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Date: Tue, 11 Nov 2014 14:20:39 +0530
From: Kishon Vijay Abraham I <kishon@...com>
To: Vivek Gautam <gautamvivek1987@...il.com>
CC: Vivek Gautam <gautam.vivek@...sung.com>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Linux USB Mailing List <linux-usb@...r.kernel.org>,
<andrew.kim@...el.com>
Subject: Re: [PATCHv4 2/6] phy: improved lookup method
Hi,
On Tuesday 11 November 2014 02:07 PM, Vivek Gautam wrote:
> On Tue, Nov 11, 2014 at 12:12 PM, Kishon Vijay Abraham I <kishon@...com> 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@...ux.intel.com> 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@...ux.intel.com>
>>>> Tested-by: Vivek Gautam <gautam.vivek@...sung.com>
>>>> ---
>>>> 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().
right, but phy_create_lookup doesn't store the *phy* pointer in the lookup table.
Thanks
Kishon
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