diff --git a/arch/arm/dts/ast2500-u-boot.dtsi b/arch/arm/dts/ast2500-u-boot.dtsi
new file mode 100644
index 0000000000000000000000000000000000000000..c95a7ba835a0bbb17ea53891c2d2d3a9cd67c07c
--- /dev/null
+++ b/arch/arm/dts/ast2500-u-boot.dtsi
@@ -0,0 +1,53 @@
+#include <dt-bindings/clock/ast2500-scu.h>
+
+#include "ast2500.dtsi"
+
+/ {
+ scu: clock-controller@1e6e2000 {
+ compatible = "aspeed,ast2500-scu";
+ reg = <0x1e6e2000 0x1000>;
+ u-boot,dm-pre-reloc;
+ #clock-cells = <1>;
+ #reset-cells = <1>;
+ };
+
+ sdrammc: sdrammc@1e6e0000 {
+ u-boot,dm-pre-reloc;
+ compatible = "aspeed,ast2500-sdrammc";
+ reg = <0x1e6e0000 0x174
+ 0x1e6e0200 0x1d4 >;
+ clocks = <&scu PLL_MPLL>;
+ };
+
+ ahb {
+ u-boot,dm-pre-reloc;
+
+ apb {
+ u-boot,dm-pre-reloc;
+
+ timer: timer@1e782000 {
+ u-boot,dm-pre-reloc;
+ };
+
+ uart1: serial@1e783000 {
+ clocks = <&scu PCLK_UART1>;
+ };
+
+ uart2: serial@1e78d000 {
+ clocks = <&scu PCLK_UART2>;
+ };
+
+ uart3: serial@1e78e000 {
+ clocks = <&scu PCLK_UART3>;
+ };
+
+ uart4: serial@1e78f000 {
+ clocks = <&scu PCLK_UART4>;
+ };
+
+ uart5: serial@1e784000 {
+ clocks = <&scu PCLK_UART5>;
+ };
+ };
+ };
+};
diff --git a/arch/arm/dts/ast2500.dtsi b/arch/arm/dts/ast2500.dtsi
new file mode 100644
index 0000000000000000000000000000000000000000..97fac69d11f7286172180753f756c8c97d6e621d
--- /dev/null
+++ b/arch/arm/dts/ast2500.dtsi
@@ -0,0 +1,174 @@
+/*
+ * This device tree is copied from
+ * https://raw.githubusercontent.com/torvalds/linux/02440622/arch/arm/boot/dts/
+ */
+#include "skeleton.dtsi"
+
+/ {
+ model = "Aspeed BMC";
+ compatible = "aspeed,ast2500";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ interrupt-parent = <&vic>;
+
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ compatible = "arm,arm1176jzf-s";
+ device_type = "cpu";
+ reg = <0>;
+ };
+ };
+
+ ahb {
+ compatible = "simple-bus";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges;
+
+ vic: interrupt-controller@1e6c0080 {
+ compatible = "aspeed,ast2400-vic";
+ interrupt-controller;
+ #interrupt-cells = <1>;
+ valid-sources = <0xfefff7ff 0x0807ffff>;
+ reg = <0x1e6c0080 0x80>;
+ };
+
+ apb {
+ compatible = "simple-bus";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges;
+
+ clk_clkin: clk_clkin@1e6e2070 {
+ #clock-cells = <0>;
+ compatible = "aspeed,g5-clkin-clock";
+ reg = <0x1e6e2070 0x04>;
+ };
+
+ clk_hpll: clk_hpll@1e6e2024 {
+ #clock-cells = <0>;
+ compatible = "aspeed,g5-hpll-clock";
+ reg = <0x1e6e2024 0x4>;
+ clocks = <&clk_clkin>;
+ };
+
+ clk_ahb: clk_ahb@1e6e2070 {
+ #clock-cells = <0>;
+ compatible = "aspeed,g5-ahb-clock";
+ reg = <0x1e6e2070 0x4>;
+ clocks = <&clk_hpll>;
+ };
+
+ clk_apb: clk_apb@1e6e2008 {
+ #clock-cells = <0>;
+ compatible = "aspeed,g5-apb-clock";
+ reg = <0x1e6e2008 0x4>;
+ clocks = <&clk_hpll>;
+ };
+
+ clk_uart: clk_uart@1e6e2008 {
+ #clock-cells = <0>;
+ compatible = "aspeed,uart-clock";
+ reg = <0x1e6e202c 0x4>;
+ };
+
+ sram@1e720000 {
+ compatible = "mmio-sram";
+ reg = <0x1e720000 0x9000>; // 36K
+ };
+
+ timer: timer@1e782000 {
+ compatible = "aspeed,ast2400-timer";
+ reg = <0x1e782000 0x90>;
+ // The moxart_timer driver registers only one
+ // interrupt and assumes it's for timer 1
+ //interrupts = <16 17 18 35 36 37 38 39>;
+ interrupts = <16>;
+ clocks = <&clk_apb>;
+ };
+
+ wdt1: wdt@1e785000 {
+ compatible = "aspeed,wdt";
+ reg = <0x1e785000 0x1c>;
+ interrupts = <27>;
+ };
+
+ wdt2: wdt@1e785020 {
+ compatible = "aspeed,wdt";
+ reg = <0x1e785020 0x1c>;
+ interrupts = <27>;
+ status = "disabled";
+ };
+
+ wdt3: wdt@1e785040 {
+ compatible = "aspeed,wdt";
+ reg = <0x1e785074 0x1c>;
+ status = "disabled";
+ };
+
+ uart1: serial@1e783000 {
+ compatible = "ns16550a";
+ reg = <0x1e783000 0x1000>;
+ reg-shift = <2>;
+ interrupts = <9>;
+ clocks = <&clk_uart>;
