linux/arch/mips/pci/pci-ar724x.c
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   1/*
   2 *  Atheros AR724X PCI host controller driver
   3 *
   4 *  Copyright (C) 2011 René Bolldorf <xsecute@googlemail.com>
   5 *  Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
   6 *
   7 *  This program is free software; you can redistribute it and/or modify it
   8 *  under the terms of the GNU General Public License version 2 as published
   9 *  by the Free Software Foundation.
  10 */
  11
  12#include <linux/irq.h>
  13#include <linux/pci.h>
  14#include <linux/init.h>
  15#include <linux/platform_device.h>
  16#include <asm/mach-ath79/ath79.h>
  17#include <asm/mach-ath79/ar71xx_regs.h>
  18
  19#define AR724X_PCI_REG_RESET            0x18
  20#define AR724X_PCI_REG_INT_STATUS       0x4c
  21#define AR724X_PCI_REG_INT_MASK         0x50
  22
  23#define AR724X_PCI_RESET_LINK_UP        BIT(0)
  24
  25#define AR724X_PCI_INT_DEV0             BIT(14)
  26
  27#define AR724X_PCI_IRQ_COUNT            1
  28
  29#define AR7240_BAR0_WAR_VALUE   0xffff
  30
  31#define AR724X_PCI_CMD_INIT     (PCI_COMMAND_MEMORY |           \
  32                                 PCI_COMMAND_MASTER |           \
  33                                 PCI_COMMAND_INVALIDATE |       \
  34                                 PCI_COMMAND_PARITY |           \
  35                                 PCI_COMMAND_SERR |             \
  36                                 PCI_COMMAND_FAST_BACK)
  37
  38struct ar724x_pci_controller {
  39        void __iomem *devcfg_base;
  40        void __iomem *ctrl_base;
  41        void __iomem *crp_base;
  42
  43        int irq;
  44        int irq_base;
  45
  46        bool link_up;
  47        bool bar0_is_cached;
  48        u32  bar0_value;
  49
  50        struct pci_controller pci_controller;
  51        struct resource io_res;
  52        struct resource mem_res;
  53};
  54
  55static inline bool ar724x_pci_check_link(struct ar724x_pci_controller *apc)
  56{
  57        u32 reset;
  58
  59        reset = __raw_readl(apc->ctrl_base + AR724X_PCI_REG_RESET);
  60        return reset & AR724X_PCI_RESET_LINK_UP;
  61}
  62
  63static inline struct ar724x_pci_controller *
  64pci_bus_to_ar724x_controller(struct pci_bus *bus)
  65{
  66        struct pci_controller *hose;
  67
  68        hose = (struct pci_controller *) bus->sysdata;
  69        return container_of(hose, struct ar724x_pci_controller, pci_controller);
  70}
  71
  72static int ar724x_pci_local_write(struct ar724x_pci_controller *apc,
  73                                  int where, int size, u32 value)
  74{
  75        void __iomem *base;
  76        u32 data;
  77        int s;
  78
  79        WARN_ON(where & (size - 1));
  80
  81        if (!apc->link_up)
  82                return PCIBIOS_DEVICE_NOT_FOUND;
  83
  84        base = apc->crp_base;
  85        data = __raw_readl(base + (where & ~3));
  86
  87        switch (size) {
  88        case 1:
  89                s = ((where & 3) * 8);
  90                data &= ~(0xff << s);
  91                data |= ((value & 0xff) << s);
  92                break;
  93        case 2:
  94                s = ((where & 2) * 8);
  95                data &= ~(0xffff << s);
  96                data |= ((value & 0xffff) << s);
  97                break;
  98        case 4:
  99                data = value;
 100                break;
 101        default:
 102                return PCIBIOS_BAD_REGISTER_NUMBER;
 103        }
 104
 105        __raw_writel(data, base + (where & ~3));
 106        /* flush write */
 107        __raw_readl(base + (where & ~3));
 108
 109        return PCIBIOS_SUCCESSFUL;
 110}
 111
 112static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 113                            int size, uint32_t *value)
 114{
 115        struct ar724x_pci_controller *apc;
 116        void __iomem *base;
 117        u32 data;
 118
 119        apc = pci_bus_to_ar724x_controller(bus);
 120        if (!apc->link_up)
 121                return PCIBIOS_DEVICE_NOT_FOUND;
 122
 123        if (devfn)
 124                return PCIBIOS_DEVICE_NOT_FOUND;
 125
 126        base = apc->devcfg_base;
 127        data = __raw_readl(base + (where & ~3));
 128
 129        switch (size) {
 130        case 1:
 131                if (where & 1)
 132                        data >>= 8;
 133                if (where & 2)
 134                        data >>= 16;
 135                data &= 0xff;
 136                break;
 137        case 2:
 138                if (where & 2)
 139                        data >>= 16;
 140                data &= 0xffff;
 141                break;
 142        case 4:
 143                break;
 144        default:
 145                return PCIBIOS_BAD_REGISTER_NUMBER;
 146        }
 147
 148        if (where == PCI_BASE_ADDRESS_0 && size == 4 &&
 149            apc->bar0_is_cached) {
 150                /* use the cached value */
 151                *value = apc->bar0_value;
 152        } else {
 153                *value = data;
 154        }
 155
 156        return PCIBIOS_SUCCESSFUL;
 157}
 158
 159static int ar724x_pci_write(struct pci_bus *bus, unsigned int devfn, int where,
 160                             int size, uint32_t value)
 161{
 162        struct ar724x_pci_controller *apc;
 163        void __iomem *base;
 164        u32 data;
 165        int s;
 166
 167        apc = pci_bus_to_ar724x_controller(bus);
 168        if (!apc->link_up)
 169                return PCIBIOS_DEVICE_NOT_FOUND;
 170
 171        if (devfn)
 172                return PCIBIOS_DEVICE_NOT_FOUND;
 173
 174        if (soc_is_ar7240() && where == PCI_BASE_ADDRESS_0 && size == 4) {
 175                if (value != 0xffffffff) {
 176                        /*
 177                         * WAR for a hw issue. If the BAR0 register of the
 178                         * device is set to the proper base address, the
 179                         * memory space of the device is not accessible.
