/*
 *  cma_driver.c - Broadcom STB platform CMA driver
 *
 *  Copyright © 2009 - 2015 Broadcom Corporation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  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.
 *
 *  A copy of the GPL is available at
 *  http://www.broadcom.com/licenses/GPLv2.php or from the Free Software
 *  Foundation at https://www.gnu.org/licenses/ .
 */

#define pr_fmt(fmt) "cma_driver: " fmt

#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_fdt.h>
#include <linux/cdev.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/brcmstb/cma_driver.h>
#include <linux/brcmstb/memory_api.h>
#include <linux/mmzone.h>
#include <linux/vmalloc.h>
#include <linux/memblock.h>
#include <linux/device.h>
#include <linux/bitmap.h>
#include <linux/highmem.h>
#include <linux/dma-contiguous.h>
#include <linux/cma.h>
#include <linux/sizes.h>
#include <linux/vme.h>
#include <asm/div64.h>
#include <asm/setup.h>

struct cma_devs_list {
	struct list_head list;
	struct cma_dev *cma_dev;
};

struct cma_root_dev {
	u32 mmap_type;
	struct cdev cdev;
	struct device *dev;
	struct cma_devs_list cma_devs;
};

struct cma_pdev_data {
	phys_addr_t start;
	phys_addr_t size;
	int do_prealloc;
	struct cma *cma_area;
};

struct cma_region_rsv_data {
	int nr_regions_valid;
	struct cma_pdev_data regions[NR_BANKS];
	long long unsigned prm_low_lim_mb;
	int prm_low_kern_rsv_pct;
};

struct cma_rsv_region {
	phys_addr_t addr;
	phys_addr_t size;
};

static struct cma_rsv_region cma_rsv_setup_data[MAX_CMA_AREAS];
static unsigned int n_cma_regions;
static bool cma_disabled;

/* CMA region reservation */

static struct cma_region_rsv_data cma_data __initdata = {
	.prm_low_lim_mb = 32 << 20,
	.prm_low_kern_rsv_pct = 20,
};

enum scan_bitmap_op {
	GET_NUM_REGIONS = 0,
	GET_REGION_INFO,
};

/*
 * The lowest low-memory memblock size needed in order to reserve a cma region
 * on systems with no high-memory.
 */
static int __init cma_mb_low_lim_set(char *p)
{
	cma_data.prm_low_lim_mb = memparse(p, NULL);
	return !cma_data.prm_low_lim_mb ? -EINVAL : 0;
}
early_param("brcm_cma_mb_low_lim", cma_mb_low_lim_set);

/*
 * The percentage of memory reserved for the kernel on systems with no
 * high-memory.
 */
static int __init cma_low_kern_rsv_pct_set(char *p)
{
	return (get_option(&p, &cma_data.prm_low_kern_rsv_pct) == 0) ?
		-EINVAL : 0;
}
early_param("brcm_cma_low_kern_rsv_pct", cma_low_kern_rsv_pct_set);

static int __init __cma_rsv_setup(phys_addr_t addr, phys_addr_t size)
{
	if (n_cma_regions == MAX_CMA_AREAS) {
		pr_warn_once("%s: too many regions, ignoring extras\n",
				__func__);
		return -EINVAL;
	}

	cma_rsv_setup_data[n_cma_regions].addr = addr;
	cma_rsv_setup_data[n_cma_regions].size = size;
	n_cma_regions++;
	return 0;
}

/*
 * We don't do too much checking here because it will be handled by the CMA
 * reservation code
 */
static int __init cma_rsv_setup(char *str)
{
	phys_addr_t addr = 0;
	phys_addr_t size = 0;
	int ret;

	size = (phys_addr_t) memparse(str, &str);
	if (*str == '@')
		addr = (phys_addr_t)memparse(str + 1, &str);

	if (size == 0) {
		pr_info("disabling reserved memory\n");
		cma_disabled = true;
		return 0;
	}

	ret = __cma_rsv_setup(addr, size);
	if (!ret)
		brcmstb_memory_override_defaults = true;
	return ret;
}
early_param("brcm_cma", cma_rsv_setup);

static void __init cma_reserve_one(struct membank *bank, int region_idx)
{
	struct cma_rsv_region *region = &cma_rsv_setup_data[region_idx];
	struct cma *tmp_cma_area;
	phys_addr_t base;
	phys_addr_t size;
	int rc;

