plat: imx8mm: keep the necessary clock enabled for rdc reload

if NOC power down is enabled in DSM mode, when system resume
back, RDC need to reload the memory regions config into the
MRCs, so PCIE, DDR, GPU bus related clock must on to make
sure RDC MRCs can be successfully reloaded.
Signed-off-by: Jacky Bai <ping.bai@nxp.com>

plat/imx/imx8mm/gpc.c

@@ -587,6 +587,8 @@ static void imx8mm_tz380_init(void)
 	tzc380_configure_region(0, 0x00000000, TZC_ATTR_REGION_SIZE(TZC_REGION_SIZE_4G) | TZC_ATTR_REGION_EN_MASK | TZC_ATTR_SP_ALL);
 }
 
+#define CCGR(x)		(0x4000 + (x) * 16)
+
 void noc_wrapper_pre_suspend(unsigned int proc_num)
 {
 	uint32_t val;
@@ -603,9 +605,19 @@ void noc_wrapper_pre_suspend(unsigned int proc_num)
 		mmio_write_32(IMX_GPC_BASE + MST_CPU_MAPPING, val);
 
 		/* noc can only be power down when all the pu domain is off */
-		if (!pu_domain_status)
+		if (!pu_domain_status) {
 			/* enable noc power down */
 			imx_noc_slot_config(true);
+
+			/*
+			 * below clocks must be enabled to make sure RDC MRCs
+			 * can be successfully reloaded.
+			 */
+			mmio_setbits_32(IMX_CCM_BASE + 0xa300, (0x1 << 28));
+			mmio_write_32(IMX_CCM_BASE + CCGR(5), 0x3);
+			mmio_write_32(IMX_CCM_BASE + CCGR(37), 0x3);
+			mmio_write_32(IMX_CCM_BASE + CCGR(87), 0x3);
+		}
 	}
 	/*
 	 * gic redistributor context save must be called when