linux/drivers/pci/host/pci-keystone.c
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   1/*
   2 * PCIe host controller driver for Texas Instruments Keystone SoCs
   3 *
   4 * Copyright (C) 2013-2014 Texas Instruments., Ltd.
   5 *              http://www.ti.com
   6 *
   7 * Author: Murali Karicheri <m-karicheri2@ti.com>
   8 * Implementation based on pci-exynos.c and pcie-designware.c
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License version 2 as
  12 * published by the Free Software Foundation.
  13 */
  14
  15#include <linux/irqchip/chained_irq.h>
  16#include <linux/clk.h>
  17#include <linux/delay.h>
  18#include <linux/irqdomain.h>
  19#include <linux/module.h>
  20#include <linux/msi.h>
  21#include <linux/of_irq.h>
  22#include <linux/of.h>
  23#include <linux/of_pci.h>
  24#include <linux/platform_device.h>
  25#include <linux/phy/phy.h>
  26#include <linux/resource.h>
  27#include <linux/signal.h>
  28
  29#include "pcie-designware.h"
  30#include "pci-keystone.h"
  31
  32#define DRIVER_NAME     "keystone-pcie"
  33
  34/* driver specific constants */
  35#define MAX_MSI_HOST_IRQS               8
  36#define MAX_LEGACY_HOST_IRQS            4
  37
  38/* DEV_STAT_CTRL */
  39#define PCIE_CAP_BASE           0x70
  40
  41/* PCIE controller device IDs */
  42#define PCIE_RC_K2HK            0xb008
  43#define PCIE_RC_K2E             0xb009
  44#define PCIE_RC_K2L             0xb00a
  45
  46#define to_keystone_pcie(x)     container_of(x, struct keystone_pcie, pp)
  47
  48static void quirk_limit_mrrs(struct pci_dev *dev)
  49{
  50        struct pci_bus *bus = dev->bus;
  51        struct pci_dev *bridge = bus->self;
  52        static const struct pci_device_id rc_pci_devids[] = {
  53                { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2HK),
  54                 .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
  55                { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2E),
  56                 .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
  57                { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2L),
  58                 .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
  59                { 0, },
  60        };
  61
  62        if (pci_is_root_bus(bus))
  63                return;
  64
  65        /* look for the host bridge */
  66        while (!pci_is_root_bus(bus)) {
  67                bridge = bus->self;
  68                bus = bus->parent;
  69        }
  70
  71        if (bridge) {
  72                /*
  73                 * Keystone PCI controller has a h/w limitation of
  74                 * 256 bytes maximum read request size.  It can't handle
  75                 * anything higher than this.  So force this limit on
  76                 * all downstream devices.
  77                 */
  78                if (pci_match_id(rc_pci_devids, bridge)) {
  79                        if (pcie_get_readrq(dev) > 256) {
  80                                dev_info(&dev->dev, "limiting MRRS to 256\n");
  81                                pcie_set_readrq(dev, 256);
  82                        }
  83                }
  84        }
  85}
  86DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, quirk_limit_mrrs);
  87
  88static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie)
  89{
  90        struct pcie_port *pp = &ks_pcie->pp;
  91        int count = 200;
  92
  93        dw_pcie_setup_rc(pp);
  94
  95        if (dw_pcie_link_up(pp)) {
  96                dev_err(pp->dev, "Link already up\n");
  97                return 0;
  98        }
  99
 100        ks_dw_pcie_initiate_link_train(ks_pcie);
 101        /* check if the link is up or not */
 102        while (!dw_pcie_link_up(pp)) {
 103                usleep_range(100, 1000);
 104                if (--count) {
 105                        ks_dw_pcie_initiate_link_train(ks_pcie);
 106                        continue;
 107                }
 108                dev_err(pp->dev, "phy link never came up\n");
 109                return -EINVAL;
 110        }
 111
 112        return 0;
 113}
 114
 115static void ks_pcie_msi_irq_handler(unsigned int irq, struct irq_desc *desc)
 116{
 117        struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
 118        u32 offset = irq - ks_pcie->msi_host_irqs[0];
 119        struct pcie_port *pp = &ks_pcie->pp;
 120        struct irq_chip *chip = irq_desc_get_chip(desc);
 121
 122        dev_dbg(pp->dev, "%s, irq %d\n", __func__, irq);
 123
 124        /*
 125         * The chained irq handler installation would have replaced normal
 126         * interrupt driver handler so we need to take care of mask/unmask and
 127         * ack operation.