	if ((bank->start <= region->addr) &&
			((bank->start + bank->size) >=
			 (region->addr + region->size))) {
		base = region->addr;
		size = region->size;
		pr_debug("reserve: %pa, %pa\n", &base, &size);
		rc = dma_contiguous_reserve_area(size, base, 0,
				&tmp_cma_area, 1);
		if (rc) {
			pr_err("reservation failed (base=%pa,size=%pa,rc=%d)\n",
					&base, &size, rc);
			/*
			 * This will help us see if a stray memory reservation
			 * is fragmenting the memblock when 'debug' is passed
			 * to the kernel at boot.
			 */
			memblock_dump_all();
		} else {
			struct cma_pdev_data *pd =
				&cma_data.regions[cma_data.nr_regions_valid];
			pd->start = PFN_PHYS(tmp_cma_area->base_pfn);
			pd->size = size;
			/* Pre-allocate all regions */
			pd->do_prealloc = 1;
			pd->cma_area = tmp_cma_area;
			cma_data.nr_regions_valid++;
		}
	}
}

void __init cma_setup_defaults(void)
{
	int iter;

	for_each_bank(iter, &meminfo) {
		phys_addr_t start, size;

		/* fill in start and size */
		if (brcmstb_memory_get_default_reserve(iter, &start, &size))
			continue;

		(void) __cma_rsv_setup(start, size);
	}
}

void __init cma_reserve(void)
{
	int iter;

	if (cma_disabled) {
		n_cma_regions = 0;
		return;
	}

	if (brcmstb_default_reserve == BRCMSTB_RESERVE_CMA &&
			!n_cma_regions &&
			!brcmstb_memory_override_defaults)
		cma_setup_defaults();

	for_each_bank(iter, &meminfo) {
		int i;

		for (i = 0; i < n_cma_regions; ++i)
			cma_reserve_one(&meminfo.bank[iter], i);
	}
}

static struct platform_device * __init cma_register_dev_one(int id,
	int region_idx)
{
	struct platform_device *pdev;

	pdev = platform_device_register_data(NULL, "brcm-cma", id,
		&cma_data.regions[region_idx], sizeof(struct cma_pdev_data));
	if (!pdev) {
		pr_err("couldn't register pdev for %d,0x%pa,0x%pa\n", id,
			&cma_data.regions[region_idx].start,
			&cma_data.regions[region_idx].size);
	}

	return pdev;
}

/*
 * Registers platform devices for the regions that were reserved in earlyboot.
 *
 * This function should be called from machine initialization.
 */
void __init cma_register(void)
{
	int i;
	int id = 0;
	struct platform_device *pdev;

	for (i = 0; i < cma_data.nr_regions_valid; i++) {
		pdev = cma_register_dev_one(id, i);
		if (!pdev) {
			pr_err("couldn't register device");
			continue;
		}

		id++;
	}
}

/* CMA driver implementation */

/* Mutex for serializing accesses to private variables */
static DEFINE_SPINLOCK(cma_dev_lock);
static dev_t cma_dev_devno;
static struct class *cma_dev_class;
static struct cma_root_dev *cma_root_dev;

static int cma_dev_open(struct inode *inode, struct file *filp)
{
	dev_dbg(cma_root_dev->dev, "opened cma root device\n");
	return 0;
}

static int cma_dev_release(struct inode *inode, struct file *filp)
{
	return 0;
}

static void cma_dev_vma_open(struct vm_area_struct *vma)
{
	dev_dbg(cma_root_dev->dev, "%s: VA=0x%lx PA=0x%lx\n", __func__,
		vma->vm_start, vma->vm_pgoff << PAGE_SHIFT);
}

static void cma_dev_vma_close(struct vm_area_struct *vma)
{
	dev_dbg(cma_root_dev->dev, "%s: VA=0x%lx PA=0x%lx\n", __func__,
		vma->vm_start, vma->vm_pgoff << PAGE_SHIFT);
}

static struct vm_operations_struct cma_dev_vm_ops = {
	.open  = cma_dev_vma_open,
	.close = cma_dev_vma_close,
};

static int cma_dev_mmap(struct file *filp, struct vm_area_struct *vma)
{
	switch (cma_root_dev->mmap_type) {
	case MMAP_TYPE_NORMAL:
		break;
	case MMAP_TYPE_UNCACHED:
		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
		break;
	case MMAP_TYPE_WC:
#if defined(__arm__)
		/*
		 * ARM has an explicit setting for WC. Use default for other
		 * architectures.
		 */
		vma->vm_page_prot = __pgprot_modify(vma->vm_page_prot,
				    L_PTE_MT_MASK, L_PTE_MT_DEV_WC);
#endif
		break;
	default:
		return -EINVAL;
	}

