Re: [PATCH] phy: Add MOXA RTL8201CP PHY support

Re: [PATCH] phy: Add MOXA RTL8201CP PHY support

[Kishon Vijay Abraham I]

Hi Jonas,

On Friday 01 November 2013 08:24 PM, Jonas Jensen wrote:

> The MOXA UC-711X hardware(s) has an ethernet controller that seem
> to be developed internally. The IC used is "RTL8201CP".
>
> This patch adds an MDIO driver and also patches realtek to include
> RTL8201CP PHY driver.
>
> Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>

Added netdev mailing list and David Miller as I don't maintain ethernet 
PHYs.

Thanks
Kishon

> ---
>
> Notes:
>      The hardware does not use a separate IRQ for PHY.
>
>      The link state change interrupt can instead be caught by MAC but the
>      current drivers/of/of_mdio.c does not allow it to be handled in MAC.
>
>      Applies to next-20131031
>
>   .../devicetree/bindings/net/moxa,moxart-mdio.txt   |  19 ++
>   drivers/net/phy/Kconfig                            |   7 +
>   drivers/net/phy/Makefile                           |   1 +
>   drivers/net/phy/mdio-moxart.c                      | 201 +++++++++++++++++++++
>   drivers/net/phy/realtek.c                          |  15 ++
>   5 files changed, 243 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/net/moxa,moxart-mdio.txt
>   create mode 100644 drivers/net/phy/mdio-moxart.c
>
> diff --git a/Documentation/devicetree/bindings/net/moxa,moxart-mdio.txt b/Documentation/devicetree/bindings/net/moxa,moxart-mdio.txt
> new file mode 100644
> index 0000000..de0b90c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/moxa,moxart-mdio.txt
> @@ -0,0 +1,19 @@
> +* MOXA ART MDIO Ethernet Controller interface
> +
> +Required properties:
> +- compatible: should be "moxa,moxart-mdio".
> +- reg: address and length of the register set for the device.
> +
> +Example:
> +mdio1: mdio@92000090 {
> +	compatible = "moxa,moxart-mdio";
> +	reg = <0x92000090 0x8>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	ethphy1: ethernet-phy@1 {
> +		device_type = "ethernet-phy";
> +		compatible = "moxa,moxart-rtl8201cp";
> +		reg = <1>;
> +	};
> +};
> diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
> index 342561a..9b5d46c 100644
> --- a/drivers/net/phy/Kconfig
> +++ b/drivers/net/phy/Kconfig
> @@ -154,6 +154,13 @@ config MDIO_SUN4I
>   	  interface units of the Allwinner SoC that have an EMAC (A10,
>   	  A12, A10s, etc.)
>
> +config MDIO_MOXART
> +        tristate "MOXA ART MDIO interface support"
> +        depends on ARCH_MOXART
> +        help
> +          This driver supports the MDIO interface found in the network
> +          interface units of the MOXA ART SoC
> +
>   config MDIO_BUS_MUX
>   	tristate
>   	depends on OF_MDIO
> diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
> index 23a2ab2..9013dfa 100644
> --- a/drivers/net/phy/Makefile
> +++ b/drivers/net/phy/Makefile
> @@ -31,3 +31,4 @@ obj-$(CONFIG_MDIO_BUS_MUX)	+= mdio-mux.o
>   obj-$(CONFIG_MDIO_BUS_MUX_GPIO)	+= mdio-mux-gpio.o
>   obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) += mdio-mux-mmioreg.o
>   obj-$(CONFIG_MDIO_SUN4I)	+= mdio-sun4i.o
> +obj-$(CONFIG_MDIO_MOXART)	+= mdio-moxart.o
> diff --git a/drivers/net/phy/mdio-moxart.c b/drivers/net/phy/mdio-moxart.c
> new file mode 100644
> index 0000000..ad5d0f8
> --- /dev/null
> +++ b/drivers/net/phy/mdio-moxart.c
> @@ -0,0 +1,201 @@
> +/* MOXA ART Ethernet (RTL8201CP) MDIO interface driver
> + *
> + * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2.  This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of_address.h>
> +#include <linux/of_mdio.h>
> +#include <linux/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +
> +#define REG_PHY_CTRL            0
> +#define REG_PHY_WRITE_DATA      4
> +
> +/* REG_PHY_CTRL */
> +#define MIIWR                   BIT(27) /* init write sequence (auto cleared)*/
> +#define MIIRD                   BIT(26)
> +#define REGAD_MASK              0x3e00000
> +#define PHYAD_MASK              0x1f0000
> +#define MIIRDATA_MASK           0xffff
> +
> +/* REG_PHY_WRITE_DATA */
> +#define MIIWDATA_MASK           0xffff
> +
> +struct moxart_mdio_data {
> +	void __iomem		*base;
> +};
> +
> +static int moxart_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
> +{
> +	struct moxart_mdio_data *data = bus->priv;
> +	u32 ctrl = 0;
> +	unsigned int count = 5;
> +
> +	dev_dbg(&bus->dev, "%s\n", __func__);
> +
> +	ctrl |= MIIRD | ((mii_id << 16) & PHYAD_MASK) |
> +		((regnum << 21) & REGAD_MASK);
> +
> +	writel(ctrl, data->base + REG_PHY_CTRL);
> +
> +	do {
> +		ctrl = readl(data->base + REG_PHY_CTRL);