 128         */
 129        chained_irq_enter(chip, desc);
 130        ks_dw_pcie_handle_msi_irq(ks_pcie, offset);
 131        chained_irq_exit(chip, desc);
 132}
 133
 134/**
 135 * ks_pcie_legacy_irq_handler() - Handle legacy interrupt
 136 * @irq: IRQ line for legacy interrupts
 137 * @desc: Pointer to irq descriptor
 138 *
 139 * Traverse through pending legacy interrupts and invoke handler for each. Also
 140 * takes care of interrupt controller level mask/ack operation.
 141 */
 142static void ks_pcie_legacy_irq_handler(unsigned int irq, struct irq_desc *desc)
 143{
 144        struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
 145        struct pcie_port *pp = &ks_pcie->pp;
 146        u32 irq_offset = irq - ks_pcie->legacy_host_irqs[0];
 147        struct irq_chip *chip = irq_desc_get_chip(desc);
 148
 149        dev_dbg(pp->dev, ": Handling legacy irq %d\n", irq);
 150
 151        /*
 152         * The chained irq handler installation would have replaced normal
 153         * interrupt driver handler so we need to take care of mask/unmask and
 154         * ack operation.
 155         */
 156        chained_irq_enter(chip, desc);
 157        ks_dw_pcie_handle_legacy_irq(ks_pcie, irq_offset);
 158        chained_irq_exit(chip, desc);
 159}
 160
 161static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
 162                                           char *controller, int *num_irqs)
 163{
 164        int temp, max_host_irqs, legacy = 1, *host_irqs, ret = -EINVAL;
 165        struct device *dev = ks_pcie->pp.dev;
 166        struct device_node *np_pcie = dev->of_node, **np_temp;
 167
 168        if (!strcmp(controller, "msi-interrupt-controller"))
 169                legacy = 0;
 170
 171        if (legacy) {
 172                np_temp = &ks_pcie->legacy_intc_np;
 173                max_host_irqs = MAX_LEGACY_HOST_IRQS;
 174                host_irqs = &ks_pcie->legacy_host_irqs[0];
 175        } else {
 176                np_temp = &ks_pcie->msi_intc_np;
 177                max_host_irqs = MAX_MSI_HOST_IRQS;
 178                host_irqs =  &ks_pcie->msi_host_irqs[0];
 179        }
 180
 181        /* interrupt controller is in a child node */
 182        *np_temp = of_find_node_by_name(np_pcie, controller);
 183        if (!(*np_temp)) {
 184                dev_err(dev, "Node for %s is absent\n", controller);
 185                goto out;
 186        }
 187        temp = of_irq_count(*np_temp);
 188        if (!temp)
 189                goto out;
 190        if (temp > max_host_irqs)
 191                dev_warn(dev, "Too many %s interrupts defined %u\n",
 192                        (legacy ? "legacy" : "MSI"), temp);
 193
 194        /*
 195         * support upto max_host_irqs. In dt from index 0 to 3 (legacy) or 0 to
 196         * 7 (MSI)
 197         */
 198        for (temp = 0; temp < max_host_irqs; temp++) {
 199                host_irqs[temp] = irq_of_parse_and_map(*np_temp, temp);
 200                if (!host_irqs[temp])
 201                        break;
 202        }
 203        if (temp) {
 204                *num_irqs = temp;
 205                ret = 0;
 206        }
 207out:
 208        return ret;
 209}
 210
 211static void ks_pcie_setup_interrupts(struct keystone_pcie *ks_pcie)
 212{
 213        int i;
 214
 215        /* Legacy IRQ */
 216        for (i = 0; i < ks_pcie->num_legacy_host_irqs; i++) {
 217                irq_set_handler_data(ks_pcie->legacy_host_irqs[i], ks_pcie);
 218                irq_set_chained_handler(ks_pcie->legacy_host_irqs[i],
 219                                        ks_pcie_legacy_irq_handler);
 220        }
 221        ks_dw_pcie_enable_legacy_irqs(ks_pcie);
 222
 223        /* MSI IRQ */
 224        if (IS_ENABLED(CONFIG_PCI_MSI)) {
 225                for (i = 0; i < ks_pcie->num_msi_host_irqs; i++) {
 226                        irq_set_chained_handler(ks_pcie->msi_host_irqs[i],
 227                                                ks_pcie_msi_irq_handler);
 228                        irq_set_handler_data(ks_pcie->msi_host_irqs[i],
 229                                             ks_pcie);
 230                }
 231        }
 232}
 233
 234/*
 235 * When a PCI device does not exist during config cycles, keystone host gets a
 236 * bus error instead of returning 0xffffffff. This handler always returns 0
 237 * for this kind of faults.
