On 06/07/2017 09:49 AM, Dr. Philipp Tomsich wrote: >> On 07 Jun 2017, at 08:28, Marek Vasut <[email protected] >> <mailto:[email protected]>> wrote: >> >> On 06/06/2017 05:11 PM, Dr. Philipp Tomsich wrote: >>> >>>> On 06 Jun 2017, at 16:35, Marek Vasut <[email protected] >>>> <mailto:[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] >>>>> <mailto:[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 ? > > 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.
Ah, hm. In that case, you should really implement the bounce buffer here I think. Letting the transfer continue will lead to really weird failures and/or memory corruption. -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
