[SCSI] mpt2sas: Support for stopping driver when Firmware encounters

Added command line option and shost sysfs attribute called
mpt2sas_fwfault_debug. When enduser writes a "1" to this parameter, this
will enable support in the driver for debugging firmware timeout related
issues.  This handling was added in three areas (a) scsi error handling
callback called task_abort, (b) IOCTL interface, and (c) other timeouts that
result in diag resets, such as manufacturing config pages.  When this
support is enabled, the driver will provide dump_stack to console, halt
controller firmware, and panic driver. The end user probably would want to
setup serial console redirection so the dump stack can be seen.

Here are the three methods for enable this support:

(a) # insmod mpt2sas.ko mpt2sas_fwfault_debug=1
(b) # echo 1 > /sys/module/mpt2sas/parameters/mpt2sas_fwfault_debug
(c) # echo 1 > /sys/class/scsi_host/host#/fwfault_debug  (where # is
the host number)

Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com>
Signed-off-by: Eric Moore <Eric.moore@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 39 insertions, 2 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_ctl.c b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
index 57d724633906..6901a6706ede 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_ctl.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
@@ -896,6 +896,7 @@ _ctl_do_mpt_command(struct MPT2SAS_ADAPTER *ioc,
                         printk(MPT2SAS_INFO_FMT "issue target reset: handle "
                             "= (0x%04x)\n", ioc->name,
                             mpi_request->FunctionDependent1);
+                        mpt2sas_halt_firmware(ioc);
                         mutex_lock(&ioc->tm_cmds.mutex);
                         mpt2sas_scsih_issue_tm(ioc,
                             mpi_request->FunctionDependent1, 0,
@@ -2474,6 +2475,43 @@ _ctl_logging_level_store(struct device *cdev, struct device_attribute *attr,
 static DEVICE_ATTR(logging_level, S_IRUGO | S_IWUSR,
     _ctl_logging_level_show, _ctl_logging_level_store);
 
+/* device attributes */
+/*
+ * _ctl_fwfault_debug_show - show/store fwfault_debug
+ * @cdev - pointer to embedded class device
+ * @buf - the buffer returned
+ *
+ * mpt2sas_fwfault_debug is command line option
+ * A sysfs 'read/write' shost attribute.
+ */
+static ssize_t
+_ctl_fwfault_debug_show(struct device *cdev,
+    struct device_attribute *attr, char *buf)
+{
+        struct Scsi_Host *shost = class_to_shost(cdev);
+        struct MPT2SAS_ADAPTER *ioc = shost_priv(shost);
+
+        return snprintf(buf, PAGE_SIZE, "%d\n", ioc->fwfault_debug);
+}
+static ssize_t
+_ctl_fwfault_debug_store(struct device *cdev,
+    struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct Scsi_Host *shost = class_to_shost(cdev);
+        struct MPT2SAS_ADAPTER *ioc = shost_priv(shost);
+        int val = 0;
+
+        if (sscanf(buf, "%d", &val) != 1)
+                return -EINVAL;
+
+        ioc->fwfault_debug = val;
+        printk(MPT2SAS_INFO_FMT "fwfault_debug=%d\n", ioc->name,
+            ioc->fwfault_debug);
+        return strlen(buf);
+}
+static DEVICE_ATTR(fwfault_debug, S_IRUGO | S_IWUSR,
+    _ctl_fwfault_debug_show, _ctl_fwfault_debug_store);
+
 struct device_attribute *mpt2sas_host_attrs[] = {
         &dev_attr_version_fw,
         &dev_attr_version_bios,
@@ -2487,13 +2525,12 @@ struct device_attribute *mpt2sas_host_attrs[] = {
         &dev_attr_io_delay,
         &dev_attr_device_delay,
         &dev_attr_logging_level,
+        &dev_attr_fwfault_debug,
         &dev_attr_fw_queue_depth,
         &dev_attr_host_sas_address,
         NULL,
 };
 
-/* device attributes */
-
 /**
  * _ctl_device_sas_address_show - sas address
  * @cdev - pointer to embedded class device