Re: [PATCH net-next 08/13] net: dsa: realtek: add new mdio interface for drivers

["Alvin Šipraga" <ALSI@bang-olufsen.dk>]

Hi Luiz,

On 12/16/21 21:13, luizluca@gmail.com wrote:
> From: Luiz Angelo Daros de Luca <luizluca@gmail.com>
> 
> This driver is a mdio_driver instead of a platform driver (like
> realtek-smi).
> 
> Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
> Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
> ---

Great work giving the switches MDIO support. Left comments down below.

I'm not so pleased with how this driver is split up - nor was I before - 
but something feels a bit off with all the code duplication. I'll think 
about it but maybe somebody else can share some experience they have 
from other drivers.

I didn't check the register access details just yet.


>   drivers/net/dsa/realtek/Kconfig        |  11 +-
>   drivers/net/dsa/realtek/Makefile       |   1 +
>   drivers/net/dsa/realtek/realtek-mdio.c | 284 +++++++++++++++++++++++++
>   drivers/net/dsa/realtek/realtek.h      |   3 +
>   4 files changed, 297 insertions(+), 2 deletions(-)
>   create mode 100644 drivers/net/dsa/realtek/realtek-mdio.c
> 
> diff --git a/drivers/net/dsa/realtek/Kconfig b/drivers/net/dsa/realtek/Kconfig
> index 874574db9177..48194d0dd51f 100644
> --- a/drivers/net/dsa/realtek/Kconfig
> +++ b/drivers/net/dsa/realtek/Kconfig
> @@ -9,6 +9,13 @@ menuconfig NET_DSA_REALTEK
>   	help
>   	  Select to enable support for Realtek Ethernet switch chips.
>   
> +config NET_DSA_REALTEK_MDIO
> +	tristate "Realtek MDIO connected switch driver"
> +	depends on NET_DSA_REALTEK
> +	default y
> +	help
> +	  Select to enable support for registering switches configured through MDIO.
> +
>   config NET_DSA_REALTEK_SMI
>   	tristate "Realtek SMI connected switch driver"
>   	depends on NET_DSA_REALTEK
> @@ -20,7 +27,7 @@ config NET_DSA_REALTEK_RTL8367C
>   	tristate "Realtek RTL8367C switch subdriver"
>   	default y
>   	depends on NET_DSA_REALTEK
> -	depends on NET_DSA_REALTEK_SMI
> +	depends on NET_DSA_REALTEK_SMI || NET_DSA_REALTEK_MDIO
>   	select NET_DSA_TAG_RTL8_4
>   	help
>   	  Select to enable support for Realtek RTL8365MB-VC. This subdriver
> @@ -32,7 +39,7 @@ config NET_DSA_REALTEK_RTL8366RB
>   	tristate "Realtek RTL8366RB switch subdriver"
>   	default y
>   	depends on NET_DSA_REALTEK
> -	depends on NET_DSA_REALTEK_SMI
> +	depends on NET_DSA_REALTEK_SMI || NET_DSA_REALTEK_MDIO
>   	select NET_DSA_TAG_RTL4_A
>   	help
>   	  Select to enable support for Realtek RTL8366RB
> diff --git a/drivers/net/dsa/realtek/Makefile b/drivers/net/dsa/realtek/Makefile
