kernel.git/drivers/usb/dwc2/hcd.c, branch linux-4.5.y

usb: dwc2: Avoid double-reset at boot time

2015-12-22T17:52:08Z

In (usb: dwc2: reset dwc2 core before dwc2_get_hwparams()) we added an extra reset to the probe path for the dwc2 USB controllers. This allowed proper detection of parameters even if the firmware had already used the USB part. Unfortunately, this extra reset is quite slow and is affecting boot speed. We can avoid the double-reset by skipping the extra reset that would happen just after the one we added. Logic that explains why this is safe: * As of the CL mentioned above, we now always call dwc2_core_reset() in dwc2_driver_probe() before dwc2_hcd_init(). * The only caller of dwc2_hcd_init() is dwc2_driver_probe(), so we're guaranteed that dwc2_core_reset() was called before dwc2_hdc_init(). * dwc2_hdc_init() is the only caller that passes an irq other than -1 to dwc2_core_init(). Thus if dwc2_core_init() is called with an irq other than -1 we're guaranteed that dwc2_core_reset was called before dwc2_core_init(). ...this allows us to remove the dwc2_core_reset() in dwc2_core_init() if irq is not < 0. Note that since "irq" wasn't used in the function dwc2_core_init() anyway and since select_phy was always set at exactly the same times we could avoid the reset, we remove "irq" and rename "select_phy" to "initial_setup" and adjust the callers accordingly. Signed-off-by: Douglas Anderson Signed-off-by: John Youn Signed-off-by: Felipe Balbi

usb: dwc2: host: Add missing spinlock in dwc2_hcd_reset_func()

2015-12-15T15:12:41Z

The dwc2_hcd_reset_func() function is only ever called directly by a delayed work function. As such no locks are already held when the function is called. Doing a read-modify-write of CPU registers and setting fields in the main hsotg data structure is a bad idea without locks. Let's add locks. The bug was found by code inspection only. It turns out that the dwc2_hcd_reset_func() is only ever called today if the "host_support_fs_ls_low_power" parameter is enabled and no code in mainline enables that parameter. Thus no known issues in mainline are fixed by this patch, but it's still probably wise to fix the function. Signed-off-by: Douglas Anderson Signed-off-by: Felipe Balbi

usb: dwc2: host: Fix missing device insertions

2015-12-15T15:12:41Z

If you've got your interrupt signals bouncing a bit as you insert your USB device, you might end up in a state when the device is connected but the driver doesn't know it. Specifically, the observed order is: 1. hardware sees connect 2. hardware sees disconnect 3. hardware sees connect 4. dwc2_port_intr() - clears connect interrupt 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() Now you'll be stuck with the cable plugged in and no further interrupts coming in but the driver will think we're disconnected. We'll fix this by checking for the missing connect interrupt and re-connecting after the disconnect is posted. We don't skip the disconnect because if there is a transitory disconnect we really want to de-enumerate and re-enumerate. Notes: 1. As part of this change we add a "force" parameter to dwc2_hcd_disconnect() so that when we're unloading the module we avoid the new behavior. The need for this was pointed out by John Youn. 2. The bit of code needed at the end of dwc2_hcd_disconnect() is exactly the same bit of code from dwc2_port_intr(). To avoid duplication, we refactor that code out into a new function dwc2_hcd_connect(). Signed-off-by: Douglas Anderson Acked-by: John Youn Tested-by: John Youn Signed-off-by: Felipe Balbi

usb: dwc2: host: use kmem cache to allocate descriptors

2015-12-15T15:12:41Z

Kmem caches help to get correct boundary for descriptor buffers which need to be 512 bytes aligned for dwc2 controller. Two kmem caches are needed for generic descriptors and for hs isochronous descriptors which doesn't have same size. Acked-by: John Youn Signed-off-by: Gregory Herrero Signed-off-by: Felipe Balbi

usb: dwc2: host: avoid usage of dma_alloc_coherent with irqs disabled

2015-12-15T15:12:41Z

Use Streaming DMA mappings to handle cache coherency of frame list and descriptor list. Cache are always flushed before controller access it or before cpu access it. Acked-by: John Youn Signed-off-by: Gregory Herrero Signed-off-by: Felipe Balbi

