mmc: Export internal host state through debugfs

When CONFIG_DEBUG_FS is set, create a few files under /sys/kernel/debug containing information about an mmc host's internal state. Currently, just a single file is created, "ios", which contains information about the current operating parameters for the bus (clock speed, bus width, etc.) Host drivers can add additional files and directories under the host's root directory by passing the debugfs_root field in struct mmc_host as the 'parent' parameter to debugfs_create_*. Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

mmc: Export internal host state through debugfs
When CONFIG_DEBUG_FS is set, create a few files under /sys/kernel/debug containing information about an mmc host's internal state. Currently, just a single file is created, "ios", which contains information about the current operating parameters for the bus (clock speed, bus width, etc.) Host drivers can add additional files and directories under the host's root directory by passing the debugfs_root field in struct mmc_host as the 'parent' parameter to debugfs_create_*. Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Haavard Skinnemoen · Pierre Ossman
1 parent c5d5e9c40f
Showing 5 changed files with 179 additions and 0 deletions Side-by-side Diff
drivers/mmc/core/Makefile
drivers/mmc/core/core.h
drivers/mmc/core/debugfs.c
drivers/mmc/core/host.c
include/linux/mmc/host.h
@@ -11,4 +11,6 @@
 				   mmc.o mmc_ops.o sd.o sd_ops.o \
 				   sdio.o sdio_ops.o sdio_bus.o \
 				   sdio_cis.o sdio_io.o sdio_irq.o
+
+mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o
@@ -52,5 +52,9 @@
  
 extern int use_spi_crc;
  
+/* Debugfs information for hosts and cards */
+void mmc_add_host_debugfs(struct mmc_host *host);
+void mmc_remove_host_debugfs(struct mmc_host *host);
+
 #endif
+/*
+ * 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/stat.h>
+
+#include <linux/mmc/host.h>
+
+#include "core.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,
+};
+
+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_ios;
+
+	return;
+
+err_ios:
+	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);
+}
@@ -127,6 +127,10 @@
 	if (err)
 		return err;
  
+#ifdef CONFIG_DEBUG_FS
+	mmc_add_host_debugfs(host);
+#endif
+
 	mmc_start_host(host);
  
 	return 0;
@@ -145,6 +149,10 @@
 void mmc_remove_host(struct mmc_host *host)
 {
 	mmc_stop_host(host);
+
+#ifdef CONFIG_DEBUG_FS
+	mmc_remove_host_debugfs(host);
+#endif
  
 	device_del(&host->class_dev);
  
