s3cmci: add debugfs support for examining driver and hardware state

Export driver state and hardware register state via debugfs entries
created under a directory formed from dev_name() on the probed device when
CONFIG_DEBUG_FS is set.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 132 insertions, 0 deletions

diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index 28a4a4535f38..8c2c8b456087 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -17,6 +17,8 @@
 #include <linux/mmc/host.h>
 #include <linux/platform_device.h>
 #include <linux/cpufreq.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 #include <linux/gpio.h>
 #include <linux/irq.h>
 #include <linux/io.h>
@@ -1244,6 +1246,127 @@ static inline void s3cmci_cpufreq_deregister(struct s3cmci_host *host)
 #endif
 
 
+#ifdef CONFIG_DEBUG_FS
+
+static int s3cmci_state_show(struct seq_file *seq, void *v)
+{
+        struct s3cmci_host *host = seq->private;
+
+        seq_printf(seq, "Register base = 0x%08x\n", (u32)host->base);
+        seq_printf(seq, "Clock rate = %ld\n", host->clk_rate);
+        seq_printf(seq, "Prescale = %d\n", host->prescaler);
+        seq_printf(seq, "is2440 = %d\n", host->is2440);
+        seq_printf(seq, "IRQ = %d\n", host->irq);
+        seq_printf(seq, "CD IRQ = %d\n", host->irq_cd);
+        seq_printf(seq, "Do DMA = %d\n", host->dodma);
+        seq_printf(seq, "SDIIMSK at %d\n", host->sdiimsk);
+        seq_printf(seq, "SDIDATA at %d\n", host->sdidata);
+
+        return 0;
+}
+
+static int s3cmci_state_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, s3cmci_state_show, inode->i_private);
+}
+
+static const struct file_operations s3cmci_fops_state = {
+        .owner          = THIS_MODULE,
+        .open           = s3cmci_state_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+#define DBG_REG(_r) { .addr = S3C2410_SDI##_r, .name = #_r }
+
+struct s3cmci_reg {
+        unsigned short  addr;
+        unsigned char   *name;
+} debug_regs[] = {
+        DBG_REG(CON),
+        DBG_REG(PRE),
+        DBG_REG(CMDARG),
+        DBG_REG(CMDCON),
+        DBG_REG(CMDSTAT),
+        DBG_REG(RSP0),
+        DBG_REG(RSP1),
+        DBG_REG(RSP2),
+        DBG_REG(RSP3),
+        DBG_REG(TIMER),
+        DBG_REG(BSIZE),
+        DBG_REG(DCON),
+        DBG_REG(DCNT),
+        DBG_REG(DSTA),
+        DBG_REG(FSTA),
+        {}
+};
+
+static int s3cmci_regs_show(struct seq_file *seq, void *v)
+{
+        struct s3cmci_host *host = seq->private;
+        struct s3cmci_reg *rptr = debug_regs;
+
+        for (; rptr->name; rptr++)
+                seq_printf(seq, "SDI%s\t=0x%08x\n", rptr->name,
+                           readl(host->base + rptr->addr));
+
+        seq_printf(seq, "SDIIMSK\t=0x%08x\n", readl(host->base + host->sdiimsk));
+
+        return 0;
+}
+
+static int s3cmci_regs_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, s3cmci_regs_show, inode->i_private);
+}
+
+static const struct file_operations s3cmci_fops_regs = {
+        .owner          = THIS_MODULE,
+        .open           = s3cmci_regs_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static void s3cmci_debugfs_attach(struct s3cmci_host *host)
+{
+        struct device *dev = &host->pdev->dev;
+
+        host->debug_root = debugfs_create_dir(dev_name(dev), NULL);
+        if (IS_ERR(host->debug_root)) {
+                dev_err(dev, "failed to create debugfs root\n");
+                return;
+        }
+
+        host->debug_state = debugfs_create_file("state", 0444,
+                                                host->debug_root, host,
+                                                &s3cmci_fops_state);
+
+        if (IS_ERR(host->debug_state))
+                dev_err(dev, "failed to create debug state file\n");
+
+        host->debug_regs = debugfs_create_file("regs", 0444,
+                                               host->debug_root, host,
+                                               &s3cmci_fops_regs);
+
+        if (IS_ERR(host->debug_regs))
+                dev_err(dev, "failed to create debug regs file\n");
+}
+
+static void s3cmci_debugfs_remove(struct s3cmci_host *host)
+{
+        debugfs_remove(host->debug_regs);
+        debugfs_remove(host->debug_state);
+        debugfs_remove(host->debug_root);
+}
+
+#else
+static inline void s3cmci_debugfs_attach(struct s3cmci_host *host) { }
+static inline void s3cmci_debugfs_remove(struct s3cmci_host *host) { }
+
+#endif /* CONFIG_DEBUG_FS */
+
 static int __devinit s3cmci_probe(struct platform_device *pdev)
 {
         struct s3cmci_host *host;
@@ -1435,6 +1558,8 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
                 goto free_cpufreq;
         }
 
+        s3cmci_debugfs_attach(host);
+
         platform_set_drvdata(pdev, mmc);
         dev_info(&pdev->dev, "initialisation done.\n");
 
@@ -1489,6 +1614,7 @@ static void s3cmci_shutdown(struct platform_device *pdev)
         if (host->irq_cd >= 0)
                 free_irq(host->irq_cd, host);
 
+        s3cmci_debugfs_remove(host);
         s3cmci_cpufreq_deregister(host);
         mmc_remove_host(mmc);
         clk_disable(host->clk);
diff --git a/drivers/mmc/host/s3cmci.h b/drivers/mmc/host/s3cmci.h
index ca1ba3d58cfd..fc96194a06f4 100644
--- a/drivers/mmc/host/s3cmci.h
+++ b/drivers/mmc/host/s3cmci.h
@@ -68,6 +68,12 @@ struct s3cmci_host {
         unsigned int            ccnt, dcnt;
         struct tasklet_struct   pio_tasklet;
 
+#ifdef CONFIG_DEBUG_FS
+        struct dentry           *debug_root;
+        struct dentry           *debug_state;
+        struct dentry           *debug_regs;
+#endif
+
 #ifdef CONFIG_CPU_FREQ
         struct notifier_block   freq_transition;
 #endif