> +
> +		if (!(ctrl & MIIRD))
> +			return ctrl & MIIRDATA_MASK;
> +
> +		mdelay(10);
> +		count--;
> +	} while (count > 0);
> +
> +	dev_err(&bus->dev, "%s timed out\n", __func__);
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static int moxart_mdio_write(struct mii_bus *bus, int mii_id,
> +			     int regnum, u16 value)
> +{
> +	struct moxart_mdio_data *data = bus->priv;
> +	u32 ctrl = 0;
> +	unsigned int count = 5;
> +
> +	dev_dbg(&bus->dev, "%s\n", __func__);
> +
> +	ctrl |= MIIWR | ((mii_id << 16) & PHYAD_MASK) |
> +		((regnum << 21) & REGAD_MASK);
> +
> +	value &= MIIWDATA_MASK;
> +
> +	writel(value, data->base + REG_PHY_WRITE_DATA);
> +	writel(ctrl, data->base + REG_PHY_CTRL);
> +
> +	do {
> +		ctrl = readl(data->base + REG_PHY_CTRL);
> +
> +		if (!(ctrl & MIIWR))
> +			return 0;
> +
> +		mdelay(10);
> +		count--;
> +	} while (count > 0);
> +
> +	dev_err(&bus->dev, "%s timed out\n", __func__);
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static int moxart_mdio_reset(struct mii_bus *bus)
> +{
> +	int data, i;
> +
> +	for (i = 0; i < PHY_MAX_ADDR; i++) {
> +		data = moxart_mdio_read(bus, i, MII_BMCR);
> +		if (data < 0)
> +			continue;
> +
> +		data |= BMCR_RESET;
> +		if (moxart_mdio_write(bus, i, MII_BMCR, data) < 0)
> +			continue;
> +	}
> +
> +	return 0;
> +}
> +
> +static int moxart_mdio_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct mii_bus *bus;
> +	struct moxart_mdio_data *data;
> +	struct resource *res;
> +	int ret, i;
> +
> +	bus = mdiobus_alloc_size(sizeof(*data));
> +	if (!bus)
> +		return -ENOMEM;
> +
> +	bus->name = "MOXA ART Ethernet MII";
> +	bus->read = &moxart_mdio_read;
> +	bus->write = &moxart_mdio_write;
> +	bus->reset = &moxart_mdio_reset;
> +	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
> +	bus->parent = &pdev->dev;
> +
> +	bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
> +			GFP_KERNEL);
> +	if (!bus->irq) {
> +		ret = -ENOMEM;
> +		goto err_out_free_mdiobus;
> +	}
> +
> +	/* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
> +	 * of_mdiobus_register() sets these PHY_POLL.
> +	 * Ideally, the interrupt from MAC controller could be used to
> +	 * detect link state changes, not polling, i.e. if there was
> +	 * a way phy_driver could set PHY_HAS_INTERRUPT but have that
> +	 * interrupt handled in ethernet drivercode.
> +	 */
> +	for (i = 0; i < PHY_MAX_ADDR; i++)
> +		bus->irq[i] = PHY_IGNORE_INTERRUPT;
> +
> +	data = bus->priv;
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	data->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(data->base)) {
> +		ret = PTR_ERR(data->base);
> +		goto err_out_free_mdiobus;
> +	}
> +
> +	ret = of_mdiobus_register(bus, np);
> +	if (ret < 0)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, bus);
> +
> +	return 0;
> +
> +err_out_free_mdiobus:
> +	mdiobus_free(bus);
> +	return ret;
> +}
> +
> +static int moxart_mdio_remove(struct platform_device *pdev)
> +{
> +	struct mii_bus *bus = platform_get_drvdata(pdev);
> +
> +	mdiobus_unregister(bus);
> +	mdiobus_free(bus);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id moxart_mdio_dt_ids[] = {
> +	{ .compatible = "moxa,moxart-mdio" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
> +
> +static struct platform_driver moxart_mdio_driver = {
> +	.probe = moxart_mdio_probe,
> +	.remove = moxart_mdio_remove,
> +	.driver = {
> +		.name = "moxart-mdio",
> +		.of_match_table = moxart_mdio_dt_ids,
> +	},
> +};
> +
> +module_platform_driver(moxart_mdio_driver);
> +
> +MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
> +MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index 138de83..fa1d69a 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -64,6 +64,18 @@ static int rtl8211e_config_intr(struct phy_device *phydev)
>   	return err;
>   }
>
> +/* RTL8201CP */
> +static struct phy_driver rtl8201cp_driver = {
> +	.phy_id         = 0x00008201,
> +	.name           = "RTL8201CP Ethernet",
> +	.phy_id_mask    = 0x0000ffff,
> +	.features       = PHY_BASIC_FEATURES,
> +	.flags          = PHY_HAS_INTERRUPT,
> +	.config_aneg    = &genphy_config_aneg,
> +	.read_status    = &genphy_read_status,
> +	.driver         = { .owner = THIS_MODULE,},
> +};
> +
>   /* RTL8211B */
>   static struct phy_driver rtl8211b_driver = {
>   	.phy_id		= 0x001cc912,
> @@ -98,6 +110,9 @@ static int __init realtek_init(void)
>   {
>   	int ret;
>
> +	ret = phy_driver_register(&rtl8201cp_driver);
> +	if (ret < 0)
> +		return -ENODEV;
>   	ret = phy_driver_register(&rtl8211b_driver);
>   	if (ret < 0)
>   		return -ENODEV;
>

