net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver

ASIX AX88796[1] is a versatile ethernet adapter chip, that can be
connected to a CPU with a 8/16-bit bus or with an SPI. This driver
supports SPI connection.

The driver has been ported from the vendor kernel for ARTIK5[2]
boards. Several changes were made to adapt it to the current kernel
which include:

+ updated DT configuration,
+ clock configuration moved to DT,
+ new timer, ethtool and gpio APIs,
+ dev_* instead of pr_* and custom printk() wrappers,
+ removed awkward vendor power managemtn.
+ introduced ethtool tunable to control SPI compression

[1] https://www.asix.com.tw/products.php?op=pItemdetail&PItemID=104;65;86&PLine=65
[2] https://git.tizen.org/cgit/profile/common/platform/kernel/linux-3.10-artik/

The other ax88796 driver is for NE2000 compatible AX88796L chip. These
chips are not compatible. Hence, two separate drivers are required.
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -2899,6 +2899,12 @@ S:	Maintained
 F:	Documentation/hwmon/asc7621.rst
 F:	drivers/hwmon/asc7621.c
 
+ASIX AX88796C SPI ETHERNET ADAPTER
+M:	Łukasz Stelmach <l.stelmach@samsung.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/net/asix,ax88796c.yaml
+F:	drivers/net/ethernet/asix/ax88796c_*
+
 ASPEED PINCTRL DRIVERS
 M:	Andrew Jeffery <andrew@aj.id.au>
 L:	linux-aspeed@lists.ozlabs.org (moderated for non-subscribers)

drivers/net/ethernet/Kconfig

@@ -33,6 +33,7 @@ source "drivers/net/ethernet/apm/Kconfig"
 source "drivers/net/ethernet/apple/Kconfig"
 source "drivers/net/ethernet/aquantia/Kconfig"
 source "drivers/net/ethernet/arc/Kconfig"
+source "drivers/net/ethernet/asix/Kconfig"
 source "drivers/net/ethernet/atheros/Kconfig"
 source "drivers/net/ethernet/broadcom/Kconfig"
 source "drivers/net/ethernet/brocade/Kconfig"

drivers/net/ethernet/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_NET_XGENE) += apm/
 obj-$(CONFIG_NET_VENDOR_APPLE) += apple/
 obj-$(CONFIG_NET_VENDOR_AQUANTIA) += aquantia/
 obj-$(CONFIG_NET_VENDOR_ARC) += arc/
+obj-$(CONFIG_NET_VENDOR_ASIX) += asix/
 obj-$(CONFIG_NET_VENDOR_ATHEROS) += atheros/
 obj-$(CONFIG_NET_VENDOR_CADENCE) += cadence/
 obj-$(CONFIG_NET_VENDOR_BROADCOM) += broadcom/

drivers/net/ethernet/asix/Kconfig

+#
+# Asix network device configuration
+#
+
+config NET_VENDOR_ASIX
+	bool "Asix devices"
+	default y
+	help
+	  If you have a network (Ethernet, non-USB, not NE2000 compatible)
+	  interface based on a chip from ASIX, say Y.
+
+if NET_VENDOR_ASIX
+
+config SPI_AX88796C
+	tristate "Asix AX88796C-SPI support"
+	select PHYLIB
+	depends on SPI
+	depends on GPIOLIB
+	help
+	  Say Y here if you intend to use ASIX AX88796C attached in SPI mode.
+
+config SPI_AX88796C_COMPRESSION
+	bool "SPI transfer compression"
+	default n
+	depends on SPI_AX88796C
+	help
+	  Say Y here to enable SPI transfer compression. It saves up
+	  to 24 dummy cycles during each transfer which may noticeably
+	  speed up short transfers. This sets the default value that is
+	  inherited by network interfaces during probe. It can be
+	  changed at run time via spi-compression ethtool tunable.
+
+	  If unsure say N.
+
+endif # NET_VENDOR_ASIX

drivers/net/ethernet/asix/Makefile

+#
+# Makefile for the Asix network device drivers.
+#
+
+obj-$(CONFIG_SPI_AX88796C) += ax88796c.o
+ax88796c-y := ax88796c_main.o ax88796c_ioctl.o ax88796c_spi.o

