[SLOF] [PATCH] xhci: fix missing keys from keyboard

[Alexey Kardashevskiy]

On 04/29/2016 06:03 AM, Nikunj A Dadhania wrote:
> Current handling of the keyboard polling was very slow and
> keys were getting dropped. Done following for fixing this:
>
> * Use multiple buffers per TRB
> * Allocate buffers in xhci according to the number of TRBS.
>
> This reduces the delay of key? processing by getting rid of wait in
> the polling routine.
>
> Reported-by: Dinar Valeev <k0da at opensuse.org>
> Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
> ---
>
> Dinar, can you give this patch a test as well, logic is same,
> some polishing and got rid of magic numbers.
>
>  lib/libusb/usb-xhci.c | 52 +++++++++++++++++++++++++++++++++++++++------------
>  lib/libusb/usb-xhci.h |  2 ++
>  2 files changed, 42 insertions(+), 12 deletions(-)
>
> diff --git a/lib/libusb/usb-xhci.c b/lib/libusb/usb-xhci.c
> index 858cd12..70619c9 100644
> --- a/lib/libusb/usb-xhci.c
> +++ b/lib/libusb/usb-xhci.c
> @@ -238,7 +238,7 @@ static uint64_t xhci_poll_event(struct xhci_hcd *xhcd,
>  	flags = le32_to_cpu(event->flags);
>
>  	dprintf("Reading from event ptr %p %08x\n", event, flags);
> -	time = SLOF_GetTimer() + USB_TIMEOUT;
> +	time = SLOF_GetTimer() + ((event_type == XHCI_POLL_NO_WAIT)? 0: USB_TIMEOUT);
>
>  	while ((flags & TRB_CYCLE_STATE) != xhcd->ering.cycle_state) {
>  		mb();
> @@ -1147,11 +1147,37 @@ static inline void *xhci_get_trb(struct xhci_seg *seg)
>  	return (void *)enq;
>  }
>
> +static inline void *xhci_get_trb_deq(struct xhci_seg *seg)
> +{
> +	uint64_t val, deq;
> +	int index;
> +
> +	deq = val = seg->deq;
> +	val = val + XHCI_TRB_SIZE;

Nit:

deq = seq->deq;
val = deq + XHCI_TRB_SIZE;

and s/val/deq_next/ ?

?


> +	index = (deq - (uint64_t)seg->trbs) / XHCI_TRB_SIZE + 1;
> +	dprintf("%s: enq %llx, val %llx %x\n", __func__, enq, val, index);
> +	/* TRBs being a cyclic buffer, here we cycle back to beginning. */
> +	if (index == (seg->size - 1)) {
> +		dprintf("%s: rounding \n", __func__);
> +		seg->deq = (uint64_t)seg->trbs;
> +		mb();


mb() just here, not in the "else" branch?


