feat(mt8188): add DCM driver

DCM means dynamic clock management, and it can dynamically
slow down or gate clocks during CPU or bus idle.

1. Add MCUSYS related DCM drivers.
2. Enable MCUSYS related DCM by default.

Change-Id: I131354d72bbc190af504e9639bcc85a720e2bb17
diff --git a/plat/mediatek/drivers/dcm/mtk_dcm.c b/plat/mediatek/drivers/dcm/mtk_dcm.c
new file mode 100644
index 0000000..ca79a20
--- /dev/null
+++ b/plat/mediatek/drivers/dcm/mtk_dcm.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2022, MediaTek Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <common/debug.h>
+#include <lib/mmio.h>
+#include <lib/mtk_init/mtk_init.h>
+#include <mtk_dcm.h>
+#include <mtk_dcm_utils.h>
+
+static void dcm_armcore(bool mode)
+{
+	dcm_mp_cpusys_top_bus_pll_div_dcm(mode);
+	dcm_mp_cpusys_top_cpu_pll_div_0_dcm(mode);
+	dcm_mp_cpusys_top_cpu_pll_div_1_dcm(mode);
+}
+
+static void dcm_mcusys(bool on)
+{
+	dcm_mp_cpusys_top_adb_dcm(on);
+	dcm_mp_cpusys_top_apb_dcm(on);
+	dcm_mp_cpusys_top_cpubiu_dcm(on);
+	dcm_mp_cpusys_top_misc_dcm(on);
+	dcm_mp_cpusys_top_mp0_qdcm(on);
+
+	/* CPCCFG_REG */
+	dcm_cpccfg_reg_emi_wfifo(on);
+	dcm_mp_cpusys_top_last_cor_idle_dcm(on);
+}
+
+static void dcm_stall(bool on)
+{
+	dcm_mp_cpusys_top_core_stall_dcm(on);
+	dcm_mp_cpusys_top_fcm_stall_dcm(on);
+}
+
+static bool check_dcm_state(void)
+{
+	bool ret = true;
+
+	ret &= dcm_mp_cpusys_top_bus_pll_div_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_cpu_pll_div_0_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_cpu_pll_div_1_dcm_is_on();
+
+	ret &= dcm_mp_cpusys_top_adb_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_apb_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_cpubiu_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_misc_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_mp0_qdcm_is_on();
+	ret &= dcm_cpccfg_reg_emi_wfifo_is_on();
+	ret &= dcm_mp_cpusys_top_last_cor_idle_dcm_is_on();
+
+	ret &= dcm_mp_cpusys_top_core_stall_dcm_is_on();
+	ret &= dcm_mp_cpusys_top_fcm_stall_dcm_is_on();
+
+	return ret;
+}
+
+bool dcm_check_state(uintptr_t addr, unsigned int mask, unsigned int compare)
+{
+	return ((mmio_read_32(addr) & mask) == compare);
+}
+
+int dcm_set_init(void)
+{
+	int ret;
+
+	dcm_armcore(true);
+	dcm_mcusys(true);
+	dcm_stall(true);
+
+	if (check_dcm_state() == false) {
+		ERROR("Failed to set default dcm on!!\n");
+		ret = -1;
+	} else {
+		INFO("%s, dcm pass\n", __func__);
+		ret = 0;
+	}
+
+	return ret;
+}
+MTK_PLAT_SETUP_0_INIT(dcm_set_init);