Re: [PATCH] phy: Add MOXA RTL8201CP PHY support

[Jonas Jensen]

Thanks for the replies.

On 1 November 2013 18:01, Florian Fainelli <florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org> wrote:
>> +       dev_err(&bus->dev, "%s timed out\n", __func__);
>
> I would keep these as a debugging aid and not spawn error messages on
> the console by default.

Done.


>> +       snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
>
> If you only support device tree probing, this might be fine, but you
> might want to be safe in case someone does a !OF instantiation and
> also use pdev->id as an additional unique identifier, so something
> like:
>
> %s-%d-mii, pdev->name, pdev->id
>
> will work.

Done.


>> +       /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
>> +        * of_mdiobus_register() sets these PHY_POLL.
>> +        * Ideally, the interrupt from MAC controller could be used to
>> +        * detect link state changes, not polling, i.e. if there was
>> +        * a way phy_driver could set PHY_HAS_INTERRUPT but have that
>> +        * interrupt handled in ethernet drivercode.
>> +        */
>> +       for (i = 0; i < PHY_MAX_ADDR; i++)
>> +               bus->irq[i] = PHY_IGNORE_INTERRUPT;
>
> This type of configuration where the PHY interrupt is actually
> serviced by a link interrupt bit in the Ethernet MAC driver now works
> since 5ea94e768 ("phy: add phy_mac_interrupt() to use with
> PHY_IGNORE_INTERRUPT") so setting PHY_IGNORE_INTERRUPT is the right
> way to signal this and this will no longer make the PHY library poll
> for the link state.

Yes, I tried using phy_mac_interrupt() but had some difficulties (I'll
explain below). It seemed to be what I want and is wrapped with
EXPORT_SYMBOL().

However, as of next-20131104 I don't see how this works for DT probed
devices (those that set PHY_IGNORE_INTERRUPT).

As I tried to explain in my comment, of_mdiobus_register() assigns
PHY_POLL to the IRQ array:

drivers/of/of_mdio.c
..
int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
{
..
        /* Clear all the IRQ properties */
        if (mdio->irq)
                for (i=0; i<PHY_MAX_ADDR; i++)
                        mdio->irq[i] = PHY_POLL;
..
        for_each_available_child_of_node(np, child) {
..
                if (mdio->irq) {
                        mdio->irq[addr] = irq_of_parse_and_map(child, 0);
                        if (!mdio->irq[addr])
                                mdio->irq[addr] = PHY_POLL;
                }
..


PHY_IGNORE_INTERRUPT || PHY_POLL is not a valid interrupt.
The library ends up toggling (polling) between PHY_RUNNING and PHY_CHANGELINK:


drivers/net/phy/phy.c:
..
void phy_state_machine(struct work_struct *work)
{
..
                case PHY_RUNNING:
                        pr_info("%s: %s: PHY_RUNNING\n", __func__,
dev_name(&phydev->dev));
                        /* Only register a CHANGE if we are
                         * polling or ignoring interrupts
                         */
                        if (!phy_interrupt_is_valid(phydev))
                                phydev->state = PHY_CHANGELINK;
                        break;
..

include/linux/phy.h:
..
static inline bool phy_interrupt_is_valid(struct phy_device *phydev)
{
        return phydev->irq != PHY_POLL && phydev->irq != PHY_IGNORE_INTERRUPT;
}
..


This is why I ended up setting PHY_IGNORE_INTERRUPT and the comment
about its effectiveness. Polling works but the extra reads on the bus
seem unnecessary.
Ideas how they can be eliminated are appreciated.


