remoteproc: imx_rproc: correct firmware reload

ENABLE_M4 should be set to 1 when loading code to TCM, otherwise
you will not able to replace the firmware after you stop m4.

Besides ENABLE_M4, we still need set SW_M4C_RST, because this bit
will be automatically set with SW_M4C_NON_SCLR_RST set.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210602064206.27004-1-peng.fan@oss.nxp.com

Author: MrVan

drivers/remoteproc/imx_rproc.c

@@ -34,7 +34,8 @@
 
 #define IMX7D_M4_START			(IMX7D_ENABLE_M4 | IMX7D_SW_M4P_RST \
 					 | IMX7D_SW_M4C_RST)
-#define IMX7D_M4_STOP			IMX7D_SW_M4C_NON_SCLR_RST
+#define IMX7D_M4_STOP			(IMX7D_ENABLE_M4 | IMX7D_SW_M4C_RST | \
+					 IMX7D_SW_M4C_NON_SCLR_RST)
 
 /* Address: 0x020D8000 */
 #define IMX6SX_SRC_SCR			0x00
@@ -45,7 +46,8 @@
 
 #define IMX6SX_M4_START			(IMX6SX_ENABLE_M4 | IMX6SX_SW_M4P_RST \
 					 | IMX6SX_SW_M4C_RST)
-#define IMX6SX_M4_STOP			IMX6SX_SW_M4C_NON_SCLR_RST
+#define IMX6SX_M4_STOP			(IMX6SX_ENABLE_M4 | IMX6SX_SW_M4C_RST | \
+					 IMX6SX_SW_M4C_NON_SCLR_RST)
 #define IMX6SX_M4_RST_MASK		(IMX6SX_ENABLE_M4 | IMX6SX_SW_M4P_RST \
 					 | IMX6SX_SW_M4C_NON_SCLR_RST \
 					 | IMX6SX_SW_M4C_RST)
@@ -684,7 +686,7 @@ static int imx_rproc_detect_mode(struct imx_rproc *priv)
 		return ret;
 	}
 
-	if (!(val & dcfg->src_stop))
+	if ((val & dcfg->src_mask) != dcfg->src_stop)
 		priv->rproc->state = RPROC_DETACHED;
 
 	return 0;