	if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
			    vma->vm_end - vma->vm_start,
			    vma->vm_page_prot)) {
		return -EAGAIN;
	} else {
		vma->vm_ops = &cma_dev_vm_ops;
		cma_dev_vma_open(vma);
	}

	return 0;
}

/**
 * cma_dev_get_cma_dev() - Get a cma_dev * by memc index
 *
 * @memc: The MEMC index
 *
 * Return: a pointer to the associated CMA device, or NULL if no such
 * device.
 */
struct cma_dev *cma_dev_get_cma_dev(int memc)
{
	struct list_head *pos;
	struct cma_dev *cma_dev = NULL;
	unsigned long flags;

	if (!cma_root_dev)
		return NULL;

	spin_lock_irqsave(&cma_dev_lock, flags);

	list_for_each(pos, &cma_root_dev->cma_devs.list) {
		struct cma_dev *curr_cma_dev;
		curr_cma_dev = list_entry(pos, struct cma_dev, list);
		BUG_ON(curr_cma_dev == NULL);
		if (curr_cma_dev->cma_dev_index == memc) {
			cma_dev = curr_cma_dev;
			break;
		}
	}

	spin_unlock_irqrestore(&cma_dev_lock, flags);

	dev_dbg(cma_root_dev->dev, "cma_dev index %d not in list\n", memc);
	return cma_dev;
}
EXPORT_SYMBOL(cma_dev_get_cma_dev);

/**
 * cma_dev_get_mem() - Carve out physical memory
 *
 * @cma_dev: The CMA device
 * @addr: Out pointer which will be populated with the start
 * physical address of the contiguous region that was carved out
 * @len: Number of bytes to allocate
 * @align: Byte alignment
 *
 * Return: 0 on success, negative on failure.
 */
int cma_dev_get_mem(struct cma_dev *cma_dev, u64 *addr, u32 len,
			u32 align)
{
	int status = 0;
	struct page *page;
	struct device *dev = cma_dev->dev;

	if ((len & ~PAGE_MASK) || (len == 0)) {
		dev_dbg(dev, "bad length (0x%x)\n", len);
		status = -EINVAL;
		goto done;
	}

	if (align & ~PAGE_MASK) {
		dev_dbg(dev, "bad alignment (0x%x)\n", align);
		status = -EINVAL;
		goto done;
	}

	if (align <= PAGE_SIZE)
		page = dma_alloc_from_contiguous(dev, len >> PAGE_SHIFT, 0);
	else
		page = dma_alloc_from_contiguous(dev, len >> PAGE_SHIFT,
				get_order(align));

	if (page == NULL) {
		status = -ENOMEM;
		goto done;
	}

	*addr = page_to_phys(page);

done:
	return status;
}
EXPORT_SYMBOL(cma_dev_get_mem);

/**
 * cma_dev_put_mem() - Return carved out physical memory
 *
 * @cma_dev: The CMA device
 * @addr: Start physical address of allocated region
 * @len: Number of bytes that were allocated (this must match with get_mem
 * call!)
 *
 * Return: 0 on success, negative on failure.
 */
int cma_dev_put_mem(struct cma_dev *cma_dev, u64 addr, u32 len)
{
	struct page *page = phys_to_page(addr);
	struct device *dev = cma_dev->dev;

	if (page == NULL) {
		dev_dbg(cma_root_dev->dev, "bad addr (0x%llx)\n", addr);
		return -EINVAL;
	}

	if (len % PAGE_SIZE) {
		dev_dbg(cma_root_dev->dev, "bad length (0x%x)\n", len);
		return -EINVAL;
	}

	if (!dma_release_from_contiguous(dev, page, len / PAGE_SIZE))
		return -EIO;

	return 0;
}
EXPORT_SYMBOL(cma_dev_put_mem);

static int scan_alloc_bitmap(struct cma_dev *cma_dev, int op, int *region_count,
			     int region_num, s32 *memc, u64 *addr,
			     u32 *num_bytes)
{
	/* Get information about n-th contiguous chunk */
	unsigned long i = 0, pos_head = 0, pos_tail;
	int count = 0, head_found = 0;
	struct cma *cma = dev_get_cma_area(cma_dev->dev);

	if (!cma)
		return -EFAULT;

