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linux/drivers/mmc/core/debugfs.c
Linus Walleij 04566831a7 mmc: Aggressive clock gating framework 
This patch modifies the MMC core code to optionally call the set_ios()
operation on the driver with the clock frequency set to 0 (gate) after
a grace period of at least 8 MCLK cycles, then restore it (ungate)
before any new request. This gives the driver the option to shut down
the MCI clock to the MMC/SD card when the clock frequency is 0, i.e.
the core has stated that the MCI clock does not need to be generated.

It is inspired by existing clock gating code found in the OMAP and
Atmel drivers and brings this up to the host abstraction.  Gating is
performed before and after any MMC request.

This patchset implements this for the MMCI/PL180 MMC/SD host controller,
but it should be simple to switch OMAP/Atmel over to using this instead.

mmc_set_{gated,ungated}() add variable protection to the state holders
for the clock gating code.  This is particularly important when ordinary
.set_ios() calls would race with the .set_ios() call resulting from a
delayed gate operation.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-by: Chris Ball <cjb@laptop.org>
Tested-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-01-08 22:48:03 -05:00

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/*
* 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;
#ifdef CONFIG_MMC_CLKGATE
if (!debugfs_create_u32("clk_delay", (S_IRUSR | S_IWUSR),
root, &host->clk_delay))
goto err_node;
#endif
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);
}
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