diff mbox

[RFC,2/4] xhci: Add quirk for DWC3-Exynos controller

Message ID 1386672926-26885-3-git-send-email-gautam.vivek@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Vivek Gautam Dec. 10, 2013, 10:55 a.m. UTC
The DWC3-exynos eXtensible host controller on Exynos5420 SoC
is quirky in a way that the PHY needs to be tuned to get it
working at SuperSpeed.
By default this PHY works as High-speed phy and therefore
detects even Super-speed devices as high-speed ones.
So, the PHY needs to be tuned after controller has been reset.

Adding a xHCI quirk for this purpose.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
---
 drivers/usb/host/xhci-plat.c |   19 +++++++++++++++++++
 drivers/usb/host/xhci.h      |    1 +
 2 files changed, 20 insertions(+), 0 deletions(-)

Comments

Julius Werner Dec. 10, 2013, 6:25 p.m. UTC | #1
On Tue, Dec 10, 2013 at 2:55 AM, Vivek Gautam <gautam.vivek@samsung.com> wrote:
> The DWC3-exynos eXtensible host controller on Exynos5420 SoC
> is quirky in a way that the PHY needs to be tuned to get it
> working at SuperSpeed.
> By default this PHY works as High-speed phy and therefore
> detects even Super-speed devices as high-speed ones.
> So, the PHY needs to be tuned after controller has been reset.
>
> Adding a xHCI quirk for this purpose.
>
> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> ---
>  drivers/usb/host/xhci-plat.c |   19 +++++++++++++++++++
>  drivers/usb/host/xhci.h      |    1 +
>  2 files changed, 20 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index d9c169f..395c9e9 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -21,6 +21,25 @@
>
>  static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
>  {
> +       struct device *parent_dev;
> +       struct device *vendor_parent_dev;
> +
> +       parent_dev = dev->parent;
> +       vendor_parent_dev = parent_dev->parent;

Is this guaranteed to exist for all current and future xhci-plat
controllers or should you maybe check one or both for NULL?

> +
> +       /*
> +        * The DWC3-exynos host controller on Exynos5420 SoC is quirky
> +        * in a way that the PHY needs to be tuned to get it working
> +        * at SuperSpeed. By default this PHY works as High-speed phy
> +        * and so detects even Super-speed devices as high-speed ones.
> +        * Therefor the PHY needs to be tuned after controller
> +        * has been reset, since a controller reset actually forces the
> +        * PHY to fall back to its default state wherein it works as
> +        * High-Speed PHY only.
> +        */
> +       if (!strstr(dev_name(vendor_parent_dev), "exynos"))
> +               xhci->quirks |= XHCI_DWC3_EXYNOS;
> +
>         /*
>          * As of now platform drivers don't provide MSI support so we ensure
>          * here that the generic code does not try to make a pci_dev from our
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index 7807f62..f69af8c 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1560,6 +1560,7 @@ struct xhci_hcd {
>  #define XHCI_PLAT              (1 << 16)
>  #define XHCI_SLOW_SUSPEND      (1 << 17)
>  #define XHCI_SPURIOUS_WAKEUP   (1 << 18)
> +#define XHCI_DWC3_EXYNOS       (1 << 19)

I think in general it's better to name quirks after what they do
rather than a specific device, that way you might be able to reuse
them. How about XHCI_TUNE_AFTER_RESET? (Or you could leave out the
quirk completely and just differentiate by whether the PHY implements
the tune() method or not.)

>         unsigned int            num_active_eps;
>         unsigned int            limit_active_eps;
>         /* There are two roothubs to keep track of bus suspend info for */
> --
> 1.7.6.5
>
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diff mbox

Patch

diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index d9c169f..395c9e9 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -21,6 +21,25 @@ 
 
 static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
 {
+	struct device *parent_dev;
+	struct device *vendor_parent_dev;
+
+	parent_dev = dev->parent;
+	vendor_parent_dev = parent_dev->parent;
+
+	/*
+	 * The DWC3-exynos host controller on Exynos5420 SoC is quirky
+	 * in a way that the PHY needs to be tuned to get it working
+	 * at SuperSpeed. By default this PHY works as High-speed phy
+	 * and so detects even Super-speed devices as high-speed ones.
+	 * Therefor the PHY needs to be tuned after controller
+	 * has been reset, since a controller reset actually forces the
+	 * PHY to fall back to its default state wherein it works as
+	 * High-Speed PHY only.
+	 */
+	if (!strstr(dev_name(vendor_parent_dev), "exynos"))
+		xhci->quirks |= XHCI_DWC3_EXYNOS;
+
 	/*
 	 * As of now platform drivers don't provide MSI support so we ensure
 	 * here that the generic code does not try to make a pci_dev from our
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 7807f62..f69af8c 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1560,6 +1560,7 @@  struct xhci_hcd {
 #define XHCI_PLAT		(1 << 16)
 #define XHCI_SLOW_SUSPEND	(1 << 17)
 #define XHCI_SPURIOUS_WAKEUP	(1 << 18)
+#define XHCI_DWC3_EXYNOS	(1 << 19)
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
 	/* There are two roothubs to keep track of bus suspend info for */