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SubjectRe: [PATCH v10 5/5] usb: dwc3: add rockchip specific glue layer
Date

Hi,

"William.wu" <William.wu@rock-chips.com> writes:
>> William Wu <william.wu@rock-chips.com> writes:
>>> Add rockchip specific glue layer to support USB3 Peripheral mode
>>> and Host mode on rockchip platforms (e.g. rk3399).
>>>
>>> The DesignWare USB3 integrated in rockchip SoCs is a configurable
>>> IP Core which can be instantiated as Dual-Role Device (DRD), Host
>>> Only (XHCI) and Peripheral Only configurations.
>>>
>>> We use extcon notifier to manage usb cable detection and mode switch.
>>> Enable DWC3 PM runtime auto suspend to allow core enter runtime_suspend
>>> if USB cable is dettached. For host mode, it requires to keep whole
>>> DWC3 controller in reset state to hold pipe power state in P2 before
>>> initializing PHY. And it need to reconfigure USB PHY interface of DWC3
>>> core after deassert DWC3 controller reset.
>>>
>>> The current driver supports Host only and Peripheral Only well, for
>>> now, we will add support for OTG after we have it all stabilized.
>>>
>>> Signed-off-by: William Wu <william.wu@rock-chips.com>
>>> ---
>>> Changes in v10:
>>> - fix building error
>>>
>>> Changes in v9:
>>> - Add a new dwc3-rockchip.c driver for rk3399, rather than use dwc3-of-simple.c
>>>
>>> drivers/usb/dwc3/Kconfig | 9 +
>>> drivers/usb/dwc3/Makefile | 1 +
>>> drivers/usb/dwc3/core.c | 2 +-
>>> drivers/usb/dwc3/core.h | 1 +
>>> drivers/usb/dwc3/dwc3-rockchip.c | 441 +++++++++++++++++++++++++++++++++++++++
>> William, if you need to touch core dwc3 to introduce a glue layer,
>> you're doing it wrong.
>
> Sorry, I realized that it's not better to touch core dwc3 in a specific
> glue layer.
> I touched dwc3 in glue layer, because I want to support dual-role mode, and
> according to our dwc3 IP and usb3 PHY IP design, it need to reinit dwc3
> core
> whenever usb cable attached.
>
> Anyway, it's wrong to do that.:-[
>
>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>>> index e887b38..3da6215 100644
>>> --- a/drivers/usb/dwc3/core.c
>>> +++ b/drivers/usb/dwc3/core.c
>>> @@ -405,7 +405,7 @@ static void dwc3_cache_hwparams(struct dwc3 *dwc)
>>> * initialized. The PHY interfaces and the PHYs get initialized together with
>>> * the core in dwc3_core_init.
>>> */
>>> -static int dwc3_phy_setup(struct dwc3 *dwc)
>>> +int dwc3_phy_setup(struct dwc3 *dwc)
>> there's no way I'll let this slip through the cracks :-)
>
> Why I need dwc3_phy_setup in glue layer is because usb3 IP design
> in rockchip platform. If dwc3 works on host mode, it requires to put
> dwc3 controller in reset state before usb3 phy initializing,and after
> deassert reset, we need to reconfigure UTMI+ PHY interface because
> our dwc3 core can't configure PHY interface correctly.
>
> Thank you for give me a chance to explain it.:-)
>
>>
>>> diff --git a/drivers/usb/dwc3/dwc3-rockchip.c b/drivers/usb/dwc3/dwc3-rockchip.c
>>> new file mode 100644
>>> index 0000000..eeae1a9
>>> --- /dev/null
>>> +++ b/drivers/usb/dwc3/dwc3-rockchip.c
>>> @@ -0,0 +1,441 @@
>> [...]
>>
>>> +static int dwc3_rockchip_probe(struct platform_device *pdev)
>>> +{
>>> + struct dwc3_rockchip *rockchip;
>>> + struct device *dev = &pdev->dev;
>>> + struct device_node *np = dev->of_node, *child;
>>> + struct platform_device *child_pdev;
>>> +
>>> + unsigned int count;
>>> + int ret;
>>> + int i;
>>> +
>>> + rockchip = devm_kzalloc(dev, sizeof(*rockchip), GFP_KERNEL);
>>> +
>>> + if (!rockchip)
>>> + return -ENOMEM;
>>> +
>>> + count = of_clk_get_parent_count(np);
>>> + if (!count)
>>> + return -ENOENT;
>>> +
>>> + rockchip->num_clocks = count;
>>> +
>>> + rockchip->clks = devm_kcalloc(dev, rockchip->num_clocks,
>>> + sizeof(struct clk *), GFP_KERNEL);
>>> + if (!rockchip->clks)
>>> + return -ENOMEM;
>>> +
>>> + platform_set_drvdata(pdev, rockchip);
>>> +
>>> + rockchip->dev = dev;
