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

Masahiro Yamada
2016-05-17T08:57:45Z

Hi Roger,

2016-05-17 17:20 GMT+09:00 Roger Quadros <rogerq@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@socionext.com>
>> Reviewed-by: Marek Vasut <marex@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