Date:	Thu, 3 Dec 2015 10:47:24 +0000
From:	Graeme Gregory <gg@...mlogic.co.uk>
To:	yankejian <yankejian@...wei.com>
Cc:	rjw@...ysocki.net, lenb@...nel.org, davem@...emloft.net,
	liguozhu@...wei.com, yisen.zhuang@...wei.com,
	huangdaode@...ilicon.com, lipeng321@...wei.com,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	linuxarm@...wei.com
Subject: Re: [PATCH] ACPI: Add phylib support code for mdio

On Thu, Dec 03, 2015 at 09:54:43AM +0800, yankejian wrote:
> Add support for getting the PHY devices on an MDIO bus by ACPI.
> Currently many of the ethernet drivers are open coding a solution
> for reading data out of ACPI to find the correct PHY device.
> This patch implements a set of common routines are similar to of_mdio.c
> 

The general conclusion for the ACPI on ARM64 discussion so far has been that
things like PHYs should be setup by the firmware before the kernel takes
control.

I am unsure that this doing it the same way as DT with a different
description language is the way to go.

Graeme

> Signed-off-by: yankejian <yankejian@...wei.com>
> ---
>  drivers/acpi/Makefile     |   3 +
>  drivers/acpi/acpi_mdio.c  | 263 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/acpi_mdio.h |  68 ++++++++++++
>  3 files changed, 334 insertions(+)
>  create mode 100644 drivers/acpi/acpi_mdio.c
>  create mode 100644 include/linux/acpi_mdio.h
> 
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 675eaf3..832e7d6 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -35,6 +35,7 @@ acpi-y				+= bus.o glue.o
>  acpi-y				+= scan.o
>  acpi-y				+= resource.o
>  acpi-y				+= acpi_processor.o
> +acpi-y				+= acpi_mdio.o
>  acpi-y				+= processor_core.o
>  acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o
>  acpi-y				+= ec.o
> @@ -65,6 +66,7 @@ obj-$(CONFIG_ACPI_BUTTON)	+= button.o
>  obj-$(CONFIG_ACPI_FAN)		+= fan.o
>  obj-$(CONFIG_ACPI_VIDEO)	+= video.o
>  obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
> +obj-$(CONFIG_PCI_MMCONFIG)	+= mcfg.o
>  obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
>  obj-y				+= container.o
>  obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
> @@ -79,6 +81,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS)	+= ec_sys.o
>  obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
>  obj-$(CONFIG_ACPI_BGRT)		+= bgrt.o
>  obj-$(CONFIG_ACPI_CPPC_LIB)	+= cppc_acpi.o
> +obj-$(CONFIG_IORT_TABLE) 	+= iort.o
>  
>  # processor has its own "processor." module_param namespace
>  processor-y			:= processor_driver.o
> diff --git a/drivers/acpi/acpi_mdio.c b/drivers/acpi/acpi_mdio.c
> new file mode 100644
> index 0000000..3a5871d
> --- /dev/null
> +++ b/drivers/acpi/acpi_mdio.c
> @@ -0,0 +1,263 @@
> +/*
> + * Copyright (c) 2015 Hisilicon Limited.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/acpi_mdio.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/netdevice.h>
> +#include <linux/phy.h>
> +#include <linux/phy_fixed.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock_types.h>
> +
> +static
> +int acpi_mdiobus_register_phy(struct mii_bus *mdio, struct fwnode_handle *child,
> +			      u32 addr)
> +{
> +	struct phy_device *phy;
> +	const char *phy_type;
> +	bool is_c45;
> +	int rc;
> +
> +	rc = fwnode_property_read_string(child, "ethernet-phy", &phy_type);
> +	if (rc < 0)
> +		return rc;
> +
> +	if (!strncmp(phy_type, "ethernet-phy-ieee802.3-c45",
> +		     sizeof("ethernet-phy-ieee802.3-c45")))
> +		is_c45 = 1;
> +	else if (!strncmp(phy_type, "ethernet-phy-ieee802.3-c22",
> +			  sizeof("ethernet-phy-ieee802.3-c22")))
> +		is_c45 = 0;
> +	else
> +		return -ENODATA;
> +
> +	phy = get_phy_device(mdio, addr, is_c45);
> +	if (!phy || IS_ERR(phy))
> +		return 1;
> +
> +	/* Associate the fw node with the device structure so it
> +	 * can be looked up later
> +	 */
> +	phy->dev.fwnode = child;
> +
> +	if (mdio->irq)
> +		phy->irq = mdio->irq[addr];
> +
> +	if (fwnode_property_read_bool(child, "broken-turn-around"))
