/* Copyright (c) 2010-2012, Code Aurora Forum. 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.
 */

#include <linux/slab.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/sched.h>

#include <asm/cacheflush.h>

#include <mach/scm.h>
#include <mach/msm_watchdog.h>

static int simlock_mask;
static int unlock_mask;
static char *simlock_code = "";
static int security_level;

module_param_named(simlock_code, simlock_code, charp, S_IRUGO | S_IWUSR | S_IWGRP);

#define SCM_ENOMEM		-5
#define SCM_EOPNOTSUPP		-4
#define SCM_EINVAL_ADDR		-3
#define SCM_EINVAL_ARG		-2
#define SCM_ERROR		-1
#define SCM_INTERRUPTED		1

static DEFINE_MUTEX(scm_lock);

#define TAG "[SEC] "
#undef PDEBUG
#define PDEBUG(fmt, args...) printk(KERN_INFO TAG "[K] %s(%i, %s): " fmt "\n", \
		__func__, current->pid, current->comm, ##args)

#undef PERR
#define PERR(fmt, args...) printk(KERN_ERR TAG "[E] %s(%i, %s): " fmt "\n", \
		__func__, current->pid, current->comm, ##args)

#undef PINFO
#define PINFO(fmt, ...) printk(KERN_INFO TAG "[I] %s(%i, %s): " fmt "\n", \
		__func__, current->pid, current->comm, ##__VA_ARGS__)

struct scm_command {
	u32	len;
	u32	buf_offset;
	u32	resp_hdr_offset;
	u32	id;
	u32	buf[0];
};

struct scm_response {
	u32	len;
	u32	buf_offset;
	u32	is_complete;
};

struct oem_simlock_unlock_req {
	u32	unlock;
	void *code;
};

struct oem_log_oper_req {
	u32	address;
	u32	size;
	u32	buf_addr;
	u32	buf_len;
	int	revert;
};

struct oem_access_item_req {
	u32	is_write;
	u32	id;
	u32	buf_len;
	void *buf;
};

struct oem_3rd_party_syscall_req {
	u32 id;
	void *buf;
	u32 len;
};

static struct scm_command *alloc_scm_command(size_t cmd_size, size_t resp_size)
{
	struct scm_command *cmd;
	size_t len = sizeof(*cmd) + sizeof(struct scm_response) + cmd_size +
		resp_size;

	cmd = kzalloc(PAGE_ALIGN(len), GFP_KERNEL);
	if (cmd) {
		cmd->len = len;
		cmd->buf_offset = offsetof(struct scm_command, buf);
		cmd->resp_hdr_offset = cmd->buf_offset + cmd_size;
	}
	return cmd;
}

static inline void free_scm_command(struct scm_command *cmd)
{
	kfree(cmd);
}

static inline struct scm_response *scm_command_to_response(
		const struct scm_command *cmd)
{
	return (void *)cmd + cmd->resp_hdr_offset;
}

static inline void *scm_get_command_buffer(const struct scm_command *cmd)
{
	return (void *)cmd->buf;
}

static inline void *scm_get_response_buffer(const struct scm_response *rsp)
{
	return (void *)rsp + rsp->buf_offset;
}

static int scm_remap_error(int err)
{
	switch (err) {
	case SCM_ERROR:
		return -EIO;
	case SCM_EINVAL_ADDR:
	case SCM_EINVAL_ARG:
		return -EINVAL;
	case SCM_EOPNOTSUPP:
		return -EOPNOTSUPP;
	case SCM_ENOMEM:
		return -ENOMEM;
	}
	return -EINVAL;
}

static u32 smc(u32 cmd_addr)
{
	int context_id;
	register u32 r0 asm("r0") = 1;
	register u32 r1 asm("r1") = (u32)&context_id;
	register u32 r2 asm("r2") = cmd_addr;
	do {
		asm volatile(
			__asmeq("%0", "r0")
			__asmeq("%1", "r0")
			__asmeq("%2", "r1")
			__asmeq("%3", "r2")
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
			"smc	#0	@ switch to secure world\n"
			: "=r" (r0)
			: "r" (r0), "r" (r1), "r" (r2)
			: "r3");
	} while (r0 == SCM_INTERRUPTED);

	return r0;
}

static int __scm_call(const struct scm_command *cmd)
{
	int ret;
	u32 cmd_addr = virt_to_phys(cmd);

