pci/hmm/hmm_reserved_pool.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Support for Medifield PNW Camera Imaging ISP subsystem.
 *
 * Copyright (c) 2010 Intel Corporation. All Rights Reserved.
 *
 * Copyright (c) 2010 Silicon Hive www.siliconhive.com.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License 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.
 *
 *
 */
/*
 * This file contains functions for reserved memory pool management
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/mm.h>

#include <asm/set_memory.h>

#include "atomisp_internal.h"
#include "hmm/hmm_pool.h"

/*
 * reserved memory pool ops.
 */
static unsigned int get_pages_from_reserved_pool(void *pool,
	struct hmm_page_object *page_obj,
	unsigned int size, bool cached)
{
	unsigned long flags;
	unsigned int i = 0;
	unsigned int repool_pgnr;
	int j;
	struct hmm_reserved_pool_info *repool_info = pool;

	if (!repool_info)
		return 0;

	spin_lock_irqsave(&repool_info->list_lock, flags);
	if (repool_info->initialized) {
		repool_pgnr = repool_info->index;

		for (j = repool_pgnr - 1; j >= 0; j--) {
			page_obj[i].page = repool_info->pages[j];
			page_obj[i].type = HMM_PAGE_TYPE_RESERVED;
			i++;
			repool_info->index--;
			if (i == size)
				break;
		}
	}
	spin_unlock_irqrestore(&repool_info->list_lock, flags);
	return i;
}

static void free_pages_to_reserved_pool(void *pool,
					struct hmm_page_object *page_obj)
{
	unsigned long flags;
	struct hmm_reserved_pool_info *repool_info = pool;

	if (!repool_info)
		return;

	spin_lock_irqsave(&repool_info->list_lock, flags);

	if (repool_info->initialized &&
	    repool_info->index < repool_info->pgnr &&
	    page_obj->type == HMM_PAGE_TYPE_RESERVED) {
		repool_info->pages[repool_info->index++] = page_obj->page;
	}

	spin_unlock_irqrestore(&repool_info->list_lock, flags);
}

static int hmm_reserved_pool_setup(struct hmm_reserved_pool_info **repool_info,
				   unsigned int pool_size)
{
	struct hmm_reserved_pool_info *pool_info;

	pool_info = kmalloc(sizeof(struct hmm_reserved_pool_info),
			    GFP_KERNEL);
	if (unlikely(!pool_info))
		return -ENOMEM;

	pool_info->pages = kmalloc(sizeof(struct page *) * pool_size,
				   GFP_KERNEL);
	if (unlikely(!pool_info->pages)) {
		kfree(pool_info);
		return -ENOMEM;
	}

	pool_info->index = 0;
	pool_info->pgnr = 0;
	spin_lock_init(&pool_info->list_lock);
	pool_info->initialized = true;

	*repool_info = pool_info;

	return 0;
}

static int hmm_reserved_pool_init(void **pool, unsigned int pool_size)
{
	int ret;
	unsigned int blk_pgnr;
	unsigned int pgnr = pool_size;
	unsigned int order = 0;
	unsigned int i = 0;
	int fail_number = 0;
	struct page *pages;
	int j;
	struct hmm_reserved_pool_info *repool_info;

	if (pool_size == 0)
		return 0;

	ret = hmm_reserved_pool_setup(&repool_info, pool_size);
	if (ret) {
		dev_err(atomisp_dev, "hmm_reserved_pool_setup failed.\n");
		return ret;
	}

	pgnr = pool_size;

	i = 0;
	order = MAX_ORDER;

	while (pgnr) {
		blk_pgnr = 1U << order;
		while (blk_pgnr > pgnr) {
			order--;
			blk_pgnr >>= 1U;
		}
		BUG_ON(order > MAX_ORDER);

		pages = alloc_pages(GFP_KERNEL | __GFP_NOWARN, order);
		if (unlikely(!pages)) {
			if (order == 0) {
				fail_number++;
				dev_err(atomisp_dev, "%s: alloc_pages failed: %d\n",
					__func__, fail_number);
				/* if fail five times, will goto end */

				/* FIXME: whether is the mechanism is ok? */
				if (fail_number == ALLOC_PAGE_FAIL_NUM)
					goto end;
			} else {
				order--;
			}
		} else {
			blk_pgnr = 1U << order;

			ret = set_pages_uc(pages, blk_pgnr);
			if (ret) {
				dev_err(atomisp_dev,
					"set pages uncached failed\n");
				__free_pages(pages, order);
				goto end;
			}

			for (j = 0; j < blk_pgnr; j++)
				repool_info->pages[i++] = pages + j;

			repool_info->index += blk_pgnr;
			repool_info->pgnr += blk_pgnr;

			pgnr -= blk_pgnr;

			fail_number = 0;
		}
	}

end:
	repool_info->initialized = true;

	*pool = repool_info;

	dev_info(atomisp_dev,
		 "hmm_reserved_pool init successfully,hmm_reserved_pool is with %d pages.\n",
		 repool_info->pgnr);
	return 0;
}

static void hmm_reserved_pool_exit(void **pool)
{
	unsigned long flags;
	int i, ret;
	unsigned int pgnr;
	struct hmm_reserved_pool_info *repool_info = *pool;

	if (!repool_info)
		return;

	spin_lock_irqsave(&repool_info->list_lock, flags);
	if (!repool_info->initialized) {
		spin_unlock_irqrestore(&repool_info->list_lock, flags);
		return;
	}
	pgnr = repool_info->pgnr;
	repool_info->index = 0;
	repool_info->pgnr = 0;
	repool_info->initialized = false;
	spin_unlock_irqrestore(&repool_info->list_lock, flags);

	for (i = 0; i < pgnr; i++) {
		ret = set_pages_wb(repool_info->pages[i], 1);
		if (ret)
			dev_err(atomisp_dev,
				"set page to WB err...ret=%d\n", ret);
		/*
		W/A: set_pages_wb seldom return value = -EFAULT
		indicate that address of page is not in valid
		range(0xffff880000000000~0xffffc7ffffffffff)
		then, _free_pages would panic; Do not know why
		page address be valid, it maybe memory corruption by lowmemory
		*/
		if (!ret)
			__free_pages(repool_info->pages[i], 0);
	}

	kfree(repool_info->pages);
	kfree(repool_info);

	*pool = NULL;
}

static int hmm_reserved_pool_inited(void *pool)
{
	struct hmm_reserved_pool_info *repool_info = pool;

	if (!repool_info)
		return 0;

	return repool_info->initialized;
}

struct hmm_pool_ops reserved_pops = {
	.pool_init		= hmm_reserved_pool_init,
	.pool_exit		= hmm_reserved_pool_exit,
	.pool_alloc_pages	= get_pages_from_reserved_pool,
	.pool_free_pages	= free_pages_to_reserved_pool,
	.pool_inited		= hmm_reserved_pool_inited,
};