> +		mdio->phy_ignore_ta_mask |= 1 << addr;
> +
> +	/* All data is now stored in the phy struct;
> +	 * register it
> +	 */
> +	rc = phy_device_register(phy);
> +	if (rc) {
> +		phy_device_free(phy);
> +		return 1;
> +	}
> +
> +	dev_dbg(&mdio->dev, "registered phy at address %i\n", addr);
> +
> +	return 0;
> +}
> +
> +int acpi_mdio_parse_addr(struct device *dev, struct fwnode_handle *fwnode)
> +{
> +	u32 addr;
> +	int ret;
> +
> +	ret = fwnode_property_read_u32(fwnode, "phy-addr", &addr);
> +	if (ret < 0) {
> +		dev_err(dev, "has invalid PHY address ret:%d\n", ret);
> +		return ret;
> +	}
> +
> +	if (addr >= PHY_MAX_ADDR) {
> +		dev_err(dev, "PHY address %i is too large\n", addr);
> +		return -EINVAL;
> +	}
> +
> +	return addr;
> +}
> +EXPORT_SYMBOL(acpi_mdio_parse_addr);
> +
> +/**
> + * acpi_mdiobus_register - Register mii_bus and create PHYs
> + * @mdio: pointer to mii_bus structure
> + * @fwnode: pointer to framework node of MDIO bus.
> + *
> + * This function registers the mii_bus structure and registers a phy_device
> + * for each child node of mdio device.
> + */
> +int acpi_mdiobus_register(struct mii_bus *mdio, struct fwnode_handle *fwnode)
> +{
> +	struct fwnode_handle *child;
> +	struct acpi_device *adev;
> +	bool scanphys = false;
> +	int addr, rc, i;
> +
> +	/* Mask out all PHYs from auto probing.  Instead the PHYs listed in
> +	 * the framework node are populated after the bus has been registered
> +	 */
> +	mdio->phy_mask = ~0;
> +
> +	/* Clear all the IRQ properties */
> +	if (mdio->irq)
> +		for (i = 0; i < PHY_MAX_ADDR; i++)
> +			mdio->irq[i] = PHY_POLL;
> +
> +	mdio->dev.fwnode = fwnode;
> +
> +	/* Register the MDIO bus */
> +	rc = mdiobus_register(mdio);
> +	if (rc)
> +		return rc;
> +
> +	/* Loop over the child nodes and register a phy_device for each one */
> +	device_for_each_child_node(&mdio->dev, child) {
> +		adev = to_acpi_device_node(child);
> +		if (!adev)
> +			continue;
> +
> +		addr = acpi_mdio_parse_addr(&adev->dev, child);
> +		if (addr < 0) {
> +			scanphys = true;
> +			continue;
> +		}
> +
> +		rc = acpi_mdiobus_register_phy(mdio, child, addr);
> +		dev_dbg(&mdio->dev, "acpi reg phy rc:%#x addr:%#x\n", rc, addr);
> +		if (rc)
> +			continue;
> +	}
> +
> +	if (!scanphys)
> +		return 0;
> +
> +	/* auto scan for PHYs with empty reg property */
> +	device_for_each_child_node(&mdio->dev, child) {
> +		/* Skip PHYs with reg property set */
> +		if (!fwnode_property_present(child, "reg"))
> +			continue;
> +
> +		for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
> +			/* skip already registered PHYs */
> +			if (mdio->phy_map[addr])
> +				continue;
> +
> +			/* be noisy to encourage people to set reg property */
> +			dev_info(&mdio->dev, "scan phy %s at address %i\n",
> +				 acpi_dev_name(to_acpi_device_node(child)),
> +				 addr);
> +
> +			rc = acpi_mdiobus_register_phy(mdio, child, addr);
> +			if (rc)
> +				continue;
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(acpi_mdiobus_register);
> +
> +/* Helper function for acpi_phy_find_device */
> +static int acpi_phy_match(struct device *dev, void *phy_fwnode)
> +{
> +	return dev->fwnode == phy_fwnode;
> +}
> +
> +/**
> + * acpi_phy_find_device - Give a PHY node, find the phy_device
> + * @phy_fwnode: Pointer to the phy's framework node
> + *
> + * If successful, returns a pointer to the phy_device with the embedded
> + * struct device refcount incremented by one, or NULL on failure.
> + */
> +struct phy_device *acpi_phy_find_device(struct fwnode_handle *phy_fwnode)
> +{
> +	struct device *d;
> +
> +	if (!phy_fwnode)
> +		return NULL;
> +
> +	d = bus_find_device(&mdio_bus_type, NULL, phy_fwnode, acpi_phy_match);
> +
> +	return d ? to_phy_device(d) : NULL;
> +}
> +EXPORT_SYMBOL(acpi_phy_find_device);
> +
> +/**
> + * acpi_phy_attach - Attach to a PHY without starting the state machine
> + * @dev: pointer to net_device claiming the phy
> + * @phy_fwnode: framework Node pointer for the PHY
