i5100_edac: connect fault injection to debugfs node

Create a debugfs direcotry i5100_edac/mcX for each memory controller and
add nodes to control how fault injection is preformed.

After configuring an injection using inject_channel, inject_deviceptr1,
inject_deviceptr2, inject_eccmask1, inject_eccmask2 and inject_hlinesel
trigger the injection by writing anything to inject_enable.

Example of a CE injection:

echo 0 > /sys/kernel/debug/i5100_edac/mc0/inject_channel
echo 1 > /sys/kernel/debug/i5100_edac/mc0/inject_hlinesel
echo 61440 > /sys/kernel/debug/i5100_edac/mc0/inject_eccmask1
echo 1 > /sys/kernel/debug/i5100_edac/mc0/inject_enable

Example of UE injection:

echo 0 > /sys/kernel/debug/i5100_edac/mc0/inject_channel
echo 2 > /sys/kernel/debug/i5100_edac/mc0/inject_hlinesel
echo 65535 > /sys/kernel/debug/i5100_edac/mc0/inject_eccmask1
echo 65535 > /sys/kernel/debug/i5100_edac/mc0/inject_eccmask2
echo 17 > /sys/kernel/debug/i5100_edac/mc0/inject_deviceptr1
echo 0 > /sys/kernel/debug/i5100_edac/mc0/inject_deviceptr2
echo 1 > /sys/kernel/debug/i5100_edac/mc0/inject_enable

Sometimes it is needed to enable the injection more then once (echo to
the inject_enable node) for the injection to happen, I am not sure why.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ericsson.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 70 insertions, 1 deletions

diff --git a/drivers/edac/i5100_edac.c b/drivers/edac/i5100_edac.c
index 0a0345bd7432..ad4cc898dc60 100644
--- a/drivers/edac/i5100_edac.c
+++ b/drivers/edac/i5100_edac.c
@@ -27,6 +27,7 @@
 #include <linux/edac.h>
 #include <linux/delay.h>
 #include <linux/mmzone.h>
+#include <linux/debugfs.h>
 
 #include "edac_core.h"
 
@@ -360,8 +361,12 @@ struct i5100_priv {
         u8 inject_deviceptr2;
         u16 inject_eccmask1;
         u16 inject_eccmask2;
+
+        struct dentry *debugfs;
 };
 
+static struct dentry *i5100_debugfs;
+
 /* map a rank/chan to a slot number on the mainboard */
 static int i5100_rank_to_slot(const struct mem_ctl_info *mci,
                               int chan, int rank)
@@ -944,6 +949,61 @@ static void i5100_do_inject(struct mem_ctl_info *mci)
         pci_write_config_byte(priv->einj, I5100_DINJ0, 0xab);
 }
 
+#define to_mci(k) container_of(k, struct mem_ctl_info, dev)
+static ssize_t inject_enable_write(struct file *file, const char __user *data,
+                size_t count, loff_t *ppos)
+{
+        struct device *dev = file->private_data;
+        struct mem_ctl_info *mci = to_mci(dev);
+
+        i5100_do_inject(mci);
+
+        return count;
+}
+
+static int inject_enable_open(struct inode *inode, struct file *file)
+{
+        file->private_data = inode->i_private;
+        return 0;
+}
+
+static const struct file_operations i5100_inject_enable_fops = {
+        .open = inject_enable_open,
+        .write = inject_enable_write,
+        .llseek = generic_file_llseek,
+};
+
+static int i5100_setup_debugfs(struct mem_ctl_info *mci)
+{
+        struct i5100_priv *priv = mci->pvt_info;
+
+        if (!i5100_debugfs)
+                return -ENODEV;
+
+        priv->debugfs = debugfs_create_dir(mci->bus.name, i5100_debugfs);
+
+        if (!priv->debugfs)
+                return -ENOMEM;
+
+        debugfs_create_x8("inject_channel", S_IRUGO | S_IWUSR, priv->debugfs,
+                        &priv->inject_channel);
+        debugfs_create_x8("inject_hlinesel", S_IRUGO | S_IWUSR, priv->debugfs,
+                        &priv->inject_hlinesel);
+        debugfs_create_x8("inject_deviceptr1", S_IRUGO | S_IWUSR, priv->debugfs,
+                        &priv->inject_deviceptr1);
+        debugfs_create_x8("inject_deviceptr2", S_IRUGO | S_IWUSR, priv->debugfs,
+                        &priv->inject_deviceptr2);
+        debugfs_create_x16("inject_eccmask1", S_IRUGO | S_IWUSR, priv->debugfs,
+                        &priv->inject_eccmask1);
+        debugfs_create_x16("inject_eccmask2", S_IRUGO | S_IWUSR, priv->debugfs,
+                        &priv->inject_eccmask2);
+        debugfs_create_file("inject_enable", S_IWUSR, priv->debugfs,
+                        &mci->dev, &i5100_inject_enable_fops);
+
+        return 0;
+
+}
+
 static int i5100_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 {
         int rc;
@@ -1097,6 +1157,8 @@ static int i5100_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
                 goto bail_scrub;
         }
 
+        i5100_setup_debugfs(mci);
+
         return ret;
 
 bail_scrub:
@@ -1141,6 +1203,9 @@ static void i5100_remove_one(struct pci_dev *pdev)
 
         priv = mci->pvt_info;
 
+        if (priv->debugfs)
+                debugfs_remove_recursive(priv->debugfs);
+
         priv->scrub_enable = 0;
         cancel_delayed_work_sync(&(priv->i5100_scrubbing));
 
@@ -1173,13 +1238,17 @@ static int __init i5100_init(void)
 {
         int pci_rc;
 
-        pci_rc = pci_register_driver(&i5100_driver);
+        i5100_debugfs = debugfs_create_dir("i5100_edac", NULL);
 
+        pci_rc = pci_register_driver(&i5100_driver);
         return (pci_rc < 0) ? pci_rc : 0;
 }
 
 static void __exit i5100_exit(void)
 {
+        if (i5100_debugfs)
+                debugfs_remove(i5100_debugfs);
+
         pci_unregister_driver(&i5100_driver);
 }