diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 19a1a254a0c5f81d8e0a36815caf4b870b6497cc..889e5f898f6f99485c6b031aee41f5a6ff86d0aa 100644
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -12,3 +12,4 @@ mmc_core-y			:= core.o bus.o host.o \
 				   sdio.o sdio_ops.o sdio_bus.o \
 				   sdio_cis.o sdio_io.o sdio_irq.o
 
+mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index cdb332b7dedc87340ef5ff0aacedc71f8b4fe931..745da9881aa7e3c5a38ac982d52d9d227eae7afd 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -52,5 +52,9 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr);
 
 extern int use_spi_crc;
 
+/* Debugfs information for hosts and cards */
+void mmc_add_host_debugfs(struct mmc_host *host);
+void mmc_remove_host_debugfs(struct mmc_host *host);
+
 #endif
 
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
new file mode 100644
index 0000000000000000000000000000000000000000..133c6e51f26b7f66ffdda512083f9bb1ce9f6612
--- /dev/null
+++ b/drivers/mmc/core/debugfs.c
@@ -0,0 +1,164 @@
+/*
+ * Debugfs support for hosts and cards
+ *
+ * Copyright (C) 2008 Atmel Corporation
+ *
+ * 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.
+ */
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+
+#include <linux/mmc/host.h>
+
+#include "core.h"
+
+/* The debugfs functions are optimized away when CONFIG_DEBUG_FS isn't set. */
+static int mmc_ios_show(struct seq_file *s, void *data)
+{
+	static const char *vdd_str[] = {
+		[8]	= "2.0",
+		[9]	= "2.1",
+		[10]	= "2.2",
+		[11]	= "2.3",
+		[12]	= "2.4",
+		[13]	= "2.5",
+		[14]	= "2.6",
+		[15]	= "2.7",
+		[16]	= "2.8",
+		[17]	= "2.9",
+		[18]	= "3.0",
+		[19]	= "3.1",
+		[20]	= "3.2",
+		[21]	= "3.3",
+		[22]	= "3.4",
+		[23]	= "3.5",
+		[24]	= "3.6",
+	};
+	struct mmc_host	*host = s->private;
+	struct mmc_ios	*ios = &host->ios;
+	const char *str;
+
+	seq_printf(s, "clock:\t\t%u Hz\n", ios->clock);
+	seq_printf(s, "vdd:\t\t%u ", ios->vdd);
+	if ((1 << ios->vdd) & MMC_VDD_165_195)
+		seq_printf(s, "(1.65 - 1.95 V)\n");
+	else if (ios->vdd < (ARRAY_SIZE(vdd_str) - 1)
+			&& vdd_str[ios->vdd] && vdd_str[ios->vdd + 1])
+		seq_printf(s, "(%s ~ %s V)\n", vdd_str[ios->vdd],
+				vdd_str[ios->vdd + 1]);
+	else
+		seq_printf(s, "(invalid)\n");
+
+	switch (ios->bus_mode) {
+	case MMC_BUSMODE_OPENDRAIN:
+		str = "open drain";
+		break;
+	case MMC_BUSMODE_PUSHPULL:
+		str = "push-pull";
+		break;
+	default:
+		str = "invalid";
+		break;
+	}
+	seq_printf(s, "bus mode:\t%u (%s)\n", ios->bus_mode, str);
+
+	switch (ios->chip_select) {
+	case MMC_CS_DONTCARE:
+		str = "don't care";
+		break;
+	case MMC_CS_HIGH:
+		str = "active high";
+		break;
+	case MMC_CS_LOW:
+		str = "active low";
+		break;
+	default:
+		str = "invalid";
+		break;
+	}
+	seq_printf(s, "chip select:\t%u (%s)\n", ios->chip_select, str);
+
+	switch (ios->power_mode) {
+	case MMC_POWER_OFF:
+		str = "off";
+		break;
+	case MMC_POWER_UP:
+		str = "up";
+		break;
+	case MMC_POWER_ON:
+		str = "on";
+		break;
+	default:
+		str = "invalid";
+		break;
+	}
+	seq_printf(s, "power mode:\t%u (%s)\n", ios->power_mode, str);
+	seq_printf(s, "bus width:\t%u (%u bits)\n",
+			ios->bus_width, 1 << ios->bus_width);
+
+	switch (ios->timing) {
+	case MMC_TIMING_LEGACY:
+		str = "legacy";
+		break;
+	case MMC_TIMING_MMC_HS:
+		str = "mmc high-speed";
+		break;
+	case MMC_TIMING_SD_HS:
+		str = "sd high-speed";
+		break;
+	default:
+		str = "invalid";
+		break;
+	}
+	seq_printf(s, "timing spec:\t%u (%s)\n", ios->timing, str);
+
+	return 0;
+}
+
+static int mmc_ios_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, mmc_ios_show, inode->i_private);
+}
+
+static const struct file_operations mmc_ios_fops = {
+	.open		= mmc_ios_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+void mmc_add_host_debugfs(struct mmc_host *host)
+{
+	struct dentry *root;
+
+	root = debugfs_create_dir(mmc_hostname(host), NULL);
+	if (IS_ERR(root))
+		/* Don't complain -- debugfs just isn't enabled */
+		return;
+	if (!root)
+		/* Complain -- debugfs is enabled, but it failed to
+		 * create the directory. */
+		goto err_root;
+
+	host->debugfs_root = root;
+
+	if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
+		goto err_ios;
+
+	return;
+
+err_ios:
+	debugfs_remove_recursive(root);
+	host->debugfs_root = NULL;
+err_root:
+	dev_err(&host->class_dev, "failed to initialize debugfs\n");
+}
+
+void mmc_remove_host_debugfs(struct mmc_host *host)
+{
+	debugfs_remove_recursive(host->debugfs_root);
+}
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 1d795c5379b548f5869b83d7aabf05848a6d27b1..6da80fd4d974669223ac2caf54576f6521c52083 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -127,6 +127,10 @@ int mmc_add_host(struct mmc_host *host)
 	if (err)
 		return err;
 
+#ifdef CONFIG_DEBUG_FS
+	mmc_add_host_debugfs(host);
+#endif
+
 	mmc_start_host(host);
 
 	return 0;
@@ -146,6 +150,10 @@ void mmc_remove_host(struct mmc_host *host)
 {
 	mmc_stop_host(host);
 
+#ifdef CONFIG_DEBUG_FS
+	mmc_remove_host_debugfs(host);
+#endif
+
 	device_del(&host->class_dev);
 
 	led_trigger_unregister_simple(host->led);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 10a2080086ca9e6402eec37178bd8dea384f3f92..9c288c9098783cfc3ef1b4d6357081b7d3f44849 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -157,6 +157,8 @@ struct mmc_host {
 	struct led_trigger	*led;		/* activity led */
 #endif
 
+	struct dentry		*debugfs_root;
+
 	unsigned long		private[0] ____cacheline_aligned;
 };