usb: xhci: Program max burst size for endpoint

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>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 8aed4283edb02fa50523d2b6527a9b38fb8723b5..dfb188d5e4681c1f468c89824cb452b8bb9c80ae 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -395,6 +395,22 @@ 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
@@ -493,6 +509,7 @@ 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;
@@ -545,6 +562,8 @@ 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);
@@ -570,7 +589,7 @@ 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)