	flush_cache_all();
	ret = smc(cmd_addr);
	if (ret < 0)
		ret = scm_remap_error(ret);

	return ret;
}

static u32 cacheline_size;

void scm_inv_range(unsigned long start, unsigned long end)
{
	start = round_down(start, cacheline_size);
	end = round_up(end, cacheline_size);
	while (start < end) {
		asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start)
		     : "memory");
		start += cacheline_size;
	}
	dsb();
	isb();
}
EXPORT_SYMBOL(scm_inv_range);

int scm_call(u32 svc_id, u32 cmd_id, const void *cmd_buf, size_t cmd_len,
		void *resp_buf, size_t resp_len)
{
	int ret;
	struct scm_command *cmd;
	struct scm_response *rsp;
	unsigned long start, end;

	cmd = alloc_scm_command(cmd_len, resp_len);
	if (!cmd)
		return -ENOMEM;

	cmd->id = (svc_id << 10) | cmd_id;
	if (cmd_buf)
		memcpy(scm_get_command_buffer(cmd), cmd_buf, cmd_len);

	mutex_lock(&scm_lock);
	ret = __scm_call(cmd);
	mutex_unlock(&scm_lock);
	if (ret)
		goto out;

	rsp = scm_command_to_response(cmd);
	start = (unsigned long)rsp;

	do {
		scm_inv_range(start, start + sizeof(*rsp));
	} while (!rsp->is_complete);

	end = (unsigned long)scm_get_response_buffer(rsp) + resp_len;
	scm_inv_range(start, end);

	if (resp_buf)
		memcpy(resp_buf, scm_get_response_buffer(rsp), resp_len);
out:
	free_scm_command(cmd);
	return ret;
}
EXPORT_SYMBOL(scm_call);

#define SCM_CLASS_REGISTER	(0x2 << 8)
#define SCM_MASK_IRQS		BIT(5)
#define SCM_ATOMIC(svc, cmd, n) (((((svc) << 10)|((cmd) & 0x3ff)) << 12) | \
				SCM_CLASS_REGISTER | \
				SCM_MASK_IRQS | \
				(n & 0xf))

s32 scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
{
	int context_id;
	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 1);
	register u32 r1 asm("r1") = (u32)&context_id;
	register u32 r2 asm("r2") = arg1;

	asm volatile(
		__asmeq("%0", "r0")
		__asmeq("%1", "r0")
		__asmeq("%2", "r1")
		__asmeq("%3", "r2")
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
		"smc	#0	@ switch to secure world\n"
		: "=r" (r0)
		: "r" (r0), "r" (r1), "r" (r2)
		: "r3");
	return r0;
}
EXPORT_SYMBOL(scm_call_atomic1);

s32 scm_call_atomic2(u32 svc, u32 cmd, u32 arg1, u32 arg2)
{
	int context_id;
	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 2);
	register u32 r1 asm("r1") = (u32)&context_id;
	register u32 r2 asm("r2") = arg1;
	register u32 r3 asm("r3") = arg2;

	asm volatile(
		__asmeq("%0", "r0")
		__asmeq("%1", "r0")
		__asmeq("%2", "r1")
		__asmeq("%3", "r2")
		__asmeq("%4", "r3")
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
		"smc	#0	@ switch to secure world\n"
		: "=r" (r0)
		: "r" (r0), "r" (r1), "r" (r2), "r" (r3));
	return r0;
}
EXPORT_SYMBOL(scm_call_atomic2);

s32 scm_call_atomic4_3(u32 svc, u32 cmd, u32 arg1, u32 arg2,
		u32 arg3, u32 arg4, u32 *ret1, u32 *ret2)
{
	int ret;
	int context_id;
	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 4);
	register u32 r1 asm("r1") = (u32)&context_id;
	register u32 r2 asm("r2") = arg1;
	register u32 r3 asm("r3") = arg2;
	register u32 r4 asm("r4") = arg3;
	register u32 r5 asm("r5") = arg4;

	asm volatile(
		__asmeq("%0", "r0")
		__asmeq("%1", "r1")
		__asmeq("%2", "r2")
		__asmeq("%3", "r0")
		__asmeq("%4", "r1")
		__asmeq("%5", "r2")
		__asmeq("%6", "r3")
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
		"smc	#0	@ switch to secure world\n"
		: "=r" (r0), "=r" (r1), "=r" (r2)
		: "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4), "r" (r5));
	ret = r0;
	if (ret1)
		*ret1 = r1;
	if (ret2)
		*ret2 = r2;
	return r0;
}
EXPORT_SYMBOL(scm_call_atomic4_3);

