Hi Kishon,
On 15/05/2014 11:01, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Thursday 15 May 2014 12:31 PM, Gregory CLEMENT wrote:
>> Hi Kishon,
>>
>> On 14/05/2014 17:35, Gregory CLEMENT wrote:
>>> On 14/05/2014 16:27, Kishon Vijay Abraham I wrote:
>>>> Hi,
>>>>
>>>> On Tuesday 13 May 2014 03:11 PM, Gregory CLEMENT wrote:
>>>>> On 13/05/2014 10:06, Gregory CLEMENT wrote:
>>>>>> On 13/05/2014 07:53, Kishon Vijay Abraham I wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> On Sunday 11 May 2014 11:47 PM, Thomas Petazzoni wrote:
>>>>>>>> From: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>>>>>>>>
>>>>>>>> The Armada 375 SoC comes with an USB2 host and device controller and
>>>>>>>> an USB3 controller. The USB cluster control register allows to manage
>>>>>>>> common features of both USB controllers.
>>>>>>>>
>>>>>>>> This commit adds a driver integrated in the generic PHY framework to
>>>>>>>> control this USB cluster feature.
>>>>>>>>
>>>>>>>> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>>>>>>>> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
>>>>>>>> ---
>>>>>>>> drivers/phy/Kconfig | 6 ++
>>>>>>>> drivers/phy/Makefile | 1 +
>>>>>>>> drivers/phy/phy-armada375-usb2.c | 157 +++++++++++++++++++++++++++++++++++++++
>>>>>>>> 3 files changed, 164 insertions(+)
>>>>>>>> create mode 100644 drivers/phy/phy-armada375-usb2.c
>>>>>>>>
>>>>>>>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>>>>>>>> index 3bb05f1..e63cf9d 100644
>>>>>>>> --- a/drivers/phy/Kconfig
>>>>>>>> +++ b/drivers/phy/Kconfig
>>>>>>>> @@ -15,6 +15,12 @@ config GENERIC_PHY
>>>>>>>> phy users can obtain reference to the PHY. All the users of this
>>>>>>>> framework should select this config.
>>>>>>>>
>>>>>>>> +config ARMADA375_USBCLUSTER_PHY
>>>>>>>> + def_bool y
>>>>>>>> + depends on MACH_ARMADA_375 || COMPILE_TEST
>>>>>>>> + depends on OF
>>>>>>>> + select GENERIC_PHY
>>>>>>>> +
>>>>>>>> config PHY_EXYNOS_MIPI_VIDEO
>>>>>>>> tristate "S5P/EXYNOS SoC series MIPI CSI-2/DSI PHY driver"
>>>>>>>> depends on HAS_IOMEM
>>>>>>>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>>>>>>>> index 2faf78e..47d5a86 100644
>>>>>>>> --- a/drivers/phy/Makefile
>>>>>>>> +++ b/drivers/phy/Makefile
>>>>>>>> @@ -3,6 +3,7 @@
>>>>>>>> #
>>>>>>>>
>>>>>>>> obj-$(CONFIG_GENERIC_PHY) += phy-core.o
>>>>>>>> +obj-$(CONFIG_ARMADA375_USBCLUSTER_PHY) += phy-armada375-usb2.o
>>>>>>>> obj-$(CONFIG_BCM_KONA_USB2_PHY) += phy-bcm-kona-usb2.o
>>>>>>>> obj-$(CONFIG_PHY_EXYNOS_DP_VIDEO) += phy-exynos-dp-video.o
>>>>>>>> obj-$(CONFIG_PHY_EXYNOS_MIPI_VIDEO) += phy-exynos-mipi-video.o
>>>>>>>> diff --git a/drivers/phy/phy-armada375-usb2.c b/drivers/phy/phy-armada375-usb2.c
>>>>>>>> new file mode 100644
>>>>>>>> index 0000000..a6f746d
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/drivers/phy/phy-armada375-usb2.c
>>>>>>>> @@ -0,0 +1,157 @@
>>>>>>>> +/*
>>>>>>>> + * USB cluster support for Armada 375 platform.
