drivers/pci/host/pcie-tango.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/irqchip/chained_irq.h>
   3 #include <linux/irqdomain.h>
   4 #include <linux/pci-ecam.h>
   5 #include <linux/delay.h>
   6 #include <linux/msi.h>
   7 #include <linux/of_address.h>
   8
   9 #define MSI_MAX                 256
  10
  11 #define SMP8759_MUX             0x48
  12 #define SMP8759_TEST_OUT        0x74
  13 #define SMP8759_DOORBELL        0x7c
  14 #define SMP8759_STATUS          0x80
  15 #define SMP8759_ENABLE          0xa0
  16
  17 struct tango_pcie {
  18         DECLARE_BITMAP(used_msi, MSI_MAX);
  19         u64                     msi_doorbell;
  20         spinlock_t              used_msi_lock;
  21         void __iomem            *base;
  22         struct irq_domain       *dom;
  23 };
  24
  25 static void tango_msi_isr(struct irq_desc *desc)
  26 {
  27         struct irq_chip *chip = irq_desc_get_chip(desc);
  28         struct tango_pcie *pcie = irq_desc_get_handler_data(desc);
  29         unsigned long status, base, virq, idx, pos = 0;
  30
  31         chained_irq_enter(chip, desc);
  32         spin_lock(&pcie->used_msi_lock);
  33
  34         while ((pos = find_next_bit(pcie->used_msi, MSI_MAX, pos)) < MSI_MAX) {
  35                 base = round_down(pos, 32);
  36                 status = readl_relaxed(pcie->base + SMP8759_STATUS + base / 8);
  37                 for_each_set_bit(idx, &status, 32) {
  38                         virq = irq_find_mapping(pcie->dom, base + idx);
  39                         generic_handle_irq(virq);
  40                 }
  41                 pos = base + 32;
  42         }
  43
  44         spin_unlock(&pcie->used_msi_lock);
  45         chained_irq_exit(chip, desc);
  46 }
  47
  48 static void tango_ack(struct irq_data *d)
  49 {
  50         struct tango_pcie *pcie = d->chip_data;
  51         u32 offset = (d->hwirq / 32) * 4;
  52         u32 bit = BIT(d->hwirq % 32);
  53
  54         writel_relaxed(bit, pcie->base + SMP8759_STATUS + offset);
  55 }
  56
  57 static void update_msi_enable(struct irq_data *d, bool unmask)
  58 {
  59         unsigned long flags;
  60         struct tango_pcie *pcie = d->chip_data;
  61         u32 offset = (d->hwirq / 32) * 4;
  62         u32 bit = BIT(d->hwirq % 32);
  63         u32 val;
  64
  65         spin_lock_irqsave(&pcie->used_msi_lock, flags);
  66         val = readl_relaxed(pcie->base + SMP8759_ENABLE + offset);
  67         val = unmask ? val | bit : val & ~bit;
  68         writel_relaxed(val, pcie->base + SMP8759_ENABLE + offset);
  69         spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
  70 }
  71
  72 static void tango_mask(struct irq_data *d)
  73 {
  74         update_msi_enable(d, false);
  75 }
  76
  77 static void tango_unmask(struct irq_data *d)
  78 {
  79         update_msi_enable(d, true);
  80 }
  81
  82 static int tango_set_affinity(struct irq_data *d, const struct cpumask *mask,
  83                               bool force)
  84 {
  85         return -EINVAL;
  86 }
  87
  88 static void tango_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
  89 {
  90         struct tango_pcie *pcie = d->chip_data;
  91         msg->address_lo = lower_32_bits(pcie->msi_doorbell);
  92         msg->address_hi = upper_32_bits(pcie->msi_doorbell);
  93         msg->data = d->hwirq;
  94 }
  95
  96 static struct irq_chip tango_chip = {
  97         .irq_ack                = tango_ack,
  98         .irq_mask               = tango_mask,
  99         .irq_unmask             = tango_unmask,
 100         .irq_set_affinity       = tango_set_affinity,
 101         .irq_compose_msi_msg    = tango_compose_msi_msg,
 102 };
 103
 104 static void msi_ack(struct irq_data *d)
 105 {
 106         irq_chip_ack_parent(d);
 107 }
 108
 109 static void msi_mask(struct irq_data *d)
 110 {
 111         pci_msi_mask_irq(d);
 112         irq_chip_mask_parent(d);
 113 }
 114
 115 static void msi_unmask(struct irq_data *d)
 116 {
 117         pci_msi_unmask_irq(d);
 118         irq_chip_unmask_parent(d);
 119 }
 120
 121 static struct irq_chip msi_chip = {
 122         .name = "MSI",
 123         .irq_ack = msi_ack,