u32 scm_get_version(void)
{
	int context_id;
	static u32 version = -1;
	register u32 r0 asm("r0");
	register u32 r1 asm("r1");

	if (version != -1)
		return version;

	mutex_lock(&scm_lock);

	r0 = 0x1 << 8;
	r1 = (u32)&context_id;
	do {
		asm volatile(
			__asmeq("%0", "r0")
			__asmeq("%1", "r1")
			__asmeq("%2", "r0")
			__asmeq("%3", "r1")
#ifdef REQUIRES_SEC
			".arch_extension sec\n"
#endif
			"smc	#0	@ switch to secure world\n"
			: "=r" (r0), "=r" (r1)
			: "r" (r0), "r" (r1)
			: "r2", "r3");
	} while (r0 == SCM_INTERRUPTED);

	version = r1;
	mutex_unlock(&scm_lock);

	return version;
}
EXPORT_SYMBOL(scm_get_version);

int secure_read_simlock_mask(void)
{
	int ret;
	u32 dummy;

	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_READ_SIMLOCK_MASK,
			&dummy, sizeof(dummy), NULL, 0);

	PINFO("TZ_HTC_SVC_READ_SIMLOCK_MASK ret = %d", ret);
	if (ret > 0)
		ret &= 0x1F;
	PINFO("TZ_HTC_SVC_READ_SIMLOCK_MASK modified ret = %d", ret);

	return ret;
}
EXPORT_SYMBOL(secure_read_simlock_mask);

int secure_simlock_unlock(unsigned int unlock, unsigned char *code)
{
	int ret;
	struct oem_simlock_unlock_req req;

	req.unlock = unlock;
	req.code = (void *)virt_to_phys(code);

	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_SIMLOCK_UNLOCK,
			&req, sizeof(req), NULL, 0);

	PINFO("TZ_HTC_SVC_SIMLOCK_UNLOCK ret = %d", ret);
	return ret;
}
EXPORT_SYMBOL(secure_simlock_unlock);

int secure_get_security_level(void)
{
	int ret;
	u32 dummy;

	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_GET_SECURITY_LEVEL,
			&dummy, sizeof(dummy), NULL, 0);

	PINFO("TZ_HTC_SVC_GET_SECURITY_LEVEL ret = %d", ret);
	if (ret > 0)
		ret &= 0x0F;
	PINFO("TZ_HTC_SVC_GET_SECURITY_LEVEL modified ret = %d", ret);

	return ret;
}
EXPORT_SYMBOL(secure_get_security_level);

int secure_memprot(void)
{
	int ret;
	u32 dummy;

	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_MEMPROT,
			&dummy, sizeof(dummy), NULL, 0);

	PINFO("TZ_HTC_SVC_MEMPROT ret = %d", ret);
	return ret;
}
EXPORT_SYMBOL(secure_memprot);

int secure_log_operation(unsigned int address, unsigned int size,
		unsigned int buf_addr, unsigned buf_len, int revert)
{
	int ret;
	struct oem_log_oper_req req;
	req.address = address;
	req.size = size;
	req.buf_addr = buf_addr;
	req.buf_len = buf_len;
	req.revert = revert;
	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_LOG_OPERATOR,
			&req, sizeof(req), NULL, 0);
	PINFO("TZ_HTC_SVC_LOG_OPERATOR ret = %d", ret);
	return ret;
}
EXPORT_SYMBOL(secure_log_operation);

int secure_access_item(unsigned int is_write, unsigned int id, unsigned int buf_len, unsigned char *buf)
{
	int ret;
	struct oem_access_item_req req;

	req.is_write = is_write;
	req.id = id;
	req.buf_len = buf_len;
	req.buf = (void *)virt_to_phys(buf);

	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_ACCESS_ITEM,
			&req, sizeof(req), NULL, 0);

