[U-Boot] [PATCH v2 2/6] drivers: net: add a DSA sandbox driver

[Alex Marginean <alexandru.marginean@nxp.com>]

The DSA sandbox driver is used for DSA unit testing.  It implements a
simple 4 port switch that uses a very simple tag to identify the ports.
The DSA driver comes paired with an Ethernet driver that loops packets
back and can selectively filter traffic on DSA switch ports.

Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
---
 drivers/net/Kconfig       |   8 ++
 drivers/net/Makefile      |   1 +
 drivers/net/dsa_sandbox.c | 272 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 281 insertions(+)
 create mode 100644 drivers/net/dsa_sandbox.c

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index a4157cb122..ac420cb474 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -70,6 +70,14 @@ config MDIO_MUX_SANDBOX
 
 	  This driver is used for testing in test/dm/mdio.c
 
+config DSA_SANDBOX
+	depends on DM_DSA && SANDBOX
+	default y
+	bool "Sandbox: Mocked DSA driver"
+	help
+	  This driver implements a dummy switch and a dummy Ethernet device used
+	  to test DSA class code.
+
 menuconfig NETDEVICES
 	bool "Network device support"
 	depends on NET
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 30991834ec..8be49f6335 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -82,3 +82,4 @@ obj-y += mscc_eswitch/
 obj-$(CONFIG_HIGMACV300_ETH) += higmacv300.o
 obj-$(CONFIG_MDIO_SANDBOX) += mdio_sandbox.o
 obj-$(CONFIG_FSL_ENETC) += fsl_enetc.o fsl_enetc_mdio.o
+obj-$(CONFIG_DSA_SANDBOX) += dsa_sandbox.o
diff --git a/drivers/net/dsa_sandbox.c b/drivers/net/dsa_sandbox.c
new file mode 100644
index 0000000000..07230eb033
--- /dev/null
+++ b/drivers/net/dsa_sandbox.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019 NXP
+ */
+
+#include <dsa.h>
+
+#define DSA_SANDBOX_MAGIC	0x00415344
+#define DSA_SANDBOX_TAG_LEN	sizeof(struct dsa_sandbox_tag)
+/*
+ * This global flag is used to enable DSA just for DSA test so it doesn't affect
+ * the existing eth unit test.
+ */
+int dsa_sandbox_port_mask;
+
+struct dsa_sandbox_priv {
+	int enabled;
+	int port_enabled;
+};
+
+struct dsa_sandbox_tag {
+	u32 magic;
+	u32 port;
+};
+
+static int dsa_sandbox_port_enable(struct udevice *dev, int port,
+				   struct phy_device *phy)
+{
+	struct dsa_sandbox_priv *priv = dev->priv;
+
+	if (!priv->enabled)
+		return -EFAULT;
+
+	priv->port_enabled |= BIT(port);
+
+	return 0;
+}
+
+static void dsa_sandbox_port_disable(struct udevice *dev, int port,
+				     struct phy_device *phy)
+{
+	struct dsa_sandbox_priv *priv = dev->priv;
+
+	if (!priv->enabled)
+		return;
+
+	priv->port_enabled &= ~BIT(port);
+}
+
+static int dsa_sandbox_xmit(struct udevice *dev, int port, void *packet,
+			    int length)
+{
+	struct dsa_sandbox_priv *priv = dev->priv;
+	struct dsa_sandbox_tag *tag = packet;
+
+	if (!priv->enabled)
+		return -EFAULT;
+
+	if (!(priv->port_enabled & BIT(port)))
+		return -EFAULT;
+
+	tag->magic = DSA_SANDBOX_MAGIC;
+	tag->port = port;
+
+	return 0;
+}
+
+static int dsa_sandbox_rcv(struct udevice *dev, int *port, void *packet,
+			   int length)
+{
+	struct dsa_sandbox_priv *priv = dev->priv;
+	struct dsa_sandbox_tag *tag = packet;
+
+	if (!priv->enabled)
+		return -EFAULT;
+
+	if (tag->magic != DSA_SANDBOX_MAGIC)
+		return -EFAULT;
+
+	*port = tag->port;
+	if (!(priv->port_enabled & BIT(*port)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static const struct dsa_ops dsa_sandbox_ops = {
+	.port_enable = dsa_sandbox_port_enable,
+	.port_disable = dsa_sandbox_port_disable,
+	.xmit = dsa_sandbox_xmit,
+	.rcv = dsa_sandbox_rcv,
+};
+
+static int dsa_sandbox_bind(struct udevice *dev)
+{
+	struct dsa_perdev_platdata *pdata = dev->platdata;
+
+	/* must be at least 4 to match sandbox test DT */
