mmc: mmc host test driver

A dummy driver that performs a series of requests that are often mis-
handled by host drivers.

Signed-off-by: Pierre Ossman <[e-mail]>

drivers/mmc/card/Kconfig

···
 	  SDIO function driver for SDIO cards that implements the UART
 	  class, as well as the GPS class which appears like a UART.
 
+config MMC_TEST
+	tristate "MMC host test driver"
+	default n
+	help
+	  Development driver that performs a series of reads and writes
+	  to a memory card in order to expose certain well known bugs
+	  in host controllers. The tests are executed by writing to the
+	  "test" file in sysfs under each card. Note that whatever is
+	  on your card will be overwritten by these tests.
+
+	  This driver is only of interest to those developing or
+	  testing a host driver. Most people should say N here.

drivers/mmc/card/Makefile

···
 
 obj-$(CONFIG_MMC_BLOCK)		+= mmc_block.o
 mmc_block-objs			:= block.o queue.o
+obj-$(CONFIG_MMC_TEST)		+= mmc_test.o
 
 obj-$(CONFIG_SDIO_UART)		+= sdio_uart.o
 

drivers/mmc/card/mmc_test.c

···
+/*
+ *  linux/drivers/mmc/card/mmc_test.c
+ *
+ *  Copyright 2007 Pierre Ossman
+ *
+ * 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 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/mmc/core.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+
+#include <linux/scatterlist.h>
+
+#define RESULT_OK		0
+#define RESULT_FAIL		1
+#define RESULT_UNSUP_HOST	2
+#define RESULT_UNSUP_CARD	3
+
+#define BUFFER_SIZE	(PAGE_SIZE * 4)
+
+struct mmc_test_card {
+	struct mmc_card	*card;
+
+	u8		*buffer;
+};
+
+/*******************************************************************/
+/*  Helper functions                                               */
+/*******************************************************************/
+
+static int mmc_test_set_blksize(struct mmc_test_card *test, unsigned size)
+{
+	struct mmc_command cmd;
+	int ret;
+
+	cmd.opcode = MMC_SET_BLOCKLEN;
+	cmd.arg = size;
+	cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+	ret = mmc_wait_for_cmd(test->card->host, &cmd, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int __mmc_test_transfer(struct mmc_test_card *test, int write,
+	unsigned broken_xfer, u8 *buffer, unsigned addr,
+	unsigned blocks, unsigned blksz)
+{
+	int ret, busy;
+
+	struct mmc_request mrq;
+	struct mmc_command cmd;
+	struct mmc_command stop;
+	struct mmc_data data;
+
+	struct scatterlist sg;
+
+	memset(&mrq, 0, sizeof(struct mmc_request));
+
+	mrq.cmd = &cmd;
+	mrq.data = &data;
+
+	memset(&cmd, 0, sizeof(struct mmc_command));
+
+	if (broken_xfer) {
+		if (blocks > 1) {
+			cmd.opcode = write ?
+				MMC_WRITE_BLOCK : MMC_READ_SINGLE_BLOCK;
+		} else {
+			cmd.opcode = MMC_SEND_STATUS;
+		}
+	} else {
+		if (blocks > 1) {
+			cmd.opcode = write ?
+				MMC_WRITE_MULTIPLE_BLOCK : MMC_READ_MULTIPLE_BLOCK;
+		} else {
+			cmd.opcode = write ?
+				MMC_WRITE_BLOCK : MMC_READ_SINGLE_BLOCK;
+		}
+	}
+
+	if (broken_xfer && blocks == 1)
+		cmd.arg = test->card->rca << 16;
+	else
+		cmd.arg = addr;
+	cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+
+	memset(&stop, 0, sizeof(struct mmc_command));
+
+	if (!broken_xfer && (blocks > 1)) {
+		stop.opcode = MMC_STOP_TRANSMISSION;
+		stop.arg = 0;
+		stop.flags = MMC_RSP_R1B | MMC_CMD_AC;
+
+		mrq.stop = &stop;
+	}
+
+	memset(&data, 0, sizeof(struct mmc_data));
+
+	data.blksz = blksz;
+	data.blocks = blocks;
+	data.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ;
+	data.sg = &sg;
+	data.sg_len = 1;
+
+	sg_init_one(&sg, buffer, blocks * blksz);
+
+	mmc_set_data_timeout(&data, test->card);
+
+	mmc_wait_for_req(test->card->host, &mrq);
+
+	ret = 0;
+
+	if (broken_xfer) {
+		if (!ret && cmd.error)
+			ret = cmd.error;
+		if (!ret && data.error == 0)
+			ret = RESULT_FAIL;
+		if (!ret && data.error != -ETIMEDOUT)
+			ret = data.error;
+		if (!ret && stop.error)
