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| author | Adam Wallis <awallis@codeaurora.org> | 2017-12-08 16:59:13 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-08 17:43:52 +0100 |
| commit | ab725cbec3e83dc29cc00b733bd26063b588fa98 (patch) | |
| tree | 9466ec276003810875ae7e896031c038ed8a8fff /drivers/usb/host/xhci-pci.c | |
| parent | usb: xhci: Cleanup printk debug message for ERST (diff) | |
| download | linux-ab725cbec3e83dc29cc00b733bd26063b588fa98.tar.xz linux-ab725cbec3e83dc29cc00b733bd26063b588fa98.zip | |
usb: xhci: allow imod-interval to be configurable
The xHCI driver currently has the IMOD set to 160, which
translates to an IMOD interval of 40,000ns (160 * 250)ns
Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
introduced a QUIRK for the MTK platform to adjust this interval to 20,
which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
due to the fact that the MTK controller IMOD interval is 8 times
as much as defined in xHCI spec.
Instead of adding more quirk bits for additional platforms, this patch
introduces the ability for vendors to set the IMOD_INTERVAL as is
optimal for their platform. By using device_property_read_u32() on
"imod-interval-ns", the IMOD INTERVAL can be specified in nano seconds.
If no interval is specified, the default of 40,000ns (IMOD=160) will be
used.
No bounds checking has been implemented due to the fact that a vendor
may have violated the spec and would need to specify a value outside of
the max 8,000 IRQs/second limit specified in the xHCI spec.
Tested-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci-pci.c')
| -rw-r--r-- | drivers/usb/host/xhci-pci.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index 7ef1274ef7f7..4bcddd424a07 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -234,6 +234,9 @@ static int xhci_pci_setup(struct usb_hcd *hcd) if (!xhci->sbrn) pci_read_config_byte(pdev, XHCI_SBRN_OFFSET, &xhci->sbrn); + /* imod_interval is the interrupt moderation value in nanoseconds. */ + xhci->imod_interval = 40000; + retval = xhci_gen_setup(hcd, xhci_pci_quirks); if (retval) return retval; |