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>

diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 19a1a254a0c5f81d8e0a36815caf4b870b6497cc..889e5f898f6f99485c6b031aee41f5a6ff86d0aa 100644 (file)
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -12,3 +12,4 @@ mmc_core-y                    := core.o bus.o host.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

diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index cdb332b7dedc87340ef5ff0aacedc71f8b4fe931..745da9881aa7e3c5a38ac982d52d9d227eae7afd 100644 (file)
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -52,5 +52,9 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr);
 
 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
 

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
new file mode 100644 (file)
index 0000000..133c6e5
--- /dev/null
+++ b/drivers/mmc/core/debugfs.c
@@ -0,0 +1,164 @@
+/*
+ * 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);
+}

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 1d795c5379b548f5869b83d7aabf05848a6d27b1..6da80fd4d974669223ac2caf54576f6521c52083 100644 (file)
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -127,6 +127,10 @@ int mmc_add_host(struct mmc_host *host)
        if (err)
                return err;
 
+#ifdef CONFIG_DEBUG_FS
+       mmc_add_host_debugfs(host);
+#endif
+
        mmc_start_host(host);
 
        return 0;
@@ -146,6 +150,10 @@ 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);
 
        led_trigger_unregister_simple(host->led);

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 10a2080086ca9e6402eec37178bd8dea384f3f92..9c288c9098783cfc3ef1b4d6357081b7d3f44849 100644 (file)
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -157,6 +157,8 @@ struct mmc_host {
        struct led_trigger      *led;           /* activity led */
 #endif
 
+       struct dentry           *debugfs_root;
+
        unsigned long           private[0] ____cacheline_aligned;
 };