 238 */
 239static int keystone_pcie_fault(unsigned long addr, unsigned int fsr,
 240                                struct pt_regs *regs)
 241{
 242        unsigned long instr = *(unsigned long *) instruction_pointer(regs);
 243
 244        if ((instr & 0x0e100090) == 0x00100090) {
 245                int reg = (instr >> 12) & 15;
 246
 247                regs->uregs[reg] = -1;
 248                regs->ARM_pc += 4;
 249        }
 250
 251        return 0;
 252}
 253
 254static void __init ks_pcie_host_init(struct pcie_port *pp)
 255{
 256        struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
 257        u32 val;
 258
 259        ks_pcie_establish_link(ks_pcie);
 260        ks_dw_pcie_setup_rc_app_regs(ks_pcie);
 261        ks_pcie_setup_interrupts(ks_pcie);
 262        writew(PCI_IO_RANGE_TYPE_32 | (PCI_IO_RANGE_TYPE_32 << 8),
 263                        pp->dbi_base + PCI_IO_BASE);
 264
 265        /* update the Vendor ID */
 266        writew(ks_pcie->device_id, pp->dbi_base + PCI_DEVICE_ID);
 267
 268        /* update the DEV_STAT_CTRL to publish right mrrs */
 269        val = readl(pp->dbi_base + PCIE_CAP_BASE + PCI_EXP_DEVCTL);
 270        val &= ~PCI_EXP_DEVCTL_READRQ;
 271        /* set the mrrs to 256 bytes */
 272        val |= BIT(12);
 273        writel(val, pp->dbi_base + PCIE_CAP_BASE + PCI_EXP_DEVCTL);
 274
 275        /*
 276         * PCIe access errors that result into OCP errors are caught by ARM as
 277         * "External aborts"
 278         */
 279        hook_fault_code(17, keystone_pcie_fault, SIGBUS, 0,
 280                        "Asynchronous external abort");
 281}
 282
 283static struct pcie_host_ops keystone_pcie_host_ops = {
 284        .rd_other_conf = ks_dw_pcie_rd_other_conf,
 285        .wr_other_conf = ks_dw_pcie_wr_other_conf,
 286        .link_up = ks_dw_pcie_link_up,
 287        .host_init = ks_pcie_host_init,
 288        .msi_set_irq = ks_dw_pcie_msi_set_irq,
 289        .msi_clear_irq = ks_dw_pcie_msi_clear_irq,
 290        .get_msi_addr = ks_dw_pcie_get_msi_addr,
 291        .msi_host_init = ks_dw_pcie_msi_host_init,
 292        .scan_bus = ks_dw_pcie_v3_65_scan_bus,
 293};
 294
 295static int __init ks_add_pcie_port(struct keystone_pcie *ks_pcie,
 296                         struct platform_device *pdev)
 297{
 298        struct pcie_port *pp = &ks_pcie->pp;
 299        int ret;
 300
 301        ret = ks_pcie_get_irq_controller_info(ks_pcie,
 302                                        "legacy-interrupt-controller",
 303                                        &ks_pcie->num_legacy_host_irqs);
 304        if (ret)
 305                return ret;
 306
 307        if (IS_ENABLED(CONFIG_PCI_MSI)) {
 308                ret = ks_pcie_get_irq_controller_info(ks_pcie,
 309                                                "msi-interrupt-controller",
 310                                                &ks_pcie->num_msi_host_irqs);
 311                if (ret)
 312                        return ret;
 313        }
 314
 315        pp->root_bus_nr = -1;
 316        pp->ops = &keystone_pcie_host_ops;
