linux/drivers/mmc/core/debugfs.c
Andy Shevchenko 703aae3d09 mmc: add a file to debugfs for changing host clock at runtime
For debugging power management features it is convenient to have the
possibility of changing the MMC host controller clock at runtime.  This
patch adds a 'clock' file for this under the MMC host root of debugfs.

Usage is as follows:

	# cat /sys/kernel/debug/mmc0/clock
	52000000

	# echo "1000000000" > /sys/kernel/debug/mmc0/clock
	# cat /sys/kernel/debug/mmc0/clock
	52000000

	# echo "48000000" > /sys/kernel/debug/mmc0/clock
	# cat /sys/kernel/debug/mmc0/clock
	48000000

The middle example shows limits being applied by the host driver.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
[cjb: modify changelog language]
Signed-off-by: Chris Ball <cjb@laptop.org>
2010-10-23 21:11:20 +08:00

325 lines
6.7 KiB
C

/*
* 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/slab.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)
{
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,
};
static int mmc_clock_opt_get(void *data, u64 *val)
{
struct mmc_host *host = data;
*val = host->ios.clock;
return 0;
}
static int mmc_clock_opt_set(void *data, u64 val)
{
struct mmc_host *host = data;
/* We need this check due to input value is u64 */
if (val > host->f_max)
return -EINVAL;
mmc_claim_host(host);
mmc_set_clock(host, (unsigned int) val);
mmc_release_host(host);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
"%llu\n");
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_node;
if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
&mmc_clock_fops))
goto err_node;
return;
err_node:
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);
}
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");
#define EXT_CSD_STR_LEN 1025
static int mmc_ext_csd_open(struct inode *inode, struct file *filp)
{
struct mmc_card *card = inode->i_private;
char *buf;
ssize_t n = 0;
u8 *ext_csd;
int err, i;
buf = kmalloc(EXT_CSD_STR_LEN + 1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
ext_csd = kmalloc(512, GFP_KERNEL);
if (!ext_csd) {
err = -ENOMEM;
goto out_free;
}
mmc_claim_host(card->host);
err = mmc_send_ext_csd(card, ext_csd);
mmc_release_host(card->host);
if (err)
goto out_free;
for (i = 511; i >= 0; i--)
n += sprintf(buf + n, "%02x", ext_csd[i]);
n += sprintf(buf + n, "\n");
BUG_ON(n != EXT_CSD_STR_LEN);
filp->private_data = buf;
kfree(ext_csd);
return 0;
out_free:
kfree(buf);
kfree(ext_csd);
return err;
}
static ssize_t mmc_ext_csd_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, EXT_CSD_STR_LEN);
}
static int mmc_ext_csd_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
}
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,
.llseek = default_llseek,
};
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;
if (mmc_card_mmc(card))
if (!debugfs_create_file("ext_csd", S_IRUSR, root, card,
&mmc_dbg_ext_csd_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);
}