 180                         *
 181                         * Cache the intended value so it can be read back,
 182                         * and write a SoC specific constant value to the
 183                         * BAR0 register in order to make the device memory
 184                         * accessible.
 185                         */
 186                        apc->bar0_is_cached = true;
 187                        apc->bar0_value = value;
 188
 189                        value = AR7240_BAR0_WAR_VALUE;
 190                } else {
 191                        apc->bar0_is_cached = false;
 192                }
 193        }
 194
 195        base = apc->devcfg_base;
 196        data = __raw_readl(base + (where & ~3));
 197
 198        switch (size) {
 199        case 1:
 200                s = ((where & 3) * 8);
 201                data &= ~(0xff << s);
 202                data |= ((value & 0xff) << s);
 203                break;
 204        case 2:
 205                s = ((where & 2) * 8);
 206                data &= ~(0xffff << s);
 207                data |= ((value & 0xffff) << s);
 208                break;
 209        case 4:
 210                data = value;
 211                break;
 212        default:
 213                return PCIBIOS_BAD_REGISTER_NUMBER;
 214        }
 215
 216        __raw_writel(data, base + (where & ~3));
 217        /* flush write */
 218        __raw_readl(base + (where & ~3));
 219
 220        return PCIBIOS_SUCCESSFUL;
 221}
 222
 223static struct pci_ops ar724x_pci_ops = {
 224        .read   = ar724x_pci_read,
 225        .write  = ar724x_pci_write,
 226};
 227
 228static void ar724x_pci_irq_handler(struct irq_desc *desc)
 229{
 230        struct ar724x_pci_controller *apc;
 231        void __iomem *base;
 232        u32 pending;
 233
 234        apc = irq_desc_get_handler_data(desc);
 235        base = apc->ctrl_base;
 236
 237        pending = __raw_readl(base + AR724X_PCI_REG_INT_STATUS) &
 238                  __raw_readl(base + AR724X_PCI_REG_INT_MASK);
 239
 240        if (pending & AR724X_PCI_INT_DEV0)
 241                generic_handle_irq(apc->irq_base + 0);
 242
 243        else
 244                spurious_interrupt();
 245}
 246
 247static void ar724x_pci_irq_unmask(struct irq_data *d)
 248{
 249        struct ar724x_pci_controller *apc;
 250        void __iomem *base;
 251        int offset;
 252        u32 t;
 253
 254        apc = irq_data_get_irq_chip_data(d);
 255        base = apc->ctrl_base;
 256        offset = apc->irq_base - d->irq;
 257
 258        switch (offset) {
 259        case 0:
 260                t = __raw_readl(base + AR724X_PCI_REG_INT_MASK);
 261                __raw_writel(t | AR724X_PCI_INT_DEV0,
 262                             base + AR724X_PCI_REG_INT_MASK);
 263                /* flush write */
 264                __raw_readl(base + AR724X_PCI_REG_INT_MASK);
 265        }
 266}
 267
 268static void ar724x_pci_irq_mask(struct irq_data *d)
 269{
 270        struct ar724x_pci_controller *apc;
 271        void __iomem *base;
 272        int offset;
 273        u32 t;
 274
 275        apc = irq_data_get_irq_chip_data(d);
 276        base = apc->ctrl_base;
 277        offset = apc->irq_base - d->irq;
 278
 279        switch (offset) {
 280        case 0:
 281                t = __raw_readl(base + AR724X_PCI_REG_INT_MASK);
 282                __raw_writel(t & ~AR724X_PCI_INT_DEV0,
 283                             base + AR724X_PCI_REG_INT_MASK);
 284
 285                /* flush write */
 286                __raw_readl(base + AR724X_PCI_REG_INT_MASK);
 287
 288                t = __raw_readl(base + AR724X_PCI_REG_INT_STATUS);
 289                __raw_writel(t | AR724X_PCI_INT_DEV0,
 290                             base + AR724X_PCI_REG_INT_STATUS);
 291
 292                /* flush write */
 293                __raw_readl(base + AR724X_PCI_REG_INT_STATUS);
 294        }
 295}
 296
 297static struct irq_chip ar724x_pci_irq_chip = {
 298        .name           = "AR724X PCI ",
