match_table = altera_msi_of_match,
 301         },
 302         .probe = altera_msi_probe,
 303         .remove = altera_msi_remove,
 304 };
 305
 306 static int __init altera_msi_init(void)
 307 {
 308         return platform_driver_register(&altera_msi_driver);
 309 }
 310 subsys_initcall(altera_msi_init);
 311
 312 MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
 313 MODULE_DESCRIPTION("Altera PCIe MSI support");
 314 MODULE_LICENSE("GPL v2");