>>>>>>>> + *
>>>>>>>> + * Copyright (C) 2014 Marvell
>>>>>>>> + *
>>>>>>>> + * Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>>>>>>>> + *
>>>>>>>> + * This file is licensed under the terms of the GNU General Public
>>>>>>>> + * License version 2 or later. This program is licensed "as is"
>>>>>>>> + * without any warranty of any kind, whether express or implied.
>>>>>>>> + *
>>>>>>>> + * Armada 375 comes with an USB2 host and device controller and an
>>>>>>>> + * USB3 controller. The USB cluster control register allows to manage
>>>>>>>> + * common features of both USB controllers.
>>>>>>>> + */
>>>>>>>> +
>>>>>>>> +#include <linux/init.h>
>>>>>>>> +#include <linux/io.h>
>>>>>>>> +#include <linux/kernel.h>
>>>>>>>> +#include <linux/module.h>
>>>>>>>> +#include <linux/of_address.h>
>>>>>>>> +#include <linux/phy/phy.h>
>>>>>>>> +#include <linux/platform_device.h>
>>>>>>>> +#include <linux/slab.h>
>>>>>>>> +
>>>>>>>> +#define USB2_PHY_CONFIG_DISABLE BIT(0)
>>>>>>>> +
>>>>>>>> +/* The USB cluster allows to choose between two PHYs */
>>>>>>>> +#define NB_PHY 2
>>>>>>>> +
>>>>>>>> +enum {
>>>>>>>> + PHY_USB2 = 0,
>>>>>>>> + PHY_USB3 = 1,
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct armada375_cluster_phy {
>>>>>>>> + struct phy *phy;
>>>>>>>> + void __iomem *reg;
>>>>>>>> + bool enable;
>>>>>>>> + bool use_usb3;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct armada375_cluster_phy usb_cluster_phy[NB_PHY];
>>>>>>>> +
>>>>>>>> +static int armada375_usb_phy_init(struct phy *phy)
>>>>>>>> +{
>>>>>>>> + struct armada375_cluster_phy *cluster_phy = phy_get_drvdata(phy);
>>>>>>>> + u32 reg;
>>>>>>>
>>>>>>> This function should be protected since both your PHYs use this ops.
>>>>>>
>>>>>> Right
>>>>>
>>>>> Actually only one PHY can access this register. See the probe function,
>>>>> cluster_phy->enable is only set to true for one PHY.
>>>>>
>>>>>>
>>>>>>>> +
>>>>>>>> + if (!cluster_phy->enable)
>>>>>>>> + return -ENODEV;
>>>>>>>> +
>>>>>>>> + reg = readl(cluster_phy->reg);
>>>>>>>> + if (cluster_phy->use_usb3)
>>>>>>>> + reg |= USB2_PHY_CONFIG_DISABLE;
>>>>>>>> + else
>>>>>>>> + reg &= ~USB2_PHY_CONFIG_DISABLE;
>>>>>>>> + writel(reg, cluster_phy->reg);
>>>>>>>
>>>>>>> This is confusing since both your PHYs control the same bit?
>>>>>
>>>>> Same here at the end the bit is accessed by only one PHY.
>>>>>
>>>>>>>> +
>>>>>>>> + return 0;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static struct phy_ops armada375_usb_phy_ops = {
>>>>>>>> + .init = armada375_usb_phy_init,
>>>>>>>> + .owner = THIS_MODULE,
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static struct phy *armada375_usb_phy_xlate(struct device *dev,
>>>>>>>> + struct of_phandle_args *args)
>>>>>>>> +{
>>>>>>>> + if (WARN_ON(args->args[0] >= NB_PHY))
>>>>>>>> + return ERR_PTR(-ENODEV);
>>>>>>>> +
>>>>>>>> + return usb_cluster_phy[args->args[0]].phy;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static int armada375_usb_phy_probe(struct platform_device *pdev)
>>>>>>>> +{
>>>>>>>> + struct device *dev = &pdev->dev;
>>>>>>>> + struct phy *phy;
>>>>>>>> + struct phy_provider *phy_provider;
>>>>>>>> + void __iomem *usb_cluster_base;
>>>>>>>> + struct device_node *xhci_node;
>>>>>>>> + struct resource *res;
>>>>>>>> + int i;
>>>>>>>> +
>>>>>>>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>>>>>> + usb_cluster_base = devm_ioremap_resource(&pdev->dev, res);
>>>>>>>> + if (!usb_cluster_base)
>>>>>>>> + return -ENOMEM;
>>>>>>>> +
>>>>>>>> + for (i = 0; i < NB_PHY; i++) {
>>>>>>>
>>>>>>> For devices which have multiple PHYs, each PHY should be modelled as the
>>>>>>> sub-node of the *PHY provider* device node.
