Messages in this thread Patch in this message | | | Date | Mon, 30 Jun 2014 17:43:26 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH v3] USB: ehci-pci: USB host controller support for Intel Quark X1000 |
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Hello.
On 06/30/2014 09:06 PM, Chen, Alvin wrote:
> From: Bryan O'Donoghue <bryan.odonoghue@intel.com>
> 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 <bryan.odonoghue@intel.com> > Signed-off-by: Alvin (Weike) Chen <alvin.chen@intel.com> > --- > changelog v3: > *Update the description to explain why set in/out threshold > as maximal as possible. > *Improve the threshold value micros more readable. > *Remove 'usb_set_qrk_bulk_thresh'. > *Set threshold value by 'ehci_writel' instead of 'usb_set_qrk_bulk_thresh'. > *Change the function name from 'usb_is_intel_quark_x1000' > to 'is_intel_quark_x1000'.
> drivers/usb/host/ehci-pci.c | 40 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+)
> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c > index 3e86bf4..78f1622 100644 > --- a/drivers/usb/host/ehci-pci.c > +++ b/drivers/usb/host/ehci-pci.c > @@ -35,11 +35,35 @@ 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; > +}
Why not just put this check inline into ehci_pci_reinit()?
> + > +/* > + * The offset of in/out threshold register is 0x84. > + * And it is the register of 'hostpc' > + * in memory-mapped EHCI controller. > +*/
The preferred multi-line kernel style is this:
/* * bla * bla */
> +#define intel_quark_x1000_insnreg01 hostpc > + > +/* The maximal ehci packet buffer size is 512 bytes */
s/ehci/EHCI/
> +#define INTEL_QUARK_X1000_EHCI_MAX_PACKET_BUFFER_SIZE 512 > + > +/* The threshold value set the register is in DWORD */ > +#define INTEL_QUARK_X1000_EHCI_THRESHOLD(size) ((size)/4u) > +#define INTEL_QUARK_X1000_EHCI_THRESHOLD_OUT_SHIFT 16 > +#define INTEL_QUARK_X1000_EHCI_THRESHOLD_IN_SHIFT 0 > + >
Too many empty lines...
> /* called after powerup, by probe or system-pm "wakeup" */ > static int ehci_pci_reinit(struct ehci_hcd *ehci, struct pci_dev *pdev) > { > int retval; > + u32 val; > + u32 thr;
Why not declare these where they are used?
> > /* we expect static quirk code to handle the "extended capabilities" > * (currently just BIOS handoff) allowed starting with EHCI 0.96 > @@ -50,6 +74,22 @@ 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)) { > + /* > + * In order to support the isochronous/interrupt > + * transactions, 508 bytes should be used as > + * max threshold values to maximize the > + * performance > + */
Same comment about the comment style...
> + thr = INTEL_QUARK_X1000_EHCI_THRESHOLD( > + INTEL_QUARK_X1000_EHCI_MAX_PACKET_BUFFER_SIZE - 4 > + ); > + val = thr<<INTEL_QUARK_X1000_EHCI_THRESHOLD_OUT_SHIFT | > + thr<<INTEL_QUARK_X1000_EHCI_THRESHOLD_IN_SHIFT;
Please surround << with spaces for consistency.
> + ehci_writel(ehci, val, ehci->regs->intel_quark_x1000_insnreg01); > + } > + > return 0; > } WBR, Sergei
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