+ no-loopback-test;
+ status = "disabled";
+ };
+
+ uart2: serial@1e78d000 {
+ compatible = "ns16550a";
+ reg = <0x1e78d000 0x1000>;
+ reg-shift = <2>;
+ interrupts = <32>;
+ clocks = <&clk_uart>;
+ no-loopback-test;
+ status = "disabled";
+ };
+
+ uart3: serial@1e78e000 {
+ compatible = "ns16550a";
+ reg = <0x1e78e000 0x1000>;
+ reg-shift = <2>;
+ interrupts = <33>;
+ clocks = <&clk_uart>;
+ no-loopback-test;
+ status = "disabled";
+ };
+
+ uart4: serial@1e78f000 {
+ compatible = "ns16550a";
+ reg = <0x1e78f000 0x1000>;
+ reg-shift = <2>;
+ interrupts = <34>;
+ clocks = <&clk_uart>;
+ no-loopback-test;
+ status = "disabled";
+ };
+
+ uart5: serial@1e784000 {
+ compatible = "ns16550a";
+ reg = <0x1e784000 0x1000>;
+ reg-shift = <2>;
+ interrupts = <10>;
+ clocks = <&clk_uart>;
+ current-speed = <38400>;
+ no-loopback-test;
+ status = "disabled";
+ };
+
+ uart6: serial@1e787000 {
+ compatible = "ns16550a";
+ reg = <0x1e787000 0x1000>;
+ reg-shift = <2>;
+ interrupts = <10>;
+ clocks = <&clk_uart>;
+ no-loopback-test;
+ status = "disabled";
+ };
+ };
+ };
+};
diff --git a/arch/arm/include/asm/arch-aspeed/scu_ast2500.h b/arch/arm/include/asm/arch-aspeed/scu_ast2500.h
new file mode 100644
index 0000000000000000000000000000000000000000..fc0c01ae3303c36431099db5fbf7ff2473563954
--- /dev/null
+++ b/arch/arm/include/asm/arch-aspeed/scu_ast2500.h
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef _ASM_ARCH_SCU_AST2500_H
+#define _ASM_ARCH_SCU_AST2500_H
+
+#define SCU_UNLOCK_VALUE 0x1688a8a8
+
+#define SCU_HWSTRAP_VGAMEM_MASK 3
+#define SCU_HWSTRAP_VGAMEM_SHIFT 2
+#define SCU_HWSTRAP_DDR4 (1 << 24)
+#define SCU_HWSTRAP_CLKIN_25MHZ (1 << 23)
+
+#define SCU_MPLL_DENUM_SHIFT 0
+#define SCU_MPLL_DENUM_MASK 0x1f
+#define SCU_MPLL_NUM_SHIFT 5
+#define SCU_MPLL_NUM_MASK 0xff
+#define SCU_MPLL_POST_SHIFT 13
+#define SCU_MPLL_POST_MASK 0x3f
+
+#define SCU_HPLL_DENUM_SHIFT 0
+#define SCU_HPLL_DENUM_MASK 0x1f
+#define SCU_HPLL_NUM_SHIFT 5
+#define SCU_HPLL_NUM_MASK 0xff
+#define SCU_HPLL_POST_SHIFT 13
+#define SCU_HPLL_POST_MASK 0x3f
+
+#define SCU_MISC2_UARTCLK_SHIFT 24
+
+#define SCU_MISC_UARTCLK_DIV13 (1 << 12)
+
+#ifndef __ASSEMBLY__
+
+struct ast2500_clk_priv {
+ struct ast2500_scu *scu;
+};
+
+struct ast2500_scu {
+ u32 protection_key;
+ u32 sysreset_ctrl1;
+ u32 clk_sel1;
+ u32 clk_stop_ctrl1;
+ u32 freq_counter_ctrl;
+ u32 freq_counter_cmp;
+ u32 intr_ctrl;
+ u32 d2_pll_param;
+ u32 m_pll_param;
+ u32 h_pll_param;
+ u32 d_pll_param;
+ u32 misc_ctrl1;
+ u32 pci_config[3];
+ u32 sysreset_status;
+ u32 vga_handshake[2];
+ u32 mac_clk_delay;
+ u32 misc_ctrl2;
+ u32 vga_scratch[8];
+ u32 hwstrap;
+ u32 rng_ctrl;
+ u32 rng_data;
+ u32 rev_id;
+ u32 pinmux_ctrl[6];
+ u32 reserved0;
+ u32 extrst_sel;
+ u32 pinmux_ctrl1[4];
+ u32 reserved1[2];
+ u32 mac_clk_delay_100M;
+ u32 mac_clk_delay_10M;
+ u32 wakeup_enable;
+ u32 wakeup_control;
+ u32 reserved2[3];
+ u32 sysreset_ctrl2;
+ u32 clk_sel2;
+ u32 clk_stop_ctrl2;
+ u32 freerun_counter;
+ u32 freerun_counter_ext;
+ u32 clk_duty_meas_ctrl;
+ u32 clk_duty_meas_res;
+ u32 reserved3[4];
+ /* The next registers are not key-protected */
+ struct ast2500_cpu2 {
+ u32 ctrl;
+ u32 base_addr[9];
+ u32 cache_ctrl;
+ } cpu2;
+ u32 reserved4;
+ u32 d_pll_ext_param[3];
+ u32 d2_pll_ext_param[3];
+ u32 mh_pll_ext_param;
+ u32 reserved5;
+ u32 chip_id[2];
+ u32 reserved6[2];
+ u32 uart_clk_ctrl;
+ u32 reserved7[7];
+ u32 pcie_config;
+ u32 mmio_decode;
+ u32 reloc_ctrl_decode[2];
+ u32 mailbox_addr;
+ u32 shared_sram_decode[2];
+ u32 bmc_rev_id;
+ u32 reserved8;
+ u32 bmc_device_id;
+ u32 reserved9[13];
+ u32 clk_duty_sel;
+};
+
+/**
+ * ast_get_clk() - get a pointer to Clock Driver
+ *
+ * @devp, OUT - pointer to Clock Driver
+ * @return zero on success, error code (< 0) otherwise.
