Re: [PATCH 08/12] xhci: Add Intel extended cap / otg phy mux handling

Andy Shevchenko
2018-02-16T13:53:35Z

On Fri, Feb 16, 2018 at 12:47 PM, Hans de Goede <hdegoede@redhat.com> wrote:
> The xHCI controller on various Intel SoCs has an extended cap mmio-range
> which contains registers to control the muxing to the xHCI (host mode)
> or the dwc3 (device mode) and vbus-detection for the otg usb-phy.
>
> Having a role-sw driver included in the xhci code (under drivers/usb/host)
> is not desirable. So this commit adds a simple handler for this extended
> capability, which creates a platform device with the caps mmio region as
> resource, this allows us to write a separate platform role-sw driver for
> the role-switch.
>
> Note this commit adds a call to the new xhci_ext_cap_init() function
> to xhci_pci_probe(), it is added here because xhci_ext_cap_init() must
> be called only once. If in the future we also want to handle ext-caps
> on non pci xHCI HCDs from xhci_ext_cap_init() a call to it should also
> be added to other bus probe paths.

SPDX?

> +/*
> + * XHCI extended capability handling
> + *
> + * Copyright (c) 2017 Hans de Goede <hdegoede@redhat.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */

> + pdev = platform_device_alloc("intel_xhci_usb_sw", PLATFORM_DEVID_NONE);

Perhaps,

#define USB_SW_DRV_NAME "..."

> + if (!pdev) {
> + xhci_err(xhci, "couldn't allocate intel_xhci_usb_sw pdev\n");

...and re-use it everywhere here.

pdev -> platform device.

> + return -ENOMEM;
> + }
> +
> + res.start = hcd->rsrc_start + cap_offset;
> + res.end = res.start + 0x3ff;

Is this magic always the same? Where its value comes from?
At least define with comment.

> +int xhci_ext_cap_init(struct xhci_hcd *xhci)
> +{
> + void __iomem *base = &xhci->cap_regs->hc_capbase;
> + u32 cap_offset, val;
> + int ret;
> +
> + cap_offset = xhci_find_next_ext_cap(base, 0, 0);
> +
> + while (cap_offset) {
> + val = readl(base + cap_offset);
> +
> + switch (XHCI_EXT_CAPS_ID(val)) {
> + case XHCI_EXT_CAPS_VENDOR_INTEL:
> + if (xhci->quirks & XHCI_INTEL_USB_ROLE_SW) {

> + ret = xhci_create_intel_xhci_sw_pdev(
> + xhci, cap_offset);

Can we leave xhci on previous line?

> + if (ret)
> + return ret;
> + }
> + break;
> + }
> + cap_offset = xhci_find_next_ext_cap(base, cap_offset, 0);
> + }
> +
> + return 0;
> +}

--
With Best Regards,
Andy Shevchenko