 299        .irq_mask       = ar724x_pci_irq_mask,
 300        .irq_unmask     = ar724x_pci_irq_unmask,
 301        .irq_mask_ack   = ar724x_pci_irq_mask,
 302};
 303
 304static void ar724x_pci_irq_init(struct ar724x_pci_controller *apc,
 305                                int id)
 306{
 307        void __iomem *base;
 308        int i;
 309
 310        base = apc->ctrl_base;
 311
 312        __raw_writel(0, base + AR724X_PCI_REG_INT_MASK);
 313        __raw_writel(0, base + AR724X_PCI_REG_INT_STATUS);
 314
 315        apc->irq_base = ATH79_PCI_IRQ_BASE + (id * AR724X_PCI_IRQ_COUNT);
 316
 317        for (i = apc->irq_base;
 318             i < apc->irq_base + AR724X_PCI_IRQ_COUNT; i++) {
 319                irq_set_chip_and_handler(i, &ar724x_pci_irq_chip,
 320                                         handle_level_irq);
 321                irq_set_chip_data(i, apc);
 322        }
 323
 324        irq_set_chained_handler_and_data(apc->irq, ar724x_pci_irq_handler,
 325                                         apc);
 326}
 327
 328static int ar724x_pci_probe(struct platform_device *pdev)
 329{
 330        struct ar724x_pci_controller *apc;
 331        struct resource *res;
 332        int id;
 333
 334        id = pdev->id;
 335        if (id == -1)
 336                id = 0;
 337
 338        apc = devm_kzalloc(&pdev->dev, sizeof(struct ar724x_pci_controller),
 339                            GFP_KERNEL);
 340        if (!apc)
 341                return -ENOMEM;
 342
 343        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctrl_base");
 344        apc->ctrl_base = devm_ioremap_resource(&pdev->dev, res);
 345        if (IS_ERR(apc->ctrl_base))
 346                return PTR_ERR(apc->ctrl_base);
 347
 348        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg_base");
 349        apc->devcfg_base = devm_ioremap_resource(&pdev->dev, res);
 350        if (IS_ERR(apc->devcfg_base))
 351                return PTR_ERR(apc->devcfg_base);
 352
 353        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "crp_base");
 354        apc->crp_base = devm_ioremap_resource(&pdev->dev, res);
 355        if (IS_ERR(apc->crp_base))
 356                return PTR_ERR(apc->crp_base);
 357
 358        apc->irq = platform_get_irq(pdev, 0);
 359        if (apc->irq < 0)
 360                return -EINVAL;
 361
 362        res = platform_get_resource_byname(pdev, IORESOURCE_IO, "io_base");
 363        if (!res)
 364                return -EINVAL;
 365
 366        apc->io_res.parent = res;
 367        apc->io_res.name = "PCI IO space";
 368        apc->io_res.start = res->start;
 369        apc->io_res.end = res->end;
 370        apc->io_res.flags = IORESOURCE_IO;
 371
 372        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem_base");
 373        if (!res)
 374                return -EINVAL;
 375
 376        apc->mem_res.parent = res;
 377        apc->mem_res.name = "PCI memory space";
 378        apc->mem_res.start = res->start;
 379        apc->mem_res.end = res->end;
 380        apc->mem_res.flags = IORESOURCE_MEM;
 381
 382        apc->pci_controller.pci_ops = &ar724x_pci_ops;
 383        apc->pci_controller.io_resource = &apc->io_res;
 384        apc->pci_controller.mem_resource = &apc->mem_res;
 385
 386        apc->link_up = ar724x_pci_check_link(apc);
 387        if (!apc->link_up)
 388                dev_warn(&pdev->dev, "PCIe link is down\n");
 389
 390        ar724x_pci_irq_init(apc, id);
 391
 392        ar724x_pci_local_write(apc, PCI_COMMAND, 4, AR724X_PCI_CMD_INIT);
 393
 394        register_pci_controller(&apc->pci_controller);
 395
 396        return 0;
 397}
 398
 399static struct platform_driver ar724x_pci_driver = {
 400        .probe = ar724x_pci_probe,
 401        .driver = {
 402                .name = "ar724x-pci",
 403        },
 404};
 405
 406static int __init ar724x_pci_init(void)
 407{
 408        return platform_driver_register(&ar724x_pci_driver);
 409}
 410
 411postcore_initcall(ar724x_pci_init);
 412