drivers/net/ethernet/asix/ax88796c_ioctl.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2010 ASIX Electronics Corporation
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd.
+ *
+ * ASIX AX88796C SPI Fast Ethernet Linux driver
+ */
+
+#define pr_fmt(fmt)	"ax88796c: " fmt
+
+#include <linux/bitmap.h>
+#include <linux/iopoll.h>
+#include <linux/phy.h>
+#include <linux/netdevice.h>
+
+#include "ax88796c_main.h"
+#include "ax88796c_ioctl.h"
+
+static const char ax88796c_priv_flag_names[][ETH_GSTRING_LEN] = {
+	"SPICompression",
+};
+
+static void
+ax88796c_get_drvinfo(struct net_device *ndev, struct ethtool_drvinfo *info)
+{
+	/* Inherit standard device info */
+	strncpy(info->driver, DRV_NAME, sizeof(info->driver));
+}
+
+static u32 ax88796c_get_msglevel(struct net_device *ndev)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+
+	return ax_local->msg_enable;
+}
+
+static void ax88796c_set_msglevel(struct net_device *ndev, u32 level)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+
+	ax_local->msg_enable = level;
+}
+
+static void
+ax88796c_get_pauseparam(struct net_device *ndev, struct ethtool_pauseparam *pause)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+
+	pause->tx_pause = !!(ax_local->flowctrl & AX_FC_TX);
+	pause->rx_pause = !!(ax_local->flowctrl & AX_FC_RX);
+	pause->autoneg = (ax_local->flowctrl & AX_FC_ANEG) ?
+		AUTONEG_ENABLE :
+		AUTONEG_DISABLE;
+}
+
+static int
+ax88796c_set_pauseparam(struct net_device *ndev, struct ethtool_pauseparam *pause)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+	int fc;
+
+	/* The following logic comes from phylink_ethtool_set_pauseparam() */
+	fc = pause->tx_pause ? AX_FC_TX : 0;
+	fc |= pause->rx_pause ? AX_FC_RX : 0;
+	fc |= pause->autoneg ? AX_FC_ANEG : 0;
+
+	ax_local->flowctrl = fc;
+
+	if (pause->autoneg) {
+		phy_set_asym_pause(ax_local->phydev, pause->tx_pause,
+				   pause->rx_pause);
+	} else {
+		int maccr = 0;
+
+		phy_set_asym_pause(ax_local->phydev, 0, 0);
+		maccr |= (ax_local->flowctrl & AX_FC_RX) ? MACCR_RXFC_ENABLE : 0;
+		maccr |= (ax_local->flowctrl & AX_FC_TX) ? MACCR_TXFC_ENABLE : 0;
+
+		mutex_lock(&ax_local->spi_lock);
+
+		maccr |= AX_READ(&ax_local->ax_spi, P0_MACCR) &
+			~(MACCR_TXFC_ENABLE | MACCR_RXFC_ENABLE);
+		AX_WRITE(&ax_local->ax_spi, maccr, P0_MACCR);
+
+		mutex_unlock(&ax_local->spi_lock);
+	}
+
+	return 0;
+}
+
+static int ax88796c_get_regs_len(struct net_device *ndev)
+{
+	return AX88796C_REGDUMP_LEN + AX88796C_PHY_REGDUMP_LEN;
+}
+
+static void
+ax88796c_get_regs(struct net_device *ndev, struct ethtool_regs *regs, void *_p)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+	int offset, i;
+	u16 *p = _p;
+
+	memset(p, 0, ax88796c_get_regs_len(ndev));
+
+	mutex_lock(&ax_local->spi_lock);
+
+	for (offset = 0; offset < AX88796C_REGDUMP_LEN; offset += 2) {
+		if (!test_bit(offset / 2, ax88796c_no_regs_mask))
+			*p = AX_READ(&ax_local->ax_spi, offset);
+		p++;
+	}
+
+	mutex_unlock(&ax_local->spi_lock);
+
+	for (i = 0; i < AX88796C_PHY_REGDUMP_LEN / 2; i++) {
