net: fec: add stop mode support for imx8 platform

The current driver support stop mode by calling machine api.
The patch add dts support to set GPR register for stop request.

imx8mq enter stop/exit stop mode by setting GPR bit, which can
be accessed by A core.
imx8qm enter stop/exit stop mode by calling IMX_SC ipc APIs that
communicate with M core ipc service, and the M core set the related
GPR bit at last.
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec.h

@@ -18,6 +18,8 @@
 #include <linux/net_tstamp.h>
 #include <linux/ptp_clock_kernel.h>
 #include <linux/timecounter.h>
+#include <dt-bindings/firmware/imx/rsrc.h>
+#include <linux/firmware/imx/sci.h>
 
 #if defined(CONFIG_M523x) || defined(CONFIG_M527x) || defined(CONFIG_M528x) || \
     defined(CONFIG_M520x) || defined(CONFIG_M532x) || defined(CONFIG_ARM) || \
@@ -641,6 +643,8 @@ struct fec_enet_private {
 		u8 at_inc_corr;
 	} ptp_saved_state;
 
+	struct imx_sc_ipc *ipc_handle;
+
 	u64 ethtool_stats[];
 };
 

drivers/net/ethernet/freescale/fec_main.c

@@ -1181,6 +1181,34 @@ fec_restart(struct net_device *ndev)
 
 }
 
+static int fec_enet_ipc_handle_init(struct fec_enet_private *fep)
+{
+	if (!(of_machine_is_compatible("fsl,imx8qm") ||
+	      of_machine_is_compatible("fsl,imx8qxp") ||
+	      of_machine_is_compatible("fsl,imx8dxl")))
+		return 0;
+
+	return imx_scu_get_handle(&fep->ipc_handle);
+}
+
+static void fec_enet_ipg_stop_set(struct fec_enet_private *fep, bool enabled)
+{
+	struct device_node *np = fep->pdev->dev.of_node;
+	u32 rsrc_id, val;
+	int idx;
+
+	if (!np || !fep->ipc_handle)
+		return;
+
+	idx = of_alias_get_id(np, "ethernet");
+	if (idx < 0)
+		idx = 0;
+	rsrc_id = idx ? IMX_SC_R_ENET_1 : IMX_SC_R_ENET_0;
+
+	val = enabled ? 1 : 0;
+	imx_sc_misc_set_control(fep->ipc_handle, rsrc_id, IMX_SC_C_IPG_STOP, val);
+}
+
 static void fec_enet_stop_mode(struct fec_enet_private *fep, bool enabled)
 {
 	struct fec_platform_data *pdata = fep->pdev->dev.platform_data;
@@ -1196,6 +1224,8 @@ static void fec_enet_stop_mode(struct fec_enet_private *fep, bool enabled)
 					   BIT(stop_gpr->bit), 0);
 	} else if (pdata && pdata->sleep_mode_enable) {
 		pdata->sleep_mode_enable(enabled);
+	} else {
+		fec_enet_ipg_stop_set(fep, enabled);
 	}
 }
 
@@ -3851,6 +3881,10 @@ fec_probe(struct platform_device *pdev)
 	    !of_property_read_bool(np, "fsl,err006687-workaround-present"))
 		fep->quirks |= FEC_QUIRK_ERR006687;
 
+	ret = fec_enet_ipc_handle_init(fep);
+	if (ret)
+		goto failed_ipc_init;
+
 	if (of_get_property(np, "fsl,magic-packet", NULL))
 		fep->wol_flag |= FEC_WOL_HAS_MAGIC_PACKET;
 
@@ -4048,6 +4082,7 @@ fec_probe(struct platform_device *pdev)
 		of_phy_deregister_fixed_link(np);
 	of_node_put(phy_node);
 failed_stop_mode:
+failed_ipc_init:
 failed_phy:
 	dev_id--;
 failed_ioremap: