/******************************************************************************
 * platform-pci.c
 * 
 * Xen platform PCI device driver
 * Copyright (c) 2005, Intel Corporation.
 * Copyright (c) 2007, XenSource Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/version.h>
#include <linux/interrupt.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/hypervisor.h>
#include <asm/pgtable.h>
#include <xen/interface/memory.h>
#include <xen/interface/hvm/params.h>
#include <xen/features.h>
#include <xen/evtchn.h>
#ifdef __ia64__
#include <asm/xen/xencomm.h>
#endif

#include "platform-pci.h"

#ifdef HAVE_XEN_PLATFORM_COMPAT_H
#include <xen/platform-compat.h>
#endif

#define DRV_NAME    "xen-platform-pci"
#define DRV_VERSION "0.10"
#define DRV_RELDATE "03/03/2005"

static int max_hypercall_stub_pages, nr_hypercall_stub_pages;
char *hypercall_stubs;
EXPORT_SYMBOL(hypercall_stubs);

MODULE_AUTHOR("ssmith@xensource.com");
MODULE_DESCRIPTION("Xen platform PCI device");
MODULE_LICENSE("GPL");

/* NB. [aux-]ide-disks options do not unplug IDE CD-ROM drives. */
/* NB. aux-ide-disks is equiv to ide-disks except ignores primary master. */
static char *dev_unplug;
module_param(dev_unplug, charp, 0644);
MODULE_PARM_DESC(dev_unplug, "Emulated devices to unplug: "
		 "[all,][ide-disks,][aux-ide-disks,][nics,][never] (default is 'all')\n");

struct pci_dev *xen_platform_pdev;

static unsigned long shared_info_frame;
static uint64_t callback_via;

static int __devinit init_xen_info(void)
{
	struct xen_add_to_physmap xatp;
	extern void *shared_info_area;

#ifdef __ia64__
	xencomm_initialize();
#endif

	setup_xen_features();

	shared_info_frame = alloc_xen_mmio(PAGE_SIZE) >> PAGE_SHIFT;
	xatp.domid = DOMID_SELF;
	xatp.idx = 0;
	xatp.space = XENMAPSPACE_shared_info;
	xatp.gpfn = shared_info_frame;
	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
		BUG();

	shared_info_area =
		ioremap(shared_info_frame << PAGE_SHIFT, PAGE_SIZE);
	if (shared_info_area == NULL)
		panic("can't map shared info\n");

	return 0;
}

static unsigned long platform_mmio;
static unsigned long platform_mmio_alloc;
static unsigned long platform_mmiolen;

unsigned long alloc_xen_mmio(unsigned long len)
{
	unsigned long addr;

	addr = platform_mmio + platform_mmio_alloc;
	platform_mmio_alloc += len;
	BUG_ON(platform_mmio_alloc > platform_mmiolen);

	return addr;
}

#ifndef __ia64__

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,38)
static uint32_t xen_cpuid_base(void)
{
	uint32_t base, eax, ebx, ecx, edx;
	char signature[13];

	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
		cpuid(base, &eax, &ebx, &ecx, &edx);
		*(uint32_t*)(signature + 0) = ebx;
		*(uint32_t*)(signature + 4) = ecx;
		*(uint32_t*)(signature + 8) = edx;
		signature[12] = 0;

		if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
			return base;
	}

	return 0;
}
#endif

static int init_hypercall_stubs(void)
{
	uint32_t eax, ebx, ecx, edx, pages, msr, i, base;

	base = xen_cpuid_base();
	if (base == 0) {
		printk(KERN_WARNING
		       "Detected Xen platform device but not Xen VMM?\n");
		return -EINVAL;
	}

	cpuid(base + 1, &eax, &ebx, &ecx, &edx);

	printk(KERN_INFO "Xen version %d.%d.\n", eax >> 16, eax & 0xffff);

	/*
	 * Find largest supported number of hypercall pages.
	 * We'll create as many as possible up to this number.
	 */
	cpuid(base + 2, &pages, &msr, &ecx, &edx);

	/*
	 * Use __vmalloc() because vmalloc_exec() is not an exported symbol.
	 * PAGE_KERNEL_EXEC also is not exported, hence we use PAGE_KERNEL.
	 * hypercall_stubs = vmalloc_exec(pages * PAGE_SIZE);
	 */
	while (pages > 0) {
		hypercall_stubs = __vmalloc(
			pages * PAGE_SIZE,
			GFP_KERNEL | __GFP_HIGHMEM,
			__pgprot(__PAGE_KERNEL & ~_PAGE_NX));
		if (hypercall_stubs != NULL)
			break;
		pages--; /* vmalloc failed: try one fewer pages */
	}

	if (hypercall_stubs == NULL)
		return -ENOMEM;

	for (i = 0; i < pages; i++) {
		unsigned long pfn;
		pfn = vmalloc_to_pfn((char *)hypercall_stubs + i*PAGE_SIZE);
		wrmsrl(msr, ((u64)pfn << PAGE_SHIFT) + i);
	}