+			ret = stop.error;
+		if (blocks > 1) {
+			if (!ret && data.bytes_xfered > blksz)
+				ret = RESULT_FAIL;
+		} else {
+			if (!ret && data.bytes_xfered > 0)
+				ret = RESULT_FAIL;
+		}
+	} else {
+		if (!ret && cmd.error)
+			ret = cmd.error;
+		if (!ret && data.error)
+			ret = data.error;
+		if (!ret && stop.error)
+			ret = stop.error;
+		if (!ret && data.bytes_xfered != blocks * blksz)
+			ret = RESULT_FAIL;
+	}
+
+	if (ret == -EINVAL)
+		ret = RESULT_UNSUP_HOST;
+
+	busy = 0;
+	do {
+		int ret2;
+
+		memset(&cmd, 0, sizeof(struct mmc_command));
+
+		cmd.opcode = MMC_SEND_STATUS;
+		cmd.arg = test->card->rca << 16;
+		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+
+		ret2 = mmc_wait_for_cmd(test->card->host, &cmd, 0);
+		if (ret2)
+			break;
+
+		if (!busy && !(cmd.resp[0] & R1_READY_FOR_DATA)) {
+			busy = 1;
+			printk(KERN_INFO "%s: Warning: Host did not "
+				"wait for busy state to end.\n",
+				mmc_hostname(test->card->host));
+		}
+	} while (!(cmd.resp[0] & R1_READY_FOR_DATA));
+
+	return ret;
+}
+
+static int mmc_test_transfer(struct mmc_test_card *test, int write,
+	u8 *buffer, unsigned addr, unsigned blocks, unsigned blksz)
+{
+	return __mmc_test_transfer(test, write, 0, buffer,
+			addr, blocks, blksz);
+}
+
+static int mmc_test_prepare_verify(struct mmc_test_card *test, int write)
+{
+	int ret, i;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	if (write)
+		memset(test->buffer, 0xDF, BUFFER_SIZE);
+	else {
+		for (i = 0;i < BUFFER_SIZE;i++)
+			test->buffer[i] = i;
+	}
+
+	for (i = 0;i < BUFFER_SIZE / 512;i++) {
+		ret = mmc_test_transfer(test, 1, test->buffer + i * 512,
+			i * 512, 1, 512);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_prepare_verify_write(struct mmc_test_card *test)
+{
+	return mmc_test_prepare_verify(test, 1);
+}
+
+static int mmc_test_prepare_verify_read(struct mmc_test_card *test)
+{
+	return mmc_test_prepare_verify(test, 0);
+}
+
+static int mmc_test_verified_transfer(struct mmc_test_card *test, int write,
+	u8 *buffer, unsigned addr, unsigned blocks, unsigned blksz)
+{
+	int ret, i, sectors;
+
+	/*
+	 * It is assumed that the above preparation has been done.
+	 */
+
+	memset(test->buffer, 0, BUFFER_SIZE);
+
+	if (write) {
+		for (i = 0;i < blocks * blksz;i++)
+			buffer[i] = i;
+	}
+
+	ret = mmc_test_set_blksize(test, blksz);
+	if (ret)
+		return ret;
+
+	ret = mmc_test_transfer(test, write, buffer, addr, blocks, blksz);
+	if (ret)
+		return ret;
+
+	if (write) {
+		ret = mmc_test_set_blksize(test, 512);
+		if (ret)
+			return ret;
+
+		sectors = (blocks * blksz + 511) / 512;
+		if ((sectors * 512) == (blocks * blksz))
+			sectors++;
+
+		if ((sectors * 512) > BUFFER_SIZE)
+			return -EINVAL;
+
+		memset(test->buffer, 0, sectors * 512);
+
+		for (i = 0;i < sectors;i++) {
+			ret = mmc_test_transfer(test, 0,
+				test->buffer + i * 512,
+				addr + i * 512, 1, 512);
+			if (ret)
+				return ret;
+		}
+
+		for (i = 0;i < blocks * blksz;i++) {
+			if (test->buffer[i] != (u8)i)
+				return RESULT_FAIL;
+		}
+
+		for (;i < sectors * 512;i++) {
+			if (test->buffer[i] != 0xDF)
+				return RESULT_FAIL;
+		}
+	} else {
+		for (i = 0;i < blocks * blksz;i++) {
+			if (buffer[i] != (u8)i)
+				return RESULT_FAIL;
+		}
+	}
+
+	return 0;
+}
+
+static int mmc_test_cleanup_verify(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	memset(test->buffer, 0, BUFFER_SIZE);
+
+	for (i = 0;i < BUFFER_SIZE / 512;i++) {
+		ret = mmc_test_transfer(test, 1, test->buffer + i * 512,
+			i * 512, 1, 512);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*******************************************************************/
+/*  Tests                                                          */
+/*******************************************************************/
+
+struct mmc_test_case {
+	const char *name;
+
+	int (*prepare)(struct mmc_test_card *);
