[RFC v4 net-next 16/17] net: dsa: ocelot: add external ocelot switch control

[Colin Foster <colin.foster@in-advantage.com>]

Add control of an external VSC7512 chip.

Currently the four copper phy ports are fully functional. Communication to
external phys is also functional, but the SGMII / QSGMII interfaces are
currently non-functional.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
---

v4
    * Add forward-compatibility for device trees that have ports 4-7
      defined by saying they are OCELOT_PORT_MODE_NONE
    * Utilize new "resource_names" instead of "*_io_res". Many thanks
      to Vladimir for making this possible.
      - Also remove ocelot_ext_regmap_init() function
    * Remove dev_set_drvdata(dev, NULL) from remove() to match other
      drivers

v3
    * Remove additional entry in vsc7512_port_modes array
    * Add MFD_OCELOT namespace import, which is needed for
      vsc7512_*_io_res

v2
    * Add MAINTAINERS update
    * Remove phrase "by way of the ocelot-mfd interface" from the commit
      message
    * Move MFD resource addition to a separate patch
    * Update Kconfig help
    * Remove "ocelot_ext_reset()" - it is now shared with ocelot_lib
    * Remove unnecessary includes
    * Remove "_EXT" from OCELOT_EXT_PORT_MODE_SERDES
    * Remove _ext from the compatible string
    * Remove no-longer-necessary GCB register definitions

v1 from previous RFC:
    * Remove unnecessary byteorder and kconfig header includes.
    * Create OCELOT_EXT_PORT_MODE_SERDES macro to match vsc9959.
    * Utilize readx_poll_timeout for SYS_RESET_CFG_MEM_INIT.
    * *_io_res struct arrays have been moved to the MFD files.
    * Changes to utilize phylink_generic_validate() have been squashed.
    * dev_err_probe() is used in the probe function.
    * Make ocelot_ext_switch_of_match static.
    * Relocate ocelot_ext_ops structure to be next to vsc7512_info, to
      match what was done in other felix drivers.
    * Utilize dev_get_regmap() instead of the obsolete
      ocelot_init_regmap_from_resource() routine.

---
 MAINTAINERS                         |   1 +
 drivers/net/dsa/ocelot/Kconfig      |  19 +++
 drivers/net/dsa/ocelot/Makefile     |   5 +
 drivers/net/dsa/ocelot/ocelot_ext.c | 178 ++++++++++++++++++++++++++++
 4 files changed, 203 insertions(+)
 create mode 100644 drivers/net/dsa/ocelot/ocelot_ext.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 9ca84cb5ab4a..15593f0dd128 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14751,6 +14751,7 @@ M:	Colin Foster <colin.foster@in-advantage.com>
 S:	Supported
 F:	Documentation/devicetree/bindings/mfd/mscc,ocelot.yaml
 F:	drivers/mfd/ocelot*
+F:	drivers/net/dsa/ocelot/ocelot_ext.c
 F:	include/linux/mfd/ocelot.h
 
