net: dsa: vsc73xx: add support for parallel mode

This patch add platform part of vsc73xx driver.
It allows to use chip connected to a parallel memory bus and work in
memory-mapped I/O mode. (aka PI bus in chip manual)

By default device is working in big endian mode.
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/Kconfig

@@ -116,4 +116,13 @@ config NET_DSA_VITESSE_VSC73XX_SPI
 	---help---
 	  This enables support for the Vitesse VSC7385, VSC7388, VSC7395
 	  and VSC7398 SparX integrated ethernet switches in SPI managed mode.
+
+config NET_DSA_VITESSE_VSC73XX_PLATFORM
+	tristate "Vitesse VSC7385/7388/7395/7398 Platform mode support"
+	depends on HAS_IOMEM
+	select NET_DSA_VITESSE_VSC73XX
+	---help---
+	  This enables support for the Vitesse VSC7385, VSC7388, VSC7395
+	  and VSC7398 SparX integrated ethernet switches, connected over
+	  a CPU-attached address bus and work in memory-mapped I/O mode.
 endmenu

drivers/net/dsa/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_NET_DSA_SMSC_LAN9303) += lan9303-core.o
 obj-$(CONFIG_NET_DSA_SMSC_LAN9303_I2C) += lan9303_i2c.o
 obj-$(CONFIG_NET_DSA_SMSC_LAN9303_MDIO) += lan9303_mdio.o
 obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX) += vitesse-vsc73xx-core.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX_PLATFORM) += vitesse-vsc73xx-platform.o
 obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX_SPI) += vitesse-vsc73xx-spi.o
 obj-y				+= b53/
 obj-y				+= microchip/