> index 84d5ab062c89..01df2ccbb77f 100644
> --- a/drivers/net/dsa/realtek/Makefile
> +++ b/drivers/net/dsa/realtek/Makefile
> @@ -1,4 +1,5 @@
>   # SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_NET_DSA_REALTEK_MDIO) 	+= realtek-mdio.o
>   obj-$(CONFIG_NET_DSA_REALTEK_SMI) 	+= realtek-smi.o
>   obj-$(CONFIG_NET_DSA_REALTEK_RTL8366RB) += rtl8366.o
>   rtl8366-objs 				:= rtl8366-core.o rtl8366rb.o
> diff --git a/drivers/net/dsa/realtek/realtek-mdio.c b/drivers/net/dsa/realtek/realtek-mdio.c
> new file mode 100644
> index 000000000000..b7febd63e04f
> --- /dev/null
> +++ b/drivers/net/dsa/realtek/realtek-mdio.c
> @@ -0,0 +1,284 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/* Realtek MDIO interface driver
> + *
> + *
> + * ASICs we intend to support with this driver:
> + *
> + * RTL8366   - The original version, apparently
> + * RTL8369   - Similar enough to have the same datsheet as RTL8366
> + * RTL8366RB - Probably reads out "RTL8366 revision B", has a quite
> + *             different register layout from the other two
> + * RTL8366S  - Is this "RTL8366 super"?
> + * RTL8367   - Has an OpenWRT driver as well
> + * RTL8368S  - Seems to be an alternative name for RTL8366RB
> + * RTL8370   - Also uses SMI
> + *
> + * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
> + * Copyright (C) 2010 Antti Seppälä <a.seppala@gmail.com>
> + * Copyright (C) 2010 Roman Yeryomin <roman@advem.lv>
> + * Copyright (C) 2011 Colin Leitner <colin.leitner@googlemail.com>
> + * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/spinlock.h>
> +#include <linux/skbuff.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_mdio.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/bitops.h>
> +#include <linux/if_bridge.h>
> +
> +#include "realtek.h"
> +
> +/* Read/write via mdiobus */
> +#define MDC_MDIO_CTRL0_REG              31
> +#define MDC_MDIO_START_REG              29
> +#define MDC_MDIO_CTRL1_REG              21
> +#define MDC_MDIO_ADDRESS_REG            23
> +#define MDC_MDIO_DATA_WRITE_REG         24
> +#define MDC_MDIO_DATA_READ_REG          25
> +
> +#define MDC_MDIO_START_OP               0xFFFF
> +#define MDC_MDIO_ADDR_OP                0x000E
> +#define MDC_MDIO_READ_OP                0x0001
> +#define MDC_MDIO_WRITE_OP               0x0003
> +#define MDC_REALTEK_DEFAULT_PHY_ADDR    0x0
> +
> +int realtek_mdio_read_reg(struct realtek_priv *priv, u32 addr, u32 *data)
> +{
> +        u32 phy_id = priv->phy_id;
> +	struct mii_bus *bus = priv->bus;
> +
> +        BUG_ON(in_interrupt());