 124         .irq_mask = msi_mask,
 125         .irq_unmask = msi_unmask,
 126 };
 127
 128 static struct msi_domain_info msi_dom_info = {
 129         .flags  = MSI_FLAG_PCI_MSIX
 130                 | MSI_FLAG_USE_DEF_DOM_OPS
 131                 | MSI_FLAG_USE_DEF_CHIP_OPS,
 132         .chip   = &msi_chip,
 133 };
 134
 135 static int tango_irq_domain_alloc(struct irq_domain *dom, unsigned int virq,
 136                                   unsigned int nr_irqs, void *args)
 137 {
 138         struct tango_pcie *pcie = dom->host_data;
 139         unsigned long flags;
 140         int pos;
 141
 142         spin_lock_irqsave(&pcie->used_msi_lock, flags);
 143         pos = find_first_zero_bit(pcie->used_msi, MSI_MAX);
 144         if (pos >= MSI_MAX) {
 145                 spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
 146                 return -ENOSPC;
 147         }
 148         __set_bit(pos, pcie->used_msi);
 149         spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
 150         irq_domain_set_info(dom, virq, pos, &tango_chip,
 151                         pcie, handle_edge_irq, NULL, NULL);
 152
 153         return 0;
 154 }
 155
 156 static void tango_irq_domain_free(struct irq_domain *dom, unsigned int virq,
 157                                   unsigned int nr_irqs)
 158 {
 159         unsigned long flags;
 160         struct irq_data *d = irq_domain_get_irq_data(dom, virq);
 161         struct tango_pcie *pcie = d->chip_data;
 162
 163         spin_lock_irqsave(&pcie->used_msi_lock, flags);
 164         __clear_bit(d->hwirq, pcie->used_msi);
 165         spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
 166 }
 167
 168 static const struct irq_domain_ops dom_ops = {
 169         .alloc  = tango_irq_domain_alloc,
 170         .free   = tango_irq_domain_free,
 171 };
 172
 173 static int smp8759_config_read(struct pci_bus *bus, unsigned int devfn,
 174                                int where, int size, u32 *val)
 175 {
 176         struct pci_config_window *cfg = bus->sysdata;
 177         struct tango_pcie *pcie = dev_get_drvdata(cfg->parent);
 178         int ret;
 179
 180         /* Reads in configuration space outside devfn 0 return garbage */
 181         if (devfn != 0)
 182                 return PCIBIOS_FUNC_NOT_SUPPORTED;
 183
 184         /*
 185          * PCI config and MMIO accesses are muxed.  Linux doesn't have a
 186          * mutual exclusion mechanism for config vs. MMIO accesses, so
 187          * concurrent accesses may cause corruption.
 188          */
 189         writel_relaxed(1, pcie->base + SMP8759_MUX);
 190         ret = pci_generic_config_read(bus, devfn, where, size, val);
 191         writel_relaxed(0, pcie->base + SMP8759_MUX);
 192
 193         return ret;
 194 }
 195
 196 static int smp8759_config_write(struct pci_bus *bus, unsigned int devfn,
 197                                 int where, int size, u32 val)
 198 {
 199         struct pci_config_window *cfg = bus->sysdata;
 200         struct tango_pcie *pcie = dev_get_drvdata(cfg->parent);
 201         int ret;
 202
 203         writel_relaxed(1, pcie->base + SMP8759_MUX);
 204         ret = pci_generic_config_write(bus, devfn, where, size, val);
 205         writel_relaxed(0, pcie->base + SMP8759_MUX);
 206
 207         return ret;
 208 }
 209
 210 static struct pci_ecam_ops smp8759_ecam_ops = {
 211         .bus_shift      = 20,
 212         .pci_ops        = {
 213                 .map_bus        = pci_ecam_map_bus,
 214                 .read           = smp8759_config_read,
 215                 .write          = smp8759_config_write,
 216         }
 217 };
 218
 219 static int tango_pcie_link_up(struct tango_pcie *pcie)
 220 {
 221         void __iomem *test_out = pcie->base + SMP8759_TEST_OUT;
 222         int i;
 223
 224         writel_relaxed(16, test_out);
 225         for (i = 0; i < 10; ++i) {
 226                 u32 ltssm_state = readl_relaxed(test_out) >> 8;
 227                 if ((ltssm_state & 0x1f) == 0xf) /* L0 */
 228                         return 1;
 229                 usleep_range(3000, 4000);
 230         }
 231
 232         return 0;
 233 }
 234
