The 'Max Burst Size' indicates to the xHC the maximum number of consecutive USB transactions that should be executed per scheduling opportunity. This is a “zero-based” value, where 0 to 15 represents burst sizes of 1 to 16, but at present this is always set to zero. Let's program the required value according to real needs.
Signed-off-by: Bin Meng bmeng.cn@gmail.com ---
Changes in v3: None
drivers/usb/host/xhci.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 02bbab5..b039ab0 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -396,6 +396,22 @@ static u32 xhci_get_endpoint_mult(struct usb_device *udev, return ss_ep_comp_desc->bmAttributes; }
+static u32 xhci_get_endpoint_max_burst(struct usb_device *udev, + struct usb_endpoint_descriptor *endpt_desc, + struct usb_ss_ep_comp_descriptor *ss_ep_comp_desc) +{ + /* Super speed and Plus have max burst in ep companion desc */ + if (udev->speed >= USB_SPEED_SUPER) + return ss_ep_comp_desc->bMaxBurst; + + if (udev->speed == USB_SPEED_HIGH && + (usb_endpoint_xfer_isoc(endpt_desc) || + usb_endpoint_xfer_int(endpt_desc))) + return usb_endpoint_maxp_mult(endpt_desc) - 1; + + return 0; +} + /* * Return the maximum endpoint service interval time (ESIT) payload. * Basically, this is the maxpacket size, multiplied by the burst size @@ -494,6 +510,7 @@ static int xhci_set_configuration(struct usb_device *udev) u32 max_esit_payload; unsigned int interval; unsigned int mult; + unsigned int max_burst; unsigned int avg_trb_len;
out_ctx = virt_dev->out_ctx; @@ -546,6 +563,8 @@ static int xhci_set_configuration(struct usb_device *udev) interval = xhci_get_endpoint_interval(udev, endpt_desc); mult = xhci_get_endpoint_mult(udev, endpt_desc, ss_ep_comp_desc); + max_burst = xhci_get_endpoint_max_burst(udev, endpt_desc, + ss_ep_comp_desc); avg_trb_len = max_esit_payload;
ep_index = xhci_get_ep_index(endpt_desc); @@ -571,7 +590,7 @@ static int xhci_set_configuration(struct usb_device *udev) (get_unaligned(&endpt_desc->wMaxPacketSize)));
ep_ctx[ep_index]->ep_info2 |= - cpu_to_le32(((0 & MAX_BURST_MASK) << MAX_BURST_SHIFT) | + cpu_to_le32(MAX_BURST(max_burst)| ((3 & ERROR_COUNT_MASK) << ERROR_COUNT_SHIFT));
trb_64 = (uintptr_t)