	nr_hypercall_stub_pages = pages;
	max_hypercall_stub_pages = pages;

	printk(KERN_INFO "Hypercall area is %u pages.\n", pages);

	return 0;
}

static void resume_hypercall_stubs(void)
{
	uint32_t base, ecx, edx, pages, msr, i;

	base = xen_cpuid_base();
	BUG_ON(base == 0);

	cpuid(base + 2, &pages, &msr, &ecx, &edx);

	if (pages > max_hypercall_stub_pages)
		pages = max_hypercall_stub_pages;

	for (i = 0; i < pages; i++) {
		unsigned long pfn;
		pfn = vmalloc_to_pfn((char *)hypercall_stubs + i*PAGE_SIZE);
		wrmsrl(msr, ((u64)pfn << PAGE_SHIFT) + i);
	}

	nr_hypercall_stub_pages = pages;
}

#else /* __ia64__ */

#define init_hypercall_stubs()		(0)
#define resume_hypercall_stubs()	((void)0)

#endif

static uint64_t get_callback_via(struct pci_dev *pdev)
{
	u8 pin;
	int irq;

#ifdef __ia64__
	for (irq = 0; irq < 16; irq++) {
		if (isa_irq_to_vector(irq) == pdev->irq)
			return irq; /* ISA IRQ */
	}
#else /* !__ia64__ */
	irq = pdev->irq;
	if (irq < 16)
		return irq; /* ISA IRQ */
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
	pin = pdev->pin;
#else
	pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
#endif

	/* We don't know the GSI. Specify the PCI INTx line instead. */
	return (((uint64_t)0x01 << 56) | /* PCI INTx identifier */
		((uint64_t)pci_domain_nr(pdev->bus) << 32) |
		((uint64_t)pdev->bus->number << 16) |
		((uint64_t)(pdev->devfn & 0xff) << 8) |
		((uint64_t)(pin - 1) & 3));
}

static int set_callback_via(uint64_t via)
{
	struct xen_hvm_param a;

	a.domid = DOMID_SELF;
	a.index = HVM_PARAM_CALLBACK_IRQ;
	a.value = via;
	return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
}

int xen_irq_init(struct pci_dev *pdev);
int xenbus_init(void);
int xen_reboot_init(void);
int xen_panic_handler_init(void);
int gnttab_init(void);

#define XEN_IOPORT_BASE 0x10

#define XEN_IOPORT_PLATFLAGS	(XEN_IOPORT_BASE + 0) /* 1 byte access (R/W) */
#define XEN_IOPORT_MAGIC	(XEN_IOPORT_BASE + 0) /* 2 byte access (R) */
#define XEN_IOPORT_UNPLUG	(XEN_IOPORT_BASE + 0) /* 2 byte access (W) */
#define XEN_IOPORT_DRVVER	(XEN_IOPORT_BASE + 0) /* 4 byte access (W) */

#define XEN_IOPORT_SYSLOG	(XEN_IOPORT_BASE + 2) /* 1 byte access (W) */
#define XEN_IOPORT_PROTOVER	(XEN_IOPORT_BASE + 2) /* 1 byte access (R) */
#define XEN_IOPORT_PRODNUM	(XEN_IOPORT_BASE + 2) /* 2 byte access (W) */

#define XEN_IOPORT_MAGIC_VAL 0x49d2
#define XEN_IOPORT_LINUX_PRODNUM 0xffff /* NB: register a proper one */
#define XEN_IOPORT_LINUX_DRVVER  ((LINUX_VERSION_CODE << 8) + 0x0)

#define UNPLUG_ALL_IDE_DISKS 1
#define UNPLUG_ALL_NICS 2
#define UNPLUG_AUX_IDE_DISKS 4
#define UNPLUG_ALL 7

static int check_platform_magic(struct device *dev, long ioaddr, long iolen)
{
	short magic, unplug = 0;
	char protocol, *p, *q, *err;

	/* Unconditionally unplug everything */
	if (!dev_unplug)
		unplug = UNPLUG_ALL;

	for (p = dev_unplug; p; p = q) {
		q = strchr(dev_unplug, ',');
		if (q)
			*q++ = '\0';
		if (!strcmp(p, "all"))
			unplug |= UNPLUG_ALL;
		else if (!strcmp(p, "ide-disks"))
			unplug |= UNPLUG_ALL_IDE_DISKS;
		else if (!strcmp(p, "aux-ide-disks"))
			unplug |= UNPLUG_AUX_IDE_DISKS;
		else if (!strcmp(p, "nics"))
			unplug |= UNPLUG_ALL_NICS;
		else if (!strcmp(p, "never"))
			unplug = 0;
		else
			dev_warn(dev, "unrecognised option '%s' "
				 "in module parameter 'dev_unplug'\n", p);
	}

	if (iolen < 0x16) {
		err = "backend too old";
		goto no_dev;
	}

	magic = inw(XEN_IOPORT_MAGIC);

