path: root/drivers/pci/hotplug/cpqphp_pci.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Compaq Hot Plug Controller Driver
 *
 * Copyright (C) 1995,2001 Compaq Computer Corporation
 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2001 IBM Corp.
 *
 * All rights reserved.
 *
 * Send feedback to <greg@kroah.com>
 *
 */

#define pr_fmt(fmt) "cpqphp: " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/proc_fs.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include "../pci.h"
#include "cpqphp.h"
#include "cpqphp_nvram.h"


u8 cpqhp_nic_irq;
u8 cpqhp_disk_irq;

static u16 unused_IRQ;

/*
 * detect_HRT_floating_pointer
 *
 * find the Hot Plug Resource Table in the specified region of memory.
 *
 */
static void __iomem *detect_HRT_floating_pointer(void __iomem *begin, void __iomem *end)
{
	void __iomem *fp;
	void __iomem *endp;
	u8 temp1, temp2, temp3, temp4;
	int status = 0;

	endp = (end - sizeof(struct hrt) + 1);

	for (fp = begin; fp <= endp; fp += 16) {
		temp1 = readb(fp + SIG0);
		temp2 = readb(fp + SIG1);
		temp3 = readb(fp + SIG2);
		temp4 = readb(fp + SIG3);
		if (temp1 == '$' &&
		    temp2 == 'H' &&
		    temp3 == 'R' &&
		    temp4 == 'T') {
			status = 1;
			break;
		}
	}

	if (!status)
		fp = NULL;

	dbg("Discovered Hotplug Resource Table at %p\n", fp);
	return fp;
}


int cpqhp_configure_device(struct controller *ctrl, struct pci_func *func)
{
	struct pci_bus *child;
	int num;

	pci_lock_rescan_remove();

	if (func->pci_dev == NULL)
		func->pci_dev = pci_get_domain_bus_and_slot(0, func->bus,
							PCI_DEVFN(func->device,
							func->function));

	/* No pci device, we need to create it then */
	if (func->pci_dev == NULL) {
		dbg("INFO: pci_dev still null\n");

		num = pci_scan_slot(ctrl->pci_dev->bus, PCI_DEVFN(func->device, func->function));
		if (num)
			pci_bus_add_devices(ctrl->pci_dev->bus);

		func->pci_dev = pci_get_domain_bus_and_slot(0, func->bus,
							PCI_DEVFN(func->device,
							func->function));
		if (func->pci_dev == NULL) {
			dbg("ERROR: pci_dev still null\n");
			goto out;
		}
	}

	if (func->pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
		pci_hp_add_bridge(func->pci_dev);
		child = func->pci_dev->subordinate;
		if (child)
			pci_bus_add_devices(child);
	}

	pci_dev_put(func->pci_dev);

 out:
	pci_unlock_rescan_remove();
	return 0;
}


int cpqhp_unconfigure_device(struct pci_func *func)
{
	int j;

	dbg("%s: bus/dev/func = %x/%x/%x\n", __func__, func->bus, func->device, func->function);

	pci_lock_rescan_remove();
	for (j = 0; j < 8 ; j++) {
		struct pci_dev *temp = pci_get_domain_bus_and_slot(0,
							func->bus,
							PCI_DEVFN(func->device,
							j));
		if (temp) {
			pci_dev_put(temp);
			pci_stop_and_remove_bus_device(temp);
		}
	}
	pci_unlock_rescan_remove();
	return 0;
}

/*
 * cpqhp_set_irq
 *
 * @bus_num: bus number of PCI device
 * @dev_num: device number of PCI device
 * @slot: pointer to u8 where slot number will be returned
 */
int cpqhp_set_irq(u8 bus_num, u8 dev_num, u8 int_pin, u8 irq_num)
{
	int rc = 0;

	if (cpqhp_legacy_mode) {
		struct pci_dev *fakedev;
		struct pci_bus *fakebus;
		u16 temp_word;

		fakedev = kmalloc_obj(*fakedev);
		fakebus = kmalloc_obj(*fakebus);
		if (!fakedev || !fakebus) {
			kfree(fakedev);
			kfree(fakebus);
			return -ENOMEM;
		}

		fakedev->devfn = dev_num << 3;
		fakedev->bus = fakebus;
		fakebus->number = bus_num;
		dbg("%s: dev %d, bus %d, pin %d, num %d\n",
		    __func__, dev_num, bus_num, int_pin, irq_num);
		rc = pcibios_set_irq_routing(fakedev, int_pin - 1, irq_num);
		kfree(fakedev);
		kfree(fakebus);
		dbg("%s: rc %d\n", __func__, rc);
		if (!rc)
			return !rc;