+ */
+int ast_get_clk(struct udevice **devp);
+
+/**
+ * ast_get_scu() - get a pointer to SCU registers
+ *
+ * @return pointer to struct ast2500_scu on success, ERR_PTR otherwise
+ */
+void *ast_get_scu(void);
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ARCH_SCU_AST2500_H */
diff --git a/arch/arm/include/asm/arch-aspeed/sdram_ast2500.h b/arch/arm/include/asm/arch-aspeed/sdram_ast2500.h
new file mode 100644
index 0000000000000000000000000000000000000000..a5f8615ae29080759c5a7a0d038aaf5acb27ad97
--- /dev/null
+++ b/arch/arm/include/asm/arch-aspeed/sdram_ast2500.h
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef _ASM_ARCH_SDRAM_AST2500_H
+#define _ASM_ARCH_SDRAM_AST2500_H
+
+#define SDRAM_UNLOCK_KEY 0xfc600309
+#define SDRAM_VIDEO_UNLOCK_KEY 0x2003000f
+
+#define SDRAM_PCR_CKE_EN (1 << 0)
+#define SDRAM_PCR_AUTOPWRDN_EN (1 << 1)
+#define SDRAM_PCR_CKE_DELAY_SHIFT 4
+#define SDRAM_PCR_CKE_DELAY_MASK 7
+#define SDRAM_PCR_RESETN_DIS (1 << 7)
+#define SDRAM_PCR_ODT_EN (1 << 8)
+#define SDRAM_PCR_ODT_AUTO_ON (1 << 10)
+#define SDRAM_PCR_ODT_EXT_EN (1 << 11)
+#define SDRAM_PCR_TCKE_PW_SHIFT 12
+#define SDRAM_PCR_TCKE_PW_MASK 7
+#define SDRAM_PCR_RGAP_CTRL_EN (1 << 15)
+#define SDRAM_PCR_MREQI_DIS (1 << 17)
+
+/* Fixed priority DRAM Requests mask */
+#define SDRAM_REQ_VGA_HW_CURSOR (1 << 0)
+#define SDRAM_REQ_VGA_TEXT_CG_FONT (1 << 1)
+#define SDRAM_REQ_VGA_TEXT_ASCII (1 << 2)
+#define SDRAM_REQ_VGA_CRT (1 << 3)
+#define SDRAM_REQ_SOC_DC_CURSOR (1 << 4)
+#define SDRAM_REQ_SOC_DC_OCD (1 << 5)
+#define SDRAM_REQ_SOC_DC_CRT (1 << 6)
+#define SDRAM_REQ_VIDEO_HIPRI_WRITE (1 << 7)
+#define SDRAM_REQ_USB20_EHCI1 (1 << 8)
+#define SDRAM_REQ_USB20_EHCI2 (1 << 9)
+#define SDRAM_REQ_CPU (1 << 10)
+#define SDRAM_REQ_AHB2 (1 << 11)
+#define SDRAM_REQ_AHB (1 << 12)
+#define SDRAM_REQ_MAC0 (1 << 13)
+#define SDRAM_REQ_MAC1 (1 << 14)
+#define SDRAM_REQ_PCIE (1 << 16)
+#define SDRAM_REQ_XDMA (1 << 17)
+#define SDRAM_REQ_ENCRYPTION (1 << 18)
+#define SDRAM_REQ_VIDEO_FLAG (1 << 21)
+#define SDRAM_REQ_VIDEO_LOW_PRI_WRITE (1 << 28)
+#define SDRAM_REQ_2D_RW (1 << 29)
+#define SDRAM_REQ_MEMCHECK (1 << 30)
+
+#define SDRAM_ICR_RESET_ALL (1 << 31)
+
+#define SDRAM_CONF_CAP_SHIFT 0
+#define SDRAM_CONF_CAP_MASK 3
+#define SDRAM_CONF_DDR4 (1 << 4)
+#define SDRAM_CONF_SCRAMBLE (1 << 8)
+#define SDRAM_CONF_SCRAMBLE_PAT2 (1 << 9)
+#define SDRAM_CONF_CACHE_EN (1 << 10)
+#define SDRAM_CONF_CACHE_INIT_EN (1 << 12)
+#define SDRAM_CONF_DUALX8 (1 << 13)
+#define SDRAM_CONF_CACHE_INIT_DONE (1 << 19)
+
+#define SDRAM_CONF_CAP_128M 0
+#define SDRAM_CONF_CAP_256M 1
+#define SDRAM_CONF_CAP_512M 2
+#define SDRAM_CONF_CAP_1024M 3
+
+#define SDRAM_MISC_DDR4_TREFRESH (1 << 3)
+
+#define SDRAM_PHYCTRL0_INIT (1 << 0)
+#define SDRAM_PHYCTRL0_AUTO_UPDATE (1 << 1)
+#define SDRAM_PHYCTRL0_NRST (1 << 2)
+
+#define SDRAM_REFRESH_CYCLES_SHIFT 0
+#define SDRAM_REFRESH_CYCLES_MASK 0xf
+#define SDRAM_REFRESH_ZQCS_EN (1 << 7)
+#define SDRAM_REFRESH_PERIOD_SHIFT 8
+#define SDRAM_REFRESH_PERIOD_MASK 0xf
+
+#define SDRAM_TEST_LEN_SHIFT 4
+#define SDRAM_TEST_LEN_MASK 0xfffff
+#define SDRAM_TEST_START_ADDR_SHIFT 24
+#define SDRAM_TEST_START_ADDR_MASK 0x3f
+
+#define SDRAM_TEST_EN (1 << 0)
+#define SDRAM_TEST_MODE_SHIFT 1
+#define SDRAM_TEST_MODE_MASK 3
+#define SDRAM_TEST_MODE_WO 0
+#define SDRAM_TEST_MODE_RB 1
+#define SDRAM_TEST_MODE_RW 2
+#define SDRAM_TEST_GEN_MODE_SHIFT 3
+#define SDRAM_TEST_GEN_MODE_MASK 7
+#define SDRAM_TEST_TWO_MODES (1 << 6)
+#define SDRAM_TEST_ERRSTOP (1 << 7)
+#define SDRAM_TEST_DONE (1 << 12)
+#define SDRAM_TEST_FAIL (1 << 13)
+
+#define SDRAM_AC_TRFC_SHIFT 0
+#define SDRAM_AC_TRFC_MASK 0xff
+
+#ifndef __ASSEMBLY__
+
+struct ast2500_sdrammc_regs {
+ u32 protection_key;
+ u32 config;
+ u32 gm_protection_key;
+ u32 refresh_timing;
+ u32 ac_timing[3];
+ u32 misc_control;
+ u32 mr46_mode_setting;
+ u32 mr5_mode_setting;
+ u32 mode_setting_control;
+ u32 mr02_mode_setting;
+ u32 mr13_mode_setting;
+ u32 power_control;
+ u32 req_limit_mask;
+ u32 pri_group_setting;
+ u32 max_grant_len[4];
+ u32 intr_ctrl;
+ u32 ecc_range_ctrl;
+ u32 first_ecc_err_addr;
+ u32 last_ecc_err_addr;
+ u32 phy_ctrl[4];
+ u32 ecc_test_ctrl;
+ u32 test_addr;
+ u32 test_fail_dq_bit;
+ u32 test_init_val;
+ u32 phy_debug_ctrl;
+ u32 phy_debug_data;
+ u32 reserved1[30];
+ u32 scu_passwd;
+ u32 reserved2[7];
+ u32 scu_mpll;
+ u32 reserved3[19];
+ u32 scu_hwstrap;
+};
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ARCH_SDRAM_AST2500_H */
diff --git a/arch/arm/mach-aspeed/Kconfig b/arch/arm/mach-aspeed/Kconfig
index b72ed89af74fb7ad4b7bd1ce1f94eaebbe43e7a4..c5b90bd96a43c479c8f9ff23df06144ba21efc36 100644
--- a/arch/arm/mach-aspeed/Kconfig
+++ b/arch/arm/mach-aspeed/Kconfig
@@ -24,4 +24,6 @@ config WDT_NUM
The number of Watchdot Timers on a SoC.