 317        ret = ks_dw_pcie_host_init(ks_pcie, ks_pcie->msi_intc_np);
 318        if (ret) {
 319                dev_err(&pdev->dev, "failed to initialize host\n");
 320                return ret;
 321        }
 322
 323        return ret;
 324}
 325
 326static const struct of_device_id ks_pcie_of_match[] = {
 327        {
 328                .type = "pci",
 329                .compatible = "ti,keystone-pcie",
 330        },
 331        { },
 332};
 333MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
 334
 335static int __exit ks_pcie_remove(struct platform_device *pdev)
 336{
 337        struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
 338
 339        clk_disable_unprepare(ks_pcie->clk);
 340
 341        return 0;
 342}
 343
 344static int __init ks_pcie_probe(struct platform_device *pdev)
 345{
 346        struct device *dev = &pdev->dev;
 347        struct keystone_pcie *ks_pcie;
 348        struct pcie_port *pp;
 349        struct resource *res;
 350        void __iomem *reg_p;
 351        struct phy *phy;
 352        int ret = 0;
 353
 354        ks_pcie = devm_kzalloc(&pdev->dev, sizeof(*ks_pcie),
 355                                GFP_KERNEL);
 356        if (!ks_pcie)
 357                return -ENOMEM;
 358
 359        pp = &ks_pcie->pp;
 360
 361        /* initialize SerDes Phy if present */
 362        phy = devm_phy_get(dev, "pcie-phy");
 363        if (!IS_ERR_OR_NULL(phy)) {
 364                ret = phy_init(phy);
 365                if (ret < 0)
 366                        return ret;
 367        }
 368
 369        /* index 2 is to read PCI DEVICE_ID */
 370        res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
 371        reg_p = devm_ioremap_resource(dev, res);
 372        if (IS_ERR(reg_p))
 373                return PTR_ERR(reg_p);
 374        ks_pcie->device_id = readl(reg_p) >> 16;
 375        devm_iounmap(dev, reg_p);
 376        devm_release_mem_region(dev, res->start, resource_size(res));
 377
 378        pp->dev = dev;
 379        platform_set_drvdata(pdev, ks_pcie);
 380        ks_pcie->clk = devm_clk_get(dev, "pcie");
 381        if (IS_ERR(ks_pcie->clk)) {
 382                dev_err(dev, "Failed to get pcie rc clock\n");
 383                return PTR_ERR(ks_pcie->clk);
 384        }
 385        ret = clk_prepare_enable(ks_pcie->clk);
 386        if (ret)
 387                return ret;
 388
 389        ret = ks_add_pcie_port(ks_pcie, pdev);
 390        if (ret < 0)
 391                goto fail_clk;
 392
 393        return 0;
 394fail_clk:
 395        clk_disable_unprepare(ks_pcie->clk);
 396
 397        return ret;
 398}
 399
 400static struct platform_driver ks_pcie_driver __refdata = {
 401        .probe  = ks_pcie_probe,
 402        .remove = __exit_p(ks_pcie_remove),
 403        .driver = {
 404                .name   = "keystone-pcie",
 405                .of_match_table = of_match_ptr(ks_pcie_of_match),
 406        },
 407};
 408
 409module_platform_driver(ks_pcie_driver);
 410
 411MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
 412MODULE_DESCRIPTION("Keystone PCIe host controller driver");
 413MODULE_LICENSE("GPL v2");
 414