kernel.git/drivers/usb/dwc2/hcd.c, branch linux-4.6.y

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: Use periodic interrupt even with DMA

2016-03-04T13:14:42Z

The old code in dwc2_process_periodic_channels() would only enable the "periodic empty" interrupt if we weren't using DMA. That wasn't right since we can still get into cases where we have small FIFOs even on systems that have DMA (the rk3288 is a prime example). Let's always enable/disable the "periodic empty" when appropriate. As part of this: * Always call dwc2_process_periodic_channels() even if there's nothing in periodic_sched_assigned (we move the queue empty check so we still avoid the extra work). That will make extra certain that we will properly disable the "periodic empty" interrupt even if there's nothing queued up. * Move the enable of "periodic empty" due to non-empty periodic_sched_assigned to be for slave mode (non-DMA mode) only. Presumably this was the original intention of the check for DMA since it seems to match the comments above where in slave mode we leave things on the assigned queue. Note that even before this change slave mode didn't work for me, so I can't say for sure that my understanding of slave mode is correct. However, this shouldn't change anything for slave mode so if slave mode worked for someone in the past it ought to still work. With this change, I no longer get constant misses reported by my other debugging code (and with future patches) when I've got: * 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. -> Jabra Speaker in port 3 -> Logitech, Inc. Webcam C600 in port 4 -> Microsoft Sidewinder X6 Keyboard in port 5 ...and I'm playing music on the USB speaker and capturing video from the webcam. 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: Giveback URB in tasklet context

2016-03-04T13:14:41Z

In commit 94dfd7edfd5c ("USB: HCD: support giveback of URB in tasklet context") support was added to give back the URB in tasklet context. Let's take advantage of this in dwc2. This speeds up the dwc2 interrupt handler considerably. Note that this requires the change ("usb: dwc2: host: Add a delay before releasing periodic bandwidth") to come first. Note that, as per Alan Stern in , we also need to make sure that the extra delay before the device drivers submit more data doesn't break the scheduler. At the moment the scheduler is pretty broken (see future patches) so it's hard to be 100% certain, but I have yet to see any new breakage introduced by this delay. ...and speeding up interrupt processing for dwc2 is a huge deal because it means we've got a better chance of not missing SOF interrupts. That means we've got an overall win here. Note that when playing USB audio and using a USB webcam and having several USB keyboards plugged in, the crackling on the USB audio device is noticably reduced with this patch. 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: 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: host: Always add to the tail of queues

2016-03-04T13:14:40Z

The queues the the dwc2 host controller used are truly queues. That means FIFO or first in first out. Unfortunately though the code was iterating through these queues starting from the head, some places in the code was adding things to the queue by adding at the head instead of the tail. That means last in first out. Doh. Go through and just always add to the tail. Doing this makes things much happier when I've got: * 7-port USB 2.0 Single-TT hub * - Microsoft 2.4 GHz Transceiver v7.0 dongle * - Jabra speakerphone playing music 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: Avoid use of chan->qh after qh freed

2016-03-04T13:14:40Z

When poking around with USB devices with slub_debug enabled, I found another obvious use after free. Turns out that in dwc2_hc_n_intr() I was in a state when the contents of chan->qh was filled with 0x6b, indicating that chan->qh was freed but chan still had a reference to it. Let's make sure that whenever we free qh we also make sure we remove a reference from its channel. The bug fixed here doesn't appear to be new--I believe I just got lucky and happened to see it while stress testing. 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