 OCXL (Open Coherent Accelerator Processor Interface OpenCAPI) DRIVER
diff --git a/drivers/net/dsa/ocelot/Kconfig b/drivers/net/dsa/ocelot/Kconfig
index 08db9cf76818..74a900e16d76 100644
--- a/drivers/net/dsa/ocelot/Kconfig
+++ b/drivers/net/dsa/ocelot/Kconfig
@@ -1,4 +1,23 @@
 # SPDX-License-Identifier: GPL-2.0-only
+config NET_DSA_MSCC_OCELOT_EXT
+	tristate "Ocelot External Ethernet switch support"
+	depends on NET_DSA && SPI
+	depends on NET_VENDOR_MICROSEMI
+	select MDIO_MSCC_MIIM
+	select MFD_OCELOT_CORE
+	select MSCC_OCELOT_SWITCH_LIB
+	select NET_DSA_TAG_OCELOT_8021Q
+	select NET_DSA_TAG_OCELOT
+	help
+	  This driver supports the VSC7511, VSC7512, VSC7513 and VSC7514 chips
+	  when controlled through SPI.
+
+	  The Ocelot switch family is a set of multi-port networking chips. All
+	  of these chips have the ability to be controlled externally through
+	  SPI or PCIe interfaces.
+
+	  Say "Y" here to enable external control to these chips.
+
 config NET_DSA_MSCC_FELIX
 	tristate "Ocelot / Felix Ethernet switch support"
 	depends on NET_DSA && PCI
diff --git a/drivers/net/dsa/ocelot/Makefile b/drivers/net/dsa/ocelot/Makefile
index f6dd131e7491..d7f3f5a4461c 100644
--- a/drivers/net/dsa/ocelot/Makefile
+++ b/drivers/net/dsa/ocelot/Makefile
@@ -1,11 +1,16 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_NET_DSA_MSCC_FELIX) += mscc_felix.o
+obj-$(CONFIG_NET_DSA_MSCC_OCELOT_EXT) += mscc_ocelot_ext.o
 obj-$(CONFIG_NET_DSA_MSCC_SEVILLE) += mscc_seville.o
 
