Re: [PATCHv4 2/6] phy: improved lookup method

[Vivek Gautam]

On Tue, Nov 11, 2014 at 12:12 PM, Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
> Hi,
>
> On Friday 31 October 2014 06:03 PM, Vivek Gautam wrote:
>> Hi Heikki,
>>
>>
>> On Fri, Oct 17, 2014 at 8:09 PM, Heikki Krogerus
>> <heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
>>> Removes the need for the phys to be aware of their users
>>> even when not using DT. The method is copied from clkdev.c.
>>>
>>> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
>>> Tested-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
>>> ---
>>>  Documentation/phy.txt   |  66 ++++++++---------------
>>>  drivers/phy/phy-core.c  | 135 +++++++++++++++++++++++++++++++++++++++++++++++-
>>>  include/linux/phy/phy.h |  27 ++++++++++
>>>  3 files changed, 183 insertions(+), 45 deletions(-)
>>>
>>> diff --git a/Documentation/phy.txt b/Documentation/phy.txt
>>> index c6594af..8add515 100644
>>> --- a/Documentation/phy.txt
>>> +++ b/Documentation/phy.txt
>>> @@ -54,18 +54,14 @@ The PHY driver should create the PHY in order for other peripheral controllers
>>>  to make use of it. The PHY framework provides 2 APIs to create the PHY.
>>>
>>>  struct phy *phy_create(struct device *dev, struct device_node *node,
>>> -                      const struct phy_ops *ops,
>>> -                      struct phy_init_data *init_data);
>>> +                      const struct phy_ops *ops);
>>>  struct phy *devm_phy_create(struct device *dev, struct device_node *node,
>>> -                           const struct phy_ops *ops,
>>> -                           struct phy_init_data *init_data);
>>> +                           const struct phy_ops *ops);
>>>
>>>  The PHY drivers can use one of the above 2 APIs to create the PHY by passing
>>> -the device pointer, phy ops and init_data.
>>> +the device pointer and phy ops.
>>>  phy_ops is a set of function pointers for performing PHY operations such as
>>> -init, exit, power_on and power_off. *init_data* is mandatory to get a reference
>>> -to the PHY in the case of non-dt boot. See section *Board File Initialization*
>>> -on how init_data should be used.
>>> +init, exit, power_on and power_off.
>>>
>>>  Inorder to dereference the private data (in phy_ops), the phy provider driver
>>>  can use phy_set_drvdata() after creating the PHY and use phy_get_drvdata() in
>>> @@ -137,42 +133,24 @@ There are exported APIs like phy_pm_runtime_get, phy_pm_runtime_get_sync,
>>>  phy_pm_runtime_put, phy_pm_runtime_put_sync, phy_pm_runtime_allow and
>>>  phy_pm_runtime_forbid for performing PM operations.
>>>
>>> -8. Board File Initialization
>>> -
>>> -Certain board file initialization is necessary in order to get a reference
>>> -to the PHY in the case of non-dt boot.
>>> -Say we have a single device that implements 3 PHYs that of USB, SATA and PCIe,
>>> -then in the board file the following initialization should be done.
>>> -
>>> -struct phy_consumer consumers[] = {
>>> -       PHY_CONSUMER("dwc3.0", "usb"),
>>> -       PHY_CONSUMER("pcie.0", "pcie"),
>>> -       PHY_CONSUMER("sata.0", "sata"),
>>> -};
>>> -PHY_CONSUMER takes 2 parameters, first is the device name of the controller
>>> -(PHY consumer) and second is the port name.
>>> -
>>> -struct phy_init_data init_data = {
>>> -       .consumers = consumers,
>>> -       .num_consumers = ARRAY_SIZE(consumers),
>>> -};
>>> -
>>> -static const struct platform_device pipe3_phy_dev = {
>>> -       .name = "pipe3-phy",
>>> -       .id = -1,
>>> -       .dev = {
>>> -               .platform_data = {
>>> -                       .init_data = &init_data,
>>> -               },
>>> -       },
>>> -};
>>> -
>>> -then, while doing phy_create, the PHY driver should pass this init_data
>>> -       phy_create(dev, ops, pdata->init_data);
>>> -
>>> -and the controller driver (phy consumer) should pass the port name along with
>>> -the device to get a reference to the PHY
>>> -       phy_get(dev, "pcie");
>>> +8. PHY Mappings
>>> +
>>> +In order to get reference to a PHY without help from DeviceTree, the framework
>>> +offers lookups which can be compared to clkdev that allow clk structures to be
>>> +bound to devices. A lookup can be made statically by directly registering
>>> +phy_lookup structure which contains the name of the PHY device, the name of the
>>> +device which the PHY will be bind to and Connection ID string. Alternatively a
>>> +lookup can be made during runtime when a handle to the struct phy already
>>> +exists.
>>> +
>>> +The framework offers the following APIs for registering and unregistering the
>>> +lookups.
>>> +
>>> +void phy_register_lookup(struct phy_lookup *pl);
>>> +int phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id);
>>> +
>>> +void phy_unregister_lookup(struct phy_lookup *pl);
>>> +void phy_remove_lookup(struct phy *phy, const char *con_id, const char *dev_id);
>>>
>>>  9. DeviceTree Binding
>>>
>>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>>> index ff5eec5..c8d0f66 100644
>>> --- a/drivers/phy/phy-core.c
>>> +++ b/drivers/phy/phy-core.c
>>> @@ -26,6 +26,7 @@
>>>  static struct class *phy_class;
>>>  static DEFINE_MUTEX(phy_provider_mutex);
>>>  static LIST_HEAD(phy_provider_list);