+		*p = phy_read(ax_local->phydev, i);
+		p++;
+	}
+}
+
+static void
+ax88796c_get_strings(struct net_device *ndev, u32 stringset, u8 *data)
+{
+	switch (stringset) {
+	case ETH_SS_PRIV_FLAGS:
+		memcpy(data, ax88796c_priv_flag_names,
+		       sizeof(ax88796c_priv_flag_names));
+		break;
+	}
+}
+
+static int
+ax88796c_get_sset_count(struct net_device *ndev, int stringset)
+{
+	int ret = 0;
+
+	switch (stringset) {
+	case ETH_SS_PRIV_FLAGS:
+		ret = ARRAY_SIZE(ax88796c_priv_flag_names);
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+	}
+
+	return ret;
+}
+
+static int ax88796c_set_priv_flags(struct net_device *ndev, u32 flags)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+
+	if (flags & ~AX_PRIV_FLAGS_MASK)
+		return -EOPNOTSUPP;
+
+	if ((ax_local->priv_flags ^ flags) & AX_CAP_COMP)
+		if (netif_running(ndev))
+			return -EBUSY;
+
+	ax_local->priv_flags = flags;
+
+	return 0;
+}
+
+static u32 ax88796c_get_priv_flags(struct net_device *ndev)
+{
+	struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
+
+	return ax_local->priv_flags;
+}
+
+int ax88796c_mdio_read(struct mii_bus *mdiobus, int phy_id, int loc)
+{
+	struct ax88796c_device *ax_local = mdiobus->priv;
+	int ret;
+
+	mutex_lock(&ax_local->spi_lock);
+	AX_WRITE(&ax_local->ax_spi, MDIOCR_RADDR(loc)
+			| MDIOCR_FADDR(phy_id) | MDIOCR_READ, P2_MDIOCR);
+
+	ret = read_poll_timeout(AX_READ, ret,
+				(ret != 0),
+				0, jiffies_to_usecs(HZ / 100), false,
+				&ax_local->ax_spi, P2_MDIOCR);
+	if (!ret)
+		ret = AX_READ(&ax_local->ax_spi, P2_MDIODR);
+
+	mutex_unlock(&ax_local->spi_lock);
+
+	return ret;
+}
+
+int
+ax88796c_mdio_write(struct mii_bus *mdiobus, int phy_id, int loc, u16 val)
+{
+	struct ax88796c_device *ax_local = mdiobus->priv;
+	int ret;
+
+	mutex_lock(&ax_local->spi_lock);
+	AX_WRITE(&ax_local->ax_spi, val, P2_MDIODR);
+
+	AX_WRITE(&ax_local->ax_spi,
+		 MDIOCR_RADDR(loc) | MDIOCR_FADDR(phy_id)
+		 | MDIOCR_WRITE, P2_MDIOCR);
+
+	ret = read_poll_timeout(AX_READ, ret,
+				((ret & MDIOCR_VALID) != 0), 0,
+				jiffies_to_usecs(HZ / 100), false,
+				&ax_local->ax_spi, P2_MDIOCR);
+	mutex_unlock(&ax_local->spi_lock);
+
+	return ret;
+}
+
+const struct ethtool_ops ax88796c_ethtool_ops = {
+	.get_drvinfo		= ax88796c_get_drvinfo,
+	.get_link		= ethtool_op_get_link,
+	.get_msglevel		= ax88796c_get_msglevel,
+	.set_msglevel		= ax88796c_set_msglevel,
+	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
+	.set_link_ksettings	= phy_ethtool_set_link_ksettings,
+	.nway_reset		= phy_ethtool_nway_reset,
+	.get_pauseparam		= ax88796c_get_pauseparam,
+	.set_pauseparam		= ax88796c_set_pauseparam,
+	.get_regs_len		= ax88796c_get_regs_len,
+	.get_regs		= ax88796c_get_regs,
+	.get_strings		= ax88796c_get_strings,
+	.get_sset_count		= ax88796c_get_sset_count,
+	.get_priv_flags		= ax88796c_get_priv_flags,
+	.set_priv_flags		= ax88796c_set_priv_flags,
+};
+
+int ax88796c_ioctl(struct net_device *ndev, struct ifreq *ifr, int cmd)
+{
+	int ret;
+
+	ret = phy_mii_ioctl(ndev->phydev, ifr, cmd);
+
+	return ret;
+}

