usb: dwc2: retry NAK'd interrupt transfers
PATCH 1/1 usb: dwc2: retry NAK'd interrupt transfers
IIUC, interrupt transfers are NAK'd by devices until they wish to trigger an interrupt, and e.g. EHCI controllers retry these in HW until they are ACK'd. However, DWC2 doesn't seem to retry, so we need to do this in SW. In practice, I've seen DWC2_HCINT_FRMOVRUN happen too. I'm not quite sure what this error implies; perhaps it's related to how near the end of a USB frame we're at when the interrupt transfer is initiated? Anyway, retrying this temporary error seems to be necessary too.
With all these commits applied, both my USB keyboards (one LS Lenovo and one FS Dell) work correctly when there is no USB hub between the SoC and the keyboard; We still need split transactions to be implemented for hubs to work.
---
This replaces [RFC PATCH] usb: kbd: add transfer error interrupt handling.
Tested with this series on top of u-boot-usb/topic/dwc2 plus a patch to enable USB keyboard in include/configs/rpi-common.h (see my github):
Model A, model A+:
* USB SD card reader
* Both keyboards
Early model B, model B, model B+, RPi 2:
* USB SD card reader
* Built-in Ethernet
Compute module:
* USB SD card reader
* For some reason, the keyboards are enumerated by don't yield keyboard events. I don't know why this is. Perhaps a USB power issue?
NVIDIA Tegra Seabord
* Built-in USB keyboard
--- drivers/usb/host/dwc2.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-)
drivers/usb/host/dwc2.c +19 -6
@@ -723,6 +723,8 @@ int wait_for_chhltd(uint32_t *sub, int *toggle, bool ignore_ack)return ret; hcint =readl (&hc_regs->hcint); +if (hcint & (DWC2_HCINT_NAK |DWC2_HCINT_FRMOVRUN )) +return -EAGAIN ;if (ignore_ack) hcint &= ~DWC2_HCINT_ACK ;else
@@ -758,7 +760,7 @@ int chunk_msg(struct usb_device *dev, unsigned long pipe, int *pid, int in,int max =usb_maxpacket (dev, pipe);int eptype = dwc2_eptype[usb_pipetype (pipe)];int done =0 ; -int ret; +int ret =0 ;uint32_t sub;uint32_t xfer_len;uint32_t num_packets;
@@ -813,10 +815,8 @@ int chunk_msg(struct usb_device *dev, unsigned long pipe, int *pid, int in, DWC2_HCCHAR_CHEN); ret =wait_for_chhltd (&sub, pid, ignore_ack); -if (ret) { - stop_transfer =1 ; +if (ret)break ; - }if (in) { xfer_len -= sub;
@@ -835,7 +835,7 @@ int chunk_msg(struct usb_device *dev, unsigned long pipe, int *pid, int in, dev->status =0 ; dev->act_len = done; -return 0 ; +return ret; }/* U-Boot USB transmission interface */
@@ -904,8 +904,21 @@ int submit_control_msg(struct usb_device *dev, unsigned long pipe, void *buffer,int submit_int_msg (struct usb_device *dev,unsigned long pipe,void *buffer,int len,int interval) { +unsigned long timeout; +int ret; +/* FIXME: what is interval? */ -return submit_bulk_msg (dev, pipe, buffer, len); + + timeout =get_timer (0 ) +USB_TIMEOUT_MS (pipe); +for (;;) { +if (get_timer (0 ) > timeout) { +printf ("Timeout poll on interrupt endpoint\n" ); +return -ETIMEDOUT ; + } + ret =submit_bulk_msg (dev, pipe, buffer, len); +if (ret != -EAGAIN ) +return ret; + } }/* U-Boot USB control interface */
Signature · 1 line
1.9.1
PATCH 1/1 usb: dwc2: retry NAK'd interrupt transfers
Quoted 8 lines · Stephen Warren
IIUC, interrupt transfers are NAK'd by devices until they wish to trigger an interrupt, and e.g. EHCI controllers retry these in HW until they are ACK'd. However, DWC2 doesn't seem to retry, so we need to do this in SW. In practice, I've seen
DWC2_HCINT_FRMOVRUNhappen too. I'm not quite sure what this error implies; perhaps it's related to how near the end of a USB frame we're at when the interrupt transfer is initiated? Anyway, retrying this temporary error seems to be necessary too.
Quoted 6 lines
With all these commits applied, both my USB keyboards (one LS Lenovo and one FS Dell) work correctly when there is no USB hub between the SoC and the keyboard; We still need split transactions to be implemented for hubs to work.
Signed-off-by Stephen Warren <[email protected]>
Applied to u-boot-usb/topic/dwc2 , thanks!
Best regards,
Marek Vasut