>>> +static LIST_HEAD(phys);
>>>  static DEFINE_IDA(phy_ida);
>>>
>>>  static void devm_phy_release(struct device *dev, void *res)
>>> @@ -84,6 +85,138 @@ static struct phy *phy_lookup(struct device *device, const char *port)
>>>         return ERR_PTR(-ENODEV);
>>>  }
>>>
>>> +/**
>>> + * phy_register_lookup() - register PHY/device association
>>> + * @pl: association to register
>>> + */
>>> +void phy_register_lookup(struct phy_lookup *pl)
>>> +{
>>> +       mutex_lock(&phy_provider_mutex);
>>> +       list_add_tail(&pl->node, &phys);
>>> +       mutex_unlock(&phy_provider_mutex);
>>> +}
>>> +
>>> +/**
>>> + * phy_unregister_lookup() - remove PHY/device association
>>> + * @pl: association to be removed
>>> + */
>>> +void phy_unregister_lookup(struct phy_lookup *pl)
>>> +{
>>> +       mutex_lock(&phy_provider_mutex);
>>> +       list_del(&pl->node);
>>> +       mutex_unlock(&phy_provider_mutex);
>>> +}
>>> +
>>> +/**
>>> + * phy_create_lookup() - allocate and register PHY/device association
>>> + * @phy: the phy of the association
>>> + * @con_id: connection ID string on device
>>> + * @dev_id: the device of the association
>>> + *
>>> + * Creates and registers phy_lookup entry.
>>> + */
>>> +int phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id)
>>> +{
>>> +       struct phy_lookup *pl;
>>> +
>>> +       if (!phy || (!dev_id && !con_id))
>>> +               return -EINVAL;
>>> +
>>> +       pl = kzalloc(sizeof(*pl), GFP_KERNEL);
>>> +       if (!pl)
>>> +               return -ENOMEM;
>>> +
>>> +       pl->phy_name = dev_name(phy->dev.parent);
>>> +       pl->dev_id = dev_id;
>>> +       pl->con_id = con_id;
>>> +
>>> +       phy_register_lookup(pl);
>>> +
>>> +       return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(phy_create_lookup);
>>> +
>>> +/**
>>> + * phy_remove_lookup() - find and remove PHY/device association
>>> + * @phy: the phy of the association
>>> + * @con_id: connection ID string on device
>>> + * @dev_id: the device of the association
>>> + *
>>> + * Finds and unregisters phy_lookup entry that was created with
>>> + * phy_create_lookup().
>>> + */
>>> +void phy_remove_lookup(struct phy *phy, const char *con_id, const char *dev_id)
>>> +{
>>> +       struct phy_lookup *pl;
>>> +
>>> +       if (!phy || (!dev_id && !con_id))
>>> +               return;
>>> +
>>> +       list_for_each_entry(pl, &phys, node)
>>> +               if (!strcmp(pl->phy_name, dev_name(phy->dev.parent)) &&
>>> +                   !strcmp(pl->dev_id, dev_id) &&
>>> +                   !strcmp(pl->con_id, con_id)) {
>>> +                       phy_unregister_lookup(pl);
>>> +                       kfree(pl);
>>> +                       return;
>>> +               }
>>> +}
>>> +EXPORT_SYMBOL_GPL(phy_remove_lookup);
>>> +
>>> +static struct phy *phy_find(struct device *dev, const char *con_id)
>>> +{
>>> +       const char *dev_id = dev ? dev_name(dev) : NULL;
>>> +       int match, best_found = 0, best_possible = 0;
>>> +       struct phy *phy = ERR_PTR(-ENODEV);
>>> +       struct phy_lookup *p, *pl = NULL;
>>> +
>>> +       if (dev_id)
>>> +               best_possible += 2;
>>> +       if (con_id)
>>> +               best_possible += 1;
>>> +
>>> +       list_for_each_entry(p, &phys, node) {
>>> +               match = 0;
>>> +               if (p->dev_id) {
>>> +                       if (!dev_id || strcmp(p->dev_id, dev_id))
>>> +                               continue;
>>> +                       match += 2;
>>> +               }
>>> +               if (p->con_id) {
>>> +                       if (!con_id || strcmp(p->con_id, con_id))
>>> +                               continue;
>>> +                       match += 1;
>>> +               }
>>> +
>>> +               if (match > best_found) {
>>> +                       pl = p;
>>> +                       if (match != best_possible)
>>> +                               best_found = match;
>>> +                       else
>>> +                               break;
>>> +               }
>>> +       }
>>> +
>>> +       if (pl) {
>>> +               struct class_dev_iter iter;
>>> +               struct device *phy_dev;
>>> +
>>> +               class_dev_iter_init(&iter, phy_class, NULL, NULL);
>>> +               while ((phy_dev = class_dev_iter_next(&iter))) {
>>
>> We have the case with phy-exynos5-usbdrd driver, which registers two
>> phys usb2-phy and usb3-phy
>> both being used by xhci (after dwc3 creates a lookup table).
>>
>> The phy_dev is coming same for both the PHYs, and that's the reason
>> when i try to get
>> "usb2-phy" and "usb3-phy" i end up getting only usb2-phy.
>> This is happening with V4 of this patch; V3 seems fine. The only
>> differnece i see is
>> we are creating the phy_lookup_table using phy_dev->parent.
>>
>> Is there something that i am missing ?
>
> looks like a genuine problem.
>>
>>> +                       if (!strcmp(dev_name(phy_dev->parent), pl->phy_name)) {
>
> here there are two phys which has the same parent and the first one that
> matches will be returned. Hence you always get "usb2-phy".
>
> IIUC just with device names of parent, we won't be able to get the PHY. We need
> another 'variable' to differentiate it's children.