AST2500 has three WDTsk earlier versions have two or fewer.
+source "arch/arm/mach-aspeed/ast2500/Kconfig"
+
endif
diff --git a/arch/arm/mach-aspeed/Makefile b/arch/arm/mach-aspeed/Makefile
index a14b8f751d28b7183ba72b3ce472e038b4c2c0d1..1f7af71b033f0b8a2f444a78a233e8c7001ae545 100644
--- a/arch/arm/mach-aspeed/Makefile
+++ b/arch/arm/mach-aspeed/Makefile
@@ -5,3 +5,4 @@
#
obj-$(CONFIG_ARCH_ASPEED) += ast_wdt.o
+obj-$(CONFIG_ASPEED_AST2500) += ast2500/
diff --git a/arch/arm/mach-aspeed/ast2500/Kconfig b/arch/arm/mach-aspeed/ast2500/Kconfig
new file mode 100644
index 0000000000000000000000000000000000000000..05cb27ea1fdc193432011c9c8c3d276739f96ac5
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/Kconfig
@@ -0,0 +1,14 @@
+if ASPEED_AST2500
+
+config SYS_CPU
+ default "arm1176"
+
+config TARGET_EVB_AST2500
+ bool "Evb-AST2500"
+ help
+ Evb-AST2500 is Aspeed evaluation board for AST2500 chip.
+ It has 512M of RAM, 32M of SPI flash, two Ethernet ports,
+ 4 Serial ports, 4 USB ports, VGA port, PCIe, SD card slot,
+ 20 pin JTAG, pinouts for 14 I2Cs, 3 SPIs and eSPI, 8 PWMs.
+
+endif
diff --git a/arch/arm/mach-aspeed/ast2500/Makefile b/arch/arm/mach-aspeed/ast2500/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..a35b239ef35ed16311e0c13693b5e1c7376e25e3
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/Makefile
@@ -0,0 +1 @@
+obj-y += clk_ast2500.o sdram_ast2500.o
diff --git a/arch/arm/mach-aspeed/ast2500/clk_ast2500.c b/arch/arm/mach-aspeed/ast2500/clk_ast2500.c
new file mode 100644
index 0000000000000000000000000000000000000000..079909fa6462218a93ada767df11349657c443f2
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/clk_ast2500.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/arch/scu_ast2500.h>
+
+int ast_get_clk(struct udevice **devp)
+{
+ return uclass_get_device_by_driver(UCLASS_CLK,
+ DM_GET_DRIVER(aspeed_ast2500_scu), devp);
+}
+
+void *ast_get_scu(void)
+{
+ struct ast2500_clk_priv *priv;
+ struct udevice *dev;
+ int ret;
+
+ ret = ast_get_clk(&dev);
+ if (ret)
+ return ERR_PTR(ret);
+
+ priv = dev_get_priv(dev);
+
+ return priv->scu;
+}
diff --git a/arch/arm/mach-aspeed/ast2500/sdram_ast2500.c b/arch/arm/mach-aspeed/ast2500/sdram_ast2500.c
new file mode 100644
index 0000000000000000000000000000000000000000..ace102811661215e1d9089129e92786abd0a58d5
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/sdram_ast2500.c
@@ -0,0 +1,432 @@
+/*
+ * Copyright (C) 2012-2020 ASPEED Technology Inc.
+ *
+ * Copyright 2016 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <errno.h>
+#include <ram.h>
+#include <regmap.h>
+#include <asm/io.h>
+#include <asm/arch/scu_ast2500.h>
+#include <asm/arch/sdram_ast2500.h>
+#include <asm/arch/wdt.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <dt-bindings/clock/ast2500-scu.h>
+
+/* These configuration parameters are taken from Aspeed SDK */
+#define DDR4_MR46_MODE 0x08000000
+#define DDR4_MR5_MODE 0x400
+#define DDR4_MR13_MODE 0x101
+#define DDR4_MR02_MODE 0x410
+#define DDR4_TRFC 0x45457188
+
+#define PHY_CFG_SIZE 15
+
+static const u32 ddr4_ac_timing[3] = {0x63604e37, 0xe97afa99, 0x00019000};
+static const struct {
+ u32 index[PHY_CFG_SIZE];
+ u32 value[PHY_CFG_SIZE];
+} ddr4_phy_config = {
+ .index = {0, 1, 3, 4, 5, 56, 57, 58, 59, 60, 61, 62, 36, 49, 50},
+ .value = {
+ 0x42492aae, 0x09002000, 0x55e00b0b, 0x20000000, 0x24,
+ 0x03002900, 0x0e0000a0, 0x000e001c, 0x35b8c106, 0x08080607,
+ 0x9b000900, 0x0e400a00, 0x00100008, 0x3c183c3c, 0x00631e0e,
+ },
+};
+
+#define SDRAM_MAX_SIZE (1024 * 1024 * 1024)
+#define SDRAM_MIN_SIZE (128 * 1024 * 1024)
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Bandwidth configuration parameters for different SDRAM requests.
+ * These are hardcoded settings taken from Aspeed SDK.
+ */
+static const u32 ddr_max_grant_params[4] = {
+ 0x88448844, 0x24422288, 0x22222222, 0x22222222
+};
+
+/*
+ * These registers are not documented by Aspeed at all.
+ * All writes and reads are taken pretty much as is from SDK.
