From: "Alvin (Weike) Chen" <[email protected]>
Hi,
Intel Quark X1000 consists of one USB host controller which can be PCI
enumerated. And the exsiting EHCI-PCI framework supports it with the
default packet buffer in/out threshold. We reconfigure the in/out threshold
as maximal as possible to maximize the performance.
Bryan O'Donoghue (1):
USB: ehci-pci: USB host controller support for Intel Quark X1000
drivers/usb/host/ehci-pci.c | 25 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 25 insertions(+)
--
1.7.9.5
From: Bryan O'Donoghue <[email protected]>
The EHCI packet buffer in/out threshold is programmable for Intel Quark X1000
USB host controller, and the default value is 0x20 dwords. The in/out threshold
can be programmed to 0x80 dwords (512 Bytes) to maximize the perfomrance,
but only when isochronous/interrupt transactions are not initiated by the USB
host controller. This patch is to reconfigure the packet buffer in/out
threshold as maximal as possible to maximize the performance, and 0x7F dwords
(508 Bytes) should be used because the USB host controller initiates
isochronous/interrupt transactions.
Signed-off-by: Bryan O'Donoghue <[email protected]>
Signed-off-by: Alvin (Weike) Chen <[email protected]>
---
changelog v4:
* Just define the maximum threshold value, and clarify it in the comments.
* Improve the comments.
drivers/usb/host/ehci-pci.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 3e86bf4..429434d 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -35,6 +35,21 @@ static const char hcd_name[] = "ehci-pci";
#define PCI_DEVICE_ID_INTEL_CE4100_USB 0x2e70
/*-------------------------------------------------------------------------*/
+#define PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC 0x0939
+static inline bool is_intel_quark_x1000(struct pci_dev *pdev)
+{
+ return pdev->vendor == PCI_VENDOR_ID_INTEL &&
+ pdev->device == PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC;
+}
+
+/*
+ * 0x84 is the offset of in/out threshold register,
+ * and it is the same offset as the register of 'hostpc'.
+ */
+#define intel_quark_x1000_insnreg01 hostpc
+
+/* Maximum usable threshold value is 0x7f dwords for both IN and OUT */
+#define INTEL_QUARK_X1000_EHCI_MAX_THRESHOLD 0x007f007f
/* called after powerup, by probe or system-pm "wakeup" */
static int ehci_pci_reinit(struct ehci_hcd *ehci, struct pci_dev *pdev)
@@ -50,6 +65,16 @@ 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 (is_intel_quark_x1000(pdev)) {
+ /*
+ * For the Intel QUARK X1000, raise the I/O threshold to the
+ * maximum usable value in order to improve performance.
+ */
+ ehci_writel(ehci, INTEL_QUARK_X1000_EHCI_MAX_THRESHOLD,
+ ehci->regs->intel_quark_x1000_insnreg01);
+ }
+
return 0;
}
--
1.7.9.5
On Tue, 1 Jul 2014, Chen, Alvin wrote:
> From: Bryan O'Donoghue <[email protected]>
>
> The EHCI packet buffer in/out threshold is programmable for Intel Quark X1000
> USB host controller, and the default value is 0x20 dwords. The in/out threshold
> can be programmed to 0x80 dwords (512 Bytes) to maximize the perfomrance,
> but only when isochronous/interrupt transactions are not initiated by the USB
> host controller. This patch is to reconfigure the packet buffer in/out
> threshold as maximal as possible to maximize the performance, and 0x7F dwords
> (508 Bytes) should be used because the USB host controller initiates
> isochronous/interrupt transactions.
>
> Signed-off-by: Bryan O'Donoghue <[email protected]>
> Signed-off-by: Alvin (Weike) Chen <[email protected]>
Acked-by: Alan Stern <[email protected]>
There's one error in the style...
> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> index 3e86bf4..429434d 100644
> --- a/drivers/usb/host/ehci-pci.c
> +++ b/drivers/usb/host/ehci-pci.c
> @@ -35,6 +35,21 @@ static const char hcd_name[] = "ehci-pci";
> #define PCI_DEVICE_ID_INTEL_CE4100_USB 0x2e70
>
> /*-------------------------------------------------------------------------*/
> +#define PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC 0x0939
> +static inline bool is_intel_quark_x1000(struct pci_dev *pdev)
> +{
> + return pdev->vendor == PCI_VENDOR_ID_INTEL &&
> + pdev->device == PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC;
> +}
> +
> +/*
> + * 0x84 is the offset of in/out threshold register,
> + * and it is the same offset as the register of 'hostpc'.
> + */
This comment isn't formatted right. It should be like this:
/*
* blah blah blah
* blah blah blah
*/
If you want to submit a corrected version, you can. Or Greg may be
willing to fix the style when he merges this patch.
Alan Stern
On Tuesday, July 01, 2014 11:12 PM, Alan Stern wrote:
> On Tue, 1 Jul 2014, Chen, Alvin wrote:
>
> > From: Bryan O'Donoghue <[email protected]>
> >
> > The EHCI packet buffer in/out threshold is programmable for Intel Quark X1000
> > USB host controller, and the default value is 0x20 dwords. The in/out threshold
> > can be programmed to 0x80 dwords (512 Bytes) to maximize the perfomrance,
> > but only when isochronous/interrupt transactions are not initiated by the USB
> > host controller. This patch is to reconfigure the packet buffer in/out
> > threshold as maximal as possible to maximize the performance, and 0x7F dwords
> > (508 Bytes) should be used because the USB host controller initiates
> > isochronous/interrupt transactions.
> >
> > Signed-off-by: Bryan O'Donoghue <[email protected]>
> > Signed-off-by: Alvin (Weike) Chen <[email protected]>
>
> Acked-by: Alan Stern <[email protected]>
Reviewed-by: Jingoo Han <[email protected]>
Best regards,
Jingoo Han
>
> There's one error in the style...
>
> > diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> > index 3e86bf4..429434d 100644
> > --- a/drivers/usb/host/ehci-pci.c
> > +++ b/drivers/usb/host/ehci-pci.c
> > @@ -35,6 +35,21 @@ static const char hcd_name[] = "ehci-pci";
> > #define PCI_DEVICE_ID_INTEL_CE4100_USB 0x2e70
> >
> > /*-------------------------------------------------------------------------*/
> > +#define PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC 0x0939
> > +static inline bool is_intel_quark_x1000(struct pci_dev *pdev)
> > +{
> > + return pdev->vendor == PCI_VENDOR_ID_INTEL &&
> > + pdev->device == PCI_DEVICE_ID_INTEL_QUARK_X1000_SOC;
> > +}
> > +
> > +/*
> > + * 0x84 is the offset of in/out threshold register,
> > + * and it is the same offset as the register of 'hostpc'.
> > + */
>
> This comment isn't formatted right. It should be like this:
>
> /*
> * blah blah blah
> * blah blah blah
> */
>
> If you want to submit a corrected version, you can. Or Greg may be
> willing to fix the style when he merges this patch.
>
> Alan Stern