>>> + rockchip->edev = NULL;
>>> +
>>> + pm_runtime_set_active(dev);
>>> + pm_runtime_enable(dev);
>>> + ret = pm_runtime_get_sync(dev);
>>> + if (ret < 0) {
>>> + dev_err(dev, "get_sync failed with err %d\n", ret);
>>> + goto err1;
>>> + }
>>> +
>>> + for (i = 0; i < rockchip->num_clocks; i++) {
>>> + struct clk *clk;
>>> +
>>> + clk = of_clk_get(np, i);
>>> + if (IS_ERR(clk)) {
>>> + while (--i >= 0)
>>> + clk_put(rockchip->clks[i]);
>>> + ret = PTR_ERR(clk);
>>> +
>>> + goto err1;
>>> + }
>>> +
>>> + ret = clk_prepare_enable(clk);
>>> + if (ret < 0) {
>>> + while (--i >= 0) {
>>> + clk_disable_unprepare(rockchip->clks[i]);
>>> + clk_put(rockchip->clks[i]);
>>> + }
>>> + clk_put(clk);
>>> +
>>> + goto err1;
>>> + }
>>> +
>>> + rockchip->clks[i] = clk;
>>> + }
>>> +
>>> + rockchip->otg_rst = devm_reset_control_get(dev, "usb3-otg");
>>> + if (IS_ERR(rockchip->otg_rst)) {
>>> + dev_err(dev, "could not get reset controller\n");
>>> + ret = PTR_ERR(rockchip->otg_rst);
>>> + goto err2;
>>> + }
>>> +
>>> + ret = dwc3_rockchip_extcon_register(rockchip);
>>> + if (ret < 0)
>>> + goto err2;
>>> +
>>> + child = of_get_child_by_name(np, "dwc3");
>>> + if (!child) {
>>> + dev_err(dev, "failed to find dwc3 core node\n");
>>> + ret = -ENODEV;
>>> + goto err3;
>>> + }
>>> +
>>> + /* Allocate and initialize the core */
>>> + ret = of_platform_populate(np, NULL, NULL, dev);
>>> + if (ret) {
>>> + dev_err(dev, "failed to create dwc3 core\n");
>>> + goto err3;
>>> + }
>>> +
>>> + child_pdev = of_find_device_by_node(child);
>>> + if (!child_pdev) {
>>> + dev_err(dev, "failed to find dwc3 core device\n");
>>> + ret = -ENODEV;
>>> + goto err4;
>>> + }
>>> +
>>> + rockchip->dwc = platform_get_drvdata(child_pdev);
>> No! You will *NOT* the core struct device. Don't even try to come up
>> with tricks like this.
>>
>> Let's do this: introduce a glue layer that gets peripheral-only
>> working. Remove PM for now, too. Start with something simple, get the
>> bare minimum working upstream and add more stuff as you go.
>>
>> Trying to do everything in one patch just makes it much more likely for
>> your patch to be NAKed. What you're doing here is bypassing all the
>> layering we've built. That won't work very well. The only thing you'll
>> get is for your patches to continue to be NAKed.
>>
>> Avoid the tricks and abuses. Just because you _can_ do it somehow, it
>> doesn't mean you _should_ do it :-)
>>
>> Your best option right now, is to remove PM and dual-role support and a
>> minimal glue layer supported.
>>
>> In fact, all you *really* need is to add a compatible to
>> dwc3-of-simple.c. That should be enough to get your dwc3 working. Don't
>> do anything more than that. For dual-role and PM, we can add it
>> generically to dwc3-of-simple.c when all pieces fall into place.
>>
> Ah, thanks very much for your kind explanation. I think I just only need
> to add a compatible to dwc3-of-simple.c,for now, and I have tested
> my dwc3, it worked well on peripheral only mode and host only mode
> without PM. Further, if dwc3-of-simple.c adds generic handling of dual-role
> and PM, I can improve our dwc3 feature.:-)

that's my point exactly. We can add more support generically so that
other platforms can benefit from the work. PM should be simple for
dwc3-of-simple.c. Dual-role will take a little more effort. In almost
there actually. There are a few missing pieces but it should be doable
(hopefully) within the next two major releases.

Your integration is no different than other companies' using DWC3 in
dual-role setup. For example TI's DWC3 have the same requirements as you
do, so it makes sense to add it straight to dwc3-core. Roger Quadros
(now in Cc) has been working on dual-role for TI's platforms and we've
been discussing about how to add missing pieces generically. Perhaps
you'd want to join the discussion.

--
balbi
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