+ */
+struct ast2500_ddr_phy {
+ u32 phy[117];
+};
+
+struct dram_info {
+ struct ram_info info;
+ struct clk ddr_clk;
+ struct ast2500_sdrammc_regs *regs;
+ struct ast2500_scu *scu;
+ struct ast2500_ddr_phy *phy;
+ ulong clock_rate;
+};
+
+static int ast2500_sdrammc_init_phy(struct ast2500_ddr_phy *phy)
+{
+ writel(0, &phy->phy[2]);
+ writel(0, &phy->phy[6]);
+ writel(0, &phy->phy[8]);
+ writel(0, &phy->phy[10]);
+ writel(0, &phy->phy[12]);
+ writel(0, &phy->phy[42]);
+ writel(0, &phy->phy[44]);
+
+ writel(0x86000000, &phy->phy[16]);
+ writel(0x00008600, &phy->phy[17]);
+ writel(0x80000000, &phy->phy[18]);
+ writel(0x80808080, &phy->phy[19]);
+
+ return 0;
+}
+
+static void ast2500_ddr_phy_init_process(struct dram_info *info)
+{
+ struct ast2500_sdrammc_regs *regs = info->regs;
+
+ writel(0, ®s->phy_ctrl[0]);
+ writel(0x4040, &info->phy->phy[51]);
+
+ writel(SDRAM_PHYCTRL0_NRST | SDRAM_PHYCTRL0_INIT, ®s->phy_ctrl[0]);
+ while ((readl(®s->phy_ctrl[0]) & SDRAM_PHYCTRL0_INIT))
+ ;
+ writel(SDRAM_PHYCTRL0_NRST | SDRAM_PHYCTRL0_AUTO_UPDATE,
+ ®s->phy_ctrl[0]);
+}
+
+static void ast2500_sdrammc_set_vref(struct dram_info *info, u32 vref)
+{
+ writel(0, &info->regs->phy_ctrl[0]);
+ writel((vref << 8) | 0x6, &info->phy->phy[48]);
+ ast2500_ddr_phy_init_process(info);
+}
+
+static int ast2500_ddr_cbr_test(struct dram_info *info)
+{
+ struct ast2500_sdrammc_regs *regs = info->regs;
+ int i;
+ const u32 test_params = SDRAM_TEST_EN
+ | SDRAM_TEST_ERRSTOP
+ | SDRAM_TEST_TWO_MODES;
+ int ret = 0;
+
+ writel((1 << SDRAM_REFRESH_CYCLES_SHIFT) |
+ (0x5c << SDRAM_REFRESH_PERIOD_SHIFT), ®s->refresh_timing);
+ writel((0xfff << SDRAM_TEST_LEN_SHIFT), ®s->test_addr);
+ writel(0xff00ff00, ®s->test_init_val);
+ writel(SDRAM_TEST_EN | (SDRAM_TEST_MODE_RW << SDRAM_TEST_MODE_SHIFT) |
+ SDRAM_TEST_ERRSTOP, ®s->ecc_test_ctrl);
+
+ while (!(readl(®s->ecc_test_ctrl) & SDRAM_TEST_DONE))
+ ;
+
+ if (readl(®s->ecc_test_ctrl) & SDRAM_TEST_FAIL) {
+ ret = -EIO;
+ } else {
+ for (i = 0; i <= SDRAM_TEST_GEN_MODE_MASK; ++i) {
+ writel((i << SDRAM_TEST_GEN_MODE_SHIFT) | test_params,
+ ®s->ecc_test_ctrl);
+ while (!(readl(®s->ecc_test_ctrl) & SDRAM_TEST_DONE))
+ ;
+ if (readl(®s->ecc_test_ctrl) & SDRAM_TEST_FAIL) {
+ ret = -EIO;
+ break;
+ }
+ }
+ }
+
+ writel(0, ®s->refresh_timing);
+ writel(0, ®s->ecc_test_ctrl);
+
+ return ret;
+}
+
+static int ast2500_sdrammc_ddr4_calibrate_vref(struct dram_info *info)
+{
+ int i;
+ int vref_min = 0xff;
+ int vref_max = 0;
+ int range_size = 0;
+
+ for (i = 1; i < 0x40; ++i) {
+ int res;
+
+ ast2500_sdrammc_set_vref(info, i);
+ res = ast2500_ddr_cbr_test(info);
+ if (res < 0) {
+ if (range_size > 0)
+ break;
+ } else {
+ ++range_size;
+ vref_min = min(vref_min, i);
+ vref_max = max(vref_max, i);
+ }
+ }
+
+ /* Pick average setting */
+ ast2500_sdrammc_set_vref(info, (vref_min + vref_max + 1) / 2);
+
+ return 0;
+}
+
+static size_t ast2500_sdrammc_get_vga_mem_size(struct dram_info *info)
+{
+ size_t vga_mem_size_base = 8 * 1024 * 1024;
+ u32 vga_hwconf = (readl(&info->scu->hwstrap)
+ >> SCU_HWSTRAP_VGAMEM_SHIFT)
+ & SCU_HWSTRAP_VGAMEM_MASK;
+
+ return vga_mem_size_base << vga_hwconf;
+}
+
+/*
+ * Find out RAM size and save it in dram_info
+ *
+ * The procedure is taken from Aspeed SDK
+ */
+static void ast2500_sdrammc_calc_size(struct dram_info *info)
+{
+ /* The controller supports 128/256/512/1024 MB ram */
+ size_t ram_size = SDRAM_MIN_SIZE;
+ const int write_test_offset = 0x100000;
+ u32 test_pattern = 0xdeadbeef;
+ u32 cap_param = SDRAM_CONF_CAP_1024M;
+ u32 refresh_timing_param = DDR4_TRFC;
+ const u32 write_addr_base = CONFIG_SYS_SDRAM_BASE + write_test_offset;
+
+ for (ram_size = SDRAM_MAX_SIZE; ram_size > SDRAM_MIN_SIZE;
+ ram_size >>= 1) {
+ writel(test_pattern, write_addr_base + (ram_size >> 1));
+ test_pattern = (test_pattern >> 4) | (test_pattern << 28);
+ }
+
+ /* One last write to overwrite all wrapped values */
+ writel(test_pattern, write_addr_base);
+
+ /* Reset the pattern and see which value was really written */
+ test_pattern = 0xdeadbeef;
+ for (ram_size = SDRAM_MAX_SIZE; ram_size > SDRAM_MIN_SIZE;
+ ram_size >>= 1) {
+ if (readl(write_addr_base + (ram_size >> 1)) == test_pattern)
+ break;
+
+ --cap_param;
+ refresh_timing_param >>= 8;
+ test_pattern = (test_pattern >> 4) | (test_pattern << 28);
+ }
+
+ clrsetbits_le32(&info->regs->ac_timing[1],
+ (SDRAM_AC_TRFC_MASK << SDRAM_AC_TRFC_SHIFT),
+ ((refresh_timing_param & SDRAM_AC_TRFC_MASK)
+ << SDRAM_AC_TRFC_SHIFT));
+
+ info->info.base = CONFIG_SYS_SDRAM_BASE;