Another problem, when phy_mac_interrupt() is called from NAPI it looks
like it's trying to take a lock it already has. I tried moving it out
of poll, placing it directly in IRQ handler, with the same result:

[   18.230000] moxart-ethernet 90900000.mac eth0: moxart_poll: PHYSTS_CHG
[   18.240000]
[   18.240000] =================================
[   18.240000] [ INFO: inconsistent lock state ]
[   18.240000] 3.12.0-rc7-next-20131104+ #1067 Not tainted
[   18.240000] ---------------------------------
[   18.240000] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
[   18.240000] kworker/0:1/123 [HC0[0]:SC0[0]:HE1:SE1] takes:
[   18.240000]  ((&dev->phy_queue)){+.?...}, at: [<c0028c08>]
process_one_work+0x13c/0x430
[   18.240000] {IN-SOFTIRQ-W} state was registered at:
[   18.240000]   [<c0055648>] mark_lock+0x144/0x670
[   18.240000]   [<c005777c>] __lock_acquire+0x5e4/0x1c24
[   18.240000]   [<c00592cc>] lock_acquire+0x6c/0x80
[   18.240000]   [<c002a024>] flush_work+0x44/0x278
[   18.240000]   [<c002a2e0>] __cancel_work_timer+0x88/0x124
[   18.240000]   [<c002a390>] cancel_work_sync+0x14/0x18
[   18.240000]   [<c01b0190>] phy_mac_interrupt+0x20/0x40
[   18.240000]   [<c01b3450>] moxart_poll+0x2b4/0x4b4
[   18.240000]   [<c01fe3c8>] net_rx_action+0x130/0x22c
[   18.240000]   [<c00174cc>] __do_softirq+0xe8/0x238
[   18.240000]   [<c0017a2c>] irq_exit+0xac/0xfc
[   18.240000]   [<c0009b40>] handle_IRQ+0x3c/0x8c
[   18.240000]   [<c0008534>] handle_irq+0x98/0xa8
[   18.240000]   [<c000c478>] __irq_svc+0x38/0x68
[   18.240000]   [<c00487ec>] rcu_idle_exit+0x78/0xdc
[   18.240000]   [<c0040618>] cpu_startup_entry+0x88/0x130
[   18.240000]   [<c026d3c8>] rest_init+0xb8/0xe0
[   18.240000]   [<c033ea1c>] start_kernel+0x298/0x2dc
[   18.240000] irq event stamp: 2659
[   18.240000] hardirqs last  enabled at (2659): [<c0276298>]
_raw_spin_unlock_irq+0x2c/0x60
[   18.240000] hardirqs last disabled at (2658): [<c02760f0>]
_raw_spin_lock_irq+0x28/0x78
[   18.240000] softirqs last  enabled at (2654): [<c0017568>]
__do_softirq+0x184/0x238
[   18.240000] softirqs last disabled at (2637): [<c0017a2c>] irq_exit+0xac/0xfc
[   18.240000]
[   18.240000] other info that might help us debug this:
[   18.240000]  Possible unsafe locking scenario:
[   18.240000]
[   18.240000]        CPU0
[   18.240000]        ----
[   18.240000]   lock([   18.240000] moxart-ethernet 90900000.mac
eth0: TX ring end reached
[   18.240000] (&dev->phy_queue));
[   18.240000]   <Interrupt>
[   18.240000]     lock((&dev->phy_queue));
[   18.240000]
[   18.240000]  *** DEADLOCK ***
[   18.240000]
[   18.240000] 1 lock held by kworker/0:1/123:
[   18.240000]  #0:  (events){.+.+..}, at: [<c0028c08>]
process_one_work+0x13c/0x430
[   18.240000]
[   18.240000] stack backtrace:
[   18.240000] CPU: 0 PID: 123 Comm: kworker/0:1 Not tainted
3.12.0-rc7-next-20131104+ #1067
[   18.240000] Workqueue: events phy_change
[   18.240000] [<c000d214>] (unwind_backtrace+0x0/0xf4) from
[<c000b964>] (show_stack+0x18/0x1c)
[   18.240000] [<c000b964>] (show_stack+0x18/0x1c) from [<c0271614>]
(dump_stack+0x20/0x28)
[   18.240000] [<c0271614>] (dump_stack+0x20/0x28) from [<c026fee0>]
(print_usage_bug.part.26+0x220/0x288)
[   18.240000] [<c026fee0>] (print_usage_bug.part.26+0x220/0x288) from
[<c0055b3c>] (mark_lock+0x638/0x670)
[   18.240000] [<c0055b3c>] (mark_lock+0x638/0x670) from [<c00577c4>]
(__lock_acquire+0x62c/0x1c24)
[   18.240000] [<c00577c4>] (__lock_acquire+0x62c/0x1c24) from
[<c00592cc>] (lock_acquire+0x6c/0x80)
[   18.240000] [<c00592cc>] (lock_acquire+0x6c/0x80) from [<c0028c70>]
(process_one_work+0x1a4/0x430)
[   18.240000] [<c0028c70>] (process_one_work+0x1a4/0x430) from
[<c0029304>] (worker_thread+0x13c/0x3dc)
[   18.240000] [<c0029304>] (worker_thread+0x13c/0x3dc) from
[<c002f500>] (kthread+0xb8/0xd4)
[   18.240000] [<c002f500>] (kthread+0xb8/0xd4) from [<c0009360>]
(ret_from_fork+0x14/0x34)
[   18.610000] libphy: phy_change


>> +       ret = of_mdiobus_register(bus, np);
>> +       if (ret < 0)
>> +               return ret;
>
> You still need to call mdiobus_free() here in case registration fails.

Done.


