Mike, This issue is specific to Blackfin architecture. Platforms like DaVinci, OMAP etc. do not have this restriction or have not observed any hangs in double buffering mode. I do not see the change implemented specific Blackfin context. Pl. modify the patch accordingly. Regards swami -----Original Message----- From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Mike Frysinger Sent: Friday, January 29, 2010 7:14 AM To: linux-usb@xxxxxxxxxxxxxxx; Felipe Balbi Cc: uclinux-dist-devel@xxxxxxxxxxxxxxxxxxxx; Greg Kroah-Hartman; Cliff Cai Subject: [PATCH 2/2 v2] USB: musb: disable double buffering for older RTL versions From: Cliff Cai <cliff.cai@xxxxxxxxxx> Trying to use double buffer modes in RTL versions <2.0 may result in infinite hangs or data corruption. So avoid them with older versions. Signed-off-by: Cliff Cai <cliff.cai@xxxxxxxxxx> Signed-off-by: Mike Frysinger <vapier@xxxxxxxxxx> --- v2 - fix checks in musb_host too drivers/usb/musb/musb_gadget.c | 17 +++++++++++++++-- drivers/usb/musb/musb_host.c | 10 ++++++++-- 2 files changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index cbcf14a..41de3a9 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -895,7 +895,14 @@ static int musb_gadget_enable(struct usb_ep *ep, /* REVISIT if can_bulk_split(), use by updating "tmp"; * likewise high bandwidth periodic tx */ - musb_writew(regs, MUSB_TXMAXP, tmp); + /* Set TXMAXP with the FIFO size of the endpoint + * to disable double buffering mode. Currently, It seems that double + * buffering has problem if musb RTL revision number < 2.0. + */ + if (musb->hwvers < MUSB_HWVERS_2000) + musb_writew(regs, MUSB_TXMAXP, hw_ep->max_packet_sz_tx); + else + musb_writew(regs, MUSB_TXMAXP, tmp); csr = MUSB_TXCSR_MODE | MUSB_TXCSR_CLRDATATOG; if (musb_readw(regs, MUSB_TXCSR) @@ -925,7 +932,13 @@ static int musb_gadget_enable(struct usb_ep *ep, /* REVISIT if can_bulk_combine() use by updating "tmp" * likewise high bandwidth periodic rx */ - musb_writew(regs, MUSB_RXMAXP, tmp); + /* Set RXMAXP with the FIFO size of the endpoint + * to disable double buffering mode. + */ + if (musb->hwvers < MUSB_HWVERS_2000) + musb_writew(regs, MUSB_RXMAXP, hw_ep->max_packet_sz_rx); + else + musb_writew(regs, MUSB_RXMAXP, tmp); /* force shared fifo to OUT-only mode */ if (hw_ep->is_shared_fifo) { diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 74c4c36..d21fffa 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -605,8 +605,14 @@ musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep) musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg); musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg); /* NOTE: bulk combining rewrites high bits of maxpacket */ - musb_writew(ep->regs, MUSB_RXMAXP, - qh->maxpacket | ((qh->hb_mult - 1) << 11)); + /* Set RXMAXP with the FIFO size of the endpoint + * to disable double buffer mode. + */ + if (musb->hwvers < MUSB_HWVERS_2000) + musb_writew(ep->regs, MUSB_RXMAXP, ep->max_packet_sz_rx); + else + musb_writew(ep->regs, MUSB_RXMAXP, + qh->maxpacket | ((qh->hb_mult - 1) << 11)); ep->rx_reinit = 0; } -- 1.6.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
