net: stmmac: socfpga: add additional ocp reset line for Stratix10

The Stratix10 platform has an additional reset line, OCP(Open Core Protocol),
that also needs to get deasserted for the stmmac ethernet controller to work.
Thus we need to update the Kconfig to include ARCH_STRATIX10 in order to build
dwmac-socfpga.

Also, remove the redundant check for the reset controller pointer. The
reset driver already checks for the pointer and returns 0 if the pointer
is NULL.
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -111,7 +111,7 @@ config DWMAC_ROCKCHIP
 config DWMAC_SOCFPGA
 	tristate "SOCFPGA dwmac support"
 	default ARCH_SOCFPGA
-	depends on OF && (ARCH_SOCFPGA || COMPILE_TEST)
+	depends on OF && (ARCH_SOCFPGA || ARCH_STRATIX10 || COMPILE_TEST)
 	select MFD_SYSCON
 	help
 	  Support for ethernet controller on Altera SOCFPGA

drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c

@@ -55,6 +55,7 @@ struct socfpga_dwmac {
 	struct	device *dev;
 	struct regmap *sys_mgr_base_addr;
 	struct reset_control *stmmac_rst;
+	struct reset_control *stmmac_ocp_rst;
 	void __iomem *splitter_base;
 	bool f2h_ptp_ref_clk;
 	struct tse_pcs pcs;
@@ -262,7 +263,7 @@ static int socfpga_dwmac_set_phy_mode(struct socfpga_dwmac *dwmac)
 		val = SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII;
 
 	/* Assert reset to the enet controller before changing the phy mode */
-	if (dwmac->stmmac_rst)
+	reset_control_assert(dwmac->stmmac_ocp_rst);
 	reset_control_assert(dwmac->stmmac_rst);
 
 	regmap_read(sys_mgr_base_addr, reg_offset, &ctrl);
@@ -288,7 +289,7 @@ static int socfpga_dwmac_set_phy_mode(struct socfpga_dwmac *dwmac)
 	/* Deassert reset for the phy configuration to be sampled by
 	 * the enet controller, and operation to start in requested mode
 	 */
-	if (dwmac->stmmac_rst)
+	reset_control_deassert(dwmac->stmmac_ocp_rst);
 	reset_control_deassert(dwmac->stmmac_rst);
 	if (phymode == PHY_INTERFACE_MODE_SGMII) {
 		if (tse_pcs_init(dwmac->pcs.tse_pcs_base, &dwmac->pcs) != 0) {
@@ -324,6 +325,15 @@ static int socfpga_dwmac_probe(struct platform_device *pdev)
 		goto err_remove_config_dt;
 	}
 
+	dwmac->stmmac_ocp_rst = devm_reset_control_get_optional(dev, "stmmaceth-ocp");
+	if (IS_ERR(dwmac->stmmac_ocp_rst)) {
+		ret = PTR_ERR(dwmac->stmmac_ocp_rst);
+		dev_err(dev, "error getting reset control of ocp %d\n", ret);
+		goto err_remove_config_dt;
+	}
+
+	reset_control_deassert(dwmac->stmmac_ocp_rst);
+
 	ret = socfpga_dwmac_parse_data(dwmac, dev);
 	if (ret) {
 		dev_err(dev, "Unable to parse OF data\n");