	/* Count the number of contiguous chunks */
	do {
		if (head_found) {
			pos_tail = find_next_zero_bit(cma->bitmap, cma->count,
						      i);

			if (op == GET_NUM_REGIONS)
				count++;
			else if (op == GET_REGION_INFO) {
				if (count == region_num) {
					*memc = (s32)cma_dev->memc;
					*addr = cma_dev->range.base +
						(pos_head * PAGE_SIZE);
					*num_bytes = (pos_tail - pos_head) *
						PAGE_SIZE;
					return 0;
				} else
					count++;
			}

			head_found = 0;
			i = pos_tail + 1;

		} else {
			pos_head = find_next_bit(cma->bitmap, cma->count, i);
			i = pos_head + 1;
			head_found = 1;
		}
	} while (i < cma->count);

	if (op == GET_NUM_REGIONS) {
		*region_count = count;
		return 0;
	} else
		return -EINVAL;
}

/**
 * cma_dev_get_num_regions() - Get number of allocated regions
 *
 * @cma_dev: The CMA device
 *
 * Return: 0 on success, negative on failure
 */
int cma_dev_get_num_regions(struct cma_dev *cma_dev)
{
	int count;
	int rc = scan_alloc_bitmap(cma_dev, GET_NUM_REGIONS, &count, 0, NULL,
				   NULL, NULL);
	return rc ? rc : count;
}
EXPORT_SYMBOL(cma_dev_get_num_regions);

/**
 * cma_dev_get_region_info() - Get information about allocate region
 *
 * @cma_dev: The CMA device
 * @region_num: Region index
 * @memc: MEMC index associated with the region
 * @addr: Physical address of region
 * @num_bytes: Size of region in bytes
 *
 * Return: 0 on success, negative on failure.
 */
int cma_dev_get_region_info(struct cma_dev *cma_dev, int region_num,
			    s32 *memc, u64 *addr, u32 *num_bytes)
{
	int rc = scan_alloc_bitmap(cma_dev, GET_REGION_INFO, NULL, region_num,
				   memc, addr, num_bytes);
	return rc;
}
EXPORT_SYMBOL(cma_dev_get_region_info);

static int pte_callback(pte_t *pte, unsigned long x, unsigned long y,
			struct mm_walk *walk)
{
	const pgprot_t pte_prot = __pgprot(*pte);
	const pgprot_t req_prot = *((pgprot_t *)walk->private);
	const pgprot_t prot_msk = L_PTE_MT_MASK | L_PTE_VALID;
	return (((pte_prot ^ req_prot) & prot_msk) == 0) ? 0 : -1;
}

static void *page_to_virt_contig(const struct page *page, unsigned int pg_cnt,
					pgprot_t pgprot)
{
	int rc;
	struct mm_walk walk;
	unsigned long pfn;
	unsigned long pfn_start;
	unsigned long pfn_end;
	unsigned long va_start;
	unsigned long va_end;

	if ((page == NULL) || !pg_cnt)
		return ERR_PTR(-EINVAL);

	pfn_start = page_to_pfn(page);
	pfn_end = pfn_start + pg_cnt;
	for (pfn = pfn_start; pfn < pfn_end; pfn++) {
		const struct page *cur_pg = pfn_to_page(pfn);
		phys_addr_t pa;

		/* Verify range is in low memory only */
		if (PageHighMem(cur_pg))
			return NULL;

		/* Must be mapped */
		pa = page_to_phys(cur_pg);
		if (page_address(cur_pg) == NULL)
			return NULL;
	}

	/*
	 * Aliased mappings with different cacheability attributes on ARM can
	 * lead to trouble!
	 */
	memset(&walk, 0, sizeof(walk));
	walk.pte_entry = &pte_callback;
	walk.private = (void *)&pgprot;
	walk.mm = current->mm;
	va_start = (unsigned long)page_address(page);
	va_end = (unsigned long)(page_address(page) + (pg_cnt << PAGE_SHIFT));
	rc = walk_page_range(va_start,
			     va_end,
			     &walk);
	if (rc)
		pr_debug("cacheability mismatch\n");

	return rc ? NULL : page_address(page);
}

static int cma_dev_ioctl_check_cmd(unsigned int cmd, unsigned long arg)
{
	int ret = 0;

	if (_IOC_TYPE(cmd) != CMA_DEV_MAGIC)
		return -ENOTTY;

	if (_IOC_NR(cmd) > CMA_DEV_IOC_MAXNR)
		return -ENOTTY;

	if (_IOC_DIR(cmd) & _IOC_READ)
		ret = !access_ok(VERIFY_WRITE, (void __user *)arg,
				 _IOC_SIZE(cmd));
	else if (_IOC_DIR(cmd) & _IOC_WRITE)
		ret = !access_ok(VERIFY_READ, (void __user *)arg,
				 _IOC_SIZE(cmd));

	if (ret)
		return -EFAULT;

	return 0;
}

static struct page **get_pages(struct page *page, int num_pages)
{
	struct page **pages;
	long pfn;
	int i;

	if (num_pages == 0) {
		pr_err("bad count\n");
		return NULL;
	}

	if (page == NULL) {
		pr_err("bad page\n");
		return NULL;
	}

	pages = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
	if (pages == NULL)
		return NULL;

	pfn = page_to_pfn(page);
	for (i = 0; i < num_pages; i++) {
		/*
		 * pfn_to_page() should resolve to simple arithmetic for the
		 * FLATMEM memory model.
		 */
		pages[i] = pfn_to_page(pfn++);
	}

	return pages;
}

/**
 * cma_dev_kva_map() - Map page(s) to a kernel virtual address
 *
 * @page: A struct page * that points to the beginning of a chunk of physical
 * contiguous memory.
 * @num_pages: Number of pages
 * @pgprot: Page protection bits
 *
 * Return: pointer to mapping, or NULL on failure
 */
void *cma_dev_kva_map(struct page *page, int num_pages, pgprot_t pgprot)
{
	void *va;

	/* get the virtual address for this range if it exists */
	va = page_to_virt_contig(page, num_pages, pgprot);
	if (IS_ERR(va)) {
		pr_debug("page_to_virt_contig() failed (%ld)\n", PTR_ERR(va));
		return NULL;
	} else if (va == NULL || is_vmalloc_addr(va)) {
		struct page **pages;

		pages = get_pages(page, num_pages);
		if (pages == NULL) {
			pr_err("couldn't get pages\n");
			return NULL;
		}

		va = vmap(pages, num_pages, 0, pgprot);

		kfree(pages);

		if (va == NULL) {
			pr_err("vmap failed (num_pgs=%d)\n", num_pages);
			return NULL;
		}
	}

	return va;
}
EXPORT_SYMBOL(cma_dev_kva_map);

/**
 * cma_dev_kva_unmap() - Unmap a kernel virtual address associated
 * to physical pages mapped by cma_dev_kva_map()
 *
 * @kva: Kernel virtual address previously mapped by cma_dev_kva_map()
 *
 * Return: 0 on success, negative on failure.
 */
int cma_dev_kva_unmap(const void *kva)
{
	if (kva == NULL)
		return -EINVAL;

	if (!is_vmalloc_addr(kva)) {
		/* unmapping not necessary for low memory VAs */
		return 0;
	}

	vunmap(kva);

	return 0;
}
EXPORT_SYMBOL(cma_dev_kva_unmap);

static long cma_dev_ioctl(struct file *filp, unsigned int cmd,
			  unsigned long arg)
{
	int ret = 0;
	struct device *dev = cma_root_dev->dev;
	struct cma_dev *cma_dev;
	struct ioc_params p;

	ret = cma_dev_ioctl_check_cmd(cmd, arg);
	if (ret)
		return ret;

	if (cmd < CMA_DEV_IOC_GET_PG_PROT) {
		if (copy_from_user(&p, (void __user *)(arg), sizeof(p)))
			return -EFAULT;
	}

	switch (cmd) {
	case CMA_DEV_IOC_GETMEM: {
		ret = -EINVAL;

		cma_dev = cma_dev_get_cma_dev(p.cma_dev_index);
		if (cma_dev == NULL)
			break;

		p.status = cma_dev_get_mem(cma_dev, &p.addr, p.num_bytes,
						p.align_bytes);

		ret = 0;

		break;
	}
	case CMA_DEV_IOC_PUTMEM: {
		ret = -EINVAL;

		cma_dev = cma_dev_get_cma_dev(p.cma_dev_index);
		if (cma_dev == NULL)
			break;

		p.status = cma_dev_put_mem(cma_dev, p.addr, p.num_bytes);

		ret = 0;

