3 files changed, 108 insertions, 0 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.h b/drivers/scsi/mpt2sas/mpt2sas_base.h
index 2aeb6f974602..3d1a30ab9a41 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.h
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.h
@@ -1096,6 +1096,8 @@ int mpt2sas_config_get_iounit_pg1(struct MPT2SAS_ADAPTER *ioc, Mpi2ConfigReply_t
     *mpi_reply, Mpi2IOUnitPage1_t *config_page);
 int mpt2sas_config_set_iounit_pg1(struct MPT2SAS_ADAPTER *ioc, Mpi2ConfigReply_t
     *mpi_reply, Mpi2IOUnitPage1_t *config_page);
+int mpt2sas_config_get_iounit_pg3(struct MPT2SAS_ADAPTER *ioc,
+	Mpi2ConfigReply_t *mpi_reply, Mpi2IOUnitPage3_t *config_page, u16 sz);
 int mpt2sas_config_get_sas_iounit_pg1(struct MPT2SAS_ADAPTER *ioc, Mpi2ConfigReply_t
     *mpi_reply, Mpi2SasIOUnitPage1_t *config_page, u16 sz);
 int mpt2sas_config_set_sas_iounit_pg1(struct MPT2SAS_ADAPTER *ioc,
diff --git a/drivers/scsi/mpt2sas/mpt2sas_config.c b/drivers/scsi/mpt2sas/mpt2sas_config.c
index 323309b22c8d..863778071a9d 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_config.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_config.c
@@ -683,6 +683,42 @@ mpt2sas_config_set_iounit_pg1(struct MPT2SAS_ADAPTER *ioc,
 }
 
 /**
+ * mpt2sas_config_get_iounit_pg3 - obtain iounit page 3
+ * @ioc: per adapter object
+ * @mpi_reply: reply mf payload returned from firmware
+ * @config_page: contents of the config page
+ * @sz: size of buffer passed in config_page
+ * Context: sleep.
+ *
+ * Returns 0 for success, non-zero for failure.
+ */
+int
+mpt2sas_config_get_iounit_pg3(struct MPT2SAS_ADAPTER *ioc,
+	Mpi2ConfigReply_t *mpi_reply, Mpi2IOUnitPage3_t *config_page, u16 sz)
+{
+	Mpi2ConfigRequest_t mpi_request;
+	int r;
+
+	memset(&mpi_request, 0, sizeof(Mpi2ConfigRequest_t));
+	mpi_request.Function = MPI2_FUNCTION_CONFIG;
+	mpi_request.Action = MPI2_CONFIG_ACTION_PAGE_HEADER;
+	mpi_request.Header.PageType = MPI2_CONFIG_PAGETYPE_IO_UNIT;
+	mpi_request.Header.PageNumber = 3;
+	mpi_request.Header.PageVersion = MPI2_IOUNITPAGE3_PAGEVERSION;
+	mpt2sas_base_build_zero_len_sge(ioc, &mpi_request.PageBufferSGE);
+	r = _config_request(ioc, &mpi_request, mpi_reply,
+	    MPT2_CONFIG_PAGE_DEFAULT_TIMEOUT, NULL, 0);
+	if (r)
+		goto out;
+
+	mpi_request.Action = MPI2_CONFIG_ACTION_PAGE_READ_CURRENT;
+	r = _config_request(ioc, &mpi_request, mpi_reply,
+	    MPT2_CONFIG_PAGE_DEFAULT_TIMEOUT, config_page, sz);
+ out:
+	return r;
+}
+
+/**
  * mpt2sas_config_get_ioc_pg8 - obtain ioc page 8
  * @ioc: per adapter object
  * @mpi_reply: reply mf payload returned from firmware
diff --git a/drivers/scsi/mpt2sas/mpt2sas_ctl.c b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
index 6da4a408358c..64254416a178 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_ctl.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
@@ -2690,6 +2690,75 @@ _ctl_ioc_reply_queue_count_show(struct device *cdev,
 static DEVICE_ATTR(reply_queue_count, S_IRUGO,
 	 _ctl_ioc_reply_queue_count_show, NULL);
 
+/**
+ * _ctl_BRM_status_show - Backup Rail Monitor Status
+ * @cdev - pointer to embedded class device
+ * @buf - the buffer returned
+ *
+ * This is number of reply queues
+ *
+ * A sysfs 'read-only' shost attribute.
+ */
+static ssize_t
+_ctl_BRM_status_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);
+	Mpi2IOUnitPage3_t *io_unit_pg3 = NULL;
+	Mpi2ConfigReply_t mpi_reply;
+	u16 backup_rail_monitor_status = 0;
+	u16 ioc_status;
+	int sz;
+	ssize_t rc = 0;
+
+	if (!ioc->is_warpdrive) {
+		printk(MPT2SAS_ERR_FMT "%s: BRM attribute is only for"\
+		    "warpdrive\n", ioc->name, __func__);
+		goto out;
+	}
+
+	/* allocate upto GPIOVal 36 entries */
+	sz = offsetof(Mpi2IOUnitPage3_t, GPIOVal) + (sizeof(u16) * 36);
+	io_unit_pg3 = kzalloc(sz, GFP_KERNEL);
+	if (!io_unit_pg3) {
+		printk(MPT2SAS_ERR_FMT "%s: failed allocating memory"\
+		    "for iounit_pg3: (%d) bytes\n", ioc->name, __func__, sz);
+		goto out;
+	}
+
+	if (mpt2sas_config_get_iounit_pg3(ioc, &mpi_reply, io_unit_pg3, sz) !=
+	    0) {
+		printk(MPT2SAS_ERR_FMT
+		    "%s: failed reading iounit_pg3\n", ioc->name,
+		    __func__);
+		goto out;
+	}
+
+	ioc_status = le16_to_cpu(mpi_reply.IOCStatus) & MPI2_IOCSTATUS_MASK;
+	if (ioc_status != MPI2_IOCSTATUS_SUCCESS) {
+		printk(MPT2SAS_ERR_FMT "%s: iounit_pg3 failed with"\
+		    "ioc_status(0x%04x)\n", ioc->name, __func__, ioc_status);
+		goto out;
+	}
+
+	if (io_unit_pg3->GPIOCount < 25) {
+		printk(MPT2SAS_ERR_FMT "%s: iounit_pg3->GPIOCount less than"\
+		     "25 entries, detected (%d) entries\n", ioc->name, __func__,
+		    io_unit_pg3->GPIOCount);
+		goto out;
+	}
+
+	/* BRM status is in bit zero of GPIOVal[24] */
+	backup_rail_monitor_status = le16_to_cpu(io_unit_pg3->GPIOVal[24]);
+	rc = snprintf(buf, PAGE_SIZE, "%d\n", (backup_rail_monitor_status & 1));
+
+ out:
+	kfree(io_unit_pg3);
+	return rc;
+}
+static DEVICE_ATTR(BRM_status, S_IRUGO, _ctl_BRM_status_show, NULL);
+
 struct DIAG_BUFFER_START {
 	__le32 Size;
 	__le32 DiagVersion;
@@ -2901,6 +2970,7 @@ struct device_attribute *mpt2sas_host_attrs[] = {
 	&dev_attr_host_trace_buffer,
 	&dev_attr_host_trace_buffer_enable,
 	&dev_attr_reply_queue_count,
+	&dev_attr_BRM_status,
 	NULL,
 };