Date:   Tue, 15 Aug 2023 14:54:28 +0800
From:   Yinbo Zhu <zhuyinbo@...ngson.cn>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Minas Harutyunyan <hminas@...opsys.com>, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jianmin Lv <lvjianmin@...ngson.cn>,
        wanghongliang@...ngson.cn, loongson-kernel@...ts.loongnix.cn,
        zhuyinbo@...ngson.cn
Subject: Re: [PATCH v2] usb: dwc2: add pci_device_id driver_data parse support



在 2023/8/14 下午11:12, Greg Kroah-Hartman 写道:
> On Mon, Aug 14, 2023 at 04:25:56PM +0800, Yinbo Zhu wrote:
>>
>>
>> Friendly ping ?
> 
> Sorry, missed this.
> 
>> 在 2023/7/21 下午4:13, Yinbo Zhu 写道:
>>>
>>> Hi greg k-h,
>>>
>>> I'm sorry to bother you,  I want to request your opinion on what I have
>>> said.
>>>
>>> Thanks,
>>> Yinbo
>>>
>>>
>>> 在 2023/6/14 上午11:55, zhuyinbo 写道:
>>>>
>>>>
>>>> 在 2023/6/13 下午6:19, Greg Kroah-Hartman 写道:
>>>>> On Mon, Jun 12, 2023 at 02:51:05PM +0800, zhuyinbo wrote:
>>>>>>
>>>>>>
>>>>>> 在 2023/6/9 下午5:31, Greg Kroah-Hartman 写道:
>>>>>>> On Fri, Jun 09, 2023 at 11:25:15AM +0200, Greg Kroah-Hartman wrote:
>>>>>>>> On Fri, Jun 09, 2023 at 05:07:03PM +0800, zhuyinbo wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 在 2023/6/9 下午2:13, Greg Kroah-Hartman 写道:
>>>>>>>>>> On Fri, Jun 09, 2023 at 10:50:47AM +0800, Yinbo Zhu wrote:
>>>>>>>>>>> The dwc2 driver has everything we need to run in PCI mode except
>>>>>>>>>>> for pci_device_id driver_data parse.  With that to set Loongson
>>>>>>>>>>> dwc2 element and added identified as PCI_VENDOR_ID_LOONGSON
>>>>>>>>>>> and PCI_DEVICE_ID_LOONGSON_DWC2 in dwc2_pci_ids, the Loongson
>>>>>>>>>>> dwc2 controller will work.
>>>>>>>>>>>
>>>>>>>>>>> Signed-off-by: Yinbo Zhu <zhuyinbo@...ngson.cn>
>>>>>>>>>>> ---
>>>>>>>>>>> Change in v2:
>>>>>>>>>>>          1. Move the dwc2 pci ID from pci_ids.h to params.c.
>>>>>>>>>>>          2. Add some code logic to ensure
>>>>>>>>>>> that the current device is
>>>>>>>>>>>             a PCI device.
>>>>>>>>>>>          3. Fix the compile issue when dwc2 pci driver as module.
>>>>>>>>>>>
>>>>>>>>>>>      drivers/usb/dwc2/core.h   |  1 +
>>>>>>>>>>>      drivers/usb/dwc2/params.c | 39
>>>>>>>>>>> ++++++++++++++++++++++++++++++++++++++-
>>>>>>>>>>>      drivers/usb/dwc2/pci.c    | 14 +-------------
>>>>>>>>>>>      3 files changed, 40 insertions(+), 14 deletions(-)
>>>>>>>>>>>
>>>>>>>>>>> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
>>>>>>>>>>> index 0bb4c0c845bf..c92a1da46a01 100644
>>>>>>>>>>> --- a/drivers/usb/dwc2/core.h
>>>>>>>>>>> +++ b/drivers/usb/dwc2/core.h
>>>>>>>>>>> @@ -1330,6 +1330,7 @@ irqreturn_t
>>>>>>>>>>> dwc2_handle_common_intr(int irq, void
>>>>>>>>>>> *dev);
>>>>>>>>>>>      /* The device ID match table */
>>>>>>>>>>>      extern const struct of_device_id dwc2_of_match_table[];
>>>>>>>>>>>      extern const struct acpi_device_id dwc2_acpi_match[];
>>>>>>>>>>> +extern const struct pci_device_id dwc2_pci_ids[];
>>>>>>>>>>>      int dwc2_lowlevel_hw_enable(struct dwc2_hsotg *hsotg);
>>>>>>>>>>>      int dwc2_lowlevel_hw_disable(struct dwc2_hsotg *hsotg);
>>>>>>>>>>> diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
>>>>>>>>>>> index 21d16533bd2f..6b68a8830781 100644
>>>>>>>>>>> --- a/drivers/usb/dwc2/params.c
>>>>>>>>>>> +++ b/drivers/usb/dwc2/params.c
>>>>>>>>>>> @@ -7,9 +7,14 @@
>>>>>>>>>>>      #include <linux/module.h>
>>>>>>>>>>>      #include <linux/of_device.h>