drivers/net/ethernet/asix/ax88796c_ioctl.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2010 ASIX Electronics Corporation
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd.
+ *
+ * ASIX AX88796C SPI Fast Ethernet Linux driver
+ */
+
+#ifndef _AX88796C_IOCTL_H
+#define _AX88796C_IOCTL_H
+
+#include <linux/ethtool.h>
+#include <linux/netdevice.h>
+
+#include "ax88796c_main.h"
+
+extern const struct ethtool_ops ax88796c_ethtool_ops;
+
+bool ax88796c_check_power(const struct ax88796c_device *ax_local);
+bool ax88796c_check_power_and_wake(struct ax88796c_device *ax_local);
+void ax88796c_set_power_saving(struct ax88796c_device *ax_local, u8 ps_level);
+int ax88796c_mdio_read(struct mii_bus *mdiobus, int phy_id, int loc);
+int ax88796c_mdio_write(struct mii_bus *mdiobus, int phy_id, int loc, u16 val);
+int ax88796c_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
+
+#endif

drivers/net/ethernet/asix/ax88796c_spi.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2010 ASIX Electronics Corporation
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd.
+ *
+ * ASIX AX88796C SPI Fast Ethernet Linux driver
+ */
+
+#define pr_fmt(fmt)	"ax88796c: " fmt
+
+#include <linux/string.h>
+#include <linux/spi/spi.h>
+
+#include "ax88796c_spi.h"
+
+const u8 ax88796c_rx_cmd_buf[5] = {AX_SPICMD_READ_RXQ, 0xFF, 0xFF, 0xFF, 0xFF};
+const u8 ax88796c_tx_cmd_buf[4] = {AX_SPICMD_WRITE_TXQ, 0xFF, 0xFF, 0xFF};
+
+/* driver bus management functions */
+int axspi_wakeup(struct axspi_data *ax_spi)
+{
+	int ret;
+
+	ax_spi->cmd_buf[0] = AX_SPICMD_EXIT_PWD;	/* OP */
+	ret = spi_write(ax_spi->spi, ax_spi->cmd_buf, 1);
+	if (ret)
+		dev_err(&ax_spi->spi->dev, "%s() failed: ret = %d\n", __func__, ret);
+	return ret;
+}
+
+int axspi_read_status(struct axspi_data *ax_spi, struct spi_status *status)
+{
+	int ret;
+
+	/* OP */
+	ax_spi->cmd_buf[0] = AX_SPICMD_READ_STATUS;
+	ret = spi_write_then_read(ax_spi->spi, ax_spi->cmd_buf, 1, (u8 *)&status, 3);
+	if (ret)
+		dev_err(&ax_spi->spi->dev, "%s() failed: ret = %d\n", __func__, ret);
+	else
+		le16_to_cpus(&status->isr);
+
+	return ret;
+}
+
+int axspi_read_rxq(struct axspi_data *ax_spi, void *data, int len)
+{
+	struct spi_transfer *xfer = ax_spi->spi_rx_xfer;
+	int ret;
+
+	memcpy(ax_spi->cmd_buf, ax88796c_rx_cmd_buf, 5);
+
+	xfer->tx_buf = ax_spi->cmd_buf;
+	xfer->rx_buf = NULL;
+	xfer->len = ax_spi->comp ? 2 : 5;
+	xfer->bits_per_word = 8;
+	spi_message_add_tail(xfer, &ax_spi->rx_msg);
+
+	xfer++;
+	xfer->rx_buf = data;
+	xfer->tx_buf = NULL;
+	xfer->len = len;
+	xfer->bits_per_word = 8;
+	spi_message_add_tail(xfer, &ax_spi->rx_msg);
+	ret = spi_sync(ax_spi->spi, &ax_spi->rx_msg);
+	if (ret)
+		dev_err(&ax_spi->spi->dev, "%s() failed: ret = %d\n", __func__, ret);
+
+	return ret;
+}
+
+int axspi_write_txq(const struct axspi_data *ax_spi, void *data, int len)
+{
+	return spi_write(ax_spi->spi, data, len);
+}
+
+u16 axspi_read_reg(struct axspi_data *ax_spi, u8 reg)
+{
+	int ret;
+	int len = ax_spi->comp ? 3 : 4;
+
+	ax_spi->cmd_buf[0] = 0x03;	/* OP code read register */
+	ax_spi->cmd_buf[1] = reg;	/* register address */
+	ax_spi->cmd_buf[2] = 0xFF;	/* dumy cycle */
+	ax_spi->cmd_buf[3] = 0xFF;	/* dumy cycle */
+	ret = spi_write_then_read(ax_spi->spi,
+				  ax_spi->cmd_buf, len,
+				  ax_spi->rx_buf, 2);
+	if (ret) {
+		dev_err(&ax_spi->spi->dev,
+			"%s() failed: ret = %d\n", __func__, ret);
+		return 0xFFFF;
+	}
+
+	le16_to_cpus((u16 *)ax_spi->rx_buf);
+
+	return *(u16 *)ax_spi->rx_buf;
+}
+
+int axspi_write_reg(struct axspi_data *ax_spi, u8 reg, u16 value)
+{
+	int ret;
+
+	memset(ax_spi->cmd_buf, 0, sizeof(ax_spi->cmd_buf));
+	ax_spi->cmd_buf[0] = AX_SPICMD_WRITE_REG;	/* OP code read register */
+	ax_spi->cmd_buf[1] = reg;			/* register address */
+	ax_spi->cmd_buf[2] = value;
+	ax_spi->cmd_buf[3] = value >> 8;
+
+	ret = spi_write(ax_spi->spi, ax_spi->cmd_buf, 4);
+	if (ret)
+		dev_err(&ax_spi->spi->dev, "%s() failed: ret = %d\n", __func__, ret);
+	return ret;
+}
+

