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Subject[PATCH v2 3/4] mmc: Add per-card debugfs support
Date
For each card successfully added to the bus, create a subdirectory under
the host's debugfs root with information about the card.

Depending on the card type, up to two files are added to the card
directory: "state" and "status". The former exists for all cards, and
reflects the "state" field of struct mmc_card.

The "status" field exists only for MMC and SD memory cards, not SDIO.
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>

Changes since v1:
* move card debugfs stuff into debugfs.c
* add "state" file corresponding to the "state" field in struct
mmc_card.
* only create the "status" file if the card is an MMC or SD memory
card since SDIO doesn't support the SEND_STATUS command.
---
drivers/mmc/core/bus.c | 4 +++
drivers/mmc/core/core.h | 3 ++
drivers/mmc/core/debugfs.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/card.h | 2 +
4 files changed, 70 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index fd95b18..5c0d15b 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -252,6 +252,8 @@ int mmc_add_card(struct mmc_card *card)
if (ret)
return ret;

+ mmc_add_card_debugfs(card);
+
mmc_card_set_present(card);

return 0;
@@ -263,6 +265,8 @@ int mmc_add_card(struct mmc_card *card)
*/
void mmc_remove_card(struct mmc_card *card)
{
+ mmc_remove_card_debugfs(card);
+
if (mmc_card_present(card)) {
if (mmc_host_is_spi(card->host)) {
printk(KERN_INFO "%s: SPI card removed\n",
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 745da98..c819eff 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -56,5 +56,8 @@ extern int use_spi_crc;
void mmc_add_host_debugfs(struct mmc_host *host);
void mmc_remove_host_debugfs(struct mmc_host *host);

+void mmc_add_card_debugfs(struct mmc_card *card);
+void mmc_remove_card_debugfs(struct mmc_card *card);
+
#endif

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 133c6e5..1237bb4 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);
+}
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 0d508ac..ee6e822 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -111,6 +111,8 @@ struct mmc_card {
unsigned num_info; /* number of info strings */
const char **info; /* info strings */
struct sdio_func_tuple *tuples; /* unknown common tuples */
+
+ struct dentry *debugfs_root;
};

#define mmc_card_mmc(c) ((c)->type == MMC_TYPE_MMC)
--
1.5.6


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