> Or have *phy* pointer directly in the lookup table like how clk driver does?

We do create the lookup table with actual *phy* pointer isn't it ?
Like if you see Heikki's last patch in this series:
[PATCHv4 6/6] usb: dwc3: host: convey the PHYs to xhci
We do pass the usb2_phy and usb3_phy pointers to phy_create_lookup().

But while finding the phy (using phy_find()) we don't seem to be
utilizing these.

>
> Thanks
> Kishon
>>> +                               phy = to_phy(phy_dev);
>>> +                               break;
>>> +                       }
>>> +               }
>>> +               class_dev_iter_exit(&iter);
>>> +       }
>>> +
>>> +       /* fall-back to the old lookup method for now */
>>> +       if (IS_ERR(phy))
>>> +               phy = phy_lookup(dev, con_id);
>>> +       return phy;
>>> +}
>>> +
>>>  static struct phy_provider *of_phy_provider_lookup(struct device_node *node)
>>>  {
>>>         struct phy_provider *phy_provider;
>>> @@ -463,7 +596,7 @@ struct phy *phy_get(struct device *dev, const char *string)
>>>                         string);
>>>                 phy = _of_phy_get(dev->of_node, index);
>>>         } else {
>>> -               phy = phy_lookup(dev, string);
>>> +               phy = phy_find(dev, string);
>>>         }
>>>         if (IS_ERR(phy))
>>>                 return phy;
>>> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
>>> index 9fda683..2696b95 100644
>>> --- a/include/linux/phy/phy.h
>>> +++ b/include/linux/phy/phy.h
>>> @@ -110,6 +110,20 @@ struct phy_init_data {
>>>         .port           = _port,                                \
>>>  }
>>>
>>> +struct phy_lookup {
>>> +       struct list_head node;
>>> +       const char *phy_name;
>>> +       const char *dev_id;
>>> +       const char *con_id;
>>> +};
>>> +
>>> +#define PHY_LOOKUP(a, b, c)    \
>>> +       {                               \
>>> +               .phy_name = a,          \
>>> +               .dev_id = b,            \
>>> +               .con_id = c,            \
>>> +       }
>>> +
>>>  #define        to_phy(a)       (container_of((a), struct phy, dev))
>>>
>>>  #define        of_phy_provider_register(dev, xlate)    \
>>> @@ -174,6 +188,10 @@ struct phy_provider *__devm_of_phy_provider_register(struct device *dev,
>>>  void of_phy_provider_unregister(struct phy_provider *phy_provider);
>>>  void devm_of_phy_provider_unregister(struct device *dev,
>>>         struct phy_provider *phy_provider);
>>> +void phy_register_lookup(struct phy_lookup *pl);
>>> +void phy_unregister_lookup(struct phy_lookup *pl);
>>> +int phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id);
>>> +void phy_remove_lookup(struct phy *phy, const char *con_id, const char *dev_id);
>>>  #else
>>>  static inline int phy_pm_runtime_get(struct phy *phy)
>>>  {
>>> @@ -345,6 +363,15 @@ static inline void devm_of_phy_provider_unregister(struct device *dev,
>>>         struct phy_provider *phy_provider)
>>>  {
>>>  }
>>> +static inline void phy_register_lookup(struct phy_lookup *pl) { }
>>> +static inline void phy_unregister_lookup(struct phy_lookup *pl) { }
>>> +static inline int
>>> +phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id)
>>> +{
>>> +       return 0;
>>> +}
>>> +static inline void phy_remove_lookup(struct phy *phy, const char *con_id,
>>> +                                    const char *dev_id) { }
>>>  #endif
>>>
>>>  #endif /* __DRIVERS_PHY_H */
>>> --
>>> 2.1.1
>>>
>>> --
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>>
>>
>>
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-- 
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India
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