/* Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/export.h>
#include <linux/iommu.h>
#include <linux/qcom_iommu.h>
#include <asm/sections.h>

static DEFINE_MUTEX(iommu_list_lock);
static LIST_HEAD(iommu_list);

#define MRC(reg, processor, op1, crn, crm, op2)				\
__asm__ __volatile__ (							\
"   mrc   "   #processor "," #op1 ", %0,"  #crn "," #crm "," #op2 "\n"  \
: "=r" (reg))

#define RCP15_PRRR(reg)   MRC(reg, p15, 0, c10, c2, 0)
#define RCP15_NMRR(reg)   MRC(reg, p15, 0, c10, c2, 1)

#define RCP15_MAIR0(reg)   MRC(reg, p15, 0, c10, c2, 0)
#define RCP15_MAIR1(reg)   MRC(reg, p15, 0, c10, c2, 1)

/* These values come from proc-v7-2level.S */
#define PRRR_VALUE 0xff0a81a8
#define NMRR_VALUE 0x40e040e0

/* These values come from proc-v7-3level.S */
#define MAIR0_VALUE 0xeeaa4400
#define MAIR1_VALUE 0xff000004

static struct iommu_access_ops *iommu_access_ops;

struct bus_type msm_iommu_sec_bus_type = {
	.name = "msm_iommu_sec_bus",
};

struct bus_type iommu_non_sec_bus_type = {
	.name = "msm_iommu_non_sec_bus",
};

struct bus_type *msm_iommu_non_sec_bus_type;

#ifndef CONFIG_ARM_SMMU
int msm_iommu_bus_register(void)
{
	msm_iommu_non_sec_bus_type = &platform_bus_type;
	return 0;
}
#else
int msm_iommu_bus_register(void)
{
	msm_iommu_non_sec_bus_type = &iommu_non_sec_bus_type;
	return bus_register(msm_iommu_non_sec_bus_type);
}
#endif

void msm_access_control(void)
{
	int ret;
	struct device *cb_dev;
	struct iommu_domain *domain;
	unsigned long start, kernel_start, kernel_end, end;

	start = 0;
	kernel_start = rounddown(__pa(_stext), PAGE_SIZE);
	kernel_end = ALIGN(__pa(_etext), PAGE_SIZE);
	end = 0xFFFFFFFF;

	/*
	 * If a target doesn't have the access control feature
	 * it won't have CB and that's okay
	 */
	cb_dev = msm_iommu_get_ctx("access_control");

	domain = iommu_domain_alloc(msm_iommu_non_sec_bus_type);
	if (!domain) {
		pr_err("Couldn't get domain for access control\n");
		goto err;
	}

	/*
	 * Map the region from start to kernel_start
	 */
	if (start < kernel_start) {
		ret = iommu_map(domain, start, start, kernel_start - start,
				IOMMU_READ | IOMMU_WRITE | IOMMU_DEVICE);

		if (ret) {
			pr_err("Mapping failed for region lower than kernel\n");
			goto free_dom;
		}
	}

	/*
	 * Map the region from kernel_end to end of DDR
	 */
	ret = iommu_map(domain, kernel_end, kernel_end, end - kernel_end + 1,
				IOMMU_READ | IOMMU_WRITE);

	if (ret) {
		pr_err("Mapping failed for region above kernel\n");
		goto free_dom;
	}

	ret = iommu_attach_device(domain, cb_dev);
	if (ret) {
		pr_err("Attach of access_control CB failed\n");
		goto free_dom;
	}

	return;

free_dom:
	iommu_domain_free(domain);
err:
	BUG();
}

/**
 * Pass the context bank device here. Based on the context bank
 * device, the bus is chosen and hence the respective IOMMU ops.
 */
struct bus_type *msm_iommu_get_bus(struct device *dev)
{
	if (!dev)
		return NULL;

	if (of_device_is_compatible(dev->of_node, "qcom,msm-smmu-v2-ctx")) {
		if (of_property_read_bool(dev->of_node, "qcom,secure-context"))
			return &msm_iommu_sec_bus_type;
		else
			return msm_iommu_non_sec_bus_type;
	} else
		return &platform_bus_type;
}
EXPORT_SYMBOL(msm_iommu_get_bus);