@@ -157,6 +157,8 @@
 	struct led_trigger	*led;		/* activity led */
 #endif
  
+	struct dentry		*debugfs_root;
+
 	unsigned long		private[0] ____cacheline_aligned;
 };
...	...	@@ -11,4 +11,6 @@
11	11	mmc.o mmc_ops.o sd.o sd_ops.o \
12	12	sdio.o sdio_ops.o sdio_bus.o \
13	13	sdio_cis.o sdio_io.o sdio_irq.o
	14	+
	15	+mmc_core-$(CONFIG_DEBUG_FS) += debugfs.o
...	...	@@ -52,5 +52,9 @@
52	52
53	53	extern int use_spi_crc;
54	54
	55	+/* Debugfs information for hosts and cards */
	56	+void mmc_add_host_debugfs(struct mmc_host *host);
	57	+void mmc_remove_host_debugfs(struct mmc_host *host);
	58	+
55	59	#endif
	1	+/*
	2	+ * Debugfs support for hosts and cards
	3	+ *
	4	+ * Copyright (C) 2008 Atmel Corporation
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify
	7	+ * it under the terms of the GNU General Public License version 2 as
	8	+ * published by the Free Software Foundation.
	9	+ */
	10	+#include <linux/debugfs.h>
	11	+#include <linux/fs.h>
	12	+#include <linux/seq_file.h>
	13	+#include <linux/stat.h>
	14	+
	15	+#include <linux/mmc/host.h>
	16	+
	17	+#include "core.h"
	18	+
	19	+/* The debugfs functions are optimized away when CONFIG_DEBUG_FS isn't set. */
	20	+static int mmc_ios_show(struct seq_file s, void data)
	21	+{
	22	+ static const char *vdd_str[] = {
	23	+ [8] = "2.0",
	24	+ [9] = "2.1",
	25	+ [10] = "2.2",
	26	+ [11] = "2.3",
	27	+ [12] = "2.4",
	28	+ [13] = "2.5",
	29	+ [14] = "2.6",
	30	+ [15] = "2.7",
	31	+ [16] = "2.8",
	32	+ [17] = "2.9",
	33	+ [18] = "3.0",
	34	+ [19] = "3.1",
	35	+ [20] = "3.2",
	36	+ [21] = "3.3",
	37	+ [22] = "3.4",
	38	+ [23] = "3.5",
	39	+ [24] = "3.6",
	40	+ };
	41	+ struct mmc_host *host = s->private;
	42	+ struct mmc_ios *ios = &host->ios;
	43	+ const char *str;
	44	+
	45	+ seq_printf(s, "clock:\t\t%u Hz\n", ios->clock);
	46	+ seq_printf(s, "vdd:\t\t%u ", ios->vdd);
	47	+ if ((1 << ios->vdd) & MMC_VDD_165_195)
	48	+ seq_printf(s, "(1.65 - 1.95 V)\n");
	49	+ else if (ios->vdd < (ARRAY_SIZE(vdd_str) - 1)
	50	+ && vdd_str[ios->vdd] && vdd_str[ios->vdd + 1])
	51	+ seq_printf(s, "(%s ~ %s V)\n", vdd_str[ios->vdd],
	52	+ vdd_str[ios->vdd + 1]);
	53	+ else
	54	+ seq_printf(s, "(invalid)\n");
	55	+
	56	+ switch (ios->bus_mode) {
	57	+ case MMC_BUSMODE_OPENDRAIN:
	58	+ str = "open drain";
	59	+ break;
	60	+ case MMC_BUSMODE_PUSHPULL:
	61	+ str = "push-pull";
	62	+ break;
	63	+ default:
	64	+ str = "invalid";
	65	+ break;
	66	+ }
	67	+ seq_printf(s, "bus mode:\t%u (%s)\n", ios->bus_mode, str);
	68	+
	69	+ switch (ios->chip_select) {
	70	+ case MMC_CS_DONTCARE:
	71	+ str = "don't care";
	72	+ break;
	73	+ case MMC_CS_HIGH:
	74	+ str = "active high";
	75	+ break;
	76	+ case MMC_CS_LOW:
	77	+ str = "active low";
	78	+ break;
	79	+ default:
	80	+ str = "invalid";
	81	+ break;
	82	+ }
	83	+ seq_printf(s, "chip select:\t%u (%s)\n", ios->chip_select, str);
	84	+
	85	+ switch (ios->power_mode) {
	86	+ case MMC_POWER_OFF:
	87	+ str = "off";
	88	+ break;
	89	+ case MMC_POWER_UP:
	90	+ str = "up";
	91	+ break;
	92	+ case MMC_POWER_ON:
	93	+ str = "on";
	94	+ break;
	95	+ default:
	96	+ str = "invalid";
	97	+ break;
	98	+ }
	99	+ seq_printf(s, "power mode:\t%u (%s)\n", ios->power_mode, str);
	100	+ seq_printf(s, "bus width:\t%u (%u bits)\n",
	101	+ ios->bus_width, 1 << ios->bus_width);
	102	+
	103	+ switch (ios->timing) {
	104	+ case MMC_TIMING_LEGACY:
	105	+ str = "legacy";
	106	+ break;
	107	+ case MMC_TIMING_MMC_HS:
	108	+ str = "mmc high-speed";
	109	+ break;
	110	+ case MMC_TIMING_SD_HS:
	111	+ str = "sd high-speed";
	112	+ break;
	113	+ default:
	114	+ str = "invalid";
	115	+ break;
	116	+ }
	117	+ seq_printf(s, "timing spec:\t%u (%s)\n", ios->timing, str);
	118	+
	119	+ return 0;
	120	+}
	121	+
	122	+static int mmc_ios_open(struct inode inode, struct file file)
	123	+{
	124	+ return single_open(file, mmc_ios_show, inode->i_private);
	125	+}
	126	+
	127	+static const struct file_operations mmc_ios_fops = {
	128	+ .open = mmc_ios_open,
	129	+ .read = seq_read,
	130	+ .llseek = seq_lseek,
	131	+ .release = single_release,
	132	+};
	133	+
	134	+void mmc_add_host_debugfs(struct mmc_host *host)
	135	+{
	136	+ struct dentry *root;
	137	+
	138	+ root = debugfs_create_dir(mmc_hostname(host), NULL);
	139	+ if (IS_ERR(root))
	140	+ /* Don't complain -- debugfs just isn't enabled */
	141	+ return;
	142	+ if (!root)
	143	+ /* Complain -- debugfs is enabled, but it failed to
	144	+ * create the directory. */
	145	+ goto err_root;
	146	+
	147	+ host->debugfs_root = root;
	148	+
	149	+ if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
	150	+ goto err_ios;
	151	+
	152	+ return;
	153	+
	154	+err_ios:
	155	+ debugfs_remove_recursive(root);
	156	+ host->debugfs_root = NULL;
	157	+err_root:
	158	+ dev_err(&host->class_dev, "failed to initialize debugfs\n");
	159	+}
	160	+
	161	+void mmc_remove_host_debugfs(struct mmc_host *host)
	162	+{
	163	+ debugfs_remove_recursive(host->debugfs_root);
	164	+}
...	...	@@ -127,6 +127,10 @@
127	127	if (err)
128	128	return err;
129	129
	130	+#ifdef CONFIG_DEBUG_FS
	131	+ mmc_add_host_debugfs(host);
	132	+#endif
	133	+
130	134	mmc_start_host(host);
131	135
132	136	return 0;
...	...	@@ -145,6 +149,10 @@
145	149	void mmc_remove_host(struct mmc_host *host)
146	150	{
147	151	mmc_stop_host(host);
	152	+
	153	+#ifdef CONFIG_DEBUG_FS
	154	+ mmc_remove_host_debugfs(host);
	155	+#endif
148	156
149	157	device_del(&host->class_dev);
150	158
...	...	@@ -157,6 +157,8 @@
157	157	struct led_trigger led; / activity led */
158	158	#endif
159	159
	160	+ struct dentry *debugfs_root;
	161	+
160	162	unsigned long private[0] ____cacheline_aligned;
161	163	};
162	164