[U-Boot] [PATCH v2 05/13] usb: dwc3: change DWC3 core support code into a driver

[Masahiro Yamada]

Hi Roger,


2016-05-17 17:20 GMT+09:00 Roger Quadros <rogerq at ti.com>:
> Hi Masahiro,
>
> On 16/05/16 15:51, Masahiro Yamada wrote:
>> Synopsys DWC3 IP generally works with an SoC-specific glue layer.
>> DT binding for that is like this:
>>
>>   usb3_glue {
>>           compatible = "foo,dwc3";
>>           ...
>>
>>           usb3 {
>>                   compatible = "snps,dwc3";
>>                   ...
>>           };
>>   };
>>
>> The glue layer initializes some SoC-specific parts, then populates
>> the child DWC3 core.  To see how it works, refer to
>>
>>   drivers/usb/dwc3/dwc3-exynos.c
>>   drivers/usb/dwc3/dwc3-keystone.c
>>   drivers/usb/dwc3/dwc3-omap.c
>>   drivers/usb/dwc3/dwc3-st.c
>>
>> of Linux Kernel.
>>
>> This commit implements a driver compatible with "snps,dwc3", allowing
>> to use the same binding in U-Boot.  The glue layer can be simply
>> implemented based on Simple Bus Uclass.
>>
>> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
>> Reviewed-by: Marek Vasut <marex at denx.de>
>> ---
>>
>> Changes in v2: None
>>
>>  drivers/usb/host/xhci-dwc3.c | 71 +++++++++++++++++++++++++++++++++++++++++++-
>
> "snps,dwc3" compatible is for the dual-role controller that implements both
> device and host controllers.

I know this fact.
The "snps,dwc3" on my SoC only works in host mode, though.


> So calling the driver xhci-dwc3.c is a bit misleading.



I think we have separate work for
 - drivers/usb/host/xhci-dwc3.c   (only for host mode)
 - drivers/usb/dwc3/*             (currently, for gadget ??)

This is unfortunate, though.


>>  1 file changed, 70 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/host/xhci-dwc3.c b/drivers/usb/host/xhci-dwc3.c
>> index 33961cd..c7c8324 100644
>> --- a/drivers/usb/host/xhci-dwc3.c
>> +++ b/drivers/usb/host/xhci-dwc3.c
>> @@ -9,8 +9,13 @@
>>   */
>>
>>  #include <common.h>
>> -#include <asm/io.h>
>> +#include <dm/device.h>
>> +#include <mapmem.h>
>> +#include <linux/io.h>
>>  #include <linux/usb/dwc3.h>
>> +#include <linux/sizes.h>
>> +
>> +#include "xhci.h"
>>
>>  void dwc3_set_mode(struct dwc3 *dwc3_reg, u32 mode)
>>  {
>> @@ -97,3 +102,67 @@ void dwc3_set_fladj(struct dwc3 *dwc3_reg, u32 val)
>>       setbits_le32(&dwc3_reg->g_fladj, GFLADJ_30MHZ_REG_SEL |
>>                       GFLADJ_30MHZ(val));
>>  }
>> +
>> +struct dwc3_priv {
>> +     struct xhci_ctrl ctrl;  /* should be the first member */
>> +     void __iomem *regs;
>> +};
>> +
>> +static int dwc3_probe(struct udevice *dev)
>> +{
>> +     struct dwc3_priv *priv = dev_get_priv(dev);
>> +     struct xhci_hccr *hccr;
>> +     struct xhci_hcor *hcor;
>> +     fdt_addr_t base;
>> +     int ret;
>> +
>> +     base = dev_get_addr(dev);
>> +     if (base == FDT_ADDR_T_NONE)
>> +             return -EINVAL;
>> +
>> +     priv->regs = map_sysmem(base, SZ_32K);
>> +     if (!priv->regs)
>> +             return -ENOMEM;
>> +
>> +     hccr = priv->regs;
>> +
>> +     hcor = priv->regs + HC_LENGTH(xhci_readl(&hccr->cr_capbase));
>> +
>> +     ret = dwc3_core_init(priv->regs + DWC3_REG_OFFSET);
>> +     if (ret) {
>> +             puts("XHCI: failed to initialize controller\n");
>> +             return ret;
>> +     }
>> +
>> +     /* We are hard-coding DWC3 core to Host Mode */
>> +     dwc3_set_mode(priv->regs + DWC3_REG_OFFSET, DWC3_GCTL_PRTCAP_HOST);
>
> Why are we hard-coding it to host mode?

Because this file is used for host mode.
It is enabled by CONFIG_USB_XHCI_DWC3, like follows.

obj-$(CONFIG_USB_XHCI_DWC3) += xhci-dwc3.o

Boards defining CONFIG_USB_XHCI_DWC3 expect
this driver works in the host mode, I guess.


> We need to take into account
> the dr_mode DT property and the Kconfig options to decide which mode
> we can operate in.


I thought drivers/usb/dwc3/* was working only for GADGET,
because currently USB_DWC3 depends on (USB && USB_GADGET).

As far as I understand, it will work for host mode with your series applied.
Correct?

If so, cool!
I am happy to move to drivers/usb/dwc3/*.

-- 
Best Regards
Masahiro Yamada