[PATCH 3/9] ARM: i.MX8MN: adapt early clock support

[Ahmad Fatoum]

PBL runs fine when doing the same early clock setup as for the i.MX8MM:
i2c communication works, copying to DRAM works, but boot hangs in
barebox proper. Vendor patches for U-Boot configure SYS_PLL3 as 600MHz
for i.MX8MP and i.MX8MN. barebox i.MX8MP port evidently can do without,
but for i.MX8MN, reducing PLL frequency to 600MHz was required to boot.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 arch/arm/mach-imx/imx8m.c                       | 16 +++++++++++++---
 arch/arm/mach-imx/include/mach/imx8m-ccm-regs.h |  1 +
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-imx/imx8m.c b/arch/arm/mach-imx/imx8m.c
index ac48e7aa0ab1..6b7cdac54145 100644
--- a/arch/arm/mach-imx/imx8m.c
+++ b/arch/arm/mach-imx/imx8m.c
@@ -181,7 +181,7 @@ int imx8mq_init(void)
 #define IMX8MM_CCM_ANALOG_SYS_PLL2_GEN_CTRL	0x104
 #define IMX8MM_CCM_ANALOG_SYS_PLL3_GEN_CTRL	0x114
 
-void imx8mm_early_clock_init(void)
+static void __imx8mm_early_clock_init(unsigned long pll3_freq) /* and later */
 {
 	void __iomem *ana = IOMEM(MX8M_ANATOP_BASE_ADDR);
 	void __iomem *ccm = IOMEM(MX8M_CCM_BASE_ADDR);
@@ -224,9 +224,9 @@ void imx8mm_early_clock_init(void)
 				   IMX8M_CCM_TARGET_ROOTn_MUX(3));
 	imx8m_ccgr_clock_enable(IMX8M_CCM_CCGR_GIC);
 
-	/* Configure SYS_PLL3 to 750MHz */
+	/* Configure SYS_PLL3 */
 	clk_pll1416x_early_set_rate(ana + IMX8MM_CCM_ANALOG_SYS_PLL3_GEN_CTRL,
-				    750000000UL, 25000000UL);
+				    pll3_freq, 25000000UL);
 
 	clrsetbits_le32(ccm + IMX8M_CCM_TARGET_ROOTn(IMX8M_ARM_A53_CLK_ROOT),
 			IMX8M_CCM_TARGET_ROOTn_MUX(7),
@@ -249,6 +249,16 @@ void imx8mm_early_clock_init(void)
 			FIELD_PREP(CCM_TARGET_ROOT0_DIV, 0));
 }
 
+void imx8mm_early_clock_init(void)
+{
+	__imx8mm_early_clock_init(750000000UL);
+}
+
+void imx8mn_early_clock_init(void)
+{
+	__imx8mm_early_clock_init(600000000UL);
+}
+
 #define KEEP_ALIVE			0x18
 #define VER_L				0x1c
 #define VER_H				0x20
diff --git a/arch/arm/mach-imx/include/mach/imx8m-ccm-regs.h b/arch/arm/mach-imx/include/mach/imx8m-ccm-regs.h
index 743ed6cda0d2..985391f31ac1 100644
--- a/arch/arm/mach-imx/include/mach/imx8m-ccm-regs.h
+++ b/arch/arm/mach-imx/include/mach/imx8m-ccm-regs.h
@@ -50,6 +50,7 @@
 
 void imx8m_early_setup_uart_clock(void);
 void imx8mm_early_clock_init(void);
+void imx8mn_early_clock_init(void);
 void imx8m_clock_set_target_val(int clock_id, u32 val);
 void imx8m_ccgr_clock_enable(int index);
 void imx8m_ccgr_clock_disable(int index);
-- 
2.30.2