root/drivers/pci/hotplug/cpcihp_zt5550.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * cpcihp_zt5550.c
 *
 * Intel/Ziatech ZT5550 CompactPCI Host Controller driver
 *
 * Copyright 2002 SOMA Networks, Inc.
 * Copyright 2001 Intel San Luis Obispo
 * Copyright 2000,2001 MontaVista Software Inc.
 *
 * Send feedback to <scottm@somanetworks.com>
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/signal.h>       /* IRQF_SHARED */
#include "cpci_hotplug.h"
#include "cpcihp_zt5550.h"

#define DRIVER_VERSION  "0.2"
#define DRIVER_AUTHOR   "Scott Murray <scottm@somanetworks.com>"
#define DRIVER_DESC     "ZT5550 CompactPCI Hot Plug Driver"

#define MY_NAME "cpcihp_zt5550"

#define dbg(format, arg...)                                     \
        do {                                                    \
                if (debug)                                      \
                        printk(KERN_DEBUG "%s: " format "\n",   \
                                MY_NAME, ## arg);               \
        } while (0)
#define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME, ## arg)
#define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME, ## arg)
#define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME, ## arg)

/* local variables */
static bool debug;
static bool poll;
static struct cpci_hp_controller_ops zt5550_hpc_ops;
static struct cpci_hp_controller zt5550_hpc;

/* Primary cPCI bus bridge device */
static struct pci_dev *bus0_dev;
static struct pci_bus *bus0;

/* Host controller device */
static struct pci_dev *hc_dev;

/* Host controller register addresses */
static void __iomem *hc_registers;
static void __iomem *csr_hc_index;
static void __iomem *csr_hc_data;
static void __iomem *csr_int_status;
static void __iomem *csr_int_mask;


static int zt5550_hc_config(struct pci_dev *pdev)
{
        int ret;

        /* Since we know that no boards exist with two HC chips, treat it as an error */
        if (hc_dev) {
                err("too many host controller devices?");
                return -EBUSY;
        }

        ret = pci_enable_device(pdev);
        if (ret) {
                err("cannot enable %s\n", pci_name(pdev));
                return ret;
        }

        hc_dev = pdev;
        dbg("hc_dev = %p", hc_dev);
        dbg("pci resource start %llx", (unsigned long long)pci_resource_start(hc_dev, 1));
        dbg("pci resource len %llx", (unsigned long long)pci_resource_len(hc_dev, 1));

        if (!request_mem_region(pci_resource_start(hc_dev, 1),
                                pci_resource_len(hc_dev, 1), MY_NAME)) {
                err("cannot reserve MMIO region");
                ret = -ENOMEM;
                goto exit_disable_device;
        }

        hc_registers =
            ioremap(pci_resource_start(hc_dev, 1), pci_resource_len(hc_dev, 1));
        if (!hc_registers) {
                err("cannot remap MMIO region %llx @ %llx",
                        (unsigned long long)pci_resource_len(hc_dev, 1),
                        (unsigned long long)pci_resource_start(hc_dev, 1));
                ret = -ENODEV;
                goto exit_release_region;
        }

        csr_hc_index = hc_registers + CSR_HCINDEX;
        csr_hc_data = hc_registers + CSR_HCDATA;
        csr_int_status = hc_registers + CSR_INTSTAT;
        csr_int_mask = hc_registers + CSR_INTMASK;

        /*
         * Disable host control, fault and serial interrupts
         */
        dbg("disabling host control, fault and serial interrupts");
        writeb((u8) HC_INT_MASK_REG, csr_hc_index);
        writeb((u8) ALL_INDEXED_INTS_MASK, csr_hc_data);
        dbg("disabled host control, fault and serial interrupts");

        /*
         * Disable timer0, timer1 and ENUM interrupts
         */
        dbg("disabling timer0, timer1 and ENUM interrupts");
        writeb((u8) ALL_DIRECT_INTS_MASK, csr_int_mask);
        dbg("disabled timer0, timer1 and ENUM interrupts");
        return 0;

exit_release_region:
        release_mem_region(pci_resource_start(hc_dev, 1),
                           pci_resource_len(hc_dev, 1));
exit_disable_device:
        pci_disable_device(hc_dev);
        return ret;
}

static int zt5550_hc_cleanup(void)
{
        if (!hc_dev)
                return -ENODEV;

        iounmap(hc_registers);
        release_mem_region(pci_resource_start(hc_dev, 1),
                           pci_resource_len(hc_dev, 1));
        pci_disable_device(hc_dev);
        return 0;
}

static int zt5550_hc_query_enum(void)
{
        u8 value;

