feat(plat/mdeiatek/mt8195): add display port control in SiP service

MTK display port mute/unmute control registers need to be
set in secure world.

Change-Id: Iec73650e937bd20e25c18fa28d55ae29e68b10d3
diff --git a/plat/mediatek/mt8195/drivers/dp/mt_dp.c b/plat/mediatek/mt8195/drivers/dp/mt_dp.c
new file mode 100644
index 0000000..7ab2194
--- /dev/null
+++ b/plat/mediatek/mt8195/drivers/dp/mt_dp.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020, MediaTek Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include <common/debug.h>
+#include <lib/mmio.h>
+#include <mt_dp.h>
+#include <mtk_sip_svc.h>
+#include <platform_def.h>
+
+static uint32_t dp_write_sec_reg(uint32_t is_edp, uint32_t offset,
+				uint32_t value, uint32_t mask)
+{
+	uint32_t reg = (is_edp != 0U) ? eDP_SEC_BASE : DP_SEC_BASE;
+
+	mmio_clrsetbits_32(reg + offset, mask, value);
+
+	return mmio_read_32(reg + offset);
+}
+
+int32_t dp_secure_handler(uint64_t cmd, uint64_t para, uint32_t *val)
+{
+	int32_t ret = 0L;
+	uint32_t is_edp = 0UL;
+	uint32_t regval = 0UL;
+	uint32_t regmsk = 0UL;
+	uint32_t fldmask = 0UL;
+
+	if ((cmd > DP_ATF_CMD_COUNT) || (val == NULL)) {
+		INFO("dp_secure_handler error cmd 0x%llx\n", cmd);
+		return MTK_SIP_E_INVALID_PARAM;
+	}
+
+	switch (cmd) {
+	case DP_ATF_DP_VIDEO_UNMUTE:
+		INFO("[%s] DP_ATF_DP_VIDEO_UNMUTE\n", __func__);
+		is_edp = DP_ATF_TYPE_DP;
+		ret = MTK_SIP_E_SUCCESS;
+		break;
+	case DP_ATF_EDP_VIDEO_UNMUTE:
+		INFO("[%s] DP_ATF_EDP_VIDEO_UNMUTE\n", __func__);
+		is_edp = DP_ATF_TYPE_EDP;
+		ret = MTK_SIP_E_SUCCESS;
+		break;
+	default:
+		ret = MTK_SIP_E_INVALID_PARAM;
+		break;
+	}
+
+	if (ret == MTK_SIP_E_SUCCESS) {
+		regmsk = (VIDEO_MUTE_SEL_SECURE_FLDMASK |
+				VIDEO_MUTE_SW_SECURE_FLDMASK);
+		if (para > 0U) {
+			fldmask = VIDEO_MUTE_SW_SECURE_FLDMASK;
+		} else {
+			fldmask = 0;
+		}
+
+		regval = (VIDEO_MUTE_SEL_SECURE_FLDMASK | fldmask);
+		*val = dp_write_sec_reg(is_edp, DP_TX_SECURE_REG11,
+					regval, regmsk);
+	}
+
+	return ret;
+}