On Tue, Apr 28, 2020 at 05:04:32PM +0300, Andy Shevchenko wrote: > On Tue, Apr 28, 2020 at 4:12 PM Dejin Zheng <zhengdej...@gmail.com> wrote: > > On Tue, Apr 28, 2020 at 10:42:56AM +0200, Nicolas Ferre wrote: > > > On 28/04/2020 at 05:24, Dejin Zheng wrote: > > > > On Mon, Apr 27, 2020 at 01:33:41PM +0300, Andy Shevchenko wrote: > > > > > On Sat, Apr 25, 2020 at 3:57 PM Dejin Zheng <zhengdej...@gmail.com> > > > > > wrote: > > > > > > > > > > > > A call of the function macb_init() can fail in the function > > > > > > fu540_c000_init. The related system resources were not released > > > > > > then. use devm_ioremap() to replace ioremap() for fix it. > > > > > > > > > > > > > > > > Why not to go further and convert to use > > > > > devm_platform_ioremap_resource()? > > > > > > > > > devm_platform_ioremap_resource() will call devm_request_mem_region(), > > > > and here did not do it. > > > > > > And what about devm_platform_get_and_ioremap_resource()? This would > > > streamline this whole fu540_c000_init() function. > > > > > Nicolas, the function devm_platform_get_and_ioremap_resource() will also > > call devm_request_mem_region(), after call it, These IO addresses will > > be monopolized by this driver. the devm_ioremap() and ioremap() are not > > do this. if this IO addresses will be shared with the other driver, call > > devm_platform_get_and_ioremap_resource() may be fail. > > I guess request region is a right thing to do. If driver is sharing > this IO region with something else, it is a delayed bomb attack and > has to be fixed. > > I did encounter IO address sharing, for example, some registers are shared by both PHY and USB controllers on Tegra SoCs. See link[1] for details. If many people think that devm_request_mem_region() should be added here, I will send patch v2 and convert to use devm_platform_ioremap_resource(). Thanks very much!
link[1]: https://patchwork.ozlabs.org/project/linux-tegra/patch/20200127135841.17935-1-zhengdej...@gmail.com/ BR, Dejin > > > -- > With Best Regards, > Andy Shevchenko
