2013-04-12 19:56:42

by Steve Magnani

Subject: [PATCH] mmc: debugfs: Add debugfs ability to read CID and CSD

Adds 'cid' and 'csd' debugfs entries for SD/MMC devices that allow
userland to obtain the values of the corresponding device registers.

Signed-off-by: Steven J. Magnani <[email protected]>
---
--- a/drivers/mmc/core/debugfs.c 2013-04-12 07:39:22.532586948 -0500
+++ b/drivers/mmc/core/debugfs.c 2013-04-12 07:40:14.513331587 -0500
@@ -321,7 +321,7 @@ static ssize_t mmc_ext_csd_read(struct f
buf, EXT_CSD_STR_LEN);
}

-static int mmc_ext_csd_release(struct inode *inode, struct file *file)
+static int mmc_dbg_buf_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
@@ -330,7 +330,65 @@ static int mmc_ext_csd_release(struct in
static const struct file_operations mmc_dbg_ext_csd_fops = {
.open = mmc_ext_csd_open,
.read = mmc_ext_csd_read,
- .release = mmc_ext_csd_release,
+ .release = mmc_dbg_buf_release,
+ .llseek = default_llseek,
+};
+
+/* CSD and CID have the same length and so can be handled much the same */
+#define CXD_STR_LEN 33
+
+static int mmc_cxd_open(struct file *filp, u32 *raw_cxd)
+{
+ char *buf;
+ ssize_t n = 0;
+ int i;
+
+ buf = kmalloc(CXD_STR_LEN + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ for (i = 0; i < 4; i++)
+ n += sprintf(buf + n, "%08x", raw_cxd[i]);
+ n += sprintf(buf + n, "\n");
+ BUG_ON(n != CXD_STR_LEN);
+
+ filp->private_data = buf;
+ return 0;
+}
+
+static ssize_t mmc_cxd_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char *buf = filp->private_data;
+
+ return simple_read_from_buffer(ubuf, cnt, ppos,
+ buf, CXD_STR_LEN);
+}
+
+static int mmc_csd_open(struct inode *inode, struct file *filp)
+{
+ struct mmc_card *card = inode->i_private;
+ return mmc_cxd_open(filp, card->raw_csd);
+}
+
+static const struct file_operations mmc_dbg_csd_fops = {
+ .open = mmc_csd_open,
+ .read = mmc_cxd_read,
+ .release = mmc_dbg_buf_release,
+ .llseek = default_llseek,
+};
+
+
+static int mmc_cid_open(struct inode *inode, struct file *filp)
+{
+ struct mmc_card *card = inode->i_private;
+ return mmc_cxd_open(filp, card->raw_cid);
+}
+
+static const struct file_operations mmc_dbg_cid_fops = {
+ .open = mmc_cid_open,
+ .read = mmc_cxd_read,
+ .release = mmc_dbg_buf_release,
.llseek = default_llseek,
};

@@ -356,10 +414,17 @@ void mmc_add_card_debugfs(struct mmc_car
if (!debugfs_create_x32("state", S_IRUSR, root, &card->state))
goto err;

- if (mmc_card_mmc(card) || mmc_card_sd(card))
+ 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;
+ if (!debugfs_create_file("csd", S_IRUSR, root, card,
+ &mmc_dbg_csd_fops))
+ goto err;
+ if (!debugfs_create_file("cid", S_IRUSR, root, card,
+ &mmc_dbg_cid_fops))
+ goto err;
+ }

if (mmc_card_mmc(card))
if (!debugfs_create_file("ext_csd", S_IRUSR, root, card,

2013-04-13 02:01:42

by Steven J. Magnani

Subject: Re: [PATCH] mmc: debugfs: Add debugfs ability to read CID and CSD

On Sat, 2013-04-13 at 01:06 +0200, Johan Rudholm wrote:
> I believe these registers are already available as sysfs nodes? I
> don't have access to the proper hardware right now, but I'm pretty
> sure you'll find something if you do for instance "find /sys -name
> csd".

Ahh. Thanks for the tip; I hadn't thought to look there since I found
the ext_csd under debugfs.
------------------------------------------------------------------------
Steven J. Magnani "I claim this network for MARS!
http://www.digidescorp.com Earthling, return my space modulator!"

#include <standard.disclaimer>