Subject: [PATCH 2/2] ehci-platform: Add support for controllers with big-endian regs / descriptors

From: [email-masked] (Hans de Goede)
Date: Wed, 22 Jan 2014 20:28:26 +0100

Hi,

On 01/21/2014 08:39 PM, Florian Fainelli wrote:
> 2014/1/21 Hans de Goede <[email-masked]>:
>> This uses the already documented devicetree booleans for this.
>
> (I would greatly appreciate if you could CC people who gave you
> feedback on this before)

Will do.

> A more informative commit message would be welcome, along with a
> reference to which Device Tree binding documentation you are referring
> to.

I've added a reference to the bindings doc in the commit msg for my next version.

>> Signed-off-by: Hans de Goede <[email-masked]>
>> ---
>>   drivers/usb/host/Kconfig         |  3 +++
>>   drivers/usb/host/ehci-platform.c | 33 +++++++++++++++++++++++++++++++--
>>   2 files changed, 34 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
>> index 237d7b1..4af41f3 100644
>> --- a/drivers/usb/host/Kconfig
>> +++ b/drivers/usb/host/Kconfig
>> @@ -256,6 +256,9 @@ config USB_EHCI_ATH79
>>   config USB_EHCI_HCD_PLATFORM
>>          tristate "Generic EHCI driver for a platform device"
>>          depends on !PPC_OF
>> +       # Support BE on architectures which have readl_be
>> +       select USB_EHCI_BIG_ENDIAN_DESC if (AVR32 || MIPS || MICROBLAZE || SPARC || PPC32 || PPC64)
>> +       select USB_EHCI_BIG_ENDIAN_MMIO if (AVR32 || MIPS || MICROBLAZE || SPARC || PPC32 || PPC64)
>
> I do not think this is that simple nor correct for at least Microblaze
> and MIPS since they can run in either BE or LE mode, and those
> specific platforms should already do the proper select at the
> board/SoC level. This *might* be correct for SPARC, PPC32 and PPC64,
> although I believe some specific PPC64 boards can run in little-endian
> mode like the P-series, SPARC might too.
>
> It seems to me that you should not touch this and keep the existing
> selects in place, if it turns out that the selects are missing the
> error messages you added below are catching those misuses.

As discussed with Alan, I will drop these lines from my next version.

>>          default n
>>          ---help---
>>            Adds an EHCI host driver for a generic platform device, which
>> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
>> index d8aebc0..5888abb 100644
>> --- a/drivers/usb/host/ehci-platform.c
>> +++ b/drivers/usb/host/ehci-platform.c
>> @@ -55,8 +55,10 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
>>
>>          hcd->has_tt = pdata->has_tt;
>>          ehci->has_synopsys_hc_bug = pdata->has_synopsys_hc_bug;
>> -       ehci->big_endian_desc = pdata->big_endian_desc;
>> -       ehci->big_endian_mmio = pdata->big_endian_mmio;
>> +       if (pdata->big_endian_desc)
>> +               ehci->big_endian_desc = 1;
>> +       if (pdata->big_endian_mmio)
>> +               ehci->big_endian_mmio = 1;
>>
>>          if (pdata->pre_setup) {
>>                  retval = pdata->pre_setup(hcd);
>> @@ -142,6 +144,7 @@ static int ehci_platform_probe(struct platform_device *dev)
>>          struct resource *res_mem;
>>          struct usb_ehci_pdata *pdata = dev_get_platdata(&dev->dev);
>>          struct ehci_platform_priv *priv;
>> +       struct ehci_hcd *ehci;
>>          int err, irq, clk = 0;
>>
>>          if (usb_disabled())
>> @@ -177,8 +180,34 @@ static int ehci_platform_probe(struct platform_device *dev)
>>          platform_set_drvdata(dev, hcd);
>>          dev->dev.platform_data = pdata;
>>          priv = hcd_to_ehci_priv(hcd);
>> +       ehci = hcd_to_ehci(hcd);
>>
>>          if (pdata == &ehci_platform_defaults && dev->dev.of_node) {
>> +               if (of_property_read_bool(dev->dev.of_node, "big-endian-regs"))
>> +                       ehci->big_endian_mmio = 1;
>> +
>> +               if (of_property_read_bool(dev->dev.of_node, "big-endian-desc"))
>> +                       ehci->big_endian_desc = 1;
>> +
>> +               if (of_property_read_bool(dev->dev.of_node, "big-endian"))
>> +                       ehci->big_endian_mmio = ehci->big_endian_desc = 1;
>
> Ok, so I am confused now, should you update
> pdata->ehci_big_endian_{desc,mmio} here or is it valid to directly
> modify ehci->big_endian_{desc,mmio}, is not there any risk  to undo
> what is done in ehci_platform_reset(), or is ehci_platform_reset()
> only called for non-DT cases?

Both the pdata checks in ehci_platform_reset() and the dt checks here only
ever set these flags, neither code path clears them. And in the dt case pdata
will be NULL and vice versa.

>
>> +
>> +#ifndef CONFIG_USB_EHCI_BIG_ENDIAN_MMIO
>> +               if (ehci->big_endian_mmio) {
>> +                       dev_err(&dev->dev,
>> +                               "Error big-endian-regs not compiled in\n");
>
> I do not think using the Device Tree property name would be very
> informative since this is supposed to guard against misconfigurations
> for both DT and non-DT enabled platforms

Nope this is in a dt only code path.

>> +                       err = -EINVAL;
>> +                       goto err_put_hcd;
>> +               }
>> +#endif
>> +#ifndef CONFIG_USB_EHCI_BIG_ENDIAN_DESC
>> +               if (ehci->big_endian_desc) {
>> +                       dev_err(&dev->dev,
>> +                               "Error big-endian-desc not compiled in\n");
>> +                       err = -EINVAL;
>> +                       goto err_put_hcd;
>
> And here "support for big-endian descriptors not enabled".
>
>> +               }
>> +#endif
>>                  priv->phy = devm_phy_get(&dev->dev, "usb");
>>                  if (IS_ERR(priv->phy)) {
>>                          err = PTR_ERR(priv->phy);

Regards,

Hans