 mscc_felix-objs := \
 	felix.o \
 	felix_vsc9959.o
 
+mscc_ocelot_ext-objs := \
+	felix.o \
+	ocelot_ext.o
+
 mscc_seville-objs := \
 	felix.o \
 	seville_vsc9953.o
diff --git a/drivers/net/dsa/ocelot/ocelot_ext.c b/drivers/net/dsa/ocelot/ocelot_ext.c
new file mode 100644
index 000000000000..1340b017e37d
--- /dev/null
+++ b/drivers/net/dsa/ocelot/ocelot_ext.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Copyright 2021-2022 Innovative Advantage Inc.
+ */
+
+#include <linux/mfd/ocelot.h>
+#include <linux/phylink.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <soc/mscc/ocelot.h>
+#include <soc/mscc/vsc7514_regs.h>
+#include "felix.h"
+
+#define VSC7514_NUM_PORTS		11
+
+#define OCELOT_PORT_MODE_SERDES		(OCELOT_PORT_MODE_SGMII | \
+					 OCELOT_PORT_MODE_QSGMII)
+
+static const u32 vsc7512_port_modes[VSC7514_NUM_PORTS] = {
+	OCELOT_PORT_MODE_INTERNAL,
+	OCELOT_PORT_MODE_INTERNAL,
+	OCELOT_PORT_MODE_INTERNAL,
+	OCELOT_PORT_MODE_INTERNAL,
+	OCELOT_PORT_MODE_NONE,
+	OCELOT_PORT_MODE_NONE,
+	OCELOT_PORT_MODE_NONE,
+	OCELOT_PORT_MODE_NONE,
+	OCELOT_PORT_MODE_NONE,
+	OCELOT_PORT_MODE_NONE,
+	OCELOT_PORT_MODE_NONE,
+};
+
+static void ocelot_ext_phylink_validate(struct ocelot *ocelot, int port,
+					unsigned long *supported,
+					struct phylink_link_state *state)
+{
+	struct felix *felix = ocelot_to_felix(ocelot);
+	struct dsa_switch *ds = felix->ds;
+	struct dsa_port *dp;
+
+	dp = dsa_to_port(ds, port);
+
+	phylink_generic_validate(&dp->pl_config, supported, state);
+}
+
+static const struct ocelot_ops ocelot_ext_ops = {
+	.reset		= ocelot_reset,
+	.wm_enc		= ocelot_wm_enc,
+	.wm_dec		= ocelot_wm_dec,
+	.wm_stat	= ocelot_wm_stat,
+	.port_to_netdev	= felix_port_to_netdev,
+	.netdev_to_port	= felix_netdev_to_port,
+};
+
+static const char * const vsc7512_resource_names[TARGET_MAX] = {
+	[SYS] = OCELOT_RES_NAME_SYS,
+	[REW] = OCELOT_RES_NAME_REW,
+	[S0] = OCELOT_RES_NAME_S0,
+	[S1] = OCELOT_RES_NAME_S1,
+	[S2] = OCELOT_RES_NAME_S2,
+	[QS] = OCELOT_RES_NAME_QS,
+	[QSYS] = OCELOT_RES_NAME_QSYS,
+	[ANA] = OCELOT_RES_NAME_ANA,
+};
+
+static const struct felix_info vsc7512_info = {
+	.resource_names			= vsc7512_resource_names,
+	.regfields			= vsc7514_regfields,
+	.map				= vsc7514_regmap,
+	.ops				= &ocelot_ext_ops,
+	.stats_layout			= vsc7514_stats_layout,
+	.vcap				= vsc7514_vcap_props,
+	.num_mact_rows			= 1024,
+	.num_ports			= VSC7514_NUM_PORTS,
+	.num_tx_queues			= OCELOT_NUM_TC,
+	.phylink_validate		= ocelot_ext_phylink_validate,
+	.port_modes			= vsc7512_port_modes,
+};
+
+static int ocelot_ext_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dsa_switch *ds;
+	struct ocelot *ocelot;
+	struct felix *felix;
+	int err;
+
+	felix = kzalloc(sizeof(*felix), GFP_KERNEL);
+	if (!felix)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, felix);
+
+	ocelot = &felix->ocelot;
+	ocelot->dev = dev;
+
+	ocelot->num_flooding_pgids = 1;
+
+	felix->info = &vsc7512_info;
+
+	ds = kzalloc(sizeof(*ds), GFP_KERNEL);
+	if (!ds) {
+		err = -ENOMEM;
+		dev_err_probe(dev, err, "Failed to allocate DSA switch\n");
+		goto err_free_felix;
+	}
+
+	ds->dev = dev;
+	ds->num_ports = felix->info->num_ports;
+	ds->num_tx_queues = felix->info->num_tx_queues;
+
+	ds->ops = &felix_switch_ops;
+	ds->priv = ocelot;
+	felix->ds = ds;
+	felix->tag_proto = DSA_TAG_PROTO_OCELOT;
+
+	err = dsa_register_switch(ds);
+	if (err) {
+		dev_err_probe(dev, err, "Failed to register DSA switch\n");
+		goto err_free_ds;
+	}
+
+	return 0;
+
+err_free_ds:
+	kfree(ds);
+err_free_felix:
+	kfree(felix);
+	return err;
+}
+
+static int ocelot_ext_remove(struct platform_device *pdev)
+{
+	struct felix *felix = dev_get_drvdata(&pdev->dev);
+
+	if (!felix)
+		return 0;
+
+	dsa_unregister_switch(felix->ds);
+
+	kfree(felix->ds);
+	kfree(felix);
+
+	return 0;
+}
+
+static void ocelot_ext_shutdown(struct platform_device *pdev)
+{
+	struct felix *felix = dev_get_drvdata(&pdev->dev);
+
+	if (!felix)
+		return;
+
+	dsa_switch_shutdown(felix->ds);
+
+	dev_set_drvdata(&pdev->dev, NULL);
+}
+
+static const struct of_device_id ocelot_ext_switch_of_match[] = {
+	{ .compatible = "mscc,vsc7512-switch" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ocelot_ext_switch_of_match);
+
+static struct platform_driver ocelot_ext_switch_driver = {
+	.driver = {
+		.name = "ocelot-switch",
+		.of_match_table = of_match_ptr(ocelot_ext_switch_of_match),
+	},
+	.probe = ocelot_ext_probe,
+	.remove = ocelot_ext_remove,
+	.shutdown = ocelot_ext_shutdown,
+};
+module_platform_driver(ocelot_ext_switch_driver);
+
+MODULE_DESCRIPTION("External Ocelot Switch driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(MFD_OCELOT);
-- 
2.25.1