> On 07 Jun 2017, at 08:28, Marek Vasut <ma...@denx.de> wrote: > > On 06/06/2017 05:11 PM, Dr. Philipp Tomsich wrote: >> >>> On 06 Jun 2017, at 16:35, Marek Vasut <ma...@denx.de> 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 <philipp.toms...@theobroma-systems.com> >>>> >>>> --- >>>> >>>> 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 >> ... > > So this patch is just some hypothetical fix ? What triggered creation of > this patch ?
Running buildman (w/ a GCC 6.3 configured as aarch-unknown-elf) against unrelated patch-series (for a Rockchip device that has a different USB controller) fails due to the warnings raised from this. Just casting those warnings away (without having an “assertion-like” diagnostic printed) doesn’t sound like the best plan either, though. Details of the buildman-failure are in the above commit-message. Regards, Philipp. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot