Hi Marek, On Fri, Aug 17, 2012 at 8:39 PM, Marek Szyprowski <[email protected]> wrote: > Hello, > > On Friday, August 17, 2012 4:59 PM Sekhar Nori wrote: > >> On 8/16/2012 3:43 PM, Prabhakar Lad wrote: >> > On Tuesday 14 August 2012 05:58 PM, Sekhar Nori wrote: >> >> [...] >> >> >>> +int __init da850_register_vpif_display(struct vpif_display_config >> >>> + *display_config) >> >>> +{ >> >>> + struct resource da850_vpif_display_resource[] = { >> >>> + { >> >>> + .start = IRQ_DA850_VPIFINT, >> >>> + .end = IRQ_DA850_VPIFINT, >> >>> + .flags = IORESOURCE_IRQ, >> >>> + }, >> >>> + {}, >> >>> + }; >> >>> + unsigned long phys_end_kernel; >> >>> + int ret; >> >>> + >> >>> + if (vpif_disp_cont_bufsize) { >> >>> + phys_end_kernel = virt_to_phys((void *)PAGE_OFFSET) + >> >>> + (num_physpages << PAGE_SHIFT); >> >>> + phys_end_kernel += vpif_disp_cont_buf_offset; >> >>> + da850_vpif_display_resource[1].start = phys_end_kernel; >> >>> + da850_vpif_display_resource[1].end = phys_end_kernel + >> >>> + vpif_disp_cont_bufsize - 1; >> >>> + da850_vpif_display_resource[1].flags = IORESOURCE_MEM; >> >>> + >> >>> + if (!request_mem_region(da850_vpif_display_resource[1].start, >> >>> + resource_size(&da850_vpif_display_resource[1]), >> >>> + da850_vpif_display_dev.name)) { >> >>> + pr_err("region already claimed.\n"); >> >>> + return -EBUSY; >> >>> + } >> >>> + ret = dma_declare_coherent_memory(&da850_vpif_display_dev.dev, >> >>> + phys_end_kernel, phys_end_kernel, >> >>> + vpif_disp_cont_bufsize, >> >>> + DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE); >> >>> + >> >>> + if (!ret) >> >>> + return -ENOMEM; >> >>> + } >> >>> + ret = platform_device_add_resources(&da850_vpif_display_dev, >> >>> + da850_vpif_display_resource, >> >>> + ARRAY_SIZE(da850_vpif_display_resource)); >> >> >> >> You are taking memory at the end of RAM and passing it as a IO resource >> >> to the driver. This is not correct. For contiguous memory needs can you >> >> look at the recently merged CMA framework (include/linux/dma-contiguous.h) >> >> >> > Ok. But looks like CMA is enabled for CPU_V6/V6K/V7. If CMA is enabled >> > for ARM926 too than we can use the global CMA itself rather then doing >> > it for each device, then three will be no need to do the above and all >> > the kernel parameters can be removed too. >> >> I hadn't followed the CMA development closely so I am not sure of the >> reasons behind restricting it to v6+. The patch that added this doesn't >> really talk about why it should be restricted to v6+. I am copying Marek >> here to see if he can quickly clarify, but may be you can even start a >> new thread asking about this. > > Frankly, this is a leftover from some earlier suggestions that CMA should > solve the > aliasing of coherent mappings, which might be a problem on v6+. If it works > correctly > on pre-v6, then this dependency should be removed. Feel free to submit a > patch and > I will take it to my fixes branch. >
I have created a patch for enabling CMA on CPU32_v5 [1], and also tested it works. Soon posting this patch. [1] http://git.linuxtv.org/mhadli/v4l-dvb-davinci_devices.git/commitdiff/e940a1b9262bde96eec4b18971a6307f24262667?hp=2f30ae4ee373fe4c69ab1606373538dcc99ed283 Thanks and Regards, --Prabhakar Lad > Best regards > -- > Marek Szyprowski > Samsung Poland R&D Center > > > > _______________________________________________ > linux-arm-kernel mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