> +	}
> +	else {
> +		seg->deq = val;
> +	}
> +	return (void *)deq;
> +}
> +
>  static uint64_t xhci_get_trb_phys(struct xhci_seg *seg, uint64_t trb)
>  {
>  	return seg->trbs_dma + (trb - (uint64_t)seg->trbs);
>  }
>
> +static uint32_t xhci_trb_get_index(struct xhci_seg *seg, struct xhci_transfer_trb *trb)
> +{
> +	return trb - (struct xhci_transfer_trb *)seg->trbs;
> +}
> +
>  static int usb_kb = false;
>  static int xhci_transfer_bulk(struct usb_pipe *pipe, void *td, void *td_phys,
>  			void *data, int datalen)
> @@ -1331,9 +1357,9 @@ static int xhci_get_pipe_intr(struct usb_pipe *pipe,
>  		xhci_init_seg(seg, XHCI_EVENT_TRBS_SIZE, TYPE_BULK);
>  	}
>
> -	xpipe->buf = buf;
> -	xpipe->buf_phys = SLOF_dma_map_in(buf, len, false);
> -	xpipe->buflen = len;
> +	xpipe->buflen = pipe->mps * XHCI_INTR_TRBS_SIZE/(sizeof(struct xhci_transfer_trb));
> +	xpipe->buf = SLOF_dma_alloc(xpipe->buflen);
> +	xpipe->buf_phys = SLOF_dma_map_in(xpipe->buf, xpipe->buflen, false);
>
>  	ctrl = xhci_get_control_ctx(&xdev->in_ctx);
>  	x_epno = xhci_get_epno(pipe);
> @@ -1349,7 +1375,8 @@ static int xhci_get_pipe_intr(struct usb_pipe *pipe,
>  	xpipe->seg = seg;
>
>  	trb = xhci_get_trb(seg);
> -	fill_normal_trb(trb, (void *)xpipe->buf_phys, pipe->mps);
> +	buf = (char *)(xpipe->buf_phys + xhci_trb_get_index(seg, trb) * pipe->mps);
> +	fill_normal_trb(trb, (void *)buf, pipe->mps);
>  	return true;
>  }
>
> @@ -1411,6 +1438,7 @@ static void xhci_put_pipe(struct usb_pipe *pipe)
>  	} else if (pipe->type == USB_EP_TYPE_INTR) {
>  		xpipe = xhci_pipe_get_xpipe(pipe);
>  		SLOF_dma_map_out(xpipe->buf_phys, xpipe->buf, xpipe->buflen);
> +		SLOF_dma_free(xpipe->buf, xpipe->buflen);
>  		xpipe->seg = NULL;
>  	}
>  	if (xhcd->end)
> @@ -1448,26 +1476,26 @@ static int xhci_poll_intr(struct usb_pipe *pipe, uint8_t *data)
>  	if (usb_kb == true) {
>  		/* This event was consumed by bulk transfer */
>  		usb_kb = false;
> +		xhci_get_trb_deq(seg);
>  		goto skip_poll;
>  	}
> -	buf = xpipe->buf;
> -	memset(buf, 0, 8);
>
> -	mb();


the barrier is not needed anymore?


>  	/* Ring the doorbell - x_epno */
>  	dbr = xhcd->db_regs;
>  	write_reg32(&dbr->db[xdev->slot_id], x_epno);
> -	if (!xhci_poll_event(xhcd, 0)) {
> -		printf("poll intr failed\n");
> +	if (!xhci_poll_event(xhcd, XHCI_POLL_NO_WAIT)) {
>  		return 0;
>  	}
>  	mb();
> +	trb = xhci_get_trb_deq(seg);
> +	buf = xpipe->buf + xhci_trb_get_index(seg, trb) * pipe->mps;
>  	memcpy(data, buf, 8);
> +	memset(buf, 0, 8);
>
>  skip_poll:
>  	trb = xhci_get_trb(seg);
> -	fill_normal_trb(trb, (void *)xpipe->buf_phys, pipe->mps);
> -	mb();


and here?

tbh I do not understand what is going on here, just when I see moving mb(), 
I get slightly nervous, that's it :)



> +	buf = (uint8_t *)(xpipe->buf_phys + xhci_trb_get_index(seg, trb) * pipe->mps);
> +	fill_normal_trb(trb, (void *)buf, pipe->mps);
>  	return ret;
>  }
>
> diff --git a/lib/libusb/usb-xhci.h b/lib/libusb/usb-xhci.h
> index 3fc7e78..8172a37 100644
> --- a/lib/libusb/usb-xhci.h
> +++ b/lib/libusb/usb-xhci.h
> @@ -269,6 +269,8 @@ struct xhci_seg {
>  #define XHCI_INTR_TRBS_SIZE    4096
>  #define XHCI_ERST_NUM_SEGS     1
>
> +#define XHCI_POLL_NO_WAIT      1
> +
>  #define XHCI_MAX_BULK_SIZE    0xF000
>
>  struct xhci_erst_entry {
>


-- 
Alexey