+	int (*run)(struct mmc_test_card *);
+	int (*cleanup)(struct mmc_test_card *);
+};
+
+static int mmc_test_basic_write(struct mmc_test_card *test)
+{
+	int ret;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	ret = mmc_test_transfer(test, 1, test->buffer, 0, 1, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_basic_read(struct mmc_test_card *test)
+{
+	int ret;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	ret = mmc_test_transfer(test, 0, test->buffer, 0, 1, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_verify_write(struct mmc_test_card *test)
+{
+	int ret;
+
+	ret = mmc_test_verified_transfer(test, 1, test->buffer, 0, 1, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_verify_read(struct mmc_test_card *test)
+{
+	int ret;
+
+	ret = mmc_test_verified_transfer(test, 0, test->buffer, 0, 1, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_multi_write(struct mmc_test_card *test)
+{
+	int ret;
+	unsigned int size;
+
+	if (test->card->host->max_blk_count == 1)
+		return RESULT_UNSUP_HOST;
+
+	size = PAGE_SIZE * 2;
+	size = min(size, test->card->host->max_req_size);
+	size = min(size, test->card->host->max_seg_size);
+	size = min(size, test->card->host->max_blk_count * 512);
+
+	if (size < 1024)
+		return RESULT_UNSUP_HOST;
+
+	ret = mmc_test_verified_transfer(test, 1, test->buffer, 0,
+		size / 512, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_multi_read(struct mmc_test_card *test)
+{
+	int ret;
+	unsigned int size;
+
+	if (test->card->host->max_blk_count == 1)
+		return RESULT_UNSUP_HOST;
+
+	size = PAGE_SIZE * 2;
+	size = min(size, test->card->host->max_req_size);
+	size = min(size, test->card->host->max_seg_size);
+	size = min(size, test->card->host->max_blk_count * 512);
+
+	if (size < 1024)
+		return RESULT_UNSUP_HOST;
+
+	ret = mmc_test_verified_transfer(test, 0, test->buffer, 0,
+		size / 512, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_pow2_write(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	if (!test->card->csd.write_partial)
+		return RESULT_UNSUP_CARD;
+
+	for (i = 1; i < 512;i <<= 1) {
+		ret = mmc_test_verified_transfer(test, 1,
+			test->buffer, 0, 1, i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_pow2_read(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	if (!test->card->csd.read_partial)
+		return RESULT_UNSUP_CARD;
+
+	for (i = 1; i < 512;i <<= 1) {
+		ret = mmc_test_verified_transfer(test, 0,
+			test->buffer, 0, 1, i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_weird_write(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	if (!test->card->csd.write_partial)
+		return RESULT_UNSUP_CARD;
+
+	for (i = 3; i < 512;i += 7) {
+		ret = mmc_test_verified_transfer(test, 1,
+			test->buffer, 0, 1, i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_weird_read(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	if (!test->card->csd.read_partial)
+		return RESULT_UNSUP_CARD;
+
+	for (i = 3; i < 512;i += 7) {
+		ret = mmc_test_verified_transfer(test, 0,
+			test->buffer, 0, 1, i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_align_write(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	for (i = 1;i < 4;i++) {
+		ret = mmc_test_verified_transfer(test, 1, test->buffer + i,
+			0, 1, 512);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_align_read(struct mmc_test_card *test)
+{
+	int ret, i;
+
+	for (i = 1;i < 4;i++) {
+		ret = mmc_test_verified_transfer(test, 0, test->buffer + i,
+			0, 1, 512);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_align_multi_write(struct mmc_test_card *test)
+{
+	int ret, i;
+	unsigned int size;
+
+	if (test->card->host->max_blk_count == 1)
+		return RESULT_UNSUP_HOST;
+
+	size = PAGE_SIZE * 2;
+	size = min(size, test->card->host->max_req_size);
+	size = min(size, test->card->host->max_seg_size);
+	size = min(size, test->card->host->max_blk_count * 512);