>> +/* RTL8201CP */
>> +static struct phy_driver rtl8201cp_driver = {
>> +       .phy_id         = 0x00008201,
>> +       .name           = "RTL8201CP Ethernet",
>> +       .phy_id_mask    = 0x0000ffff,
>> +       .features       = PHY_BASIC_FEATURES,
>
> If this PHY is internal to your SoC (same die/package) you should also
> add PHY_IS_INTERNAL to get a consistent ethtool reporting (among
> others).

I was wondering about that, and now I'm sure it should not be set, the
physical chip is separate, as can be seen here:

https://lh4.googleusercontent.com/-A-2FXDrObU8/UMcMc_K2vEI/AAAAAAAABwg/ldaLZ7ps1P4/w1331-h998-no/UC-7112-LX-picture4.jpg


Best regards,
Jonas
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Re: [PATCH] phy: Add MOXA RTL8201CP PHY support

[Florian Fainelli]

2013/11/4 Jonas Jensen <jonas.jensen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
> Thanks for the replies.
>
> On 1 November 2013 18:01, Florian Fainelli <florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org> wrote:
>>> +       dev_err(&bus->dev, "%s timed out\n", __func__);
>>
>> I would keep these as a debugging aid and not spawn error messages on
>> the console by default.
>
> Done.
>
>
>>> +       snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
>>
>> If you only support device tree probing, this might be fine, but you
>> might want to be safe in case someone does a !OF instantiation and
>> also use pdev->id as an additional unique identifier, so something
>> like:
>>
>> %s-%d-mii, pdev->name, pdev->id
>>
>> will work.
>
> Done.
>
>
>>> +       /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
>>> +        * of_mdiobus_register() sets these PHY_POLL.
>>> +        * Ideally, the interrupt from MAC controller could be used to
>>> +        * detect link state changes, not polling, i.e. if there was
>>> +        * a way phy_driver could set PHY_HAS_INTERRUPT but have that
>>> +        * interrupt handled in ethernet drivercode.
>>> +        */
>>> +       for (i = 0; i < PHY_MAX_ADDR; i++)
>>> +               bus->irq[i] = PHY_IGNORE_INTERRUPT;
>>
>> This type of configuration where the PHY interrupt is actually
>> serviced by a link interrupt bit in the Ethernet MAC driver now works
>> since 5ea94e768 ("phy: add phy_mac_interrupt() to use with
>> PHY_IGNORE_INTERRUPT") so setting PHY_IGNORE_INTERRUPT is the right
>> way to signal this and this will no longer make the PHY library poll
>> for the link state.
>
> Yes, I tried using phy_mac_interrupt() but had some difficulties (I'll
> explain below). It seemed to be what I want and is wrapped with
> EXPORT_SYMBOL().
>
> However, as of next-20131104 I don't see how this works for DT probed
> devices (those that set PHY_IGNORE_INTERRUPT).
>
> As I tried to explain in my comment, of_mdiobus_register() assigns
> PHY_POLL to the IRQ array:
>
> drivers/of/of_mdio.c
> ..
> int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
> {
> ..
>         /* Clear all the IRQ properties */
>         if (mdio->irq)
>                 for (i=0; i<PHY_MAX_ADDR; i++)
>                         mdio->irq[i] = PHY_POLL;

You are right, I missed that part. We can't really assign a dedicated
interrupt line for your PHY, so we need another way of dealing with
these PHY interrupts present at the Ethernet MAC level.

[snip]

> This is why I ended up setting PHY_IGNORE_INTERRUPT and the comment
> about its effectiveness. Polling works but the extra reads on the bus
> seem unnecessary.
> Ideas how they can be eliminated are appreciated.

As of today, the only way to work around it is not to use
of_mdiobus_register() and use mdiobus_register() directly which will
allow you to properly describe such a configuration.

