ipmi_si_pci.c

// 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);
}