On Wednesday, June 25, 2014 12:52 AM, Alvin Chen wrote:
> 
> From: Bryan O'Donoghue <bryan.odonog...@intel.com>
> 
> This patch is to enable USB host controller for Intel Quark X1000. Add pci 
> quirks
> to adjust the packet buffer in/out threshold value, and ensure EHCI packet 
> buffer
> i/o threshold value is reconfigured to half.

Please add more detailed description. For example, why is it necessary to
reconfigure the threshold value?

> 
> Signed-off-by: Bryan O'Donoghue <bryan.odonog...@intel.com>
> Signed-off-by: Alvin (Weike) Chen <alvin.c...@intel.com>
> ---
>  drivers/usb/host/ehci-pci.c   |    4 ++++
>  drivers/usb/host/pci-quirks.c |   42 
> +++++++++++++++++++++++++++++++++++++++++
>  drivers/usb/host/pci-quirks.h |    2 ++
>  3 files changed, 48 insertions(+)
> 
> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> index 3e86bf4..33cfa23 100644
> --- a/drivers/usb/host/ehci-pci.c
> +++ b/drivers/usb/host/ehci-pci.c
> @@ -50,6 +50,10 @@ static int ehci_pci_reinit(struct ehci_hcd *ehci, struct 
> pci_dev *pdev)
>       if (!retval)
>               ehci_dbg(ehci, "MWI active\n");
> 
> +     /* Reset the threshold limit */
> +     if(unlikely(usb_is_intel_qrk(pdev)))
> +             usb_set_qrk_bulk_thresh(pdev);
> +
>       return 0;
>  }
> 
> diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
> index 00661d3..1ea8803 100644
> --- a/drivers/usb/host/pci-quirks.c
> +++ b/drivers/usb/host/pci-quirks.c
> @@ -823,6 +823,48 @@ static int handshake(void __iomem *ptr, u32 mask, u32 
> done,
>       return -ETIMEDOUT;
>  }
> 
> +#define PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC          0x0939
> +bool usb_is_intel_qrk(struct pci_dev *pdev)
> +{
> +     return pdev->vendor == PCI_VENDOR_ID_INTEL &&
> +             pdev->device == PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC;
> +
> +}
> +EXPORT_SYMBOL_GPL(usb_is_intel_qrk);
> +
> +#define EHCI_INSNREG01               0x84
> +#define EHCI_INSNREG01_THRESH        0x007F007F      /* Threshold value */

What does this magic number mean?
Would you make it more readable?

> +void usb_set_qrk_bulk_thresh(struct pci_dev *pdev)
> +{
> +     void __iomem *base, *op_reg_base;
> +     u8 cap_length;
> +     u32 val;
> +
> +     if (!mmio_resource_enabled(pdev, 0))
> +             return;
> +
> +     base = pci_ioremap_bar(pdev, 0);
> +     if (base == NULL)
> +             return;
> +
> +     cap_length = readb(base);
> +     op_reg_base = base + cap_length;
> +
> +     val = readl(op_reg_base + EHCI_INSNREG01);
> +     dev_printk(KERN_INFO, &pdev->dev, "INSNREG01 is 0x%08x\n", val);
> +
> +     val = EHCI_INSNREG01_THRESH;
> +
> +     writel(val, op_reg_base + EHCI_INSNREG01);
> +
> +     val = readl(op_reg_base + EHCI_INSNREG01);
> +     dev_printk(KERN_INFO, &pdev->dev, "INSNREG01 is 0x%08x\n", val);

As Alan Stern said, These INFO message are noisy.
DEBUG level looks better.

Best regards,
Jingoo Han

> +
> +     iounmap(base);
> +
> +}
> +EXPORT_SYMBOL_GPL(usb_set_qrk_bulk_thresh);
> +
>  /*
>   * Intel's Panther Point chipset has two host controllers (EHCI and xHCI) 
> that
>   * share some number of ports.  These ports can be switched between either
> diff --git a/drivers/usb/host/pci-quirks.h b/drivers/usb/host/pci-quirks.h
> index c622ddf..617c22b 100644
> --- a/drivers/usb/host/pci-quirks.h
> +++ b/drivers/usb/host/pci-quirks.h
> @@ -14,6 +14,8 @@ void usb_amd_quirk_pll_enable(void);
>  void usb_enable_intel_xhci_ports(struct pci_dev *xhci_pdev);
>  void usb_disable_xhci_ports(struct pci_dev *xhci_pdev);
>  void sb800_prefetch(struct device *dev, int on);
> +bool usb_is_intel_qrk(struct pci_dev *pdev);
> +void usb_set_qrk_bulk_thresh(struct pci_dev *pdev);
>  #else
>  struct pci_dev;
>  static inline void usb_amd_quirk_pll_disable(void) {}
> --
> 1.7.9.5

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