On 06/06/2017 05:11 PM, Dr. Philipp Tomsich wrote: > 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 > ...
So this patch is just some hypothetical fix ? What triggered creation of this patch ? -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
