Message-ID: <2023081454-deduct-opal-f806@gregkh>
Date:   Mon, 14 Aug 2023 17:12:33 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Yinbo Zhu <zhuyinbo@...ngson.cn>
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
Subject: Re: [PATCH v2] usb: dwc2: add pci_device_id driver_data parse support

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.

thanks,

greg k-h

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