Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932098AbaF3JI5 (ORCPT ); Mon, 30 Jun 2014 05:08:57 -0400 Received: from mga11.intel.com ([192.55.52.93]:16866 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755141AbaF3JIy (ORCPT ); Mon, 30 Jun 2014 05:08:54 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,573,1400050800"; d="scan'208";a="555173332" From: "Chen, Alvin" To: Alan Stern Cc: Jingoo Han , David Laight , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Boon Leong Ong Subject: [PATCH v3] USB: ehci-pci: USB host controller support for Intel Quark X1000 Date: Mon, 30 Jun 2014 10:06:00 -0700 Message-Id: <1404147960-17596-2-git-send-email-alvin.chen@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1404147960-17596-1-git-send-email-alvin.chen@intel.com> References: <1404147960-17596-1-git-send-email-alvin.chen@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bryan O'Donoghue 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 Signed-off-by: Alvin (Weike) Chen --- 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; +} + +/* + * The offset of in/out threshold register is 0x84. + * And it is the register of 'hostpc' + * in memory-mapped EHCI controller. +*/ +#define intel_quark_x1000_insnreg01 hostpc + +/* The maximal ehci packet buffer size is 512 bytes */ +#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 + /* 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; /* 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 + */ + thr = INTEL_QUARK_X1000_EHCI_THRESHOLD( + INTEL_QUARK_X1000_EHCI_MAX_PACKET_BUFFER_SIZE - 4 + ); + val = thr<regs->intel_quark_x1000_insnreg01); + } + return 0; } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/