>
>
> Another problem, when phy_mac_interrupt() is called from NAPI it looks
> like it's trying to take a lock it already has. I tried moving it out
> of poll, placing it directly in IRQ handler, with the same result:
>
> [   18.230000] moxart-ethernet 90900000.mac eth0: moxart_poll: PHYSTS_CHG
> [   18.240000]
> [   18.240000] =================================
> [   18.240000] [ INFO: inconsistent lock state ]
> [   18.240000] 3.12.0-rc7-next-20131104+ #1067 Not tainted
> [   18.240000] ---------------------------------
> [   18.240000] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
> [   18.240000] kworker/0:1/123 [HC0[0]:SC0[0]:HE1:SE1] takes:
> [   18.240000]  ((&dev->phy_queue)){+.?...}, at: [<c0028c08>]
> process_one_work+0x13c/0x430
> [   18.240000] {IN-SOFTIRQ-W} state was registered at:
> [   18.240000]   [<c0055648>] mark_lock+0x144/0x670
> [   18.240000]   [<c005777c>] __lock_acquire+0x5e4/0x1c24
> [   18.240000]   [<c00592cc>] lock_acquire+0x6c/0x80
> [   18.240000]   [<c002a024>] flush_work+0x44/0x278
> [   18.240000]   [<c002a2e0>] __cancel_work_timer+0x88/0x124
> [   18.240000]   [<c002a390>] cancel_work_sync+0x14/0x18
> [   18.240000]   [<c01b0190>] phy_mac_interrupt+0x20/0x40
> [   18.240000]   [<c01b3450>] moxart_poll+0x2b4/0x4b4
> [   18.240000]   [<c01fe3c8>] net_rx_action+0x130/0x22c
> [   18.240000]   [<c00174cc>] __do_softirq+0xe8/0x238
> [   18.240000]   [<c0017a2c>] irq_exit+0xac/0xfc
> [   18.240000]   [<c0009b40>] handle_IRQ+0x3c/0x8c
> [   18.240000]   [<c0008534>] handle_irq+0x98/0xa8
> [   18.240000]   [<c000c478>] __irq_svc+0x38/0x68
> [   18.240000]   [<c00487ec>] rcu_idle_exit+0x78/0xdc
> [   18.240000]   [<c0040618>] cpu_startup_entry+0x88/0x130
> [   18.240000]   [<c026d3c8>] rest_init+0xb8/0xe0
> [   18.240000]   [<c033ea1c>] start_kernel+0x298/0x2dc
> [   18.240000] irq event stamp: 2659
> [   18.240000] hardirqs last  enabled at (2659): [<c0276298>]
> _raw_spin_unlock_irq+0x2c/0x60
> [   18.240000] hardirqs last disabled at (2658): [<c02760f0>]
> _raw_spin_lock_irq+0x28/0x78
> [   18.240000] softirqs last  enabled at (2654): [<c0017568>]
> __do_softirq+0x184/0x238
> [   18.240000] softirqs last disabled at (2637): [<c0017a2c>] irq_exit+0xac/0xfc
> [   18.240000]
> [   18.240000] other info that might help us debug this:
> [   18.240000]  Possible unsafe locking scenario:
> [   18.240000]
> [   18.240000]        CPU0
> [   18.240000]        ----
> [   18.240000]   lock([   18.240000] moxart-ethernet 90900000.mac
> eth0: TX ring end reached
> [   18.240000] (&dev->phy_queue));
> [   18.240000]   <Interrupt>
> [   18.240000]     lock((&dev->phy_queue));
> [   18.240000]
> [   18.240000]  *** DEADLOCK ***
> [   18.240000]
> [   18.240000] 1 lock held by kworker/0:1/123:
> [   18.240000]  #0:  (events){.+.+..}, at: [<c0028c08>]
> process_one_work+0x13c/0x430
> [   18.240000]
> [   18.240000] stack backtrace:
> [   18.240000] CPU: 0 PID: 123 Comm: kworker/0:1 Not tainted
> 3.12.0-rc7-next-20131104+ #1067
> [   18.240000] Workqueue: events phy_change
> [   18.240000] [<c000d214>] (unwind_backtrace+0x0/0xf4) from
> [<c000b964>] (show_stack+0x18/0x1c)
> [   18.240000] [<c000b964>] (show_stack+0x18/0x1c) from [<c0271614>]
> (dump_stack+0x20/0x28)
> [   18.240000] [<c0271614>] (dump_stack+0x20/0x28) from [<c026fee0>]
> (print_usage_bug.part.26+0x220/0x288)
> [   18.240000] [<c026fee0>] (print_usage_bug.part.26+0x220/0x288) from
> [<c0055b3c>] (mark_lock+0x638/0x670)
> [   18.240000] [<c0055b3c>] (mark_lock+0x638/0x670) from [<c00577c4>]
> (__lock_acquire+0x62c/0x1c24)
> [   18.240000] [<c00577c4>] (__lock_acquire+0x62c/0x1c24) from
> [<c00592cc>] (lock_acquire+0x6c/0x80)
> [   18.240000] [<c00592cc>] (lock_acquire+0x6c/0x80) from [<c0028c70>]
> (process_one_work+0x1a4/0x430)
> [   18.240000] [<c0028c70>] (process_one_work+0x1a4/0x430) from
> [<c0029304>] (worker_thread+0x13c/0x3dc)
> [   18.240000] [<c0029304>] (worker_thread+0x13c/0x3dc) from
> [<c002f500>] (kthread+0xb8/0xd4)
> [   18.240000] [<c002f500>] (kthread+0xb8/0xd4) from [<c0009360>]
> (ret_from_fork+0x14/0x34)
> [   18.610000] libphy: phy_change

Ok, I will take a look into this, I realize that I was calling this
from a workqueue which won't show the locking problem, thanks for the
report.

