drivers: clk: agilex5: Configure intosc as boot_clk source

Some customers prefer to minimize the use of external oscillators,
especially when using the FPGA first configuration mode.

By enabling the configuration of the HPS internal oscillator as
the boot_clk source instead of the default external oscillator,
(HPS_OSC_CLK) in non-secure boot scenarios, this allows them
to eliminate the need for an additional oscillator device and
a dedicated HPS pin, simplifying board layout and routing.

Signed-off-by: Tingting Meng <tingting.meng@altera.com>
Signed-off-by: Alif Zakuan Yuslaimi <alif.zakuan.yuslaimi@altera.com>
Reviewed-by: Tien Fong Chee <tien.fong.chee@altera.com>

diff --git a/drivers/clk/altera/clk-agilex5.c b/drivers/clk/altera/clk-agilex5.c
index 716c715..dfc25ac 100644 (file)
--- a/drivers/clk/altera/clk-agilex5.c
+++ b/drivers/clk/altera/clk-agilex5.c
@@ -1,13 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2024 Intel Corporation <www.intel.com>
+ * Copyright (C) 2025 Altera Corporation <www.altera.com>
  */
 
-#include <clk-uclass.h>
 #include <config.h>
-#include <errno.h>
-#include <dm.h>
 #include <log.h>
+#include <dm.h>
+#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <time.h>
@@ -23,9 +23,14 @@
 #include <linux/types.h>
 #include <asm/arch/clock_manager.h>
 #include <dt-bindings/clock/agilex5-clock.h>
+#include <wait_bit.h>
+#include <clk-uclass.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#define CLKMGR_CTRL_SWCTRLBTCLKEN_MASK         BIT(8)
+#define CLKMGR_CTRL_SWCTRLBTCLKSEL_MASK                BIT(9)
+
 struct socfpga_clk_plat {
        void __iomem *regs;
 };
@@ -264,9 +269,14 @@ static void clk_basic_init(struct udevice *dev,
                               CM_REG_READL(plat, CLKMGR_CTRL) & ~CLKMGR_CTRL_BOOTMODE);
        } else {
 #ifdef CONFIG_XPL_BUILD
-               /* Always force clock manager into boot mode before any configuration */
-               clk_write_ctrl(plat,
-                              CM_REG_READL(plat, CLKMGR_CTRL) | CLKMGR_CTRL_BOOTMODE);
+               /*
+                * Configure HPS Internal Oscillator as default boot_clk source,
+                * always force clock manager into boot mode before any configuration
+                */
+               clk_write_ctrl(plat, CM_REG_READL(plat, CLKMGR_CTRL) |
+                              CLKMGR_CTRL_BOOTMODE |
+                              CLKMGR_CTRL_SWCTRLBTCLKEN_MASK |
+                              CLKMGR_CTRL_SWCTRLBTCLKSEL_MASK);
 #else
                /* Skip clock configuration in SSBL if it's not in boot mode */
                if (!(CM_REG_READL(plat, CLKMGR_CTRL) & CLKMGR_CTRL_BOOTMODE))