#include <linux/device.h>#include <linux/dma-map-ops.h>#include <linux/dma-mapping.h>#include <linux/dmapool.h>#include <linux/kernel.h>#include <linux/ktime.h>#include <linux/module.h> #define NR_TESTS (100) struct dma_pool_pair {	dma_addr_t dma;	void *v;}; struct dmapool_parms {	size_t size;	size_t align;	size_t boundary;}; static const struct dmapool_parms pool_parms[] = {	{ .size = 16, .align = 16, .boundary = 0 },	{ .size = 64, .align = 64, .boundary = 0 },	{ .size = 256, .align = 256, .boundary = 0 },	{ .size = 1024, .align = 1024, .boundary = 0 },	{ .size = 4096, .align = 4096, .boundary = 0 },	{ .size = 68, .align = 32, .boundary = 4096 },}; static struct dma_pool *pool;static struct device test_dev;static u64 dma_mask; static inline int nr_blocks(int size){	return clamp_t(int, (PAGE_SIZE / size) * 512, 1024, 8192);} static int dmapool_test_alloc(struct dma_pool_pair *p, int blocks){	int i; 	for (i = 0; i < blocks; i++) {		p[i].v = dma_pool_alloc(pool, GFP_KERNEL,					&p[i].dma);		if (!p[i].v)			goto pool_fail;	} 	for (i = 0; i < blocks; i++)		dma_pool_free(pool, p[i].v, p[i].dma); 	return 0; pool_fail:	for (--i; i >= 0; i--)		dma_pool_free(pool, p[i].v, p[i].dma);	return -ENOMEM;} static int dmapool_test_block(const struct dmapool_parms *parms){	int blocks = nr_blocks(parms->size);	ktime_t start_time, end_time;	struct dma_pool_pair *p;	int i, ret; 	p = kcalloc(blocks, sizeof(*p), GFP_KERNEL);	if (!p)		return -ENOMEM; 	pool = dma_pool_create("test pool", &test_dev, parms->size,			       parms->align, parms->boundary);	if (!pool) {		ret = -ENOMEM;		goto free_pairs;	} 	start_time = ktime_get();	for (i = 0; i < NR_TESTS; i++) {		ret = dmapool_test_alloc(p, blocks);		if (ret)			goto free_pool;		if (need_resched())			cond_resched();	}	end_time = ktime_get(); 	printk("dmapool test: size:%-4zu align:%-4zu blocks:%-4d time:%llu\n",		parms->size, parms->align, blocks,		ktime_us_delta(end_time, start_time)); free_pool:	dma_pool_destroy(pool);free_pairs:	kfree(p);	return ret;} static void dmapool_test_release(struct device *dev){} static int dmapool_checks(void){	int i, ret; 	ret = dev_set_name(&test_dev, "dmapool-test");	if (ret)		return ret; 	ret = device_register(&test_dev);	if (ret) {		printk("%s: register failed:%d\n", __func__, ret);		goto put_device;	} 	test_dev.release = dmapool_test_release;	set_dma_ops(&test_dev, NULL);	test_dev.dma_mask = &dma_mask;	ret = dma_set_mask_and_coherent(&test_dev, DMA_BIT_MASK(64));	if (ret) {		printk("%s: mask failed:%d\n", __func__, ret);		goto del_device;	} 	for (i = 0; i < ARRAY_SIZE(pool_parms); i++) {		ret = dmapool_test_block(&pool_parms[i]);		if (ret)			break;	} del_device:	device_del(&test_dev);put_device:	put_device(&test_dev);	return ret;} static void dmapool_exit(void){} module_init(dmapool_checks);module_exit(dmapool_exit);MODULE_DESCRIPTION("dma_pool timing test");MODULE_LICENSE("GPL");