mmc: Add per-card debugfs support

For each card successfully added to the bus, create a subdirectory under
the host's debugfs root with information about the card.

At the moment, only a single file is added to the card directory for
all cards: "state". It reflects the "state" field in struct mmc_card,
indicating whether the card is present, readonly, etc.

For MMC and SD cards (not SDIO), another file is added: "status".
Reading this file will ask the card about its current status and
return it. This can be useful if the card just refuses to respond to
any commands, which might indicate that the card state is not what the
MMC core thinks it is (due to a missing stop command, for example.)

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 133c6e51f26b..1237bb4c722b 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -12,9 +12,11 @@
 #include <linux/seq_file.h>
 #include <linux/stat.h>
 
+#include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
 
 #include "core.h"
+#include "mmc_ops.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)
@@ -162,3 +164,62 @@ void mmc_remove_host_debugfs(struct mmc_host *host)
 {
 	debugfs_remove_recursive(host->debugfs_root);
 }
+
+static int mmc_dbg_card_status_get(void *data, u64 *val)
+{
+	struct mmc_card	*card = data;
+	u32		status;
+	int		ret;
+
+	mmc_claim_host(card->host);
+
+	ret = mmc_send_status(data, &status);
+	if (!ret)
+		*val = status;
+
+	mmc_release_host(card->host);
+
+	return ret;
+}
+DEFINE_SIMPLE_ATTRIBUTE(mmc_dbg_card_status_fops, mmc_dbg_card_status_get,
+		NULL, "%08llx\n");
+
+void mmc_add_card_debugfs(struct mmc_card *card)
+{
+	struct mmc_host	*host = card->host;
+	struct dentry	*root;
+
+	if (!host->debugfs_root)
+		return;
+
+	root = debugfs_create_dir(mmc_card_id(card), host->debugfs_root);
+	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;
+
+	card->debugfs_root = root;
+
+	if (!debugfs_create_x32("state", S_IRUSR, root, &card->state))
+		goto err;
+
+	if (mmc_card_mmc(card) || mmc_card_sd(card))
+		if (!debugfs_create_file("status", S_IRUSR, root, card,
+					&mmc_dbg_card_status_fops))
+			goto err;
+
+	return;
+
+err:
+	debugfs_remove_recursive(root);
+	card->debugfs_root = NULL;
+	dev_err(&card->dev, "failed to initialize debugfs\n");
+}
+
+void mmc_remove_card_debugfs(struct mmc_card *card)
+{
+	debugfs_remove_recursive(card->debugfs_root);
+}