USB: ehci-pci: USB host controller support for Intel Quark X1000 (6e693739) · Commits · 戴 / test

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> Acked-by:

Alan Stern <stern@rowland.harvard.edu> Reviewed-by:

Jingoo Han <jg1.han@samsung.com> Cc: stable <stable@vger.kernel.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-pci.c

+25 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

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