		break;
	}
	case CMA_DEV_IOC_GETPHYSINFO: {
		ret = -EINVAL;

		cma_dev = cma_dev_get_cma_dev(p.cma_dev_index);
		if (cma_dev == NULL)
			break;

		p.addr = cma_dev->range.base;
		p.num_bytes = cma_dev->range.size;
		p.memc = (s32)cma_dev->memc;
		p.status = 0;

		ret = 0;

		break;
	}
	case CMA_DEV_IOC_GETNUMREGS: {
		ret = -EINVAL;

		cma_dev = cma_dev_get_cma_dev(p.cma_dev_index);
		if (cma_dev == NULL)
			break;

		p.num_regions = cma_dev_get_num_regions(cma_dev);

		ret = 0;

		break;
	}
	case CMA_DEV_IOC_GETREGINFO: {
		ret = -EINVAL;

		cma_dev = cma_dev_get_cma_dev(p.cma_dev_index);
		if (cma_dev == NULL)
			break;

		p.status = cma_dev_get_region_info(cma_dev, p.region, &p.memc,
							&p.addr, &p.num_bytes);

		ret = 0;

		break;
	}
	case CMA_DEV_IOC_GET_PG_PROT: {
		__put_user(cma_root_dev->mmap_type, (u32 __user *)arg);
		break;
	}
	case CMA_DEV_IOC_SET_PG_PROT: {
		int mmap_type;

		__get_user(mmap_type, (u32 __user *)arg);

		if (mmap_type > MMAP_TYPE_WC) {
			dev_err(dev, "bad mmap_type (%d)\n", mmap_type);
			ret = -EINVAL;
		} else
			cma_root_dev->mmap_type = mmap_type;

		break;
	}
	case CMA_DEV_IOC_VERSION: {
		__put_user(CMA_DRIVER_VERSION, (__u32 __user *)arg);
		break;
	}
	default: {
		return -ENOTTY;
	}
	}

	if (cmd < CMA_DEV_IOC_GET_PG_PROT) {
		if (copy_to_user((void __user *)(arg), &p, sizeof(p)))
			return -EFAULT;
	}

	return ret;
}

static const struct file_operations cma_dev_fops = {
	.owner          = THIS_MODULE,
	.open           = cma_dev_open,
	.release        = cma_dev_release,
	.mmap           = cma_dev_mmap,
	.unlocked_ioctl = cma_dev_ioctl,
};

static int cma_drvr_alloc_devno(struct device *dev)
{
	int ret = 0;

	if (MAJOR(cma_dev_devno) == 0) {
		ret = alloc_chrdev_region(&cma_dev_devno, 0, CMA_DEV_MAX,
					  CMA_DEV_NAME);
	}

	if (ret) {
		dev_err(dev, "couldn't alloc major devno\n");
		return ret;
	}

	dev_dbg(dev, "maj=%d min=%d\n", MAJOR(cma_dev_devno),
	MINOR(cma_dev_devno));

	return ret;
}

static int cma_drvr_test_cma_dev(struct device *dev)
{
	struct page *page;

	/* Do a dummy alloc to ensure the CMA device is truly ready */
	page = dma_alloc_from_contiguous(dev, 1, 0);
	if (page == NULL)
		return -EINVAL;

	if (!dma_release_from_contiguous(dev, page, 1)) {
		dev_err(dev, "test dma release failed!\n");
		return -EINVAL;
	}

	return 0;
}

static int __init cma_drvr_config_platdev(struct platform_device *pdev,
					struct cma_dev *cma_dev)
{
	struct device *dev = &pdev->dev;
	struct cma_pdev_data *data =
		(struct cma_pdev_data *)dev->platform_data;

	if (!data) {
		dev_err(dev, "platform data not initialized\n");
		return -EINVAL;
	}

	cma_dev->range.base = data->start;
	cma_dev->range.size = data->size;
	cma_dev->cma_dev_index = pdev->id;
	cma_dev->memc = brcmstb_memory_phys_addr_to_memc(data->start);

	if (!data->cma_area) {
		pr_err("null cma area\n");
		return -EINVAL;
	}
	dev_set_cma_area(dev, data->cma_area);

	if (cma_drvr_test_cma_dev(dev)) {
		dev_err(dev, "CMA testing failed!\n");
		return -EINVAL;
	}

	return 0;
}

static int cma_drvr_init_root_dev(struct device *dev)
{
	int ret;
	struct device *dev2;
	struct cma_root_dev *my_cma_root_dev;
	struct cdev *cdev;
	int minor = 0;

	my_cma_root_dev = devm_kzalloc(dev, sizeof(*my_cma_root_dev),
					GFP_KERNEL);
	if (my_cma_root_dev == NULL)
		return -ENOMEM;

