[PATCH 11/21] megaraid_sas: Dump system interface regs from sysfs

[Shivasharan S]

Add a sysfs interface to dump the controller's system interface registers.

Signed-off-by: Sumit Saxena <sumit.sax...@broadcom.com>
Signed-off-by: Shivasharan S <shivasharan.srikanteshw...@broadcom.com>
---
 drivers/scsi/megaraid/megaraid_sas_base.c | 37 +++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c 
b/drivers/scsi/megaraid/megaraid_sas_base.c
index d0fd307e30af..5d2f346f3f49 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -2901,6 +2901,29 @@ megasas_dump_fusion_io(struct scsi_cmnd *scmd)
 
 }
 
+/*
+ * megasas_dump_sys_regs - This function will dump system registers through
+ *                         sysfs.
+ * @reg_set:               Pointer to System register set.
+ * @buf:                   Buffer to which output is to be written.
+ * @return:                Number of bytes written to buffer.
+ */
+static inline ssize_t
+megasas_dump_sys_regs(void __iomem *reg_set, char *buf)
+{
+       unsigned int i, sz = 256;
+       int bytes_wrote = 0;
+       char *loc = (char *)buf;
+
+       __le32 *reg = (__le32 *)reg_set;
+
+       for (i = 0; i < sz / sizeof(__le32); i++) {
+               bytes_wrote += snprintf(loc + bytes_wrote, PAGE_SIZE,
+                                       "%08x: %08x\n", (i * 4),
+                                       le32_to_cpu(readl(&reg[i])));
+       }
+       return bytes_wrote;
+}
 /**
  * megasas_reset_bus_host -    Bus & host reset handler entry point
  */
@@ -3223,6 +3246,17 @@ megasas_fw_cmds_outstanding_show(struct device *cdev,
        return snprintf(buf, PAGE_SIZE, "%d\n", 
atomic_read(&instance->fw_outstanding));
 }
 
+static ssize_t
+megasas_dump_system_regs_show(struct device *cdev,
+                              struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(cdev);
+       struct megasas_instance *instance =
+                       (struct megasas_instance *)shost->hostdata;
+
+       return megasas_dump_sys_regs(instance->reg_set, buf);
+}
+
 static DEVICE_ATTR(fw_crash_buffer, S_IRUGO | S_IWUSR,
        megasas_fw_crash_buffer_show, megasas_fw_crash_buffer_store);
 static DEVICE_ATTR(fw_crash_buffer_size, S_IRUGO,
@@ -3235,6 +3269,8 @@ static DEVICE_ATTR(ldio_outstanding, S_IRUGO,
        megasas_ldio_outstanding_show, NULL);
 static DEVICE_ATTR(fw_cmds_outstanding, S_IRUGO,
        megasas_fw_cmds_outstanding_show, NULL);
+static DEVICE_ATTR(dump_system_regs, S_IRUGO,
+       megasas_dump_system_regs_show, NULL);
 
 struct device_attribute *megaraid_host_attrs[] = {
        &dev_attr_fw_crash_buffer_size,
@@ -3243,6 +3279,7 @@ struct device_attribute *megaraid_host_attrs[] = {
        &dev_attr_page_size,
        &dev_attr_ldio_outstanding,
        &dev_attr_fw_cmds_outstanding,
+       &dev_attr_dump_system_regs,
        NULL,
 };
 
-- 
2.16.1