>>>>>>
>>>>>> Actually it is the opposite the same PHY is shared between the EHCI
>>>>>> and the xHCI controllers. It is more a PHY muxer than a PHY itself.
>>>>>>
>>>>>> I had to create 2 logical PHYs because once the phy_init() is called
>>>>>> by a USB driver then the .init ops is not called anymore by the next
>>>>>> call to phy_init(). One of the goal of this is to disable a port for
>>>>>> the USB controller which can't use it due to the configuration of the
>>>>>> USB cluster.
>>>>>>
>>>>>> But I can see how to make this two "pseudo" PHYs sub-node of the *PHY
>>>>>> provider* device node. It shouldn't change the internal logic of this
>>>>>> driver.
>>>>>
>>>>> I need to make a distinction when the PHY access by the xHCI or when
>>>>> it was access by the EHCI. If I create two new sub-node then I will
>>>>> also need to add a property to make this distinction. It seems a little
>>>>> overkill for the need.
>>>>
>>>> Alright, so you have a single PHY that can be used by either XHCI or EHCI? And
>>>> the use of PHY is mutually exclusive? How should it behave if you have both
>>>> XHCI and EHCI?
>>>
>>> if we have both XHCI and EHCI then it is the USB2_PHY_CONFIG_DISABLE which
>>> determine which one is used. By default we decide to select the XHCI.
>>>
>>>>
>>>> One way to configure the PHY to a particular mode is by passing it as phandle
>>>> arguments. I think you can use that to enable or disable USB2_PHY_CONFIG_DISABLE?
>>>
>>> actually it was more or less what I do:
>>> for the XHCI I use:
>>> phys = <&usbcluster 1>;
>>> which enable the USB2_PHY_CONFIG_DISABLE
>>>
>>> for the EHCI I use phys = <&usbcluster 0>;
>>> which disable the USB2_PHY_CONFIG_DISABLE
>>>
>>> If I had to create two PHY it was because of the behavior of
>>> phy_init(). I need to be able to disable a controller if it can't use
>>> the PHY. For this purpose my ops->init() exits in error. However
>>> phy_init() will call ops->init() only one time, then the internal
>>> counter init_count will be incremented, and the next call to phy_init
>>> will skip the call to ops->init. And the behavior is the same for
>>> phy_power_on().
>>>
>>> So given this I don't see how to do in an other way except by
>>> modifying the value of the counter in my ops.
>>
>> What do you prefer here? Keep the current implementation or using
>> only one PHY by passing a argument through the phandle and in the
>> same time hacking the init_count?
>
> I clearly don't prefer having of_find_compatible_node in PHY driver code. If
> you can find something without using that, it would be good.
>
> Maybe create an API in phy-core that invokes the call-backs without caring
> about the ref count and implement some sort of mutual exclusivity in your
> driver? However this needs to be reviewed and discussed.
Thanks for your feedback. This feature (usb cluster) is a nice to have
for the Armada 375 SoC, but is not mandatory for the USB support on
this SoC.
As I don't want to postpone the merge of the USB support for this. I
will resend a new patch series, without the usb-cluster support, to be
merged in 3.16 kernel. And in the same time I will submit a new series
with an extension of the phy-core API. if everything goes well, then
it will be also merged in 3.16, else it will be in the next release.
Thanks again for your time,
Gregory
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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