drivers/net/ethernet/asix/ax88796c_spi.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2010 ASIX Electronics Corporation
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd.
+ *
+ * ASIX AX88796C SPI Fast Ethernet Linux driver
+ */
+
+#ifndef _AX88796C_SPI_H
+#define _AX88796C_SPI_H
+
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+
+/* Definition of SPI command */
+#define AX_SPICMD_WRITE_TXQ		0x02
+#define AX_SPICMD_READ_REG		0x03
+#define AX_SPICMD_READ_STATUS		0x05
+#define AX_SPICMD_READ_RXQ		0x0B
+#define AX_SPICMD_BIDIR_WRQ		0xB2
+#define AX_SPICMD_WRITE_REG		0xD8
+#define AX_SPICMD_EXIT_PWD		0xAB
+
+extern const u8 ax88796c_rx_cmd_buf[];
+extern const u8 ax88796c_tx_cmd_buf[];
+
+struct axspi_data {
+	struct spi_device	*spi;
+	struct spi_message	rx_msg;
+	struct spi_transfer	spi_rx_xfer[2];
+	u8			cmd_buf[6];
+	u8			rx_buf[6];
+	u8			comp;
+};
+
+struct spi_status {
+	u16 isr;
+	u8 status;
+#	define AX_STATUS_READY		0x80
+};
+
+int axspi_read_rxq(struct axspi_data *ax_spi, void *data, int len);
+int axspi_write_txq(const struct axspi_data *ax_spi, void *data, int len);
+u16 axspi_read_reg(struct axspi_data *ax_spi, u8 reg);
+int axspi_write_reg(struct axspi_data *ax_spi, u8 reg, u16 value);
+int axspi_read_status(struct axspi_data *ax_spi, struct spi_status *status);
+int axspi_wakeup(struct axspi_data *ax_spi);
+
+static inline u16 AX_READ(struct axspi_data *ax_spi, u8 offset)
+{
+	return axspi_read_reg(ax_spi, offset);
+}
+
+static inline int AX_WRITE(struct axspi_data *ax_spi, u16 value, u8 offset)
+{
+	return axspi_write_reg(ax_spi, offset, value);
+}
+
+static inline int AX_READ_STATUS(struct axspi_data *ax_spi,
+				 struct spi_status *status)
+{
+	return axspi_read_status(ax_spi, status);
+}
+
+static inline int AX_WAKEUP(struct axspi_data *ax_spi)
+{
+	return axspi_wakeup(ax_spi);
+}
+#endif