/*
 * Copyright (c) 2015, Linaro Limited, Shannon Zhao
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <xen/xen.h>
#include <xen/page.h>
#include <xen/interface/memory.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>

static int xen_unmap_device_mmio(const struct resource *resources,
				 unsigned int count)
{
	unsigned int i, j, nr;
	int rc = 0;
	const struct resource *r;
	struct xen_remove_from_physmap xrp;

	for (i = 0; i < count; i++) {
		r = &resources[i];
		nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE);
		if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0))
			continue;

		for (j = 0; j < nr; j++) {
			xrp.domid = DOMID_SELF;
			xrp.gpfn = XEN_PFN_DOWN(r->start) + j;
			rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap,
						  &xrp);
			if (rc)
				return rc;
		}
	}

	return rc;
}

static int xen_map_device_mmio(const struct resource *resources,
			       unsigned int count)
{
	unsigned int i, j, nr;
	int rc = 0;
	const struct resource *r;
	xen_pfn_t *gpfns;
	xen_ulong_t *idxs;
	int *errs;
	struct xen_add_to_physmap_range xatp;

	for (i = 0; i < count; i++) {
		r = &resources[i];
		nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE);
		if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0))
			continue;

		gpfns = kzalloc(sizeof(xen_pfn_t) * nr, GFP_KERNEL);
		idxs = kzalloc(sizeof(xen_ulong_t) * nr, GFP_KERNEL);
		errs = kzalloc(sizeof(int) * nr, GFP_KERNEL);
		if (!gpfns || !idxs || !errs) {
			kfree(gpfns);
			kfree(idxs);
			kfree(errs);
			rc = -ENOMEM;
			goto unmap;
		}

		for (j = 0; j < nr; j++) {
			/*
			 * The regions are always mapped 1:1 to DOM0 and this is
			 * fine because the memory map for DOM0 is the same as
			 * the host (except for the RAM).
			 */
			gpfns[j] = XEN_PFN_DOWN(r->start) + j;
			idxs[j] = XEN_PFN_DOWN(r->start) + j;
		}

		xatp.domid = DOMID_SELF;
		xatp.size = nr;
		xatp.space = XENMAPSPACE_dev_mmio;

		set_xen_guest_handle(xatp.gpfns, gpfns);
		set_xen_guest_handle(xatp.idxs, idxs);
		set_xen_guest_handle(xatp.errs, errs);

		rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
		kfree(gpfns);
		kfree(idxs);
		kfree(errs);
		if (rc)
			goto unmap;
	}

	return rc;

unmap:
	xen_unmap_device_mmio(resources, i);
	return rc;
}

static int xen_platform_notifier(struct notifier_block *nb,
				 unsigned long action, void *data)
{
	struct platform_device *pdev = to_platform_device(data);
	int r = 0;

	if (pdev->num_resources == 0 || pdev->resource == NULL)
		return NOTIFY_OK;

	switch (action) {
	case BUS_NOTIFY_ADD_DEVICE:
		r = xen_map_device_mmio(pdev->resource, pdev->num_resources);
		break;
	case BUS_NOTIFY_DEL_DEVICE:
		r = xen_unmap_device_mmio(pdev->resource, pdev->num_resources);
		break;
	default:
		return NOTIFY_DONE;
	}
	if (r)
		dev_err(&pdev->dev, "Platform: Failed to %s device %s MMIO!\n",
			action == BUS_NOTIFY_ADD_DEVICE ? "map" :
			(action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"),
			pdev->name);

	return NOTIFY_OK;
}

static struct notifier_block platform_device_nb = {
	.notifier_call = xen_platform_notifier,
};

static int __init register_xen_platform_notifier(void)
{
	if (!xen_initial_domain() || acpi_disabled)
		return 0;

	return bus_register_notifier(&platform_bus_type, &platform_device_nb);
}

arch_initcall(register_xen_platform_notifier);

#ifdef CONFIG_ARM_AMBA
#include <linux/amba/bus.h>

static int xen_amba_notifier(struct notifier_block *nb,
			     unsigned long action, void *data)
{
	struct amba_device *adev = to_amba_device(data);
	int r = 0;

	switch (action) {
	case BUS_NOTIFY_ADD_DEVICE:
		r = xen_map_device_mmio(&adev->res, 1);
		break;
	case BUS_NOTIFY_DEL_DEVICE:
		r = xen_unmap_device_mmio(&adev->res, 1);
		break;
	default:
		return NOTIFY_DONE;
	}
	if (r)
		dev_err(&adev->dev, "AMBA: Failed to %s device %s MMIO!\n",
			action == BUS_NOTIFY_ADD_DEVICE ? "map" :
			(action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"),
			adev->dev.init_name);

	return NOTIFY_OK;
}

static struct notifier_block amba_device_nb = {
	.notifier_call = xen_amba_notifier,
};

static int __init register_xen_amba_notifier(void)
{
	if (!xen_initial_domain() || acpi_disabled)
		return 0;

	return bus_register_notifier(&amba_bustype, &amba_device_nb);
}

arch_initcall(register_xen_amba_notifier);
#endif