+ info->info.size = ram_size - ast2500_sdrammc_get_vga_mem_size(info);
+ clrsetbits_le32(&info->regs->config,
+ (SDRAM_CONF_CAP_MASK << SDRAM_CONF_CAP_SHIFT),
+ ((cap_param & SDRAM_CONF_CAP_MASK)
+ << SDRAM_CONF_CAP_SHIFT));
+}
+
+static int ast2500_sdrammc_init_ddr4(struct dram_info *info)
+{
+ int i;
+ const u32 power_control = SDRAM_PCR_CKE_EN
+ | (1 << SDRAM_PCR_CKE_DELAY_SHIFT)
+ | (2 << SDRAM_PCR_TCKE_PW_SHIFT)
+ | SDRAM_PCR_RESETN_DIS
+ | SDRAM_PCR_RGAP_CTRL_EN | SDRAM_PCR_ODT_EN | SDRAM_PCR_ODT_EXT_EN;
+ const u32 conf = (SDRAM_CONF_CAP_1024M << SDRAM_CONF_CAP_SHIFT)
+#ifdef CONFIG_DUALX8_RAM
+ | SDRAM_CONF_DUALX8
+#endif
+ | SDRAM_CONF_SCRAMBLE | SDRAM_CONF_SCRAMBLE_PAT2 | SDRAM_CONF_DDR4;
+ int ret;
+
+ writel(conf, &info->regs->config);
+ for (i = 0; i < ARRAY_SIZE(ddr4_ac_timing); ++i)
+ writel(ddr4_ac_timing[i], &info->regs->ac_timing[i]);
+
+ writel(DDR4_MR46_MODE, &info->regs->mr46_mode_setting);
+ writel(DDR4_MR5_MODE, &info->regs->mr5_mode_setting);
+ writel(DDR4_MR02_MODE, &info->regs->mr02_mode_setting);
+ writel(DDR4_MR13_MODE, &info->regs->mr13_mode_setting);
+
+ for (i = 0; i < PHY_CFG_SIZE; ++i) {
+ writel(ddr4_phy_config.value[i],
+ &info->phy->phy[ddr4_phy_config.index[i]]);
+ }
+
+ writel(power_control, &info->regs->power_control);
+
+ ast2500_ddr_phy_init_process(info);
+
+ ret = ast2500_sdrammc_ddr4_calibrate_vref(info);
+ if (ret < 0) {
+ debug("Vref calibration failed!\n");
+ return ret;
+ }
+
+ writel((1 << SDRAM_REFRESH_CYCLES_SHIFT)
+ | SDRAM_REFRESH_ZQCS_EN | (0x2f << SDRAM_REFRESH_PERIOD_SHIFT),
+ &info->regs->refresh_timing);
+
+ setbits_le32(&info->regs->power_control,
+ SDRAM_PCR_AUTOPWRDN_EN | SDRAM_PCR_ODT_AUTO_ON);
+
+ ast2500_sdrammc_calc_size(info);
+
+ setbits_le32(&info->regs->config, SDRAM_CONF_CACHE_INIT_EN);
+ while (!(readl(&info->regs->config) & SDRAM_CONF_CACHE_INIT_DONE))
+ ;
+ setbits_le32(&info->regs->config, SDRAM_CONF_CACHE_EN);
+
+ writel(SDRAM_MISC_DDR4_TREFRESH, &info->regs->misc_control);
+
+ /* Enable all requests except video & display */
+ writel(SDRAM_REQ_USB20_EHCI1
+ | SDRAM_REQ_USB20_EHCI2
+ | SDRAM_REQ_CPU
+ | SDRAM_REQ_AHB2
+ | SDRAM_REQ_AHB
+ | SDRAM_REQ_MAC0
+ | SDRAM_REQ_MAC1
+ | SDRAM_REQ_PCIE
+ | SDRAM_REQ_XDMA
+ | SDRAM_REQ_ENCRYPTION
+ | SDRAM_REQ_VIDEO_FLAG
+ | SDRAM_REQ_VIDEO_LOW_PRI_WRITE
+ | SDRAM_REQ_2D_RW
+ | SDRAM_REQ_MEMCHECK, &info->regs->req_limit_mask);
+
+ return 0;
+}
+
+static void ast2500_sdrammc_unlock(struct dram_info *info)
+{
+ writel(SDRAM_UNLOCK_KEY, &info->regs->protection_key);
+ while (!readl(&info->regs->protection_key))
+ ;
+}
+
+static void ast2500_sdrammc_lock(struct dram_info *info)
+{
+ writel(~SDRAM_UNLOCK_KEY, &info->regs->protection_key);
+ while (readl(&info->regs->protection_key))
+ ;
+}
+
+static int ast2500_sdrammc_probe(struct udevice *dev)
+{
+ struct dram_info *priv = (struct dram_info *)dev_get_priv(dev);
+ struct ast2500_sdrammc_regs *regs = priv->regs;
+ int i;
+ int ret = clk_get_by_index(dev, 0, &priv->ddr_clk);
+
+ if (ret) {
+ debug("DDR:No CLK\n");
+ return ret;
+ }
+
+ priv->scu = ast_get_scu();
+ if (IS_ERR(priv->scu)) {
+ debug("%s(): can't get SCU\n", __func__);
+ return PTR_ERR(priv->scu);
+ }
+
+ clk_set_rate(&priv->ddr_clk, priv->clock_rate);
+ ret = ast_wdt_reset_masked(ast_get_wdt(0), WDT_RESET_SDRAM);
+ if (ret) {
+ debug("%s(): SDRAM reset failed\n", __func__);
+ return ret;
+ }
+
+ ast2500_sdrammc_unlock(priv);
+
+ writel(SDRAM_PCR_MREQI_DIS | SDRAM_PCR_RESETN_DIS,
+ ®s->power_control);
+ writel(SDRAM_VIDEO_UNLOCK_KEY, ®s->gm_protection_key);
+
+ /* Mask all requests except CPU and AHB during PHY init */
+ writel(~(SDRAM_REQ_CPU | SDRAM_REQ_AHB), ®s->req_limit_mask);
+
+ for (i = 0; i < ARRAY_SIZE(ddr_max_grant_params); ++i)
+ writel(ddr_max_grant_params[i], ®s->max_grant_len[i]);
+
+ setbits_le32(®s->intr_ctrl, SDRAM_ICR_RESET_ALL);
+
+ ast2500_sdrammc_init_phy(priv->phy);
+ if (readl(&priv->scu->hwstrap) & SCU_HWSTRAP_DDR4) {
+ ast2500_sdrammc_init_ddr4(priv);
+ } else {
+ debug("Unsupported DRAM3\n");
+ return -EINVAL;
+ }
+
+ clrbits_le32(®s->intr_ctrl, SDRAM_ICR_RESET_ALL);
+ ast2500_sdrammc_lock(priv);
+
+ return 0;
+}
+
+static int ast2500_sdrammc_ofdata_to_platdata(struct udevice *dev)
+{
+ struct dram_info *priv = dev_get_priv(dev);
+ struct regmap *map;
+ int ret;
+
+ ret = regmap_init_mem(dev, &map);
+ if (ret)
+ return ret;
+
+ priv->regs = regmap_get_range(map, 0);
+ priv->phy = regmap_get_range(map, 1);
+
+ priv->clock_rate = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+ "clock-frequency", 0);
+
+ if (!priv->clock_rate) {