>>>>>>>>>>>      #include <linux/usb/of.h>
>>>>>>>>>>> +#include <linux/pci_ids.h>
>>>>>>>>>>> +#include <linux/pci.h>
>>>>>>>>>>>      #include "core.h"
>>>>>>>>>>> +#define PCI_PRODUCT_ID_HAPS_HSOTG    0xabc0
>>>>>>>>>>> +#define PCI_DEVICE_ID_LOONGSON_DWC2    0x7a04
>>>>>>>>>>> +
>>>>>>>>>>>      static void dwc2_set_bcm_params(struct dwc2_hsotg *hsotg)
>>>>>>>>>>>      {
>>>>>>>>>>>          struct dwc2_core_params *p = &hsotg->params;
>>>>>>>>>>> @@ -55,6 +60,14 @@ static void
>>>>>>>>>>> dwc2_set_jz4775_params(struct dwc2_hsotg
>>>>>>>>>>> *hsotg)
>>>>>>>>>>> !device_property_read_bool(hsotg->dev, "disable-over-current");
>>>>>>>>>>>      }
>>>>>>>>>>> +static void dwc2_set_loongson_params(struct dwc2_hsotg *hsotg)
>>>>>>>>>>> +{
>>>>>>>>>>> +    struct dwc2_core_params *p = &hsotg->params;
>>>>>>>>>>> +
>>>>>>>>>>> +    p->phy_utmi_width = 8;
>>>>>>>>>>> +    p->power_down = DWC2_POWER_DOWN_PARAM_PARTIAL;
>>>>>>>>>>> +}
>>>>>>>>>>> +
>>>>>>>>>>>      static void dwc2_set_x1600_params(struct dwc2_hsotg *hsotg)
>>>>>>>>>>>      {
>>>>>>>>>>>          struct dwc2_core_params *p = &hsotg->params;
>>>>>>>>>>> @@ -281,6 +294,23 @@ const struct
>>>>>>>>>>> acpi_device_id dwc2_acpi_match[] = {
>>>>>>>>>>>      };
>>>>>>>>>>>      MODULE_DEVICE_TABLE(acpi, dwc2_acpi_match);
>>>>>>>>>>> +const struct pci_device_id dwc2_pci_ids[] = {
>>>>>>>>>>> +    {
>>>>>>>>>>> +
>>>>>>>>>>> PCI_DEVICE(PCI_VENDOR_ID_SYNOPSYS,
>>>>>>>>>>> PCI_PRODUCT_ID_HAPS_HSOTG),
>>>>>>>>>>> +    },
>>>>>>>>>>> +    {
>>>>>>>>>>> +        PCI_DEVICE(PCI_VENDOR_ID_STMICRO,
>>>>>>>>>>> +               PCI_DEVICE_ID_STMICRO_USB_OTG),
>>>>>>>>>>> +    },
>>>>>>>>>>> +    {
>>>>>>>>>>> +
>>>>>>>>>>> PCI_DEVICE(PCI_VENDOR_ID_LOONGSON,
>>>>>>>>>>> PCI_DEVICE_ID_LOONGSON_DWC2),
>>>>>>>>>>> +        .driver_data = (unsigned long)dwc2_set_loongson_params,
>>>>>>>>>>> +    },
>>>>>>>>>>> +    { /* end: all zeroes */ }
>>>>>>>>>>> +};
>>>>>>>>>>> +MODULE_DEVICE_TABLE(pci, dwc2_pci_ids);
>>>>>>>>>>> +EXPORT_SYMBOL_GPL(dwc2_pci_ids);
>>>>>>>>>>> +
>>>>>>>>>>>      static void dwc2_set_param_otg_cap(struct dwc2_hsotg *hsotg)
>>>>>>>>>>>      {
>>>>>>>>>>>          switch (hsotg->hw_params.op_mode) {
>>>>>>>>>>> @@ -927,13 +957,20 @@ int
>>>>>>>>>>> dwc2_init_params(struct dwc2_hsotg
>>>>>>>>>>> *hsotg)
>>>>>>>>>>>          if (match && match->data) {
>>>>>>>>>>>              set_params = match->data;
>>>>>>>>>>>              set_params(hsotg);
>>>>>>>>>>> -    } else {
>>>>>>>>>>> +    } else if (!match) {
>>>>>>>>>>>              const struct acpi_device_id *amatch;
>>>>>>>>>>> +        const struct pci_device_id *pmatch = NULL;
>>>>>>>>>>>              amatch =
>>>>>>>>>>> acpi_match_device(dwc2_acpi_match,
>>>>>>>>>>> hsotg->dev);
>>>>>>>>>>>              if (amatch && amatch->driver_data) {
>>>>>>>>>>>                  set_params = (set_params_cb)amatch->driver_data;
>>>>>>>>>>>                  set_params(hsotg);
>>>>>>>>>>> +        } else if (!amatch)
>>>>>>>>>>> +            pmatch =
>>>>>>>>>>> pci_match_id(dwc2_pci_ids,
>>>>>>>>>>> to_pci_dev(hsotg->dev->parent));
>>>>>>>>>>
>>>>>>>>>> At this point in time, how can you guarantee that the parent device
>>>>>>>>>> really is a PCI one?  This function is being called from a platform
>>>>>>>>>> device callback, and platform devices should
>>>>>>>>>> NEVER be a child of a PCI
>>>>>>>>>> device, as that's not how PCI or platform devices work.