usb: dwc2: host: enable descriptor dma for fs devices

2015-12-15T15:12:41Z

As descriptor dma mode does not support split transfers, it can't be enabled for high speed devices. Add a core parameter to enable it for full speed devices. Ensure frame list and descriptor list are correctly freed during disconnect. Acked-by: John Youn Signed-off-by: Mian Yousaf Kaukab Signed-off-by: Gregory Herrero Signed-off-by: Felipe Balbi

usb: dwc2: host: Fix remote wakeup when not in DWC2_L2

2015-11-17T17:35:38Z

In commit 734643dfbdde ("usb: dwc2: host: add flag to reflect bus state") we changed dwc2_port_suspend() not to set the lx_state anymore (instead it sets the new bus_suspended variable). This introduced a bug where we would fail to detect device insertions if: 1. Plug empty hub into dwc2 2. Plug USB flash drive into the empty hub. 3. Wait a few seconds 4. Unplug USB flash drive 5. Less than 2 seconds after step 4, plug the USB flash drive in again. The dwc2_hcd_rem_wakeup() function should have been changed to look at the new bus_suspended variable. Let's fix it. Since commit b46146d59fda ("usb: dwc2: host: resume root hub on remote wakeup") talks about needing the root hub resumed if the bus was suspended, we'll include it in our test. It appears that the "port_l1_change" should only be set to 1 if we were in DWC2_L1 (the driver currently never sets this), so we'll update the former "else" case based on this test. Fixes: 734643dfbdde ("usb: dwc2: host: add flag to reflect bus state") Acked-by: John Youn Tested-by: Gregory Herrero Reviewed-by: Heiko Stuebner Signed-off-by: Douglas Anderson Signed-off-by: Felipe Balbi

usb: dwc2: host: Protect PCGCTL with lock in dwc2_port_resume()

2015-10-16T19:44:15Z

From code inspection, it appears to be unsafe to do a read-modify-write of PCGCTL in dwc2_port_resume(). Let's make sure the spinlock is held around this operation. Acked-by: John Youn Signed-off-by: Douglas Anderson Signed-off-by: Felipe Balbi

usb: dwc2: gadget: kill ep0 requests before reinitializing core

2015-10-01T17:40:26Z

Make sure there are no requests pending on ep0 before reinitializing core. Otherwise, dwc2_hsotg_enqueue_setup will fail afterwards. Also, take hsotg->lock before calling dwc2_hsotg_core_init_disconnected() from dwc2_conn_id_status_change() as dwc2_hsotg_complete_request() expect lock to be held. Signed-off-by: Mian Yousaf Kaukab Tested-by: Robert Baldyga Tested-by: Dinh Nguyen Tested-by: John Youn Acked-by: John Youn Signed-off-by: Felipe Balbi

usb: dwc2: host: kill remaining urbs using -ECONNRESET status

2015-10-01T17:40:18Z

On a disconnect, dwc2 will kill all remaining urbs from qh list. urbs are given back to hcd with -ETIMEDOUT status. Some usb device driver, like mass storage, will unlink all urbs using usb_hcd_unlink_urb when receiving a negative status different from -ECONNRESET. The following flow will then happen: dwc2_hcd_disconnect() -> dwc2_kill_all_urbs() try to kill first pending urb. -> dwc2_host_complete(-ETIMEDOUT) -> usb_hcd_giveback_urb(-ETIMEDOUT) -> sg_complete() -> usb_unlink_urb() -> usb_put_dev(urb->dev) -> dwc2_kill_all_urbs() try to kill next pending urb. -> dwc2_host_complete(-ETIMEDOUT) -> usb_hcd_giveback_urb(-ETIMEDOUT) -> NULL pointer dereferencing because urb->dev has been freed for all urbs of this device. The root cause of this NULL pointer is to call call usb_unlink_urb() while we are killing all urbs. To avoid this return urb with -ECONNRESET status This issue usually happens while removing mass storage device during transfer. Signed-off-by: Gregory Herrero Signed-off-by: Mian Yousaf Kaukab Tested-by: Robert Baldyga Tested-by: Dinh Nguyen Tested-by: John Youn Acked-by: John Youn Signed-off-by: Felipe Balbi