>
>
>>> +       ret = of_mdiobus_register(bus, np);
>>> +       if (ret < 0)
>>> +               return ret;
>>
>> You still need to call mdiobus_free() here in case registration fails.
>
> Done.
>
>
>>> +/* RTL8201CP */
>>> +static struct phy_driver rtl8201cp_driver = {
>>> +       .phy_id         = 0x00008201,
>>> +       .name           = "RTL8201CP Ethernet",
>>> +       .phy_id_mask    = 0x0000ffff,
>>> +       .features       = PHY_BASIC_FEATURES,
>>
>> If this PHY is internal to your SoC (same die/package) you should also
>> add PHY_IS_INTERNAL to get a consistent ethtool reporting (among
>> others).
>
> I was wondering about that, and now I'm sure it should not be set, the
> physical chip is separate, as can be seen here:
>
> https://lh4.googleusercontent.com/-A-2FXDrObU8/UMcMc_K2vEI/AAAAAAAABwg/ldaLZ7ps1P4/w1331-h998-no/UC-7112-LX-picture4.jpg

Right, then make that a separate patch instead.
--
Florian



-- 
Florian
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Re: [PATCH] phy: Add MOXA RTL8201CP PHY support

[Grant Likely]

On Mon, 4 Nov 2013 09:51:24 -0800, Florian Fainelli <f.fainelli@gmail.com> wrote:
> 2013/11/4 Jonas Jensen <jonas.jensen@gmail.com>:
> > This is why I ended up setting PHY_IGNORE_INTERRUPT and the comment
> > about its effectiveness. Polling works but the extra reads on the bus
> > seem unnecessary.
> > Ideas how they can be eliminated are appreciated.
> 
> As of today, the only way to work around it is not to use
> of_mdiobus_register() and use mdiobus_register() directly which will
> allow you to properly describe such a configuration.

of_mdiobus_register() can be changed. One option: If the caller knows
what it wants to happen in the case of no interrupt, then it can be
added as an argument to of_mdiobus_register(). No need to work around
this in an ugly way.

Is setting the irq to PHY_POLL something that should be done for the
entire bus, or only for a handful of PHYs?

g.

[PATCH v2] phy: Add MOXA MDIO driver

[Jonas Jensen]

The MOXA UC-711X hardware(s) has an ethernet controller that seem
to be developed internally. The IC used is "RTL8201CP".

This patch adds an MDIO driver which handles the MII bus.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
---

Notes:
    Thanks for the feedback.
    
    Besides what is below I plan to submit changes suggested by
    Grant as a separate patch (to Documentation/devicetree/bindings/net/phy.txt)
    
    Changes since v1:
    
    1. split changes to drivers/net/phy/realtek.c into separate patch
    
    driver code:
    2. use dev_dbg() instead of dev_err()
    3. use id "%s-%d-mii" instead of "%s-mii"
    4. call mdiobus_free() on of_mdiobus_register() failure
    
    DT binding document:
    5. remove it, submitting changes (to Documentation/devicetree/bindings/net/moxa,moxart-mac.txt) along with changes to the driver
    
    Applies to next-20131105

 drivers/net/phy/Kconfig       |   7 ++
 drivers/net/phy/Makefile      |   1 +
 drivers/net/phy/mdio-moxart.c | 201 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 209 insertions(+)
 create mode 100644 drivers/net/phy/mdio-moxart.c

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 342561a..9b5d46c 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -154,6 +154,13 @@ config MDIO_SUN4I
 	  interface units of the Allwinner SoC that have an EMAC (A10,
 	  A12, A10s, etc.)
 