+
+	if (size < 1024)
+		return RESULT_UNSUP_HOST;
+
+	for (i = 1;i < 4;i++) {
+		ret = mmc_test_verified_transfer(test, 1, test->buffer + i,
+			0, size / 512, 512);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_align_multi_read(struct mmc_test_card *test)
+{
+	int ret, i;
+	unsigned int size;
+
+	if (test->card->host->max_blk_count == 1)
+		return RESULT_UNSUP_HOST;
+
+	size = PAGE_SIZE * 2;
+	size = min(size, test->card->host->max_req_size);
+	size = min(size, test->card->host->max_seg_size);
+	size = min(size, test->card->host->max_blk_count * 512);
+
+	if (size < 1024)
+		return RESULT_UNSUP_HOST;
+
+	for (i = 1;i < 4;i++) {
+		ret = mmc_test_verified_transfer(test, 0, test->buffer + i,
+			0, size / 512, 512);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mmc_test_xfersize_write(struct mmc_test_card *test)
+{
+	int ret;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	ret = __mmc_test_transfer(test, 1, 1, test->buffer, 0, 1, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_xfersize_read(struct mmc_test_card *test)
+{
+	int ret;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	ret = __mmc_test_transfer(test, 0, 1, test->buffer, 0, 1, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_multi_xfersize_write(struct mmc_test_card *test)
+{
+	int ret;
+
+	if (test->card->host->max_blk_count == 1)
+		return RESULT_UNSUP_HOST;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	ret = __mmc_test_transfer(test, 1, 1, test->buffer, 0, 2, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int mmc_test_multi_xfersize_read(struct mmc_test_card *test)
+{
+	int ret;
+
+	if (test->card->host->max_blk_count == 1)
+		return RESULT_UNSUP_HOST;
+
+	ret = mmc_test_set_blksize(test, 512);
+	if (ret)
+		return ret;
+
+	ret = __mmc_test_transfer(test, 0, 1, test->buffer, 0, 2, 512);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct mmc_test_case mmc_test_cases[] = {
+	{
+		.name = "Basic write (no data verification)",
+		.run = mmc_test_basic_write,
+	},
+
+	{
+		.name = "Basic read (no data verification)",
+		.run = mmc_test_basic_read,
+	},
+
+	{
+		.name = "Basic write (with data verification)",
+		.prepare = mmc_test_prepare_verify_write,
+		.run = mmc_test_verify_write,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Basic read (with data verification)",
+		.prepare = mmc_test_prepare_verify_read,
+		.run = mmc_test_verify_read,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Multi-block write",
+		.prepare = mmc_test_prepare_verify_write,
+		.run = mmc_test_multi_write,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Multi-block read",
+		.prepare = mmc_test_prepare_verify_read,
+		.run = mmc_test_multi_read,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Power of two block writes",
+		.prepare = mmc_test_prepare_verify_write,
+		.run = mmc_test_pow2_write,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Power of two block reads",
+		.prepare = mmc_test_prepare_verify_read,
+		.run = mmc_test_pow2_read,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Weird sized block writes",
+		.prepare = mmc_test_prepare_verify_write,
+		.run = mmc_test_weird_write,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Weird sized block reads",
+		.prepare = mmc_test_prepare_verify_read,
+		.run = mmc_test_weird_read,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Badly aligned write",
+		.prepare = mmc_test_prepare_verify_write,
+		.run = mmc_test_align_write,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Badly aligned read",
+		.prepare = mmc_test_prepare_verify_read,
+		.run = mmc_test_align_read,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Badly aligned multi-block write",
+		.prepare = mmc_test_prepare_verify_write,
+		.run = mmc_test_align_multi_write,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Badly aligned multi-block read",