No BUG_ON please, just make sure that this never happens. This will 
crash the system.

> +
> +        mutex_lock(&bus->mdio_lock);
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);

Just noticed you are mixing tabs and spaces too. You can try running 
clang-format or similar on your code before sending v2. Be aware it will 
mess up the #defines.

> +
> +        /* Write address control code to register 31 */
> +        bus->write(bus, phy_id, MDC_MDIO_CTRL0_REG, MDC_MDIO_ADDR_OP);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Write address to register 23 */
> +        bus->write(bus, phy_id, MDC_MDIO_ADDRESS_REG, addr);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Write read control code to register 21 */
> +        bus->write(bus, phy_id, MDC_MDIO_CTRL1_REG, MDC_MDIO_READ_OP);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Read data from register 25 */
> +        *data = bus->read(bus, phy_id, MDC_MDIO_DATA_READ_REG);
> +
> +        mutex_unlock(&bus->mdio_lock);
> +
> +        return 0;
> +}
> +
> +static int realtek_mdio_write_reg(struct realtek_priv *priv, u32 addr, u32 data)
> +{
> +        u32 phy_id = priv->phy_id;
> +        struct mii_bus *bus = priv->bus;
> +
> +        BUG_ON(in_interrupt());
> +
> +        mutex_lock(&bus->mdio_lock);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Write address control code to register 31 */
> +        bus->write(bus, phy_id, MDC_MDIO_CTRL0_REG, MDC_MDIO_ADDR_OP);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Write address to register 23 */
> +        bus->write(bus, phy_id, MDC_MDIO_ADDRESS_REG, addr);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Write data to register 24 */
> +        bus->write(bus, phy_id, MDC_MDIO_DATA_WRITE_REG, data);
> +
> +        /* Write Start command to register 29 */
> +        bus->write(bus, phy_id, MDC_MDIO_START_REG, MDC_MDIO_START_OP);
> +
> +        /* Write data control code to register 21 */
> +        bus->write(bus, phy_id, MDC_MDIO_CTRL1_REG, MDC_MDIO_WRITE_OP);
> +
> +        mutex_unlock(&bus->mdio_lock);
> +        return 0;
> +}
> +
> +
> +/* Regmap accessors */
> +
> +static int realtek_mdio_write(void *ctx, u32 reg, u32 val)
> +{
> +	struct realtek_priv *priv = ctx;
> +
> +	return realtek_mdio_write_reg(priv, reg, val);
> +}
> +
> +static int realtek_mdio_read(void *ctx, u32 reg, u32 *val)
> +{
> +	struct realtek_priv *priv = ctx;
> +
> +	return realtek_mdio_read_reg(priv, reg, val);
> +}
> +
> +static const struct regmap_config realtek_mdio_regmap_config = {
> +	.reg_bits = 10, /* A4..A0 R4..R0 */
> +	.val_bits = 16,
> +	.reg_stride = 1,
> +	/* PHY regs are at 0x8000 */
> +	.max_register = 0xffff,
> +	.reg_format_endian = REGMAP_ENDIAN_BIG,
> +	.reg_read = realtek_mdio_read,
> +	.reg_write = realtek_mdio_write,
> +	.cache_type = REGCACHE_NONE,
> +};
> +
> +static int realtek_mdio_probe(struct mdio_device *mdiodev)
> +{
> +	struct realtek_priv *priv;
> +	struct device *dev = &mdiodev->dev;
> +	const struct realtek_variant *var;
> +	int ret;
> +	struct device_node *np;
> +
> +	var = of_device_get_match_data(dev);
> +	priv = devm_kzalloc(&mdiodev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->phy_id = mdiodev->addr;
> +
> +	// Start by setting up the register mapping
> +	priv->map = devm_regmap_init(dev, NULL, priv, &realtek_mdio_regmap_config);
> +
> +	priv->bus = mdiodev->bus;
> +	priv->dev = &mdiodev->dev;
> +	priv->chip_data = (void *)priv + sizeof(*priv);
> +
> +	priv->clk_delay = var->clk_delay;
> +	priv->cmd_read = var->cmd_read;
> +	priv->cmd_write = var->cmd_write;
> +	priv->ops = var->ops;
> +
> +	if (IS_ERR(priv->map))
> +		dev_warn(dev, "regmap initialization failed");
> +
> +	priv->write_reg_noack=realtek_mdio_write_reg;
> +
> +	np = dev->of_node;
> +
> +	dev_set_drvdata(dev, priv);
> +	spin_lock_init(&priv->lock);

It's not even used here.

> +
> +	/* TODO: if power is software controlled, set up any regulators here */
> +
> +	/* FIXME: maybe skip if no gpio but reset after the switch was detected */
> +	/* Assert then deassert RESET */
> +	/*
> +	priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->reset)) {
> +		dev_err(dev, "failed to get RESET GPIO\n");
> +		return PTR_ERR(priv->reset);
> +	}
> +	msleep(REALTEK_SMI_HW_STOP_DELAY);

After all the renaming I'm surprised to see _SMI in the MDIO code now...

> +	gpiod_set_value(priv->reset, 0);
> +	msleep(REALTEK_SMI_HW_START_DELAY);
> +	dev_info(dev, "deasserted RESET\n");
> +	*/

Leftover debug? Nobody wants to see block commented code :-)

> +
> +	priv->leds_disabled = of_property_read_bool(np, "realtek,disable-leds");
> +
> +	ret = priv->ops->detect(priv);
> +	if (ret) {
> +		dev_err(dev, "unable to detect switch\n");
> +		return ret;
> +	}
> +
> +	priv->ds = devm_kzalloc(dev, sizeof(*priv->ds), GFP_KERNEL);
> +	if (!priv->ds)
> +		return -ENOMEM;
> +
> +	priv->ds->dev = dev;
> +	priv->ds->num_ports = priv->num_ports;
> +	priv->ds->priv = priv;
> +	priv->ds->ops = var->ds_ops;
> +
> +	ret = dsa_register_switch(priv->ds);
> +	if (ret) {
> +		dev_err(priv->dev, "unable to register switch ret = %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void realtek_mdio_remove(struct mdio_device *mdiodev)
> +{
> +	struct realtek_priv *priv = dev_get_drvdata(&mdiodev->dev);
> +
> +	if (!priv)
> +		return;
> +
> +	dsa_unregister_switch(priv->ds);
> +	//gpiod_set_value(smi->reset, 1);

More here.

> +	dev_set_drvdata(&mdiodev->dev, NULL);
> +}
> +
> +static void realtek_mdio_shutdown(struct mdio_device *mdiodev)
> +{
> +	struct realtek_priv *priv = dev_get_drvdata(&mdiodev->dev);
> +
> +	if (!priv)
> +		return;
> +
> +        dsa_switch_shutdown(priv->ds);
> +
> +        dev_set_drvdata(&mdiodev->dev, NULL);
> +}
> +
> +static const struct of_device_id realtek_mdio_of_match[] = {
> +#if IS_ENABLED(CONFIG_NET_DSA_REALTEK_RTL8366RB)
> +	{ .compatible = "realtek,rtl8366rb", .data = &rtl8366rb_variant, },
> +#endif
> +	/* FIXME: add support for RTL8366S and more */
> +	{ .compatible = "realtek,rtl8366s", .data = NULL, },
> +#if IS_ENABLED(CONFIG_NET_DSA_REALTEK_RTL8367C)
> +	{ .compatible = "realtek,rtl8365mb", .data = &rtl8367c_variant, },

Did you test on an RTL8365MB-VC with MDIO? I know the 66RB is not tested.

> +#endif
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, realtek_mdio_of_match);
> +
> +static struct mdio_driver realtek_mdio_driver = {
> +	.mdiodrv.driver = {
> +		.name = "realtek-mdio",
> +		.of_match_table = of_match_ptr(realtek_mdio_of_match),
> +	},
> +	.probe  = realtek_mdio_probe,
> +	.remove = realtek_mdio_remove,
> +	.shutdown = realtek_mdio_shutdown,
> +};
> +mdio_module_driver(realtek_mdio_driver);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/net/dsa/realtek/realtek.h b/drivers/net/dsa/realtek/realtek.h
> index 976cb7823c92..c1f20a23ab9e 100644
> --- a/drivers/net/dsa/realtek/realtek.h
> +++ b/drivers/net/dsa/realtek/realtek.h
> @@ -50,6 +50,8 @@ struct realtek_priv {
>   	struct gpio_desc	*mdio;
>   	struct regmap		*map;
>   	struct mii_bus		*slave_mii_bus;
> +	struct mii_bus		*bus;
> +	int                     phy_id;
>   
>   	unsigned int		clk_delay;
>   	u8			cmd_read;
> @@ -66,6 +68,7 @@ struct realtek_priv {
>   	struct rtl8366_mib_counter *mib_counters;
>   
>   	const struct realtek_ops *ops;
> +	int 		 	(*setup)(struct dsa_switch *ds);

What's this for?

>   	int 		 	(*setup_interface)(struct dsa_switch *ds);
>   	int 			(*write_reg_noack)(struct realtek_priv *priv, u32 addr, u32 data);
>