aerdrv.c

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/*
 * drivers/pci/pcie/aer/aerdrv.c
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * This file implements the AER root port service driver. The driver will
 * register an irq handler. When root port triggers an AER interrupt, the irq
 * handler will collect root port status and schedule a work.
 *
 * Copyright (C) 2006 Intel Corp.
 *  Tom Long Nguyen ([email protected])
 *  Zhang Yanmin ([email protected])
 *
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/pcieport_if.h>
#include <linux/slab.h>

#include "aerdrv.h"
#include "../../pci.h"

/*
 * Version Information
 */
#define DRIVER_VERSION "v1.0"
#define DRIVER_AUTHOR "[email protected]"
#define DRIVER_DESC "Root Port Advanced Error Reporting Driver"
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

static int __devinit aer_probe(struct pcie_device *dev);
static void aer_remove(struct pcie_device *dev);
static pci_ers_result_t aer_error_detected(struct pci_dev *dev,
    enum pci_channel_state error);
static void aer_error_resume(struct pci_dev *dev);
static pci_ers_result_t aer_root_reset(struct pci_dev *dev);

static const struct pci_error_handlers aer_error_handlers = {
    .error_detected = aer_error_detected,
    .resume     = aer_error_resume,
};

static struct pcie_port_service_driver aerdriver = {
    .name       = "aer",
    .port_type  = PCI_EXP_TYPE_ROOT_PORT,
    .service    = PCIE_PORT_SERVICE_AER,

    .probe      = aer_probe,
    .remove     = aer_remove,

    .err_handler    = &aer_error_handlers,

    .reset_link = aer_root_reset,
};

static int pcie_aer_disable;

void pci_no_aer(void)
{
    pcie_aer_disable = 1;   /* has priority over 'forceload' */
}

bool pci_aer_available(void)
{
    return !pcie_aer_disable && pci_msi_enabled();
}

static int set_device_error_reporting(struct pci_dev *dev, void *data)
{
    bool enable = *((bool *)data);
    int type = pci_pcie_type(dev);

    if ((type == PCI_EXP_TYPE_ROOT_PORT) ||
        (type == PCI_EXP_TYPE_UPSTREAM) ||
        (type == PCI_EXP_TYPE_DOWNSTREAM)) {
        if (enable)
            pci_enable_pcie_error_reporting(dev);
        else
            pci_disable_pcie_error_reporting(dev);
    }

    if (enable)
        pcie_set_ecrc_checking(dev);

    return 0;
}

static void set_downstream_devices_error_reporting(struct pci_dev *dev,
                           bool enable)
{
    set_device_error_reporting(dev, &enable);

    if (!dev->subordinate)
        return;
    pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
}

static void aer_enable_rootport(struct aer_rpc *rpc)
{
    struct pci_dev *pdev = rpc->rpd->port;
    int aer_pos;
    u16 reg16;
    u32 reg32;

    /* Clear PCIe Capability's Device Status */
    pcie_capability_read_word(pdev, PCI_EXP_DEVSTA, &reg16);
    pcie_capability_write_word(pdev, PCI_EXP_DEVSTA, reg16);

    /* Disable system error generation in response to error messages */
    pcie_capability_clear_word(pdev, PCI_EXP_RTCTL,
                   SYSTEM_ERROR_INTR_ON_MESG_MASK);

    aer_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ERR);
    /* Clear error status */
    pci_read_config_dword(pdev, aer_pos + PCI_ERR_ROOT_STATUS, &reg32);
    pci_write_config_dword(pdev, aer_pos + PCI_ERR_ROOT_STATUS, reg32);
    pci_read_config_dword(pdev, aer_pos + PCI_ERR_COR_STATUS, &reg32);
    pci_write_config_dword(pdev, aer_pos + PCI_ERR_COR_STATUS, reg32);
    pci_read_config_dword(pdev, aer_pos + PCI_ERR_UNCOR_STATUS, &reg32);
    pci_write_config_dword(pdev, aer_pos + PCI_ERR_UNCOR_STATUS, reg32);

    /*
     * Enable error reporting for the root port device and downstream port
     * devices.
     */
    set_downstream_devices_error_reporting(pdev, true);

    /* Enable Root Port's interrupt in response to error messages */
    pci_read_config_dword(pdev, aer_pos + PCI_ERR_ROOT_COMMAND, &reg32);
    reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
    pci_write_config_dword(pdev, aer_pos + PCI_ERR_ROOT_COMMAND, reg32);
}

static void aer_disable_rootport(struct aer_rpc *rpc)
{
    struct pci_dev *pdev = rpc->rpd->port;
    u32 reg32;
    int pos;

    /*
     * Disable error reporting for the root port device and downstream port
     * devices.
     */
    set_downstream_devices_error_reporting(pdev, false);

    pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ERR);
    /* Disable Root's interrupt in response to error messages */
    pci_read_config_dword(pdev, pos + PCI_ERR_ROOT_COMMAND, &reg32);
    reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
    pci_write_config_dword(pdev, pos + PCI_ERR_ROOT_COMMAND, reg32);

    /* Clear Root's error status reg */
    pci_read_config_dword(pdev, pos + PCI_ERR_ROOT_STATUS, &reg32);
    pci_write_config_dword(pdev, pos + PCI_ERR_ROOT_STATUS, reg32);
}

irqreturn_t aer_irq(int irq, void *context)
{
    unsigned int status, id;
    struct pcie_device *pdev = (struct pcie_device *)context;
    struct aer_rpc *rpc = get_service_data(pdev);
    int next_prod_idx;
    unsigned long flags;
    int pos;

    pos = pci_find_ext_capability(pdev->port, PCI_EXT_CAP_ID_ERR);
    /*
     * Must lock access to Root Error Status Reg, Root Error ID Reg,
     * and Root error producer/consumer index
     */
    spin_lock_irqsave(&rpc->e_lock, flags);

