diff options
| author | Bryan O'Donoghue <bryan.odonoghue@intel.com> | 2014-07-02 12:58:18 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-10 03:16:07 +0400 |
| commit | 6e693739e9b603b3ca9ce0d4f4178f0633458465 (patch) | |
| tree | 7b2337a073f7484a7f017c4d499ef6aed3935048 /drivers/usb/host/ehci-pci.c | |
| parent | 4428524d8d01afae18844e73f330d2e8431f312e (diff) | |
| download | linux-6e693739e9b603b3ca9ce0d4f4178f0633458465.tar.xz | |
USB: ehci-pci: USB host controller support for Intel Quark X1000
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>
Diffstat (limited to 'drivers/usb/host/ehci-pci.c')
| -rw-r--r-- | drivers/usb/host/ehci-pci.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c index 3e86bf4371b3..ca7b964124af 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; } |