/* Copyright (c) 2013-2017, 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 DRIVER_NAME "msm_sharedmem"
#define pr_fmt(fmt) DRIVER_NAME ": %s: " fmt, __func__

#include <linux/uio_driver.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/dma-mapping.h>

#include <soc/qcom/secure_buffer.h>

#include "sharedmem_qmi.h"

#define CLIENT_ID_PROP "qcom,client-id"

#define MPSS_RMTS_CLIENT_ID 1

static int uio_get_mem_index(struct uio_info *info, struct vm_area_struct *vma)
{
	if (vma->vm_pgoff >= MAX_UIO_MAPS)
		return -EINVAL;

	if (info->mem[vma->vm_pgoff].size == 0)
		return -EINVAL;

	return (int)vma->vm_pgoff;
}

static int sharedmem_mmap(struct uio_info *info, struct vm_area_struct *vma)
{
	int result;
	struct uio_mem *mem;
	int mem_index = uio_get_mem_index(info, vma);

	if (mem_index < 0) {
		pr_err("mem_index is invalid errno %d\n", mem_index);
		return mem_index;
	}

	mem = info->mem + mem_index;

	if (vma->vm_end - vma->vm_start > mem->size) {
		pr_err("vm_end[%lu] - vm_start[%lu] [%lu] > mem->size[%pa]\n",
			vma->vm_end, vma->vm_start,
			(vma->vm_end - vma->vm_start), &mem->size);
		return -EINVAL;
	}
	pr_debug("Attempting to setup mmap.\n");

	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	result = remap_pfn_range(vma,
				 vma->vm_start,
				 mem->addr >> PAGE_SHIFT,
				 vma->vm_end - vma->vm_start,
				 vma->vm_page_prot);
	if (result != 0)
		pr_err("mmap Failed with errno %d\n", result);
	else
		pr_debug("mmap success\n");

	return result;
}

/* Setup the shared ram permissions.
 * This function currently supports the mpss client only.
 */
static void setup_shared_ram_perms(u32 client_id, phys_addr_t addr, u32 size)
{
	int ret;
	u32 source_vmlist[1] = {VMID_HLOS};
	int dest_vmids[2] = {VMID_HLOS, VMID_MSS_MSA};
	int dest_perms[2] = {PERM_READ|PERM_WRITE,
			     PERM_READ|PERM_WRITE};

	if (client_id != MPSS_RMTS_CLIENT_ID)
		return;

	ret = hyp_assign_phys(addr, size, source_vmlist, 1, dest_vmids,
				dest_perms, 2);
	if (ret != 0) {
		if (ret == -EINVAL)
			pr_warn("hyp_assign_phys is not supported!");
		else
			pr_err("hyp_assign_phys failed IPA=0x016%pa size=%u err=%d\n",
				&addr, size, ret);
	}
}

static int msm_sharedmem_probe(struct platform_device *pdev)
{
	int ret = 0;
	struct uio_info *info = NULL;
	struct resource *clnt_res = NULL;
	u32 client_id = ((u32)~0U);
	u32 shared_mem_size = 0;
	u32 shared_mem_tot_sz = 0;
	void *shared_mem = NULL;
	phys_addr_t shared_mem_pyhsical = 0;
	bool is_addr_dynamic = false;
	struct sharemem_qmi_entry qmi_entry;
	bool guard_memory = false;

	/* Get the addresses from platform-data */
	if (!pdev->dev.of_node) {
		pr_err("Node not found\n");
		ret = -ENODEV;
		goto out;
	}
	clnt_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!clnt_res) {
		pr_err("resource not found\n");
		return -ENODEV;
	}

	ret = of_property_read_u32(pdev->dev.of_node, CLIENT_ID_PROP,
				   &client_id);
	if (ret) {
		client_id = ((u32)~0U);
		pr_warn("qcom,client-id property not found\n");
	}

	info = devm_kzalloc(&pdev->dev, sizeof(struct uio_info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	shared_mem_size = resource_size(clnt_res);
	shared_mem_pyhsical = clnt_res->start;

	if (shared_mem_size == 0) {
		pr_err("Shared memory size is zero\n");
		return -EINVAL;
	}

	if (shared_mem_pyhsical == 0) {
		is_addr_dynamic = true;

