scsi: hisi_sas: Add BIST support for phy FFE

Add BIST support for phy FFE (Feed forward equalizer) setting. The user can
configure FFE through the new debugfs interface.

FFE is a parameter used for link layer control. It will affect the link
quality between the SAS controller and the backplane. In the BIST test, the
FFE interface is provided to assist board testers in optimizing link
parameters.

The modification of the FFE parameter will affect the test after BIST or
the normal running of the board. The user should save the initial FFE
values and restore them after BIST test is complete.

Link: https://lore.kernel.org/r/1598958790-232272-6-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, 76 insertions, 0 deletions

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index fdf5f0f1b60b..6cd9b25fbbe7 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -3704,6 +3704,58 @@ static const struct file_operations hisi_sas_debugfs_bist_enable_ops = {
 	.owner = THIS_MODULE,
 };
 
+static const struct {
+	char *name;
+} hisi_sas_debugfs_ffe_name[FFE_CFG_MAX] = {
+	{ "SAS_1_5_GBPS" },
+	{ "SAS_3_0_GBPS" },
+	{ "SAS_6_0_GBPS" },
+	{ "SAS_12_0_GBPS" },
+	{ "FFE_RESV" },
+	{ "SATA_1_5_GBPS" },
+	{ "SATA_3_0_GBPS" },
+	{ "SATA_6_0_GBPS" },
+};
+
+static ssize_t hisi_sas_debugfs_write(struct file *filp,
+				      const char __user *buf,
+				      size_t count, loff_t *ppos)
+{
+	struct seq_file *m = filp->private_data;
+	u32 *val = m->private;
+	int res;
+
+	res = kstrtouint_from_user(buf, count, 0, val);
+	if (res)
+		return res;
+
+	return count;
+}
+
+static int hisi_sas_debugfs_show(struct seq_file *s, void *p)
+{
+	u32 *val = s->private;
+
+	seq_printf(s, "0x%x\n", *val);
+
+	return 0;
+}
+
+static int hisi_sas_debugfs_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, hisi_sas_debugfs_show,
+			   inode->i_private);
+}
+
+static const struct file_operations hisi_sas_debugfs_ops = {
+	.open = hisi_sas_debugfs_open,
+	.read = seq_read,
+	.write = hisi_sas_debugfs_write,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.owner = THIS_MODULE,
+};
+
 static ssize_t hisi_sas_debugfs_phy_down_cnt_write(struct file *filp,
 						   const char __user *buf,
 						   size_t count, loff_t *ppos)
@@ -3901,6 +3953,9 @@ static void hisi_sas_debugfs_phy_down_cnt_init(struct hisi_hba *hisi_hba)
 
 static void hisi_sas_debugfs_bist_init(struct hisi_hba *hisi_hba)
 {
+	struct dentry *ports_dentry;
+	int phy_no;
+
 	hisi_hba->debugfs_bist_dentry =
 			debugfs_create_dir("bist", hisi_hba->debugfs_dir);
 	debugfs_create_file("link_rate", 0600,
@@ -3924,6 +3979,27 @@ static void hisi_sas_debugfs_bist_init(struct hisi_hba *hisi_hba)
 	debugfs_create_file("enable", 0600, hisi_hba->debugfs_bist_dentry,
 			    hisi_hba, &hisi_sas_debugfs_bist_enable_ops);
 
+	ports_dentry = debugfs_create_dir("port", hisi_hba->debugfs_bist_dentry);
+
+	for (phy_no = 0; phy_no < hisi_hba->n_phy; phy_no++) {
+		struct dentry *port_dentry;
+		struct dentry *ffe_dentry;
+		char name[256];
+		int i;
+
+		snprintf(name, 256, "%d", phy_no);
+		port_dentry = debugfs_create_dir(name, ports_dentry);
+		ffe_dentry = debugfs_create_dir("ffe", port_dentry);
+		for (i = 0; i < FFE_CFG_MAX; i++) {
+			if (i == FFE_RESV)
+				continue;
+			debugfs_create_file(hisi_sas_debugfs_ffe_name[i].name,
+					    0600, ffe_dentry,
+					    &hisi_hba->debugfs_bist_ffe[phy_no][i],
+					    &hisi_sas_debugfs_ops);
+		}
+	}
+
 	hisi_hba->debugfs_bist_linkrate = SAS_LINK_RATE_1_5_GBPS;
 }