void msm_set_iommu_access_ops(struct iommu_access_ops *ops)
{
	iommu_access_ops = ops;
}

struct iommu_access_ops *msm_get_iommu_access_ops()
{
	BUG_ON(iommu_access_ops == NULL);
	return iommu_access_ops;
}
EXPORT_SYMBOL(msm_get_iommu_access_ops);

void msm_iommu_add_drv(struct msm_iommu_drvdata *drv)
{
	mutex_lock(&iommu_list_lock);
	list_add(&drv->list, &iommu_list);
	mutex_unlock(&iommu_list_lock);
}

void msm_iommu_remove_drv(struct msm_iommu_drvdata *drv)
{
	mutex_lock(&iommu_list_lock);
	list_del(&drv->list);
	mutex_unlock(&iommu_list_lock);
}

static int find_iommu_ctx(struct device *dev, void *data)
{
	struct msm_iommu_ctx_drvdata *c;

	c = dev_get_drvdata(dev);
	if (!c || !c->name)
		return 0;

	return !strcmp(data, c->name);
}

static struct device *find_context(struct device *dev, const char *name)
{
	return device_find_child(dev, (void *)name, find_iommu_ctx);
}

struct device *msm_iommu_get_ctx(const char *ctx_name)
{
	struct msm_iommu_drvdata *drv;
	struct device *dev = NULL;

	mutex_lock(&iommu_list_lock);
	list_for_each_entry(drv, &iommu_list, list) {
		dev = find_context(drv->dev, ctx_name);
		if (dev)
			break;
	}
	mutex_unlock(&iommu_list_lock);

	put_device(dev);

	if (!dev || !dev_get_drvdata(dev)) {
		pr_debug("Could not find context <%s>\n", ctx_name);
		dev = ERR_PTR(-EPROBE_DEFER);
	}

	return dev;
}
EXPORT_SYMBOL(msm_iommu_get_ctx);

/*
 * Selecting NMRR, PRRR, MAIR0 and MAIR1 for SMMU has a dependency on
 * the SMMU page table formate and a CPU mode. To simplify that, refer
 * the table below.
 *
 *		+-----------+-------------+------+
 *		| ARM       | ARM_LPAE    | ARM64|
 * +------------+-----------+-------------+------+
 * | SMMUv7S    | RCP15_PRRR| PRRR        | PRRR |
 * |            | RCP15_NMRR| NMRR        | NMRR |
 * +------------+-----------+-------------+------+
 * | SMMUv7L    | MAIR0     | RCP15_MAIR0 | MAIR0|
 * |            | MAIR1     | RCP15_MAIR1 | MAIR1|
 * +------------+-----------+-------------+------+
 * | SMMUv8L    | MAIR0     | RCP15_MAIR0 | MAIR0|
 * |            | MAIR1     | RCP15_MAIR1 | MAIR1|
 * +------------+-----------+-------------+------+
 */

#ifdef CONFIG_ARM64
u32 msm_iommu_get_mair0(void)
{
	return MAIR0_VALUE;
}

u32 msm_iommu_get_mair1(void)
{
	return MAIR1_VALUE;
}

u32 msm_iommu_get_prrr(void)
{
	return PRRR_VALUE;
}

u32 msm_iommu_get_nmrr(void)
{
	return NMRR_VALUE;
}
#elif defined(CONFIG_ARM_LPAE)
u32 msm_iommu_get_mair0(void)
{
	unsigned int mair0;

	RCP15_MAIR0(mair0);
	return mair0;
}

u32 msm_iommu_get_mair1(void)
{
	unsigned int mair1;

	RCP15_MAIR1(mair1);
	return mair1;
}

u32 msm_iommu_get_prrr(void)
{
	return PRRR_VALUE;
}

u32 msm_iommu_get_nmrr(void)
{
	return NMRR_VALUE;
}
#else
u32 msm_iommu_get_mair0(void)
{
	return MAIR0_VALUE;
}

u32 msm_iommu_get_mair1(void)
{
	return MAIR1_VALUE;
}

u32 msm_iommu_get_prrr(void)
{
	u32 prrr;

	RCP15_PRRR(prrr);
	return prrr;
}

u32 msm_iommu_get_nmrr(void)
{
	u32 nmrr;

	RCP15_NMRR(nmrr);
	return nmrr;
}
#endif