net: stmmac: add Amlogic Meson glue layer

The Ethernet controller available in Meson6 and Meson8 SoCs is a
Synopsys DesignWare MAC IP core, already supported by the stmmac
driver.

This glue layer implements some platform-specific settings needed by
the Amlogic variant.
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -26,6 +26,16 @@ config STMMAC_PLATFORM
 
 	  If unsure, say N.
 
+config DWMAC_MESON
+	bool "Amlogic Meson dwmac support"
+	depends on STMMAC_PLATFORM && ARCH_MESON
+	help
+	  Support for Ethernet controller on Amlogic Meson SoCs.
+
+	  This selects the Amlogic Meson SoC glue layer support for
+	  the stmmac device driver. This driver is used for Meson6 and
+	  Meson8 SoCs.
+
 config DWMAC_SOCFPGA
 	bool "SOCFPGA dwmac support"
 	depends on STMMAC_PLATFORM && MFD_SYSCON && (ARCH_SOCFPGA || COMPILE_TEST)

drivers/net/ethernet/stmicro/stmmac/Makefile

 obj-$(CONFIG_STMMAC_ETH) += stmmac.o
 stmmac-$(CONFIG_STMMAC_PLATFORM) += stmmac_platform.o
 stmmac-$(CONFIG_STMMAC_PCI) += stmmac_pci.o
+stmmac-$(CONFIG_DWMAC_MESON) += dwmac-meson.o
 stmmac-$(CONFIG_DWMAC_SUNXI) += dwmac-sunxi.o
 stmmac-$(CONFIG_DWMAC_STI) += dwmac-sti.o
 stmmac-$(CONFIG_DWMAC_SOCFPGA) += dwmac-socfpga.o

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

+/*
+ * Amlogic Meson DWMAC glue layer
+ *
+ * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/device.h>
+#include <linux/ethtool.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/stmmac.h>
+
+#define ETHMAC_SPEED_100	BIT(1)
+
+struct meson_dwmac {
+	struct device	*dev;
+	void __iomem	*reg;
+};
+
+static void meson6_dwmac_fix_mac_speed(void *priv, unsigned int speed)
+{
+	struct meson_dwmac *dwmac = priv;
+	unsigned int val;
+
+	val = readl(dwmac->reg);
+
+	switch (speed) {
+	case SPEED_10:
+		val &= ~ETHMAC_SPEED_100;
+		break;
+	case SPEED_100:
+		val |= ETHMAC_SPEED_100;
+		break;
+	}
+
+	writel(val, dwmac->reg);
+}
+
+static void *meson6_dwmac_setup(struct platform_device *pdev)
+{
+	struct meson_dwmac *dwmac;
+	struct resource *res;
+
+	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
+	if (!dwmac)
+		return ERR_PTR(-ENOMEM);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	dwmac->reg = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dwmac->reg))
+		return dwmac->reg;
+
+	return dwmac;
+}
+
+const struct stmmac_of_data meson6_dwmac_data = {
+	.setup		= meson6_dwmac_setup,
+	.fix_mac_speed	= meson6_dwmac_fix_mac_speed,
+};

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -137,6 +137,9 @@ void stmmac_disable_eee_mode(struct stmmac_priv *priv);
 bool stmmac_eee_init(struct stmmac_priv *priv);
 
 #ifdef CONFIG_STMMAC_PLATFORM
+#ifdef CONFIG_DWMAC_MESON
+extern const struct stmmac_of_data meson6_dwmac_data;
+#endif
 #ifdef CONFIG_DWMAC_SUNXI
 extern const struct stmmac_of_data sun7i_gmac_data;
 #endif

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c

@@ -30,6 +30,9 @@
 #include "stmmac.h"
 
 static const struct of_device_id stmmac_dt_ids[] = {
+#ifdef CONFIG_DWMAC_MESON
+	{ .compatible = "amlogic,meson6-dwmac", .data = &meson6_dwmac_data},
+#endif
 #ifdef CONFIG_DWMAC_SUNXI
 	{ .compatible = "allwinner,sun7i-a20-gmac", .data = &sun7i_gmac_data},
 #endif