Messages in this thread | | | From | Scott Wood <> | Date | Sat, 29 Feb 2020 17:12:58 -0600 | Subject | Re: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable |
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On Tue, 2020-01-21 at 14:38 +0800, 王文虎 wrote: > 发件人:Scott Wood <oss@buserror.net> > 发送日期:2020-01-21 13:49:59 > 收件人:"王文虎" <wenhu.wang@vivo.com> > 抄送人:wangwenhu <wenhu.pku@gmail.com>,Kumar Gala <galak@kernel.crashing.org>,B > enjamin Herrenschmidt <benh@kernel.crashing.org>,Paul Mackerras < > paulus@samba.org>,Michael Ellerman <mpe@ellerman.id.au>, > linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org, > trivial@kernel.org,Rai Harninder <harninder.rai@nxp.com> > 主题:Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On > Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote: > > > From: Scott Wood <oss@buserror.net> > > > Date: 2020-01-21 11:25:25 > > > To: wangwenhu <wenhu.pku@gmail.com>,Kumar Gala < > > > galak@kernel.crashing.org>, > > > Benjamin Herrenschmidt <benh@kernel.crashing.org>,Paul Mackerras < > > > paulus@samba.org>,Michael Ellerman <mpe@ellerman.id.au>, > > > linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org > > > Cc: trivial@kernel.org,wenhu.wang@vivo.com,Rai Harninder < > > > harninder.rai@nxp.com> > > > Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM > > > configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote: > > > > > From: wangwenhu <wenhu.wang@vivo.com> > > > > > > > > > > When generating .config file with menuconfig on Freescale BOOKE > > > > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of > > > > > description in the Kconfig field, which makes it impossible > > > > > to support L2Cache-Sram driver. Add a description to make it > > > > > configurable. > > > > > > > > > > Signed-off-by: wangwenhu <wenhu.wang@vivo.com> > > > > > > > > The intent was that drivers using the SRAM API would select the > > > > symbol. What > > > > is the use case for selecting it manually? > > > > > > > > > > With a repository of multiple products(meaning different defconfigs) and > > > multiple > > > developers, the Kconfigs of the Kernel Source Tree change frequently. So > > > the > > > "make menuconfig" > > > process is needed for defconfigs' re-generating or updating for the > > > complexity of dependencies > > > between different features defined in the Kconfigs. > > > > That doesn't answer my question of how the SRAM code would be useful other > > than to some other driver that uses the API (which would use > > "select"). There > > is no userspace API. You could use the kernel command line to configure > > the > > SRAM but you need to get the address of it for it to be useful. > > > > Like you've asked below, via /dev/mem or direct calling within the Kernel. > And they are not submitted yes, under development.
If they are calling within the kernel, then whatever driver that is should select FSL_85XX_CACHE_SRAM. Directly accessing /dev/mem without any way for the kernel to advertise where it is or which parts of SRAM are available for use sounds like a bad idea.
-Scott
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