From b7789f1edbe5bf1478c57063d14d43d1c49ed2f4 Mon Sep 17 00:00:00 2001 From: CTCaer Date: Wed, 30 Dec 2020 13:40:16 +0200 Subject: [PATCH] xusb: Increase performance up to 96% The default interrupt moderation on XUSB controller was causing 4.62ms latency, hurting performance tremendously, especially in smaller usb packets (which are the norm). This change brings it to parity with USB2 controller. --- bdk/usb/usb_t210.h | 1 + bdk/usb/xusbd.c | 10 +++++++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/bdk/usb/usb_t210.h b/bdk/usb/usb_t210.h index 4d67c69..e677a5f 100644 --- a/bdk/usb/usb_t210.h +++ b/bdk/usb/usb_t210.h @@ -198,6 +198,7 @@ typedef struct _t210_usb2d_t #define XUSB_DEV_XHCI_ST 0x34 #define XHCI_ST_RC BIT(0) #define XHCI_ST_IP BIT(4) +#define XUSB_DEV_XHCI_RT_IMOD 0x38 #define XUSB_DEV_XHCI_PORTSC 0x3C #define XHCI_PORTSC_PR BIT(4) #define XHCI_PORTSC_PLS_MASK (0xF << 5) diff --git a/bdk/usb/xusbd.c b/bdk/usb/xusbd.c index 5595d98..4beefcd 100644 --- a/bdk/usb/xusbd.c +++ b/bdk/usb/xusbd.c @@ -895,14 +895,11 @@ int xusb_device_init() XUSB_DEV_DEV(XUSB_DEV_INTR_MASK) |= DEV_INTR_MASK_IP_INT_MASK; // AHB USB performance cfg. - //TODO: Doesn't help.. -/* AHB_GIZMO(AHB_GIZMO_AHB_MEM) |= AHB_MEM_DONT_SPLIT_AHB_WR | AHB_MEM_ENB_FAST_REARBITRATE; AHB_GIZMO(AHB_GIZMO_USB3) |= AHB_GIZMO_IMMEDIATE; AHB_GIZMO(AHB_ARBITRATION_PRIORITY_CTRL) = PRIORITY_CTRL_WEIGHT(7) | PRIORITY_SELECT_USB3; AHB_GIZMO(AHB_AHB_MEM_PREFETCH_CFG1) = MEM_PREFETCH_ENABLE | MEM_PREFETCH_USB3_MST_ID | MEM_PREFETCH_ADDR_BNDRY(12) | 0x1000; // Addr boundary 64KB, Inactivity 4096 cycles. -*/ // Initialize context. usbd_xotg = &usbd_xotg_controller_ctxt; @@ -1771,6 +1768,13 @@ int xusb_device_enumerate(usb_gadget_type gadget) usbd_xotg->gadget = gadget; + /* + * Set interrupt moderation to 0us. + * This is important because default value creates a 4.62ms latency. + * Effectively hurting transfers by having 15% to 96% performance loss. + */ + XUSB_DEV_XHCI(XUSB_DEV_XHCI_RT_IMOD) = 0; + // Disable Wake events. XUSB_PADCTL(XUSB_PADCTL_ELPG_PROGRAM_0) = 0; XUSB_PADCTL(XUSB_PADCTL_ELPG_PROGRAM_1) = 0;