>>>>>>>>>>
>>>>>>>>>> So how is this even possible?
>>>>>>>>>>
>>>>>>>>>> confused,
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Hi greg k-h,
>>>>>>>>>
>>>>>>>>> My current considerations are based on that the dwc2 drivers support
>>>>>>>>> three types of devices, they are Platform device / ACPI device / PCI
>>>>>>>>> device, and The dwc2/platform.c can all cover the three type dwc2
>>>>>>>>> device, no matter how it is registered.
>>>>>>>>>
>>>>>>>>> So, when a dwc2 device wasn't platform device and acpi device and It
>>>>>>>>> will be a PCI device, and the the dwc2/pci.c will register a dwc2
>>>>>>>>> platform device that dwc2 device is a device
>>>>>>>>> that in dwc2/platform.c's
>>>>>>>>> dwc2_driver_probe.  the "&dwc2->dev->parent" is
>>>>>>>>> the "hsotg->dev->parent"
>>>>>>>>> and it was also the &pci->dev.
>>>>>>>>
>>>>>>>> That's wrong, a PCI device should NEVER register a
>>>>>>>> platform device under
>>>>>>>> it, as obviously it's not a platform device at all.
>>>>>>>>
>>>>>>>> So please work to fix that layering violation here, as that's not
>>>>>>>> correct and will cause problems as you are showing here.
>>>>>>>>
>>>>>>>>> So, We can use "to_pci_dev(hsotg->dev->parent)" to gain a dwc2 pci
>>>>>>>>> device.
>>>>>>>>
>>>>>>>> No, not if the parent is something else as you have no way of knowing
>>>>>>>> this at this point in time.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> 1)  DWC2 PCI device driver (drivers/usb/dwc2/pci.c) :
>>>>>>>>>
>>>>>>>>> static int dwc2_pci_probe(struct pci_dev *pci,
>>>>>>>>>                              const struct pci_device_id *id)
>>>>>>>>> {
>>>>>>>>> ...
>>>>>>>>>            struct platform_device  *dwc2;
>>>>>>>>> ...
>>>>>>>>>            struct device           *dev = &pci->dev;
>>>>>>>>> ...
>>>>>>>>>      dwc2 = platform_device_alloc("dwc2", PLATFORM_DEVID_AUTO);
>>>>>>>>>                    //"dwc2" was used to match dwc2 platform driver
>>>>>>>>
>>>>>>>> This needs to be fixed, it's not ok at all.  Just use the real PCI
>>>>>>>> device here please.
>>>>>>>
>>>>>>> Also, to be fair, you didn't cause this problem, I
>>>>>>> missed it previously.
>>>>>>> But fixing it is essential, and will be required in order to get your
>>>>>>> changes to work properly.  Sorry about that.
>>>>>>>
>>>>>>
>>>>>>
>>>>>> Hi greg k-h,
>>>>>>
>>>>>> Actually,  the dwc2/pci.c's  platform_device_add(dwc2) was create a
>>>>>> platform device called "dwc2"  ensure dwc2/platform's dwc2_driver_probe
>>>>>> function can be called. After all, the dwc2/platform's
>>>>>> dwc2_driver_probe
>>>>>> is the one that truly initializes the dwc2 controller. In addition, the
>>>>>> same applies to dwc3 code.
>>>>>
>>>>> Yes, it does create a platform device, but ALSO a real platform device
>>>>> could be present in the system for the driver, one that is NOT a child
>>>>> of a PCI device, right?
>>>>
>>>>
>>>> I don't get it that why need dwc2 was a child of pci. and I just need
>>>> the dwc2->dev.parent's parent device was a child of dwc2 pci device.
>>>> If my patch conditions are met (match and amatch was NULL), this always
>>>> seems to hold true.
