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小弟最近做了5块板子,用的创龙的核心板,其中4块USB2.0 host都没有问题,只有一块老是周期性报如下错误:5 V3 W. W1 z m& X
hub 2-0:1.0: over-current condition on port 1, ~9 W6 F' ^9 q8 V! H; t5 x
da8xx_musb_interrupt 538: VBUS error workaround (delay coming)
0 q: G8 e7 o$ W- d我的电路图如附件,我用示波器测量过了,开始USB0_DRVVBUS脚起始是低电平,开机瞬间,它会变成高电平,USB0_VBUS也会+ B! k- l: L$ q7 C; F5 l
随着上升至5V,开机瞬间,USB0_VBUS并没有出现跌落至低于4.4V,从电路上没有发现问题,然后开始追踪linux3.3 USB驱动代码,
4 s7 D$ C0 w& q Y6 F2 y发现,在da8xx_musb_interrupt函数中,有如下代码:
; r% b. a4 L3 {; `( u' t2 ~; J0 ]if (status & (DA8XX_INTR_DRVVBUS << DA8XX_INTR_USB_SHIFT)) {0 o* b8 t# m( n% [
int drvvbus = musb_readl(reg_base, DA8XX_USB_STAT_REG); C! v; f+ R- H$ h1 O3 O ~
void __iomem *mregs = musb->mregs;' n& L* U2 W" k( U1 V
u8 devctl = musb_readb(mregs, MUSB_DEVCTL);7 u P \3 J, q+ `" o8 S
int err;/ z6 i& w( T* r7 S
( A8 q3 T0 X' p; e
err = is_host_enabled(musb) && (musb->int_usb &
9 K8 p) x; w) ]: C, @ MUSB_INTR_VBUSERROR);3 q- Q) E! E2 | r: |
if (err) {
" C- N9 Q1 a2 B+ R% n /*
3 v3 ?9 l2 k" I; L6 h+ I9 l) @3 P( K * The Mentor core doesn't debounce VBUS as needed T0 \6 L- ]' |3 O( T
* 。。。2 X m* c9 Z$ P1 O! l
*/
) Q# G3 t3 R5 E8 o" _2 T- b musb->int_usb &= ~MUSB_INTR_VBUSERROR;9 N2 m# L, ]7 p
musb->xceiv->state = OTG_STATE_A_WAIT_VFALL;
9 F: w4 A$ d$ Y mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);
) [1 W0 s v. E* Y& x WARNING("VBUS error workaround (delay coming)\n");& @2 j7 ~9 j+ o' `! p$ V
}) Z: N" c, q) j$ L, W
! K4 w* b) Y. ]1 {0 e+ S& w
一直发生MUSB_INTR_VBUSERROR错误,然后会启动定时器,周期调用otg_timer函数,2 i2 m+ A x+ k& D3 |9 \* }
跳入如下分支:: b( A8 f( M$ C+ e# Z6 k+ n
devctl = musb_readb(mregs, MUSB_DEVCTL);6 w' E2 r2 T9 }2 X/ l$ o' J
。。。$ `' k# l. U8 d2 `* d3 I( S, d
case OTG_STATE_A_WAIT_VFALL:
9 f9 f: b" n* @ /*% d! V, g7 p9 l' P( j
* Wait till VBUS falls below SessionEnd (~0.2 V); the 1.3( @2 P$ \* `/ {# o5 H. R
* RTL seems to mis-handle session "start" otherwise (or in: J/ J! ?8 X5 X
* our case "recover"), in routine "VBUS was valid by the time
& [: v) q0 n3 F9 y' O2 s * VBUSERR got reported during enumeration" cases.
2 G$ _1 t( A R' r, e% A9 K1 b+ A/ u */8 _2 s. Q! A2 V# ^
if (devctl & MUSB_DEVCTL_VBUS) {6 W; i1 P, `6 ?+ l, B
mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);# O7 Z- u! @, e' C4 \, Z2 H' d ~
break;7 b1 O6 f3 l5 s/ c; J5 s1 i
}) K4 g- T y5 @
musb->xceiv->state = OTG_STATE_A_WAIT_VRISE;
& P0 @. }1 n* _, X; h0 R musb_writel(musb->ctrl_base, DA8XX_USB_INTR_SRC_SET_REG,
" d5 M8 ^ e0 ^( k7 L MUSB_INTR_VBUSERROR << DA8XX_INTR_USB_SHIFT);# X2 o9 J+ n; H- j6 r7 t M
break;
# }4 V, U& M; x& B
# \+ X* Y* I9 L7 m其中,devctl是设备控制寄存器,我打印了它的直,是0x80, 也就是位7是1,代表着是B device,,明明是A类,
2 s; z2 y- @9 _& M2 E不知道为啥自动变成B类了。而且VBUS一直是5V,正常的啊,可是驱动也无法修复。。
# }( q4 Y& t Q! a _6 Q/ M$ q0 u 不知道亲们有没有遇到类似的情况,是怎么解决的?, G+ R4 x) \. r; c' ?
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