> + * @flags: flags to pass to the PHY
> + * @iface: PHY data interface type
> + *
> + * If successful, returns a pointer to the phy_device with the embedded
> + * struct device refcount incremented by one, or NULL on failure. The
> + * refcount must be dropped by calling phy_disconnect() or phy_detach().
> + */
> +struct phy_device *acpi_phy_attach(struct net_device *dev,
> +				   struct fwnode_handle *phy_fwnode, u32 flags,
> +				   phy_interface_t iface)
> +{
> +	struct phy_device *phy = acpi_phy_find_device(phy_fwnode);
> +	int ret;
> +
> +	if (!phy)
> +		return NULL;
> +
> +	ret = phy_attach_direct(dev, phy, flags, iface);
> +
> +	/* refcount is held by phy_attach_direct() on success */
> +	put_device(&phy->dev);
> +
> +	return ret ? NULL : phy;
> +}
> +EXPORT_SYMBOL(acpi_phy_attach);
> +
> +/**
> + * acpi_phy_connect - Connect to the phy described
> + * @dev: pointer to net_device claiming the phy
> + * @phy_fwnode: Pointer to framework node for the PHY
> + * @hndlr: Link state callback for the network device
> + * @iface: PHY data interface type
> + *
> + * If successful, returns a pointer to the phy_device with the embedded
> + * struct device refcount incremented by one, or NULL on failure. The
> + * refcount must be dropped by calling phy_disconnect() or phy_detach().
> + */
> +struct phy_device *acpi_phy_connect(struct net_device *dev,
> +				    struct fwnode_handle *phy_fwnode,
> +				    void (*hndlr)(struct net_device *),
> +				    u32 flags,
> +				    phy_interface_t iface)
> +{
> +	struct phy_device *phy = acpi_phy_find_device(phy_fwnode);
> +	int ret;
> +
> +	if (!phy)
> +		return NULL;
> +
> +	phy->dev_flags = flags;
> +
> +	ret = phy_connect_direct(dev, phy, hndlr, iface);
> +
> +	/* refcount is held by phy_connect_direct() on success */
> +	put_device(&phy->dev);
> +
> +	return ret ? NULL : phy;
> +}
> +EXPORT_SYMBOL(acpi_phy_connect);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Huawei Tech. Co., Ltd.");
> diff --git a/include/linux/acpi_mdio.h b/include/linux/acpi_mdio.h
> new file mode 100644
> index 0000000..82b5be5
> --- /dev/null
> +++ b/include/linux/acpi_mdio.h
> @@ -0,0 +1,68 @@
> +/*
> + * Copyright (c) 2015 Hisilicon Limited.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#ifndef __LINUX_ACPI_MDIO_H
> +#define __LINUX_ACPI_MDIO_H
> +
> +#include <linux/phy.h>
> +
> +#ifdef CONFIG_ACPI
> +
> +int acpi_mdio_parse_addr(struct device *dev, struct fwnode_handle *fwnode);
> +int acpi_mdiobus_register(struct mii_bus *mdio, struct fwnode_handle *fwnode);
> +struct phy_device *acpi_phy_find_device(struct fwnode_handle *phy_fwnode);
> +struct phy_device *acpi_phy_attach(struct net_device *dev,
> +				   struct fwnode_handle *phy_fwnode, u32 flags,
> +				   phy_interface_t iface);
> +struct phy_device *acpi_phy_connect(struct net_device *dev,
> +				    struct fwnode_handle *phy_fwnode,
> +				    void (*hndlr)(struct net_device *),
> +				    u32 flags,
> +				    phy_interface_t iface);
> +
> +#else
> +static inline int acpi_mdio_parse_addr(struct device *dev,
> +				       struct fwnode_handle *fwnode)
> +{
> +	return -ENXIO;
> +}
> +
> +static inline int acpi_mdiobus_register(struct mii_bus *mdio,
> +					struct fwnode_handle *fwnode)
> +{
> +	return -ENXIO;
> +}
> +
> +static inline
> +struct phy_device *acpi_phy_find_device(struct fwnode_handle *phy_fwnode)
> +{
> +	return NULL;
> +}
> +
> +static inline
> +struct phy_device *acpi_phy_attach(struct net_device *dev,
> +				   struct fwnode_handle *phy_fwnode, u32 flags,
> +				   phy_interface_t iface)
> +{
> +	return NULL;
> +}
> +
> +static inline
> +struct phy_device *acpi_phy_connect(struct net_device *dev,
> +				    struct fwnode_handle *phy_fwnode,
> +				    void (*hndlr)(struct net_device *),
> +				    u32 flags,
> +				    phy_interface_t iface)
> +{
> +	return NULL;
> +}
> +
> +#endif
> +
> +#endif /* __LINUX_ACPI_MDIO_H */
> -- 
> 1.9.1
> 
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