>>>>
>>>> dwc2_pci_probe ()
>>>> {
>>>> struct platform_device  *dwc2;
>>>> struct device *dev = &pci->dev;
>>>> dwc2->dev.parent = dev;
>>>> platform_device_add(dwc2);
>>>> }
>>>>
>>>>>
>>>>> It's not this way with your system, but it could be that way for many
>>>>> others, right?  And if so, the assumption that you can just poke around
>>>>> in the parent device and assume that you know what bus it is on is just
>>>>> wrong and will break things.
>>>>
>>>>
>>>> What you said about "system" that is unrelated to the kernel driver? I
>>>> think it should be system independent and it depends entirely on the
>>>> kernel driver, for the driver, everyone is the same. the behavior of the
>>>> driver is known, and currently I have not found any other risks it
>>>> poses.  Additionally, the key is that the issue that my patch is
>>>> addressing is a common issue. For example, if the following devices are
>>>> designed as PCI devices on hardware, they will always encounter the same
>>>> problem.
>>>>
>>>> const struct of_device_id dwc2_of_match_table[] = {
>>>>          { .compatible = "brcm,bcm2835-usb", .data =
>>>> dwc2_set_bcm_params },
>>>>          { .compatible = "hisilicon,hi6220-usb", .data =
>>>> dwc2_set_his_params },
>>>>          { .compatible = "ingenic,jz4775-otg", .data =
>>>> dwc2_set_jz4775_params },
>>>>          { .compatible = "ingenic,jz4780-otg", .data =
>>>> dwc2_set_jz4775_params },
>>>>          { .compatible = "ingenic,x1000-otg", .data =
>>>> dwc2_set_jz4775_params },
>>>>          { .compatible = "ingenic,x1600-otg", .data =
>>>> dwc2_set_x1600_params },
>>>>          { .compatible = "ingenic,x1700-otg", .data =
>>>> dwc2_set_x1600_params },
>>>>          { .compatible = "ingenic,x1830-otg", .data =
>>>> dwc2_set_x1600_params },
>>>>          { .compatible = "ingenic,x2000-otg", .data =
>>>> dwc2_set_x2000_params },
>>>>          { .compatible = "rockchip,rk3066-usb", .data =
>>>> dwc2_set_rk_params },
>>>>          { .compatible = "lantiq,arx100-usb", .data =
>>>> dwc2_set_ltq_params },
>>>>          { .compatible = "lantiq,xrx200-usb", .data =
>>>> dwc2_set_ltq_params },
>>>>
>>>>>
>>>>> You should NEVER be poking around in the information for the parent
>>>>> device, UNLESS you have just created the child device yourself and the
>>>>> ONLY code path is one that you have full control over.
>>>>>
>>>>> Does that make more sense?
>>>>
>>>>
>>>> Yes, but it seems inappropriate for dwc2. For this, please allow me
>>>> to parse some of my comments in v1:
>>>>
>>>>
>>>> Actually, I use pci_match_id was due to I noticed that xhci-pci.c,
>>>> ehci-pci.c and ohci-pci.c was all use it . and I don't use it in
>>>> dwc2/pci.c was considering set dwc2 element need dpend on elements.c and
>>>> platform.c, and usb driver (ohci,echi,xhci) was a relatively
>>>> indepent device driver when to operate usb controler. but dwc2 was not.
>>>>
>>>> If I fource the element setting of dwc2 element in dwc2/pci.c. It
>>>> will be following case. This will cause problems with
>>>> element-initial
>>>> function or element-check function.
>>>>
>>>> 1. initial dwc2 element.
>>>> 2. check the setting of dwc2 element whether was suitable
>>>> 3. set dwc2 element.
>>>>
>>>> or
>>>>
>>>> 1. set dwc2 element.
>>>> 2. initial dwc2 element.
>>>> 3. check the setting of dwc2 element whether was suitable
>>>>
>>>> The corresponding code call process as follows:
>>>>
>>>> 1. dwc2_set_default_params(hsotg);
>>>> 2. dwc2_get_device_properties(hsotg);
>>>> 3. dwc2_check_params(hsotg);
>>>> 4. dwc2_set_loongson_params;
>>>>
>>>> or
>>>>
>>>> 1. dwc2_set_loongson_params;
>>>> 2. dwc2_set_default_params(hsotg);
>>>> 3. dwc2_get_device_properties(hsotg);
>>>> 4. dwc2_check_params(hsotg);
>>>>
>>>> But the platform dwc2 device or acpi dwc2 device was all following case
>>>> and It seems was correct order.
>>>>
>>>> 1. dwc2_set_default_params(hsotg);
>>>> 2. dwc2_get_device_properties(hsotg);
>>>> 3. dwc2_set_loongson_params;
>>>> 4. dwc2_check_params(hsotg);
> 
> I don't remember at all here anymore, sorry.  I suggest doing what you
> think is best here and resubmit and I will be glad to review it then.


Okay, I will resend v2, please help review.

Thanks,
Yinbo.

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