+ debug("DDR Clock Rate not defined\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ast2500_sdrammc_get_info(struct udevice *dev, struct ram_info *info)
+{
+ struct dram_info *priv = dev_get_priv(dev);
+
+ *info = priv->info;
+
+ return 0;
+}
+
+static struct ram_ops ast2500_sdrammc_ops = {
+ .get_info = ast2500_sdrammc_get_info,
+};
+
+static const struct udevice_id ast2500_sdrammc_ids[] = {
+ { .compatible = "aspeed,ast2500-sdrammc" },
+ { }
+};
+
+U_BOOT_DRIVER(sdrammc_ast2500) = {
+ .name = "aspeed_ast2500_sdrammc",
+ .id = UCLASS_RAM,
+ .of_match = ast2500_sdrammc_ids,
+ .ops = &ast2500_sdrammc_ops,
+ .ofdata_to_platdata = ast2500_sdrammc_ofdata_to_platdata,
+ .probe = ast2500_sdrammc_probe,
+ .priv_auto_alloc_size = sizeof(struct dram_info),
+};
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index f55348e8f15f489d59499e141119adb2a2ffb10a..884c21c68b63c62bce73ee30adedc4b38785b0b7 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -17,3 +17,5 @@ obj-$(CONFIG_CLK_UNIPHIER) += uniphier/
obj-$(CONFIG_CLK_EXYNOS) += exynos/
obj-$(CONFIG_CLK_AT91) += at91/
obj-$(CONFIG_CLK_BOSTON) += clk_boston.o
+
+obj-$(CONFIG_ARCH_ASPEED) += aspeed/
diff --git a/drivers/clk/aspeed/Makefile b/drivers/clk/aspeed/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..65d1cd6e2959074c5ae852a95b22758367628ccc
--- /dev/null
+++ b/drivers/clk/aspeed/Makefile
@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2016 Google, Inc
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-$(CONFIG_ASPEED_AST2500) += clk_ast2500.o
diff --git a/drivers/clk/aspeed/clk_ast2500.c b/drivers/clk/aspeed/clk_ast2500.c
new file mode 100644
index 0000000000000000000000000000000000000000..af369cc4c8aa0f5dd9f849fe0d81e17aa09a1fc6
--- /dev/null
+++ b/drivers/clk/aspeed/clk_ast2500.c
@@ -0,0 +1,265 @@
+/*
+ * (C) Copyright 2016 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <asm/io.h>
+#include <asm/arch/scu_ast2500.h>
+#include <dm/lists.h>
+#include <dt-bindings/clock/ast2500-scu.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * For H-PLL and M-PLL the formula is
+ * (Output Frequency) = CLKIN * ((M + 1) / (N + 1)) / (P + 1)
+ * M - Numerator
+ * N - Denumerator
+ * P - Post Divider
+ * They have the same layout in their control register.
+ */
+
+/*
+ * Get the rate of the M-PLL clock from input clock frequency and
+ * the value of the M-PLL Parameter Register.
+ */
+static ulong ast2500_get_mpll_rate(ulong clkin, u32 mpll_reg)
+{
+ const ulong num = (mpll_reg >> SCU_MPLL_NUM_SHIFT) & SCU_MPLL_NUM_MASK;
+ const ulong denum = (mpll_reg >> SCU_MPLL_DENUM_SHIFT)
+ & SCU_MPLL_DENUM_MASK;
+ const ulong post_div = (mpll_reg >> SCU_MPLL_POST_SHIFT)
+ & SCU_MPLL_POST_MASK;
+
+ return (clkin * ((num + 1) / (denum + 1))) / post_div;
+}
+
+/*
+ * Get the rate of the H-PLL clock from input clock frequency and
+ * the value of the H-PLL Parameter Register.
+ */
+static ulong ast2500_get_hpll_rate(ulong clkin, u32 hpll_reg)
+{
+ const ulong num = (hpll_reg >> SCU_HPLL_NUM_SHIFT) & SCU_HPLL_NUM_MASK;
+ const ulong denum = (hpll_reg >> SCU_HPLL_DENUM_SHIFT)
+ & SCU_HPLL_DENUM_MASK;
+ const ulong post_div = (hpll_reg >> SCU_HPLL_POST_SHIFT)
+ & SCU_HPLL_POST_MASK;
+
+ return (clkin * ((num + 1) / (denum + 1))) / post_div;
+}
+
+static ulong ast2500_get_clkin(struct ast2500_scu *scu)
+{
+ return readl(&scu->hwstrap) & SCU_HWSTRAP_CLKIN_25MHZ
+ ? 25 * 1000 * 1000 : 24 * 1000 * 1000;
+}
+
+/**
+ * Get current rate or uart clock
+ *
+ * @scu SCU registers
+ * @uart_index UART index, 1-5
+ *
+ * @return current setting for uart clock rate
+ */
+static ulong ast2500_get_uart_clk_rate(struct ast2500_scu *scu, int uart_index)
+{
+ /*
+ * ast2500 datasheet is very confusing when it comes to UART clocks,
+ * especially when CLKIN = 25 MHz. The settings are in
+ * different registers and it is unclear how they interact.
+ *
+ * This has only been tested with default settings and CLKIN = 24 MHz.
+ */
+ ulong uart_clkin;
+
+ if (readl(&scu->misc_ctrl2) &
+ (1 << (uart_index - 1 + SCU_MISC2_UARTCLK_SHIFT)))
+ uart_clkin = 192 * 1000 * 1000;
+ else
+ uart_clkin = 24 * 1000 * 1000;
+
+ if (readl(&scu->misc_ctrl1) & SCU_MISC_UARTCLK_DIV13)
+ uart_clkin /= 13;
+
+ return uart_clkin;
+}
+
+static ulong ast2500_clk_get_rate(struct clk *clk)
+{
+ struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);
+ ulong clkin = ast2500_get_clkin(priv->scu);
+ ulong rate;
+
+ switch (clk->id) {
+ case PLL_HPLL:
+ case ARMCLK:
+ /*
+ * This ignores dynamic/static slowdown of ARMCLK and may
+ * be inaccurate.