        value = inb_p(ENUM_PORT);
        return ((value & ENUM_MASK) == ENUM_MASK);
}

static int zt5550_hc_check_irq(void *dev_id)
{
        int ret;
        u8 reg;

        ret = 0;
        if (dev_id == zt5550_hpc.dev_id) {
                reg = readb(csr_int_status);
                if (reg)
                        ret = 1;
        }
        return ret;
}

static int zt5550_hc_enable_irq(void)
{
        u8 reg;

        if (hc_dev == NULL)
                return -ENODEV;

        reg = readb(csr_int_mask);
        reg = reg & ~ENUM_INT_MASK;
        writeb(reg, csr_int_mask);
        return 0;
}

static int zt5550_hc_disable_irq(void)
{
        u8 reg;

        if (hc_dev == NULL)
                return -ENODEV;

        reg = readb(csr_int_mask);
        reg = reg | ENUM_INT_MASK;
        writeb(reg, csr_int_mask);
        return 0;
}

static int zt5550_hc_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        int status;

        status = zt5550_hc_config(pdev);
        if (status != 0)
                return status;

        dbg("returned from zt5550_hc_config");

        memset(&zt5550_hpc, 0, sizeof(struct cpci_hp_controller));
        zt5550_hpc_ops.query_enum = zt5550_hc_query_enum;
        zt5550_hpc.ops = &zt5550_hpc_ops;
        if (!poll) {
                zt5550_hpc.irq = hc_dev->irq;
                zt5550_hpc.irq_flags = IRQF_SHARED;
                zt5550_hpc.dev_id = hc_dev;

                zt5550_hpc_ops.enable_irq = zt5550_hc_enable_irq;
                zt5550_hpc_ops.disable_irq = zt5550_hc_disable_irq;
                zt5550_hpc_ops.check_irq = zt5550_hc_check_irq;
        } else {
                info("using ENUM# polling mode");
        }

        status = cpci_hp_register_controller(&zt5550_hpc);
        if (status != 0) {
                err("could not register cPCI hotplug controller");
                goto init_hc_error;
        }
        dbg("registered controller");

        /* Look for first device matching cPCI bus's bridge vendor and device IDs */
        bus0_dev = pci_get_device(PCI_VENDOR_ID_DEC,
                                  PCI_DEVICE_ID_DEC_21154, NULL);
        if (!bus0_dev) {
                status = -ENODEV;
                goto init_register_error;
        }
        bus0 = bus0_dev->subordinate;
        pci_dev_put(bus0_dev);

        status = cpci_hp_register_bus(bus0, 0x0a, 0x0f);
        if (status != 0) {
                err("could not register cPCI hotplug bus");
                goto init_register_error;
        }
        dbg("registered bus");

        status = cpci_hp_start();
        if (status != 0) {
                err("could not started cPCI hotplug system");
                cpci_hp_unregister_bus(bus0);
                goto init_register_error;
        }
        dbg("started cpci hp system");

        return 0;
init_register_error:
        cpci_hp_unregister_controller(&zt5550_hpc);
init_hc_error:
        err("status = %d", status);
        zt5550_hc_cleanup();
        return status;

}

static void zt5550_hc_remove_one(struct pci_dev *pdev)
{
        cpci_hp_stop();
        cpci_hp_unregister_bus(bus0);
        cpci_hp_unregister_controller(&zt5550_hpc);
        zt5550_hc_cleanup();
}


static const struct pci_device_id zt5550_hc_pci_tbl[] = {
        { PCI_VENDOR_ID_ZIATECH, PCI_DEVICE_ID_ZIATECH_5550_HC, PCI_ANY_ID, PCI_ANY_ID, },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, zt5550_hc_pci_tbl);

static struct pci_driver zt5550_hc_driver = {
        .name           = "zt5550_hc",
        .id_table       = zt5550_hc_pci_tbl,
        .probe          = zt5550_hc_init_one,
        .remove         = zt5550_hc_remove_one,
};

static int __init zt5550_init(void)
{
        struct resource *r;
        int rc;

        info(DRIVER_DESC " version: " DRIVER_VERSION);
        r = request_region(ENUM_PORT, 1, "#ENUM hotswap signal register");
        if (!r)
                return -EBUSY;

        rc = pci_register_driver(&zt5550_hc_driver);
        if (rc < 0)
                release_region(ENUM_PORT, 1);
        return rc;
}

static void __exit
zt5550_exit(void)
{
        pci_unregister_driver(&zt5550_hc_driver);
        release_region(ENUM_PORT, 1);
}

module_init(zt5550_init);
module_exit(zt5550_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
module_param(poll, bool, 0644);
MODULE_PARM_DESC(poll, "#ENUM polling mode enabled or not");