From 35d847ed908d3b1d6e58d95b3b9f326111343df5 Mon Sep 17 00:00:00 2001
From: Chee Hong Ang <chee.hong.ang@intel.com>
Date: Fri, 10 Jul 2020 20:55:22 +0800
Subject: [PATCH] clk: agilex: Handle clock configuration differently in SPL
 and U-Boot proper

Since warm reset may optionally set the CLock Manager to'boot mode',
the clock driver should always force the Agilex's Clock Manager to
'boot mode' before the clock driver start configuring the Clock Manager
in SPL.
In SSBL, clock driver will skip the Clock Manager configuration
if it's already being setup by SPL (Clock Manager NOT in 'boot
mode') to prevent any inaccurate clocking issues happened on HPS
peripherals such as UART, MAC and etc.

Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
---
 drivers/clk/altera/clk-agilex.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/clk/altera/clk-agilex.c b/drivers/clk/altera/clk-agilex.c
index 36a224d762..fc4d239551 100644
--- a/drivers/clk/altera/clk-agilex.c
+++ b/drivers/clk/altera/clk-agilex.c
@@ -171,6 +171,16 @@ static void clk_basic_init(struct udevice *dev,
 	if (!cfg)
 		return;
 
+#ifdef CONFIG_SPL_BUILD
+	/* Always force clock manager into boot mode before any configuration */
+	clk_write_ctrl(plat,
+		       CM_REG_READL(plat, CLKMGR_CTRL) | CLKMGR_CTRL_BOOTMODE);
+#else
+	/* Skip clock configuration in SSBL if it's not in boot mode */
+	if (!(CM_REG_READL(plat, CLKMGR_CTRL) & CLKMGR_CTRL_BOOTMODE))
+		return;
+#endif
+
 	/* Put both PLLs in bypass */
 	clk_write_bypass_mainpll(plat, CLKMGR_BYPASS_MAINPLL_ALL);
 	clk_write_bypass_perpll(plat, CLKMGR_BYPASS_PERPLL_ALL);
-- 
2.39.5