+ */
+ rate = ast2500_get_hpll_rate(clkin,
+ readl(&priv->scu->h_pll_param));
+ break;
+ case MCLK_DDR:
+ rate = ast2500_get_mpll_rate(clkin,
+ readl(&priv->scu->m_pll_param));
+ break;
+ case PCLK_UART1:
+ rate = ast2500_get_uart_clk_rate(priv->scu, 1);
+ break;
+ case PCLK_UART2:
+ rate = ast2500_get_uart_clk_rate(priv->scu, 2);
+ break;
+ case PCLK_UART3:
+ rate = ast2500_get_uart_clk_rate(priv->scu, 3);
+ break;
+ case PCLK_UART4:
+ rate = ast2500_get_uart_clk_rate(priv->scu, 4);
+ break;
+ case PCLK_UART5:
+ rate = ast2500_get_uart_clk_rate(priv->scu, 5);
+ break;
+ default:
+ return -ENOENT;
+ }
+
+ return rate;
+}
+
+static void ast2500_scu_unlock(struct ast2500_scu *scu)
+{
+ writel(SCU_UNLOCK_VALUE, &scu->protection_key);
+ while (!readl(&scu->protection_key))
+ ;
+}
+
+static void ast2500_scu_lock(struct ast2500_scu *scu)
+{
+ writel(~SCU_UNLOCK_VALUE, &scu->protection_key);
+ while (readl(&scu->protection_key))
+ ;
+}
+
+static ulong ast2500_configure_ddr(struct ast2500_scu *scu, ulong rate)
+{
+ ulong clkin = ast2500_get_clkin(scu);
+ u32 mpll_reg;
+
+ /*
+ * There are not that many combinations of numerator, denumerator
+ * and post divider, so just brute force the best combination.
+ * However, to avoid overflow when multiplying, use kHz.
+ */
+ const ulong clkin_khz = clkin / 1000;
+ const ulong rate_khz = rate / 1000;
+ ulong best_num = 0;
+ ulong best_denum = 0;
+ ulong best_post = 0;
+ ulong delta = rate;
+ ulong num, denum, post;
+
+ for (denum = 0; denum <= SCU_MPLL_DENUM_MASK; ++denum) {
+ for (post = 0; post <= SCU_MPLL_POST_MASK; ++post) {
+ num = (rate_khz * (post + 1) / clkin_khz) * (denum + 1);
+ ulong new_rate_khz = (clkin_khz
+ * ((num + 1) / (denum + 1)))
+ / (post + 1);
+
+ /* Keep the rate below requested one. */
+ if (new_rate_khz > rate_khz)
+ continue;
+
+ if (new_rate_khz - rate_khz < delta) {
+ delta = new_rate_khz - rate_khz;
+
+ best_num = num;
+ best_denum = denum;
+ best_post = post;
+
+ if (delta == 0)
+ goto rate_calc_done;
+ }
+ }
+ }
+
+ rate_calc_done:
+ mpll_reg = readl(&scu->m_pll_param);
+ mpll_reg &= ~((SCU_MPLL_POST_MASK << SCU_MPLL_POST_SHIFT)
+ | (SCU_MPLL_NUM_MASK << SCU_MPLL_NUM_SHIFT)
+ | (SCU_MPLL_DENUM_MASK << SCU_MPLL_DENUM_SHIFT));
+ mpll_reg |= (best_post << SCU_MPLL_POST_SHIFT)
+ | (best_num << SCU_MPLL_NUM_SHIFT)
+ | (best_denum << SCU_MPLL_DENUM_SHIFT);
+
+ ast2500_scu_unlock(scu);
+ writel(mpll_reg, &scu->m_pll_param);
+ ast2500_scu_lock(scu);
+
+ return ast2500_get_mpll_rate(clkin, mpll_reg);
+}
+
+static ulong ast2500_clk_set_rate(struct clk *clk, ulong rate)
+{
+ struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);
+
+ ulong new_rate;
+ switch (clk->id) {
+ case PLL_MPLL:
+ case MCLK_DDR:
+ new_rate = ast2500_configure_ddr(priv->scu, rate);
+ break;
+ default:
+ return -ENOENT;
+ }
+
+ return new_rate;
+}
+
+struct clk_ops ast2500_clk_ops = {
+ .get_rate = ast2500_clk_get_rate,
+ .set_rate = ast2500_clk_set_rate,
+};
+
+static int ast2500_clk_probe(struct udevice *dev)
+{
+ struct ast2500_clk_priv *priv = dev_get_priv(dev);
+
+ priv->scu = dev_get_addr_ptr(dev);
+ if (IS_ERR(priv->scu))
+ return PTR_ERR(priv->scu);
+
+ return 0;
+}
+
+static int ast2500_clk_bind(struct udevice *dev)
+{
+ int ret;
+
+ /* The reset driver does not have a device node, so bind it here */
+ ret = device_bind_driver(gd->dm_root, "ast_sysreset", "reset", &dev);
+ if (ret)
+ debug("Warning: No reset driver: ret=%d\n", ret);
+
+ return 0;
+}
+
+static const struct udevice_id ast2500_clk_ids[] = {
+ { .compatible = "aspeed,ast2500-scu" },
+ { }
+};
+
+U_BOOT_DRIVER(aspeed_ast2500_scu) = {
+ .name = "aspeed_ast2500_scu",
+ .id = UCLASS_CLK,
+ .of_match = ast2500_clk_ids,
+ .priv_auto_alloc_size = sizeof(struct ast2500_clk_priv),
+ .ops = &ast2500_clk_ops,
+ .bind = ast2500_clk_bind,
+ .probe = ast2500_clk_probe,
+};
diff --git a/include/dt-bindings/clock/ast2500-scu.h b/include/dt-bindings/clock/ast2500-scu.h
new file mode 100644
index 0000000000000000000000000000000000000000..ca58b12943b081171bb5e5304efe11d3d00d5fb3
--- /dev/null
+++ b/include/dt-bindings/clock/ast2500-scu.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+/* Core Clocks */
+#define PLL_HPLL 1
+#define PLL_DPLL 2
+#define PLL_D2PLL 3
+#define PLL_MPLL 4
+#define ARMCLK 5
+
+
+/* Bus Clocks, derived from core clocks */
+#define BCLK_PCLK 101
+#define BCLK_LHCLK 102
+#define BCLK_MACCLK 103
+#define BCLK_SDCLK 104
+#define BCLK_ARMCLK 105
+
+#define MCLK_DDR 201
+
+/* Special clocks */
+#define PCLK_UART1 501
+#define PCLK_UART2 502
+#define PCLK_UART3 503
+#define PCLK_UART4 504
+#define PCLK_UART5 505