drivers/net/dsa/vitesse-vsc73xx-platform.c

+// SPDX-License-Identifier: GPL-2.0
+/* DSA driver for:
+ * Vitesse VSC7385 SparX-G5 5+1-port Integrated Gigabit Ethernet Switch
+ * Vitesse VSC7388 SparX-G8 8-port Integrated Gigabit Ethernet Switch
+ * Vitesse VSC7395 SparX-G5e 5+1-port Integrated Gigabit Ethernet Switch
+ * Vitesse VSC7398 SparX-G8e 8-port Integrated Gigabit Ethernet Switch
+ *
+ * This driver takes control of the switch chip connected over CPU-attached
+ * address bus and configures it to route packages around when connected to
+ * a CPU port.
+ *
+ * Copyright (C) 2019 Pawel Dembicki <paweldembicki@gmail.com>
+ * Based on vitesse-vsc-spi.c by:
+ * Copyright (C) 2018 Linus Wallej <linus.walleij@linaro.org>
+ * Includes portions of code from the firmware uploader by:
+ * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "vitesse-vsc73xx.h"
+
+#define VSC73XX_CMD_PLATFORM_BLOCK_SHIFT		14
+#define VSC73XX_CMD_PLATFORM_BLOCK_MASK			0x7
+#define VSC73XX_CMD_PLATFORM_SUBBLOCK_SHIFT		10
+#define VSC73XX_CMD_PLATFORM_SUBBLOCK_MASK		0xf
+#define VSC73XX_CMD_PLATFORM_REGISTER_SHIFT		2
+
+/**
+ * struct vsc73xx_platform - VSC73xx Platform state container
+ */
+struct vsc73xx_platform {
+	struct platform_device	*pdev;
+	void __iomem		*base_addr;
+	struct vsc73xx		vsc;
+};
+
+static const struct vsc73xx_ops vsc73xx_platform_ops;
+
+static u32 vsc73xx_make_addr(u8 block, u8 subblock, u8 reg)
+{
+	u32 ret;
+
+	ret = (block & VSC73XX_CMD_PLATFORM_BLOCK_MASK)
+	    << VSC73XX_CMD_PLATFORM_BLOCK_SHIFT;
+	ret |= (subblock & VSC73XX_CMD_PLATFORM_SUBBLOCK_MASK)
+	    << VSC73XX_CMD_PLATFORM_SUBBLOCK_SHIFT;
+	ret |= reg << VSC73XX_CMD_PLATFORM_REGISTER_SHIFT;
+
+	return ret;
+}
+
+static int vsc73xx_platform_read(struct vsc73xx *vsc, u8 block, u8 subblock,
+				 u8 reg, u32 *val)
+{
+	struct vsc73xx_platform *vsc_platform = vsc->priv;
+	u32 offset;
+
+	if (!vsc73xx_is_addr_valid(block, subblock))
+		return -EINVAL;
+
+	offset = vsc73xx_make_addr(block, subblock, reg);
+	/* By default vsc73xx running in big-endian mode.
+	 * (See "Register Addressing" section 5.5.3 in the VSC7385 manual.)
+	 */
+	*val = ioread32be(vsc_platform->base_addr + offset);
+
+	return 0;
+}
+
+static int vsc73xx_platform_write(struct vsc73xx *vsc, u8 block, u8 subblock,
+				  u8 reg, u32 val)
+{
+	struct vsc73xx_platform *vsc_platform = vsc->priv;
+	u32 offset;
+
+	if (!vsc73xx_is_addr_valid(block, subblock))
+		return -EINVAL;
+
+	offset = vsc73xx_make_addr(block, subblock, reg);
+	iowrite32be(val, vsc_platform->base_addr + offset);
+
+	return 0;
+}
+
+static int vsc73xx_platform_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct vsc73xx_platform *vsc_platform;
+	struct resource *res = NULL;
+	int ret;
+
+	vsc_platform = devm_kzalloc(dev, sizeof(*vsc_platform), GFP_KERNEL);
+	if (!vsc_platform)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, vsc_platform);
+	vsc_platform->pdev = pdev;
+	vsc_platform->vsc.dev = dev;
+	vsc_platform->vsc.priv = vsc_platform;
+	vsc_platform->vsc.ops = &vsc73xx_platform_ops;
+
+	/* obtain I/O memory space */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "cannot obtain I/O memory space\n");
+		ret = -ENXIO;
+		return ret;
+	}
+
+	vsc_platform->base_addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(vsc_platform->base_addr)) {
+		dev_err(&pdev->dev, "cannot request I/O memory space\n");
+		ret = -ENXIO;
+		return ret;
+	}
+
+	return vsc73xx_probe(&vsc_platform->vsc);
+}
+
+static int vsc73xx_platform_remove(struct platform_device *pdev)
+{
+	struct vsc73xx_platform *vsc_platform = platform_get_drvdata(pdev);
+
+	return vsc73xx_remove(&vsc_platform->vsc);
+}
+
+static const struct vsc73xx_ops vsc73xx_platform_ops = {
+	.read = vsc73xx_platform_read,
+	.write = vsc73xx_platform_write,
+};
+
+static const struct of_device_id vsc73xx_of_match[] = {
+	{
+		.compatible = "vitesse,vsc7385",
+	},
+	{
+		.compatible = "vitesse,vsc7388",
+	},
+	{
+		.compatible = "vitesse,vsc7395",
+	},
+	{
+		.compatible = "vitesse,vsc7398",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, vsc73xx_of_match);
+
+static struct platform_driver vsc73xx_platform_driver = {
+	.probe = vsc73xx_platform_probe,
+	.remove = vsc73xx_platform_remove,
+	.driver = {
+		.name = "vsc73xx-platform",
+		.of_match_table = vsc73xx_of_match,
+	},
+};
+module_platform_driver(vsc73xx_platform_driver);
+
+MODULE_AUTHOR("Pawel Dembicki <paweldembicki@gmail.com>");
+MODULE_DESCRIPTION("Vitesse VSC7385/7388/7395/7398 Platform driver");
+MODULE_LICENSE("GPL v2");