    /* Read error status */
    pci_read_config_dword(pdev->port, pos + PCI_ERR_ROOT_STATUS, &status);
    if (!(status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV))) {
        spin_unlock_irqrestore(&rpc->e_lock, flags);
        return IRQ_NONE;
    }

    /* Read error source and clear error status */
    pci_read_config_dword(pdev->port, pos + PCI_ERR_ROOT_ERR_SRC, &id);
    pci_write_config_dword(pdev->port, pos + PCI_ERR_ROOT_STATUS, status);

    /* Store error source for later DPC handler */
    next_prod_idx = rpc->prod_idx + 1;
    if (next_prod_idx == AER_ERROR_SOURCES_MAX)
        next_prod_idx = 0;
    if (next_prod_idx == rpc->cons_idx) {
        /*
         * Error Storm Condition - possibly the same error occurred.
         * Drop the error.
         */
        spin_unlock_irqrestore(&rpc->e_lock, flags);
        return IRQ_HANDLED;
    }
    rpc->e_sources[rpc->prod_idx].status =  status;
    rpc->e_sources[rpc->prod_idx].id = id;
    rpc->prod_idx = next_prod_idx;
    spin_unlock_irqrestore(&rpc->e_lock, flags);

    /*  Invoke DPC handler */
    schedule_work(&rpc->dpc_handler);

    return IRQ_HANDLED;
}
EXPORT_SYMBOL_GPL(aer_irq);

static struct aer_rpc *aer_alloc_rpc(struct pcie_device *dev)
{
    struct aer_rpc *rpc;

    rpc = kzalloc(sizeof(struct aer_rpc), GFP_KERNEL);
    if (!rpc)
        return NULL;

    /* Initialize Root lock access, e_lock, to Root Error Status Reg */
    spin_lock_init(&rpc->e_lock);

    rpc->rpd = dev;
    INIT_WORK(&rpc->dpc_handler, aer_isr);
    mutex_init(&rpc->rpc_mutex);
    init_waitqueue_head(&rpc->wait_release);

    /* Use PCIe bus function to store rpc into PCIe device */
    set_service_data(dev, rpc);

    return rpc;
}

static void aer_remove(struct pcie_device *dev)
{
    struct aer_rpc *rpc = get_service_data(dev);

    if (rpc) {
        /* If register interrupt service, it must be free. */
        if (rpc->isr)
            free_irq(dev->irq, dev);

        wait_event(rpc->wait_release, rpc->prod_idx == rpc->cons_idx);

        aer_disable_rootport(rpc);
        kfree(rpc);
        set_service_data(dev, NULL);
    }
}

static int __devinit aer_probe(struct pcie_device *dev)
{
    int status;
    struct aer_rpc *rpc;
    struct device *device = &dev->device;

    /* Init */
    status = aer_init(dev);
    if (status)
        return status;

    /* Alloc rpc data structure */
    rpc = aer_alloc_rpc(dev);
    if (!rpc) {
        dev_printk(KERN_DEBUG, device, "alloc rpc failed\n");
        aer_remove(dev);
        return -ENOMEM;
    }

    /* Request IRQ ISR */
    status = request_irq(dev->irq, aer_irq, IRQF_SHARED, "aerdrv", dev);
    if (status) {
        dev_printk(KERN_DEBUG, device, "request IRQ failed\n");
        aer_remove(dev);
        return status;
    }

    rpc->isr = 1;

    aer_enable_rootport(rpc);

    return status;
}

static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
{
    u32 reg32;
    int pos;

    pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);

    /* Disable Root's interrupt in response to error messages */
    pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, &reg32);
    reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
    pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, reg32);

    aer_do_secondary_bus_reset(dev);
    dev_printk(KERN_DEBUG, &dev->dev, "Root Port link has been reset\n");

    /* Clear Root Error Status */
    pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
    pci_write_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, reg32);

    /* Enable Root Port's interrupt in response to error messages */
    pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, &reg32);
    reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
    pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, reg32);

    return PCI_ERS_RESULT_RECOVERED;
}

static pci_ers_result_t aer_error_detected(struct pci_dev *dev,
            enum pci_channel_state error)
{
    /* Root Port has no impact. Always recovers. */
    return PCI_ERS_RESULT_CAN_RECOVER;
}

static void aer_error_resume(struct pci_dev *dev)
{
    int pos;
    u32 status, mask;
    u16 reg16;

    /* Clean up Root device status */
    pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &reg16);
    pcie_capability_write_word(dev, PCI_EXP_DEVSTA, reg16);

    /* Clean AER Root Error Status */
    pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
    pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
    pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, &mask);
    if (dev->error_state == pci_channel_io_normal)
        status &= ~mask; /* Clear corresponding nonfatal bits */
    else
        status &= mask; /* Clear corresponding fatal bits */
    pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);
}

static int __init aer_service_init(void)
{
    if (!pci_aer_available() || aer_acpi_firmware_first())
        return -ENXIO;
    return pcie_port_service_register(&aerdriver);
}

static void __exit aer_service_exit(void)
{
    pcie_port_service_unregister(&aerdriver);
}

module_init(aer_service_init);
module_exit(aer_service_exit);