 235 static int tango_pcie_probe(struct platform_device *pdev)
 236 {
 237         struct device *dev = &pdev->dev;
 238         struct tango_pcie *pcie;
 239         struct resource *res;
 240         struct fwnode_handle *fwnode = of_node_to_fwnode(dev->of_node);
 241         struct irq_domain *msi_dom, *irq_dom;
 242         struct of_pci_range_parser parser;
 243         struct of_pci_range range;
 244         int virq, offset;
 245
 246         dev_warn(dev, "simultaneous PCI config and MMIO accesses may cause data corruption\n");
 247         add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
 248
 249         pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
 250         if (!pcie)
 251                 return -ENOMEM;
 252
 253         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 254         pcie->base = devm_ioremap_resource(dev, res);
 255         if (IS_ERR(pcie->base))
 256                 return PTR_ERR(pcie->base);
 257
 258         platform_set_drvdata(pdev, pcie);
 259
 260         if (!tango_pcie_link_up(pcie))
 261                 return -ENODEV;
 262
 263         if (of_pci_dma_range_parser_init(&parser, dev->of_node) < 0)
 264                 return -ENOENT;
 265
 266         if (of_pci_range_parser_one(&parser, &range) == NULL)
 267                 return -ENOENT;
 268
 269         range.pci_addr += range.size;
 270         pcie->msi_doorbell = range.pci_addr + res->start + SMP8759_DOORBELL;
 271
 272         for (offset = 0; offset < MSI_MAX / 8; offset += 4)
 273                 writel_relaxed(0, pcie->base + SMP8759_ENABLE + offset);
 274
 275         virq = platform_get_irq(pdev, 1);
 276         if (virq <= 0) {
 277                 dev_err(dev, "Failed to map IRQ\n");
 278                 return -ENXIO;
 279         }
 280
 281         irq_dom = irq_domain_create_linear(fwnode, MSI_MAX, &dom_ops, pcie);
 282         if (!irq_dom) {
 283                 dev_err(dev, "Failed to create IRQ domain\n");
 284                 return -ENOMEM;
 285         }
 286
 287         msi_dom = pci_msi_create_irq_domain(fwnode, &msi_dom_info, irq_dom);
 288         if (!msi_dom) {
 289                 dev_err(dev, "Failed to create MSI domain\n");
 290                 irq_domain_remove(irq_dom);
 291                 return -ENOMEM;
 292         }
 293
 294         pcie->dom = irq_dom;
 295         spin_lock_init(&pcie->used_msi_lock);
 296         irq_set_chained_handler_and_data(virq, tango_msi_isr, pcie);
 297
 298         return pci_host_common_probe(pdev, &smp8759_ecam_ops);
 299 }
 300
 301 static const struct of_device_id tango_pcie_ids[] = {
 302         { .compatible = "sigma,smp8759-pcie" },
 303         { },
 304 };
 305
 306 static struct platform_driver tango_pcie_driver = {
 307         .probe  = tango_pcie_probe,
 308         .driver = {
 309                 .name = KBUILD_MODNAME,
 310                 .of_match_table = tango_pcie_ids,
 311                 .suppress_bind_attrs = true,
 312         },
 313 };
 314 builtin_platform_driver(tango_pcie_driver);
 315
 316 /*
 317  * The root complex advertises the wrong device class.
 318  * Header Type 1 is for PCI-to-PCI bridges.
 319  */
 320 static void tango_fixup_class(struct pci_dev *dev)
 321 {
 322         dev->class = PCI_CLASS_BRIDGE_PCI << 8;
 323 }
 324 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0024, tango_fixup_class);
 325 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0028, tango_fixup_class);
 326
 327 /*
 328  * The root complex exposes a "fake" BAR, which is used to filter
 329  * bus-to-system accesses.  Only accesses within the range defined by this
 330  * BAR are forwarded to the host, others are ignored.
 331  *
 332  * By default, the DMA framework expects an identity mapping, and DRAM0 is
 333  * mapped at 0x80000000.
 334  */
 335 static void tango_fixup_bar(struct pci_dev *dev)
 336 {
 337         dev->non_compliant_bars = true;
 338         pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, 0x80000000);
 339 }
 340 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0024, tango_fixup_bar);
 341 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0028, tango_fixup_bar);