+config MDIO_MOXART
+        tristate "MOXA ART MDIO interface support"
+        depends on ARCH_MOXART
+        help
+          This driver supports the MDIO interface found in the network
+          interface units of the MOXA ART SoC
+
 config MDIO_BUS_MUX
 	tristate
 	depends on OF_MDIO
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 23a2ab2..9013dfa 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -31,3 +31,4 @@ obj-$(CONFIG_MDIO_BUS_MUX)	+= mdio-mux.o
 obj-$(CONFIG_MDIO_BUS_MUX_GPIO)	+= mdio-mux-gpio.o
 obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) += mdio-mux-mmioreg.o
 obj-$(CONFIG_MDIO_SUN4I)	+= mdio-sun4i.o
+obj-$(CONFIG_MDIO_MOXART)	+= mdio-moxart.o
diff --git a/drivers/net/phy/mdio-moxart.c b/drivers/net/phy/mdio-moxart.c
new file mode 100644
index 0000000..a5741cb
--- /dev/null
+++ b/drivers/net/phy/mdio-moxart.c
@@ -0,0 +1,201 @@
+/* MOXA ART Ethernet (RTL8201CP) MDIO interface driver
+ *
+ * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include <linux/of_mdio.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define REG_PHY_CTRL            0
+#define REG_PHY_WRITE_DATA      4
+
+/* REG_PHY_CTRL */
+#define MIIWR                   BIT(27) /* init write sequence (auto cleared)*/
+#define MIIRD                   BIT(26)
+#define REGAD_MASK              0x3e00000
+#define PHYAD_MASK              0x1f0000
+#define MIIRDATA_MASK           0xffff
+
+/* REG_PHY_WRITE_DATA */
+#define MIIWDATA_MASK           0xffff
+
+struct moxart_mdio_data {
+	void __iomem		*base;
+};
+
+static int moxart_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
+{
+	struct moxart_mdio_data *data = bus->priv;
+	u32 ctrl = 0;
+	unsigned int count = 5;
+
+	dev_dbg(&bus->dev, "%s\n", __func__);
+
+	ctrl |= MIIRD | ((mii_id << 16) & PHYAD_MASK) |
+		((regnum << 21) & REGAD_MASK);
+
+	writel(ctrl, data->base + REG_PHY_CTRL);
+
+	do {
+		ctrl = readl(data->base + REG_PHY_CTRL);
+
+		if (!(ctrl & MIIRD))
+			return ctrl & MIIRDATA_MASK;
+
+		mdelay(10);
+		count--;
+	} while (count > 0);
+
+	dev_dbg(&bus->dev, "%s timed out\n", __func__);
+
+	return -ETIMEDOUT;
+}
+
+static int moxart_mdio_write(struct mii_bus *bus, int mii_id,
+			     int regnum, u16 value)
+{
+	struct moxart_mdio_data *data = bus->priv;
+	u32 ctrl = 0;
+	unsigned int count = 5;
+
+	dev_dbg(&bus->dev, "%s\n", __func__);
+
+	ctrl |= MIIWR | ((mii_id << 16) & PHYAD_MASK) |
+		((regnum << 21) & REGAD_MASK);
+
+	value &= MIIWDATA_MASK;
+
+	writel(value, data->base + REG_PHY_WRITE_DATA);
+	writel(ctrl, data->base + REG_PHY_CTRL);
+
+	do {
+		ctrl = readl(data->base + REG_PHY_CTRL);
+
+		if (!(ctrl & MIIWR))
+			return 0;
+
+		mdelay(10);
+		count--;
+	} while (count > 0);
+
+	dev_dbg(&bus->dev, "%s timed out\n", __func__);
+
+	return -ETIMEDOUT;
+}
+
+static int moxart_mdio_reset(struct mii_bus *bus)
+{
+	int data, i;
+
+	for (i = 0; i < PHY_MAX_ADDR; i++) {
+		data = moxart_mdio_read(bus, i, MII_BMCR);
+		if (data < 0)
+			continue;
+
+		data |= BMCR_RESET;
+		if (moxart_mdio_write(bus, i, MII_BMCR, data) < 0)
+			continue;
+	}
+
+	return 0;
+}
+
+static int moxart_mdio_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct mii_bus *bus;
+	struct moxart_mdio_data *data;
+	struct resource *res;
+	int ret, i;
+
+	bus = mdiobus_alloc_size(sizeof(*data));
+	if (!bus)
+		return -ENOMEM;
+
+	bus->name = "MOXA ART Ethernet MII";
+	bus->read = &moxart_mdio_read;
+	bus->write = &moxart_mdio_write;
+	bus->reset = &moxart_mdio_reset;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d-mii", pdev->name, pdev->id);
+	bus->parent = &pdev->dev;
+
+	bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
+			GFP_KERNEL);
+	if (!bus->irq) {
+		ret = -ENOMEM;
+		goto err_out_free_mdiobus;
+	}
+
+	/* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
+	 * of_mdiobus_register() sets these PHY_POLL.
+	 * Ideally, the interrupt from MAC controller could be used to
+	 * detect link state changes, not polling, i.e. if there was
+	 * a way phy_driver could set PHY_HAS_INTERRUPT but have that
+	 * interrupt handled in ethernet drivercode.
+	 */
+	for (i = 0; i < PHY_MAX_ADDR; i++)
+		bus->irq[i] = PHY_IGNORE_INTERRUPT;
+
+	data = bus->priv;
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	data->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(data->base)) {
+		ret = PTR_ERR(data->base);
+		goto err_out_free_mdiobus;
+	}
+
+	ret = of_mdiobus_register(bus, np);
+	if (ret < 0)
+		goto err_out_free_mdiobus;
+
+	platform_set_drvdata(pdev, bus);
+
+	return 0;
+
+err_out_free_mdiobus:
+	mdiobus_free(bus);
+	return ret;
+}
+
+static int moxart_mdio_remove(struct platform_device *pdev)
+{
+	struct mii_bus *bus = platform_get_drvdata(pdev);
+
+	mdiobus_unregister(bus);
+	mdiobus_free(bus);
+
+	return 0;
+}
+
+static const struct of_device_id moxart_mdio_dt_ids[] = {
+	{ .compatible = "moxa,moxart-mdio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
+
+static struct platform_driver moxart_mdio_driver = {
+	.probe = moxart_mdio_probe,
+	.remove = moxart_mdio_remove,
+	.driver = {
+		.name = "moxart-mdio",
+		.of_match_table = moxart_mdio_dt_ids,
+	},
+};
+
+module_platform_driver(moxart_mdio_driver);
+
+MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
+MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
1.8.2.1

Re: [PATCH v2] phy: Add MOXA MDIO driver

[David Miller]

From: Jonas Jensen <jonas.jensen@gmail.com>
Date: Tue,  5 Nov 2013 16:55:01 +0100

> The MOXA UC-711X hardware(s) has an ethernet controller that seem
> to be developed internally. The IC used is "RTL8201CP".
> 
> This patch adds an MDIO driver which handles the MII bus.
> 
> Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>

Applied, thanks Jonas.