+	pdata->num_ports = 4;
+	pdata->headroom = DSA_SANDBOX_TAG_LEN;
+
+	return 0;
+}
+
+static int dsa_sandbox_probe(struct udevice *dev)
+{
+	struct dsa_sandbox_priv *priv = dev_get_priv(dev);
+
+	/*
+	 * return error if DSA is not being tested so we don't break existing
+	 * eth test.
+	 */
+	if (!dsa_sandbox_port_mask)
+		return -EINVAL;
+
+	priv->enabled = 1;
+
+	return 0;
+}
+
+static int dsa_sandbox_remove(struct udevice *dev)
+{
+	struct dsa_sandbox_priv *priv = dev_get_priv(dev);
+
+	priv->enabled = 0;
+
+	return 0;
+}
+
+static const struct udevice_id dsa_sandbox_ids[] = {
+	{ .compatible = "sandbox,dsa" },
+	{ }
+};
+
+U_BOOT_DRIVER(dsa_sandbox) = {
+	.name		= "dsa_sandbox",
+	.id		= UCLASS_DSA,
+	.of_match	= dsa_sandbox_ids,
+	.bind		= dsa_sandbox_bind,
+	.probe		= dsa_sandbox_probe,
+	.remove		= dsa_sandbox_remove,
+	.ops		= &dsa_sandbox_ops,
+	.priv_auto_alloc_size = sizeof(struct dsa_sandbox_priv),
+	.platdata_auto_alloc_size = sizeof(struct dsa_perdev_platdata),
+};
+
+struct dsa_sandbox_eth_priv {
+	int enabled;
+	int started;
+	int packet_length;
+	uchar packet[DSA_MAX_FRAME_SIZE];
+};
+
+static int dsa_eth_sandbox_start(struct udevice *dev)
+{
+	struct dsa_sandbox_eth_priv *priv = dev->priv;
+
+	if (!priv->enabled)
+		return -EFAULT;
+
+	priv->started = 1;
+
+	return 0;
+}
+
+static void dsa_eth_sandbox_stop(struct udevice *dev)
+{
+	struct dsa_sandbox_eth_priv *priv = dev->priv;
+
+	if (!priv->enabled)
+		return;
+
+	priv->started = 0;
+}
+
+static int dsa_eth_sandbox_send(struct udevice *dev, void *packet, int length)
+{
+	struct dsa_sandbox_eth_priv *priv = dev->priv;
+	struct dsa_sandbox_tag *tag = packet;
+
+	if (!priv->enabled || !priv->started)
+		return -EFAULT;
+
+	memcpy(priv->packet, packet, length);
+	priv->packet_length = length;
+
+	/*
+	 * for DSA test frames we only respond if the associated port is enabled
+	 * in the dsa test port mask
+	 */
+
+	if (tag->magic == DSA_SANDBOX_MAGIC) {
+		int port = tag->port;
+
+		if (!(dsa_sandbox_port_mask & BIT(port)))
+			/* drop the frame, port is not enabled */
+			priv->packet_length = 0;
+	}
+
+	return 0;
+}
+
+static int dsa_eth_sandbox_recv(struct udevice *dev, int flags, uchar **packetp)
+{
+	struct dsa_sandbox_eth_priv *priv = dev->priv;
+	int length = priv->packet_length;
+
+	if (!priv->enabled || !priv->started)
+		return -EFAULT;
+
+	if (!length) {
+		/* no frames pending, force a time-out */
+		timer_test_add_offset(100);
+		return -EAGAIN;
+	}
+
+	*packetp = priv->packet;
+	priv->packet_length = 0;
+
+	return length;
+}
+
+static const struct eth_ops dsa_eth_sandbox_ops = {
+	.start	= dsa_eth_sandbox_start,
+	.send	= dsa_eth_sandbox_send,
+	.recv	= dsa_eth_sandbox_recv,
+	.stop	= dsa_eth_sandbox_stop,
+};
+
+static int dsa_eth_sandbox_bind(struct udevice *dev)
+{
+	return 0;
+}
+
+static int dsa_eth_sandbox_probe(struct udevice *dev)
+{
+	struct dsa_sandbox_eth_priv *priv = dev->priv;
+
+	priv->enabled = 1;
+
+	/*
+	 * return error if DSA is not being tested do we don't break existing
+	 * eth test.
+	 */
+	return dsa_sandbox_port_mask ? 0 : -EINVAL;
+}
+
+static int dsa_eth_sandbox_remove(struct udevice *dev)
+{
+	struct dsa_sandbox_eth_priv *priv = dev->priv;
+
+	priv->enabled = 0;
+
+	return 0;
+}
+
+static const struct udevice_id dsa_eth_sandbox_ids[] = {
+	{ .compatible = "sandbox,dsa-eth" },
+	{ }
+};
+
+U_BOOT_DRIVER(dsa_eth_sandbox) = {
+	.name		= "dsa_eth_sandbox",
+	.id		= UCLASS_ETH,
+	.of_match	= dsa_eth_sandbox_ids,
+	.bind		= dsa_eth_sandbox_bind,
+	.probe		= dsa_eth_sandbox_probe,
+	.remove		= dsa_eth_sandbox_remove,
+	.ops		= &dsa_eth_sandbox_ops,
+	.platdata_auto_alloc_size = sizeof(struct eth_pdata),
+	.priv_auto_alloc_size = sizeof(struct dsa_sandbox_eth_priv),
+};
-- 
2.17.1