	/* Initialize list of CMA devices referenced by the root CMA device */
	INIT_LIST_HEAD(&my_cma_root_dev->cma_devs.list);

	/* Setup character device */
	cdev = &my_cma_root_dev->cdev;
	cdev_init(cdev, &cma_dev_fops);
	cdev->owner = THIS_MODULE;
	ret = cdev_add(cdev, cma_dev_devno + minor, 1);
	if (ret) {
		dev_err(dev, "cdev_add() failed (%d)\n", ret);
		goto free_cma_root_dev;
	}

	if (cma_dev_class == NULL)
		cma_dev_class = class_create(THIS_MODULE, CMA_CLASS_NAME);

	/* Setup device */
	dev2 = device_create(cma_dev_class, dev, cma_dev_devno + minor, NULL,
			     CMA_DEV_NAME"%d", minor);
	if (IS_ERR(dev2)) {
		dev_err(dev, "error creating device (%d)\n", ret);
		ret = PTR_ERR(dev2);
		goto del_cdev;
	}

	my_cma_root_dev->dev = dev2;
	cma_root_dev = my_cma_root_dev;

	dev_info(dev, "Initialized Broadcom CMA root device\n");

	goto done;

del_cdev:
	cdev_del(cdev);

free_cma_root_dev:
	devm_kfree(dev, cma_root_dev);

done:
	return ret;
}

static int __init cma_drvr_do_prealloc(struct device *dev,
	struct cma_dev *cma_dev)
{
	int ret;
	u64 addr;
	u32 size;

	size = cma_dev->range.size;

	ret = cma_dev_get_mem(cma_dev, &addr, size, 0);
	if (ret)
		dev_err(dev, "Unable to pre-allocate 0x%x bytes (%d)", size,
			ret);
	else
		dev_info(dev, "Pre-allocated 0x%x bytes @ 0x%llx", size, addr);

	return ret;
}

static int __init cma_drvr_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct cma_dev *cma_dev = NULL;
	int ret = 0;
	struct cma_pdev_data *data =
		(struct cma_pdev_data *)dev->platform_data;

	/* Prepare a major number for the devices if not already done */
	ret = cma_drvr_alloc_devno(dev);
	if (ret)
		goto free_cma_dev;

	/* Initialize the root device only once */
	if (cma_root_dev == NULL)
		ret = cma_drvr_init_root_dev(dev);

	if (ret)
		goto done;

	cma_dev = devm_kzalloc(dev, sizeof(*cma_dev), GFP_KERNEL);
	if (cma_dev == NULL) {
		dev_err(dev, "can't alloc cma_dev\n");
		ret = -ENOMEM;
		goto done;
	}

	ret = cma_drvr_config_platdev(pdev, cma_dev);
	if (ret)
		goto free_cma_dev;

	cma_dev->dev = dev;

	/*
	 * Keep a pointer to all of the devs so we don't have to search for it
	 * elsewhere.
	 */
	INIT_LIST_HEAD(&cma_dev->list);
	list_add(&cma_dev->list, &cma_root_dev->cma_devs.list);
	dev_info(dev, "Added CMA device @ PA=0x%llx LEN=0x%x\n",
		 cma_dev->range.base, cma_dev->range.size);

	if (data->do_prealloc) {
		/*
		 * Pre-allocation failure isn't truly a probe error because the
		 * device has been initialized at this point. An error will be
		 * logged if there is a failure.
		 */
		cma_drvr_do_prealloc(dev, cma_dev);
	}

	goto done;

free_cma_dev:
	devm_kfree(dev, cma_dev);

done:
	return ret;
}

int cma_drvr_is_ready(void)
{
	return cma_root_dev != NULL;
}

static struct platform_driver cma_driver = {
	.driver = {
		.name = "brcm-cma",
		.owner = THIS_MODULE,
	},
};

static int __init cma_drvr_init(void)
{
	return platform_driver_probe(&cma_driver, cma_drvr_probe);
}
module_init(cma_drvr_init);

static void __exit cma_drvr_exit(void)
{
	platform_driver_unregister(&cma_driver);
}
module_exit(cma_drvr_exit);