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

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