scsi: hisi_sas: Add trace FIFO debugfs support

The controller provides trace FIFO DFX tool to assist link fault debugging
and link optimization. This tool can be helpful when debugging link faults
without SAS analyzers. Each PHY has an independent trace FIFO interface.

The user can configure the trace FIFO tool of one PHY by using the
following six interfaces:

signal_sel: select signal group applies to different scenarios.
  0x0: linkrate negotiation
  0x1: Host 12G TX train
  0x2: Disk 12G TX train
  0x3: SAS PHY CTRL DFX 0
  0x4: SAS PHY CTRL DFX 1
  0x5: SAS PCS DFX
  other: linkrate negotiation
dump_mask: The masked hardware status bit will not be updated.
dump_mode: determines how to dump data after trigger signal is generated.
  0x0: dump forever
  0x1: dump 32 data after trigger signal is generated
  0x2: no more dump after trigger signal is generated
trigger_mode: determines the trigger mode, level or edge.
  0x0: dump when trigger signal changed
  0x1: dump when trigger signal's level equal to trigger_level
  0x2: dump when trigger signal's level different from trigger_level
trigger_level: determines the trigger level.
trigger_msk: mask trigger signal

The user can get 32-byte values from hardware by reading the rd_data.
These values consitute the status record of the hardware at different time
points.

Link: https://lore.kernel.org/r/1611659068-131975-6-git-send-email-john.garry@huawei.com
Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index 873bfffa626d..2401a9575215 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -44,6 +44,7 @@
 
 #define HISI_SAS_IOST_ITCT_CACHE_NUM 64
 #define HISI_SAS_IOST_ITCT_CACHE_DW_SZ 10
+#define HISI_SAS_FIFO_DATA_DW_SIZE 32
 
 #define HISI_SAS_STATUS_BUF_SZ (sizeof(struct hisi_sas_status_buffer))
 #define HISI_SAS_COMMAND_TABLE_SZ (sizeof(union hisi_sas_command_table))
@@ -154,6 +155,16 @@ enum hisi_sas_phy_event {
 	HISI_PHYES_NUM,
 };
 
+struct hisi_sas_debugfs_fifo {
+	u32 signal_sel;
+	u32 dump_msk;
+	u32 dump_mode;
+	u32 trigger;
+	u32 trigger_msk;
+	u32 trigger_mode;
+	u32 rd_data[HISI_SAS_FIFO_DATA_DW_SIZE];
+};
+
 struct hisi_sas_phy {
 	struct work_struct	works[HISI_PHYES_NUM];
 	struct hisi_hba	*hisi_hba;
@@ -175,6 +186,9 @@ struct hisi_sas_phy {
 	enum sas_linkrate	maximum_linkrate;
 	int enable;
 	atomic_t down_cnt;
+
+	/* Trace FIFO */
+	struct hisi_sas_debugfs_fifo fifo;
 };
 
 struct hisi_sas_port {
@@ -474,6 +488,7 @@ struct hisi_hba {
 	struct dentry *debugfs_dir;
 	struct dentry *debugfs_dump_dentry;
 	struct dentry *debugfs_bist_dentry;
+	struct dentry *debugfs_fifo_dentry;
 };
 
 /* Generic HW DMA host memory structures */