// SPDX-License-Identifier: GPL-2.0+
/*
 * ipmi_si_pci.c
 *
 * Handling for IPMI devices on the PCI bus.
 */

#define pr_fmt(fmt) "ipmi_pci: " fmt

#include <linux/module.h>
#include <linux/pci.h>
#include "ipmi_si.h"

static bool pci_registered;

static bool si_trypci = true;

module_param_named(trypci, si_trypci, bool, 0);
MODULE_PARM_DESC(trypci,
                 "Setting this to zero will disable the default scan of the interfaces identified via pci");

#define PCI_DEVICE_ID_HP_MMC 0x121A

static int ipmi_pci_probe_regspacing(struct si_sm_io *io)
{
        unsigned char status;
        int regspacing;

        if (io->si_info->type != SI_KCS)
                return DEFAULT_REGSPACING;

        io->regsize = DEFAULT_REGSIZE;
        io->regshift = 0;

        /* detect 1, 4, 16byte spacing */
        for (regspacing = DEFAULT_REGSPACING; regspacing <= 16;) {
                io->regspacing = regspacing;
                if (io->io_setup(io)) {
                        dev_err(io->dev, "Could not setup I/O space\n");
                        return DEFAULT_REGSPACING;
                }
                /* write invalid cmd */
                io->outputb(io, 1, 0x10);
                /* read status back */
                status = io->inputb(io, 1);
                io->io_cleanup(io);
                if (status)
                        return regspacing;
                regspacing *= 4;
        }

        return DEFAULT_REGSPACING;
}

static struct pci_device_id ipmi_pci_blacklist[] = {
        /*
         * This is a "Virtual IPMI device", whatever that is.  It appears
         * as a KCS device by the class, but it is not one.
         */
        { PCI_VDEVICE(REALTEK, 0x816c) },
        { 0, }
};

static int ipmi_pci_probe(struct pci_dev *pdev,
                                    const struct pci_device_id *ent)
{
        int rv;
        struct si_sm_io io;

        if (pci_match_id(ipmi_pci_blacklist, pdev))
                return -ENODEV;

        memset(&io, 0, sizeof(io));
        io.addr_source = SI_PCI;
        dev_info(&pdev->dev, "probing via PCI");

        switch (pdev->class) {
        case PCI_CLASS_SERIAL_IPMI_SMIC:
                io.si_info = &ipmi_smic_si_info;
                break;

        case PCI_CLASS_SERIAL_IPMI_KCS:
                io.si_info = &ipmi_kcs_si_info;
                break;

        case PCI_CLASS_SERIAL_IPMI_BT:
                io.si_info = &ipmi_bt_si_info;
                break;

        default:
                dev_info(&pdev->dev, "Unknown IPMI class: %x\n", pdev->class);
                return -ENOMEM;
        }

        rv = pcim_enable_device(pdev);
        if (rv) {
                dev_err(&pdev->dev, "couldn't enable PCI device\n");
                return rv;
        }

        if (pci_resource_flags(pdev, 0) & IORESOURCE_IO) {
                if (!IS_ENABLED(CONFIG_HAS_IOPORT))
                        return -ENXIO;

                io.addr_space = IPMI_IO_ADDR_SPACE;
                io.io_setup = ipmi_si_port_setup;
        } else {
                io.addr_space = IPMI_MEM_ADDR_SPACE;
                io.io_setup = ipmi_si_mem_setup;
        }
        io.addr_data = pci_resource_start(pdev, 0);

        io.dev = &pdev->dev;

        io.regspacing = ipmi_pci_probe_regspacing(&io);
        io.regsize = DEFAULT_REGSIZE;
        io.regshift = 0;

        io.irq = pdev->irq;
        if (io.irq)
                io.irq_setup = ipmi_std_irq_setup;

        dev_info(&pdev->dev, "%pR regsize %u spacing %u irq %d\n",
                 &pdev->resource[0], io.regsize, io.regspacing, io.irq);

        return ipmi_si_add_smi(&io);
}

static void ipmi_pci_remove(struct pci_dev *pdev)
{
        ipmi_si_remove_by_dev(&pdev->dev);
}

static const struct pci_device_id ipmi_pci_devices[] = {
        { PCI_VDEVICE(HP, PCI_DEVICE_ID_HP_MMC) },
        { PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_IPMI_SMIC, ~0) },
        { PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_IPMI_KCS, ~0) },
        { PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_IPMI_BT, ~0) },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, ipmi_pci_devices);

static struct pci_driver ipmi_pci_driver = {
        .name =         SI_DEVICE_NAME,
        .id_table =     ipmi_pci_devices,
        .probe =        ipmi_pci_probe,
        .remove =       ipmi_pci_remove,
};

void ipmi_si_pci_init(void)
{
        if (si_trypci) {
                int rv = pci_register_driver(&ipmi_pci_driver);
                if (rv)
                        pr_err("Unable to register PCI driver: %d\n", rv);
                else
                        pci_registered = true;
        }
}

void ipmi_si_pci_shutdown(void)
{
        if (pci_registered)
                pci_unregister_driver(&ipmi_pci_driver);
}