		/*
		 * If guard_memory is set, then the shared memory region
		 * will be guarded by SZ_4K at the start and at the end.
		 * This is needed to overcome the XPU limitation on few
		 * MSM HW, so as to make this memory not contiguous with
		 * other allocations that may possibly happen from other
		 * clients in the system.
		 */
		guard_memory = of_property_read_bool(pdev->dev.of_node,
				"qcom,guard-memory");

		shared_mem_tot_sz = guard_memory ? shared_mem_size + SZ_8K :
					shared_mem_size;

		shared_mem = dma_alloc_coherent(&pdev->dev, shared_mem_tot_sz,
					&shared_mem_pyhsical, GFP_KERNEL);
		if (shared_mem == NULL) {
			pr_err("Shared mem alloc client=%s, size=%u\n",
				clnt_res->name, shared_mem_size);
			return -ENOMEM;
		}
		if (guard_memory)
			shared_mem_pyhsical += SZ_4K;
	}

	/* Set up the permissions for the shared ram that was allocated. */
	setup_shared_ram_perms(client_id, shared_mem_pyhsical, shared_mem_size);

	/* Setup device */
	info->mmap = sharedmem_mmap; /* Custom mmap function. */
	info->name = clnt_res->name;
	info->version = "1.0";
	info->mem[0].addr = shared_mem_pyhsical;
	info->mem[0].size = shared_mem_size;
	info->mem[0].memtype = UIO_MEM_PHYS;

	ret = uio_register_device(&pdev->dev, info);
	if (ret) {
		pr_err("uio register failed ret=%d\n", ret);
		goto out;
	}
	dev_set_drvdata(&pdev->dev, info);

	qmi_entry.client_id = client_id;
	qmi_entry.client_name = info->name;
	qmi_entry.address = info->mem[0].addr;
	qmi_entry.size = info->mem[0].size;
	qmi_entry.is_addr_dynamic = is_addr_dynamic;

	sharedmem_qmi_add_entry(&qmi_entry);
	pr_info("Device created for client '%s'\n", clnt_res->name);
out:
	return ret;
}

static int msm_sharedmem_remove(struct platform_device *pdev)
{
	struct uio_info *info = dev_get_drvdata(&pdev->dev);

	uio_unregister_device(info);

	return 0;
}

static const struct of_device_id msm_sharedmem_of_match[] = {
	{.compatible = "qcom,sharedmem-uio",},
	{},
};
MODULE_DEVICE_TABLE(of, msm_sharedmem_of_match);

static struct platform_driver msm_sharedmem_driver = {
	.probe          = msm_sharedmem_probe,
	.remove         = msm_sharedmem_remove,
	.driver         = {
		.name   = DRIVER_NAME,
		.owner	= THIS_MODULE,
		.of_match_table = msm_sharedmem_of_match,
	},
};


static int __init msm_sharedmem_init(void)
{
	int result;

	result = sharedmem_qmi_init();
	if (result < 0) {
		pr_err("sharedmem_qmi_init failed result = %d\n", result);
		return result;
	}

	result = platform_driver_register(&msm_sharedmem_driver);
	if (result != 0) {
		pr_err("Platform driver registration failed\n");
		return result;
	}
	return 0;
}

static void __exit msm_sharedmem_exit(void)
{
	platform_driver_unregister(&msm_sharedmem_driver);
	sharedmem_qmi_exit();
}

module_init(msm_sharedmem_init);
module_exit(msm_sharedmem_exit);

MODULE_LICENSE("GPL v2");