		/* set the Edge Level Control Register (ELCR) */
		temp_word = inb(0x4d0);
		temp_word |= inb(0x4d1) << 8;

		temp_word |= 0x01 << irq_num;

		/* This should only be for x86 as it sets the Edge Level
		 * Control Register
		 */
		outb((u8)(temp_word & 0xFF), 0x4d0);
		outb((u8)((temp_word & 0xFF00) >> 8), 0x4d1);
		rc = 0;
	}

	return rc;
}


static int PCI_ScanBusForNonBridge(struct controller *ctrl, u8 bus_num, u8 *dev_num)
{
	u16 tdevice;
	u32 work;
	int ret = -1;

	ctrl->pci_bus->number = bus_num;

	for (tdevice = 0; tdevice < 0xFF; tdevice++) {
		/* Scan for access first */
		if (!pci_bus_read_dev_vendor_id(ctrl->pci_bus, tdevice, &work, 0))
			continue;
		ret = pci_bus_read_config_dword(ctrl->pci_bus, tdevice, PCI_CLASS_REVISION, &work);
		if (ret)
			continue;
		dbg("Looking for nonbridge bus_num %d dev_num %d\n", bus_num, tdevice);
		/* Yep we got one. Not a bridge ? */
		if ((work >> 8) != PCI_TO_PCI_BRIDGE_CLASS) {
			*dev_num = tdevice;
			dbg("found it !\n");
			return 0;
		} else {
			/*
			 * XXX: Code whose debug printout indicated
			 * recursion to buses underneath bridges might be
			 * necessary was removed because it never did
			 * any recursion.
			 */
			ret = 0;
			pr_warn("missing feature: bridge scan recursion not implemented\n");
		}
	}


	return ret;
}


static int PCI_GetBusDevHelper(struct controller *ctrl, u8 *bus_num, u8 *dev_num, u8 slot, u8 nobridge)
{
	int loop, len;
	u32 work;
	u8 tbus, tdevice, tslot;

	len = cpqhp_routing_table_length();
	for (loop = 0; loop < len; ++loop) {
		tbus = cpqhp_routing_table->slots[loop].bus;
		tdevice = cpqhp_routing_table->slots[loop].devfn;
		tslot = cpqhp_routing_table->slots[loop].slot;

		if (tslot == slot) {
			*bus_num = tbus;
			*dev_num = tdevice;
			ctrl->pci_bus->number = tbus;
			pci_bus_read_config_dword(ctrl->pci_bus, *dev_num, PCI_VENDOR_ID, &work);
			if (!nobridge || PCI_POSSIBLE_ERROR(work))
				return 0;

			dbg("bus_num %d devfn %d\n", *bus_num, *dev_num);
			pci_bus_read_config_dword(ctrl->pci_bus, *dev_num, PCI_CLASS_REVISION, &work);
			dbg("work >> 8 (%x) = BRIDGE (%x)\n", work >> 8, PCI_TO_PCI_BRIDGE_CLASS);

			if ((work >> 8) == PCI_TO_PCI_BRIDGE_CLASS) {
				pci_bus_read_config_byte(ctrl->pci_bus, *dev_num, PCI_SECONDARY_BUS, &tbus);
				dbg("Scan bus for Non Bridge: bus %d\n", tbus);
				if (PCI_ScanBusForNonBridge(ctrl, tbus, dev_num) == 0) {
					*bus_num = tbus;
					return 0;
				}
			} else
				return 0;
		}
	}
	return -1;
}


int cpqhp_get_bus_dev(struct controller *ctrl, u8 *bus_num, u8 *dev_num, u8 slot)
{
	/* plain (bridges allowed) */
	return PCI_GetBusDevHelper(ctrl, bus_num, dev_num, slot, 0);
}


/* More PCI configuration routines; this time centered around hotplug
 * controller
 */


/*
 * cpqhp_save_config
 *
 * Reads configuration for all slots in a PCI bus and saves info.
 *