Marek, > On 06 Jun 2017, at 16:35, Marek Vasut <[email protected]> wrote: > > On 06/06/2017 03:42 PM, Philipp Tomsich wrote: >> For LP64 build w/ GCC 6.3, the handling of the ep->dma_buf variable >> when (truncating and) writing into the controller's registers is >> unsafe and triggers the following compiler warning (thus failing by >> buildman tests): >> ../drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c: In function 'setdma_rx': >> ../drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c:116:9: warning: cast from >> pointer to integer of different size [-Wpointer-to-int-cast] >> writel((unsigned int) ep->dma_buf, ®->out_endp[ep_num].doepdma); >> ^ >> >> This change fixes the warning and makes the code a bit more robust by >> doing the following: >> - we check whether ep->dma_buf can be safely truncated to 32 bits >> (i.e. whether dma_buf is the same value when masked to 32 bits) and >> emit an error message if that is not the case >> - we cast to a uintptr_t and let the writel macro truncate the >> uintptr_t (potentially a 64bit value) to 32bits >> >> Signed-off-by: Philipp Tomsich <[email protected]> >> >> --- >> >> Changes in v2: >> - (new patch) fix warnings and add some robustness for the truncation >> of ep->dma_buf in dwc2-otg for LP64 builds to fix a buildman failure >> for u-boot-rockchip/master@2b19b2f >> >> drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c >> b/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c >> index 0d6d2fb..f5c926c 100644 >> --- a/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c >> +++ b/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c >> @@ -113,7 +113,11 @@ static int setdma_rx(struct dwc2_ep *ep, struct >> dwc2_request *req) >> invalidate_dcache_range((unsigned long) ep->dma_buf, >> (unsigned long) ep->dma_buf + ep->len); >> >> - writel((unsigned int) ep->dma_buf, ®->out_endp[ep_num].doepdma); >> + /* ensure that ep->dma_buf fits into 32 bits */ >> + if (((uintptr_t)ep->dma_buf & 0xffffffff) != (uintptr_t)ep->dma_buf) >> + error("ep->dma_buf does not fit into a 32 bits"); > > You print an error, but still continue with the function ? That'll > probably lead to a crash, you should rather abort. In fact, I suspect > you can use bounce-buffer to assure the dma buffer is in 32bit space.
This tries to stay close to the current behaviour (we have no hardware to test this, but I wanted to get it out of the way as it caused buildman-failures) and to provide diagnostics for whoever first encounters an issue here. Note that I would only expect a DMA error, if someone really hit this issue ... Regards, Philipp. >> + writel((uintptr_t)ep->dma_buf, ®->out_endp[ep_num].doepdma); >> writel(DOEPT_SIZ_PKT_CNT(pktcnt) | DOEPT_SIZ_XFER_SIZE(length), >> ®->out_endp[ep_num].doeptsiz); >> writel(DEPCTL_EPENA|DEPCTL_CNAK|ctrl, ®->out_endp[ep_num].doepctl); >> > > > -- > Best regards, > Marek Vasut _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