	if (magic != XEN_IOPORT_MAGIC_VAL) {
		err = "unrecognised magic value";
		goto no_dev;
	}

	protocol = inb(XEN_IOPORT_PROTOVER);

	dev_info(dev, "I/O protocol version %d\n", protocol);

	switch (protocol) {
	case 1:
		outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
		outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
		if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
			dev_err(dev, "blacklisted by host\n");
			return -ENODEV;
		}
		/* Fall through */
	case 0:
		outw(unplug, XEN_IOPORT_UNPLUG);
		break;
	default:
		err = "unknown I/O protocol version";
		goto no_dev;
	}

	return 0;

 no_dev:
	dev_warn(dev, "failed backend handshake: %s\n", err);
	if (!unplug)
		return 0;
	dev_err(dev, "failed to execute specified dev_unplug options!\n");
	return -ENODEV;
}

#ifdef HAVE_OLDMEM_PFN_IS_RAM
static int xen_oldmem_pfn_is_ram(unsigned long pfn)
{
	struct xen_hvm_get_mem_type a;
	int ret;

	a.domid = DOMID_SELF;
	a.pfn = pfn;
	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
		return -ENXIO;

	switch (a.mem_type) {
		case HVMMEM_mmio_dm:
			ret = 0;
			break;
		case HVMMEM_ram_rw:
		case HVMMEM_ram_ro:
		default:
			ret = 1;
			break;
	}

	return ret;
}
#endif

static int __devinit platform_pci_init(struct pci_dev *pdev,
				       const struct pci_device_id *ent)
{
	int i, ret;
	long ioaddr, iolen;
	long mmio_addr, mmio_len;

	if (xen_platform_pdev)
		return -EBUSY;
	xen_platform_pdev = pdev;

	i = pci_enable_device(pdev);
	if (i)
		return i;

	ioaddr = pci_resource_start(pdev, 0);
	iolen = pci_resource_len(pdev, 0);

	mmio_addr = pci_resource_start(pdev, 1);
	mmio_len = pci_resource_len(pdev, 1);

	callback_via = get_callback_via(pdev);

	if (mmio_addr == 0 || ioaddr == 0 || callback_via == 0) {
		printk(KERN_WARNING DRV_NAME ":no resources found\n");
		return -ENOENT;
	}

	ret = pci_request_region(pdev, 1, DRV_NAME);
	if (ret < 0)
		return ret;

	ret = pci_request_region(pdev, 0, DRV_NAME);
	if (ret < 0)
		goto mem_out;

	platform_mmio = mmio_addr;
	platform_mmiolen = mmio_len;

	ret = init_hypercall_stubs();
	if (ret < 0)
		goto out;

	ret = check_platform_magic(&pdev->dev, ioaddr, iolen);
	if (ret < 0)
		goto out;

	if ((ret = init_xen_info()))
		goto out;

	if ((ret = gnttab_init()))
		goto out;

	if ((ret = xen_irq_init(pdev)))
		goto out;

	if ((ret = set_callback_via(callback_via)))
		goto out;

	if ((ret = xenbus_init()))
		goto out;

	if ((ret = xen_reboot_init()))
		goto out;

	if ((ret = xen_panic_handler_init()))
		goto out;

#ifdef HAVE_OLDMEM_PFN_IS_RAM
	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
#endif
 out:
	if (ret) {
		pci_release_region(pdev, 0);
mem_out:
		pci_release_region(pdev, 1);
	}

	return ret;
}

#define XEN_PLATFORM_VENDOR_ID 0x5853
#define XEN_PLATFORM_DEVICE_ID 0x0001
static struct pci_device_id platform_pci_tbl[] __devinitdata = {
	{XEN_PLATFORM_VENDOR_ID, XEN_PLATFORM_DEVICE_ID,
	 PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
	/* Continue to recognise the old ID for now */
	{0xfffd, 0x0101, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
	{0,}
};

MODULE_DEVICE_TABLE(pci, platform_pci_tbl);

static struct pci_driver platform_driver = {
	name:     DRV_NAME,
	probe:    platform_pci_init,
	id_table: platform_pci_tbl,
};

static int pci_device_registered;

void platform_pci_resume(void)
{
	struct xen_add_to_physmap xatp;

	resume_hypercall_stubs();

	xatp.domid = DOMID_SELF;
	xatp.idx = 0;
	xatp.space = XENMAPSPACE_shared_info;
	xatp.gpfn = shared_info_frame;
	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
		BUG();

	if (set_callback_via(callback_via))
		printk("platform_pci_resume failure!\n");
}

static int __init platform_pci_module_init(void)
{
	int rc;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,10)
	rc = pci_module_init(&platform_driver);
#else
	rc = pci_register_driver(&platform_driver);
#endif
	if (rc) {
		printk(KERN_INFO DRV_NAME
		       ": No platform pci device model found\n");
		return rc;
	}

	pci_device_registered = 1;
	return 0;
}

module_init(platform_pci_module_init);