+		.prepare = mmc_test_prepare_verify_read,
+		.run = mmc_test_align_multi_read,
+		.cleanup = mmc_test_cleanup_verify,
+	},
+
+	{
+		.name = "Correct xfer_size at write (start failure)",
+		.run = mmc_test_xfersize_write,
+	},
+
+	{
+		.name = "Correct xfer_size at read (start failure)",
+		.run = mmc_test_xfersize_read,
+	},
+
+	{
+		.name = "Correct xfer_size at write (midway failure)",
+		.run = mmc_test_multi_xfersize_write,
+	},
+
+	{
+		.name = "Correct xfer_size at read (midway failure)",
+		.run = mmc_test_multi_xfersize_read,
+	},
+};
+
+static struct mutex mmc_test_lock;
+
+static void mmc_test_run(struct mmc_test_card *test)
+{
+	int i, ret;
+
+	printk(KERN_INFO "%s: Starting tests of card %s...\n",
+		mmc_hostname(test->card->host), mmc_card_id(test->card));
+
+	mmc_claim_host(test->card->host);
+
+	for (i = 0;i < ARRAY_SIZE(mmc_test_cases);i++) {
+		printk(KERN_INFO "%s: Test case %d. %s...\n",
+			mmc_hostname(test->card->host), i + 1,
+			mmc_test_cases[i].name);
+
+		if (mmc_test_cases[i].prepare) {
+			ret = mmc_test_cases[i].prepare(test);
+			if (ret) {
+				printk(KERN_INFO "%s: Result: Prepare "
+					"stage failed! (%d)\n",
+					mmc_hostname(test->card->host),
+					ret);
+				continue;
+			}
+		}
+
+		ret = mmc_test_cases[i].run(test);
+		switch (ret) {
+		case RESULT_OK:
+			printk(KERN_INFO "%s: Result: OK\n",
+				mmc_hostname(test->card->host));
+			break;
+		case RESULT_FAIL:
+			printk(KERN_INFO "%s: Result: FAILED\n",
+				mmc_hostname(test->card->host));
+			break;
+		case RESULT_UNSUP_HOST:
+			printk(KERN_INFO "%s: Result: UNSUPPORTED "
+				"(by host)\n",
+				mmc_hostname(test->card->host));
+			break;
+		case RESULT_UNSUP_CARD:
+			printk(KERN_INFO "%s: Result: UNSUPPORTED "
+				"(by card)\n",
+				mmc_hostname(test->card->host));
+			break;
+		default:
+			printk(KERN_INFO "%s: Result: ERROR (%d)\n",
+				mmc_hostname(test->card->host), ret);
+		}
+
+		if (mmc_test_cases[i].cleanup) {
+			ret = mmc_test_cases[i].cleanup(test);
+			if (ret) {
+				printk(KERN_INFO "%s: Warning: Cleanup "
+					"stage failed! (%d)\n",
+					mmc_hostname(test->card->host),
+					ret);
+			}
+		}
+	}
+
+	mmc_release_host(test->card->host);
+
+	printk(KERN_INFO "%s: Tests completed.\n",
+		mmc_hostname(test->card->host));
+}
+
+static ssize_t mmc_test_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	mutex_lock(&mmc_test_lock);
+	mutex_unlock(&mmc_test_lock);
+
+	return 0;
+}
+
+static ssize_t mmc_test_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct mmc_card *card;
+	struct mmc_test_card *test;
+
+	card = container_of(dev, struct mmc_card, dev);
+
+	test = kzalloc(sizeof(struct mmc_test_card), GFP_KERNEL);
+	if (!test)
+		return -ENOMEM;
+
+	test->card = card;
+
+	test->buffer = kzalloc(BUFFER_SIZE, GFP_KERNEL);
+	if (test->buffer) {
+		mutex_lock(&mmc_test_lock);
+		mmc_test_run(test);
+		mutex_unlock(&mmc_test_lock);
+	}
+
+	kfree(test->buffer);
+	kfree(test);
+
+	return count;
+}
+
+static DEVICE_ATTR(test, S_IWUSR | S_IRUGO, mmc_test_show, mmc_test_store);
+
+static int mmc_test_probe(struct mmc_card *card)
+{
+	int ret;
+
+	mutex_init(&mmc_test_lock);
+
+	ret = device_create_file(&card->dev, &dev_attr_test);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void mmc_test_remove(struct mmc_card *card)
+{
+	device_remove_file(&card->dev, &dev_attr_test);
+}
+
+static struct mmc_driver mmc_driver = {
+	.drv		= {
+		.name	= "mmc_test",
+	},
+	.probe		= mmc_test_probe,
+	.remove		= mmc_test_remove,
+};
+
+static int __init mmc_test_init(void)
+{
+	return mmc_register_driver(&mmc_driver);
+}
+
+static void __exit mmc_test_exit(void)
+{
+	mmc_unregister_driver(&mmc_driver);
+}
+
+module_init(mmc_test_init);
+module_exit(mmc_test_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Multimedia Card (MMC) host test driver");
+MODULE_AUTHOR("Pierre Ossman");