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| author |   Adam Wallis <awallis@codeaurora.org> | 2017-12-08 17:59:13 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-08 17:43:52 +0100 |
| commit | ab725cbec3e83dc29cc00b733bd26063b588fa98 (patch) | |
| tree | 9466ec276003810875ae7e896031c038ed8a8fff /drivers/usb/host/xhci.h | |
| parent | usb: xhci: Cleanup printk debug message for ERST (diff) | |
| download | linux-dev-ab725cbec3e83dc29cc00b733bd26063b588fa98.tar.xz linux-dev-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.h')
| -rw-r--r-- | drivers/usb/host/xhci.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 7c8781758cea..96099a245c69 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1717,6 +1717,8 @@ struct xhci_hcd { u8 max_interrupters; u8 max_ports; u8 isoc_threshold; + /* imod_interval in ns (I * 250ns) */ + u32 imod_interval; int event_ring_max; /* 4KB min, 128MB max */ int page_size; |