	PINFO("TZ_HTC_SVC_ACCESS_ITEM id %d ret = %d", id, ret);
	return ret;
}

#if 1
int scm_pas_enable_dx_bw(void);
void scm_pas_disable_dx_bw(void);

int secure_3rd_party_syscall(unsigned int id, unsigned char *buf, int len)
{
	int ret;
	int bus_ret;
	struct oem_3rd_party_syscall_req req;
	unsigned long start, end;

	req.id = id;
	req.len = len;
	req.buf = (void *)virt_to_phys(buf);

	bus_ret = scm_pas_enable_dx_bw();
	pet_watchdog();
	ret = scm_call(SCM_SVC_OEM, TZ_HTC_SVC_3RD_PARTY,
			&req, sizeof(req), NULL, 0);
	start = (unsigned long)buf;
	end = start + len;
	scm_inv_range(start, end);
	if (!bus_ret)
		scm_pas_disable_dx_bw();

	return ret;
}
#endif

#define IS_CALL_AVAIL_CMD	1
int scm_is_call_available(u32 svc_id, u32 cmd_id)
{
	int ret;
	u32 svc_cmd = (svc_id << 10) | cmd_id;
	u32 ret_val = 0;

	ret = scm_call(SCM_SVC_INFO, IS_CALL_AVAIL_CMD, &svc_cmd,
			sizeof(svc_cmd), &ret_val, sizeof(ret_val));
	if (ret)
		return ret;

	return ret_val;
}
EXPORT_SYMBOL(scm_is_call_available);

#define GET_FEAT_VERSION_CMD	3
int scm_get_feat_version(u32 feat)
{
	if (scm_is_call_available(SCM_SVC_INFO, GET_FEAT_VERSION_CMD)) {
		u32 version;
		if (!scm_call(SCM_SVC_INFO, GET_FEAT_VERSION_CMD, &feat,
				sizeof(feat), &version, sizeof(version)))
			return version;
	}
	return 0;
}
EXPORT_SYMBOL(scm_get_feat_version);

static int scm_init(void)
{
	u32 ctr;

	asm volatile("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
	cacheline_size =  4 << ((ctr >> 16) & 0xf);

	return 0;
}
early_initcall(scm_init);
static int lock_set_func(const char *val, struct kernel_param *kp)
{
	int ret;

	PINFO("started(%d)...", strlen(val));
	ret = param_set_int(val, kp);
	PINFO("finished(%d): %d...", ret, simlock_mask);

	return ret;
}

static int lock_get_func(char *val, struct kernel_param *kp)
{
	int ret;

	simlock_mask = secure_read_simlock_mask();
	ret = param_get_int(val, kp);
	PINFO("%d, %d(%x)...", ret, simlock_mask, simlock_mask);

	return ret;
}

static int unlock_set_func(const char *val, struct kernel_param *kp)
{
	int ret, ret2;
	static unsigned char scode[17];

	PINFO("started(%d)...", strlen(val));
	ret = param_set_int(val, kp);
	ret2 = strlen(simlock_code);
	strcpy(scode, simlock_code);
	scode[ret2 - 1] = 0;
	PINFO("finished(%d): %d, '%s'...", ret, unlock_mask, scode);
	ret2 = secure_simlock_unlock(unlock_mask, scode);
	PINFO("secure_simlock_unlock ret %d...", ret2);

	return ret;
}

static int unlock_get_func(char *val, struct kernel_param *kp)
{
	int ret;

	ret = param_get_int(val, kp);
	PINFO("%d, %d(%x)...", ret, unlock_mask, unlock_mask);

	return ret;
}

static int level_set_func(const char *val, struct kernel_param *kp)
{
	int ret;

	PINFO("started(%d)...", strlen(val));
	ret = param_set_int(val, kp);
	PINFO("finished(%d): %d...", ret, security_level);

	return ret;
}

static int level_get_func(char *val, struct kernel_param *kp)
{
	int ret;

	security_level = secure_get_security_level();
	ret = param_get_int(val, kp);
	PINFO("%d, %d(%x)...", ret, security_level, security_level);

	return ret;
}

module_param_call(simlock_mask, lock_set_func, lock_get_func, &simlock_mask, S_IRUGO | S_IWUSR | S_IWGRP);
module_param_call(unlock_mask, unlock_set_func, unlock_get_func, &unlock_mask, S_IRUGO | S_IWUSR | S_IWGRP);
module_param_call(security_level, level_set_func, level_get_func, &security_level, S_IRUGO | S_IWUSR | S_IWGRP);
