kernel.git/drivers/usb/dwc2/core.h, branch linux-4.6.y

usb: dwc2: fix regression on big-endian PowerPC/ARM systems

2016-07-27T15:42:09Z

commit 23e3439296a55affce3ef0ab78f1c2e03aec8767 upstream. A patch that went into Linux-4.4 to fix big-endian mode on a Lantiq MIPS system unfortunately broke big-endian operation on PowerPC APM82181 as reported by Christian Lamparter, and likely other systems. It actually introduced multiple issues: - it broke big-endian ARM kernels: any machine that was working correctly with a little-endian kernel is no longer using byteswaps on big-endian kernels, which clearly breaks them. - On PowerPC the same thing must be true: if it was working before, using big-endian kernels is now broken. Unlike ARM, 32-bit PowerPC usually uses big-endian kernels, so they are likely all broken. - The barrier for dwc2_writel is on the wrong side of the __raw_writel(), so the MMIO no longer synchronizes with DMA operations. - On architectures that require specific CPU instructions for MMIO access, using the __raw_ variant may turn this into a pointer dereference that does not have the same effect as the readl/writel. This patch is a simple revert for all architectures other than MIPS, in the hope that we can more easily backport it to fix the regression on PowerPC and ARM systems without breaking the Lantiq system again. We should follow this up with a more elaborate change to add runtime detection of endianness, to make sure it also works on all other combinations of architectures and implementations of the usb-dwc2 device. That patch however will be fairly large and not appropriate for backports to stable kernels. Felipe suggested a different approach, using an endianness switching register to always put the device into LE mode, but unfortunately the dwc2 hardware does not provide a generic way to do that. Also, I see no practical way of addressing the problem more generally by patching architecture specific code on MIPS. Fixes: 95c8bc360944 ("usb: dwc2: Use platform endianness when accessing registers") Acked-by: John Youn Tested-by: Christian Lamparter Signed-off-by: Arnd Bergmann Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman

usb: dwc2: Move host-specific core functions into hcd.c

2016-03-04T13:14:46Z

Move host core initialization and host channel routines into hcd.c. This allows these functions to only be compiled in host-enabled driver configurations (DRD or host-only). Tested-by: Douglas Anderson Reviewed-by: Douglas Anderson Signed-off-by: John Youn Signed-off-by: Felipe Balbi

usb: dwc2: Move register save and restore functions

2016-03-04T13:14:46Z

Move the register save and restore functions into the host and gadget specific files. Tested-by: Douglas Anderson Reviewed-by: Douglas Anderson Signed-off-by: John Youn Signed-off-by: Felipe Balbi

usb: dwc2: host: Totally redo the microframe scheduler

2016-03-04T13:14:45Z

This totally reimplements the microframe scheduler in dwc2 to attempt to handle periodic splits properly. The old code didn't even try, so this was a significant effort since periodic splits are one of the most complicated things in USB. I've attempted to keep the old "don't use the microframe" schduler around for now, but not sure it's needed. It has also only been lightly tested. I think it's pretty certain that this scheduler isn't perfect and might have some bugs, but it seems much better than what was there before. With this change my stressful USB test (USB webcam + USB audio + some keyboards) crackles less. Acked-by: John Youn Signed-off-by: Douglas Anderson Tested-by: Heiko Stuebner Tested-by: Stefan Wahren Signed-off-by: Felipe Balbi

usb: dwc2: host: Add dwc2_hcd_get_future_frame_number() call

2016-03-04T13:14:44Z

As we start getting more exact about our scheduling it's becoming more and more important to know exactly how far through the current frame we are. This lets us make decisions about whether there's still time left to start a new transaction in the current frame. We'll add dwc2_hcd_get_future_frame_number() which will tell you what the frame number will be a certain number of microseconds (us) from now. We can use this information to help decide if there's enough time left in the frame for a transaction that will take a certain duration. This is expected to be used by a future change ("usb: dwc2: host: Properly set even/odd frame"). Acked-by: John Youn Signed-off-by: Douglas Anderson Tested-by: Heiko Stuebner Tested-by: Stefan Wahren Signed-off-by: Felipe Balbi

usb: dwc2: host: Add scheduler logging for missed SOFs

2016-03-04T13:14:44Z

We'll use the new "scheduler verbose debugging" macro to log missed SOFs. This is fast enough (assuming you configure it to use the ftrace buffer) that we can do it without worrying about the speed hit. The overhead hit if the scheduler tracing is set to "no_printk" should be near zero. Acked-by: John Youn Signed-off-by: Douglas Anderson Tested-by: Heiko Stuebner Tested-by: Stefan Wahren Signed-off-by: Felipe Balbi

usb: dwc2: host: Add scheduler tracing

2016-03-04T13:14:41Z

In preparation for future changes to the scheduler let's add some tracing that makes it easy for us to see what's happening. By default this tracing will be off. By changing "core.h" you can easily trace to ftrace, the console, or nowhere. Acked-by: John Youn Signed-off-by: Douglas Anderson Reviewed-by: Kever Yang Tested-by: Heiko Stuebner Tested-by: Stefan Wahren Signed-off-by: Felipe Balbi

usb: dwc2: host: fix split transfer schedule sequence

2016-03-04T13:14:40Z

We're supposed to keep outstanding splits in order. Keep track of a list of the order of splits and process channel interrupts in that order. Without this change and the following setup: * Rockchip rk3288 Chromebook, using port ff540000 -> Pluggable 7-port Hub with Charging (powered) -> Microsoft Wireless Keyboard 2000 in port 1. -> Das Keyboard in port 2. ...I find that I get dropped keys on the Microsoft keyboard (I'm sure there are other combinations that fail, but this documents my test). Specifically I've been typing "hahahahahahaha" on the keyboard and often see keys dropped or repeated. After this change the above setup works properly. This patch is based on a previous patch proposed by Yunzhi Li ("usb: dwc2: hcd: fix periodic transfer schedule sequence") Acked-by: John Youn Signed-off-by: Douglas Anderson Signed-off-by: Yunzhi Li Reviewed-by: Kever Yang Tested-by: Heiko Stuebner Tested-by: Kever Yang Tested-by: Stefan Wahren Signed-off-by: Felipe Balbi

usb: dwc2: Improve handling of host and device hwparams

2015-12-22T18:00:51Z

Adds separate functions to get the host and device specific hardware parameters. The functions check whether the parameters need to be read at all, depending on dr_mode, and forces the mode only if necessary. This saves some delays during probe. This also adds two device mode parameters that will be used by the gadget. Signed-off-by: John Youn Signed-off-by: Felipe Balbi

usb: dwc2: Add functions to set and clear force mode

2015-12-22T18:00:34Z

Added functions to set force mode for host and device. These functions will check the current mode and only force if needed thus avoiding unnecessary force mode delays. However clearing the mode is currently done unconditionally and with the delay in place. This is needed during the connector ID status change interrupt in order to ensure that the mode has changed properly. This preserves the old behavior only for this case. The warning comment about this is moved into the clear mode condition. Signed-off-by: John Youn Signed-off-by: Felipe Balbi