From 99ff1a35fe5e039097ba2520f00ecd862de6f6de Mon Sep 17 00:00:00 2001
From: Jorge Troncoso <jatron@google.com>
Date: Thu, 30 Sep 2021 16:29:32 -0700
Subject: [PATCH] refactor(ufs): add retry logic to ufshc_reset

This change aims to make the UFS code more robust by adding retry logic
and timeouts to ufshc_reset. We also define a new function
ufshc_hce_enable for Host Controller Enable (HCE). The inner and outer
retry pattern is based on Linux's ufshcd_hba_execute_hce function.

Signed-off-by: Jorge Troncoso <jatron@google.com>
Change-Id: I9403a5a25d3ca50af5f2f9a65b774f6a2d7a9626
---
 drivers/ufs/ufs.c     | 38 ++++++++++++++++++++++++++++++++++----
 include/drivers/ufs.h |  4 ++++
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/drivers/ufs/ufs.c b/drivers/ufs/ufs.c
index 97a9d5e7e..695a614f2 100644
--- a/drivers/ufs/ufs.c
+++ b/drivers/ufs/ufs.c
@@ -123,21 +123,50 @@ int ufshc_dme_set(unsigned int attr, unsigned int idx, unsigned int val)
 	return 0;
 }
 
-static void ufshc_reset(uintptr_t base)
+static int ufshc_hce_enable(uintptr_t base)
 {
 	unsigned int data;
+	int retries;
 
 	/* Enable Host Controller */
 	mmio_write_32(base + HCE, HCE_ENABLE);
+
 	/* Wait until basic initialization sequence completed */
-	do {
+	for (retries = 0; retries < HCE_ENABLE_INNER_RETRIES; ++retries) {
 		data = mmio_read_32(base + HCE);
-	} while ((data & HCE_ENABLE) == 0);
+		if (data & HCE_ENABLE) {
+			break;
+		}
+		udelay(HCE_ENABLE_TIMEOUT_US);
+	}
+	if (retries >= HCE_ENABLE_INNER_RETRIES) {
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int ufshc_reset(uintptr_t base)
+{
+	unsigned int data;
+	int retries, result;
+
+	for (retries = 0; retries < HCE_ENABLE_OUTER_RETRIES; ++retries) {
+		result = ufshc_hce_enable(base);
+		if (result == 0) {
+			break;
+		}
+	}
+	if (retries >= HCE_ENABLE_OUTER_RETRIES) {
+		return -EIO;
+	}
 
 	/* Enable Interrupts */
 	data = UFS_INT_UCCS | UFS_INT_ULSS | UFS_INT_UE | UFS_INT_UTPES |
 	       UFS_INT_DFES | UFS_INT_HCFES | UFS_INT_SBFES;
 	mmio_write_32(base + IE, data);
+
+	return 0;
 }
 
 static int ufshc_link_startup(uintptr_t base)
@@ -782,7 +811,8 @@ int ufs_init(const ufs_ops_t *ops, ufs_params_t *params)
 		assert((ops != NULL) && (ops->phy_init != NULL) &&
 		       (ops->phy_set_pwr_mode != NULL));
 
-		ufshc_reset(ufs_params.reg_base);
+		result = ufshc_reset(ufs_params.reg_base);
+		assert(result == 0);
 		ops->phy_init(&ufs_params);
 		result = ufshc_link_startup(ufs_params.reg_base);
 		assert(result == 0);
diff --git a/include/drivers/ufs.h b/include/drivers/ufs.h
index 3f8f3605f..686d4c6dc 100644
--- a/include/drivers/ufs.h
+++ b/include/drivers/ufs.h
@@ -258,6 +258,10 @@
 /* maximum number of retries for a general UIC command  */
 #define UFS_UIC_COMMAND_RETRIES		3
 
+#define HCE_ENABLE_OUTER_RETRIES	3
+#define HCE_ENABLE_INNER_RETRIES	50
+#define HCE_ENABLE_TIMEOUT_US		100
+
 /**
  * ufs_dev_desc - ufs device details from the device descriptor
  * @wmanufacturerid: card details