From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: Paul Cercueil <paul@crapouillou.net>
Cc: "Zhou Yanjie" <zhouyanjie@wanyeetech.com>,
"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
"Paul Burton" <paulburton@kernel.org>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
od@zcrc.me, linux-kernel@vger.kernel.org,
linux-mips@vger.kernel.org, 漆鹏振 <aric.pzqi@ingenic.com>,
dongsheng.qiu@ingenic.com, rick.tyliu@ingenic.com,
yanfei.li@ingenic.com, xuwanhao@wanyeetech.com
Subject: Re: [PATCH 00/13] MIPS: Convert Ingenic to a generic board
Date: Fri, 21 Aug 2020 20:23:16 +0100 (BST) [thread overview]
Message-ID: <alpine.LFD.2.21.2008211949220.3460685@eddie.linux-mips.org> (raw)
In-Reply-To: <L8DPEQ.71Z8YA0QXBJA@crapouillou.net>
On Fri, 7 Aug 2020, Paul Cercueil wrote:
> > I'm not too sure if remove "cpu-feature-overrides.h" will cause some
> > problems for X2000, because according to my current test on X2000, I found
> > that it is somewhat different from the SoCs using XBurst1 CPU core, with the
> > kernel source code provided by Ingenic, for example, we must configure
> > "#define cpu_has_tlbinv 1" in "cpu-feature-overrides.h" to make the X2000
> > work normally, otherwise the kernel will get stuck. And X2000's interrupt
> > controller has also been redesigned. If these differences make it impossible
> > to share code, should we set a subdirectory of "xburst" and "xburst2" in
> > "arch/mips/ingenic"? (I am just worried about this situation, so far I have
> > not been able to successfully run the mainline kernel on X2000).
>
> The <cpu-feature-overrides.h> is kind of a hack, to hardcode settings in case
> the CPU is not properly detected. The cpu-probe.c should be able to
> auto-detect these settings, including the inverted TLB that the X2000 has,
> reading from the CPU config registers ("TLB INV" info should be in config4).
> Right now cpu_probe_ingenic() doesn't read config4 (not present on older SoCs)
> but that's trivial to add.
FAOD <cpu-feature-overrides.h> is not a hack, but an optimisation measure
so that features known to be hardwired for a given machine/CPU do not have
to be dynamically queried every time referred. In some cases that results
in large portions of code being optimised away by the compiler as well.
The hardcoded value for a feature defined in <cpu-feature-overrides.h>
always has to be the same as one in the corresponding bit of the `options'
member of `struct cpuinfo_mips', in this case MIPS_CPU_TLBINV.
Maciej
next prev parent reply other threads:[~2020-08-21 19:31 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-03 17:01 [PATCH 00/13] MIPS: Convert Ingenic to a generic board Paul Cercueil
2020-08-03 17:01 ` [PATCH 01/13] MIPS: cpu-probe: Set Ingenic's writecombine to _CACHE_CACHABLE_WA Paul Cercueil
2020-08-03 17:01 ` [PATCH 02/13] MIPS: cpu-probe: Mark XBurst CPU as having vtagged caches Paul Cercueil
2020-08-03 17:01 ` [PATCH 03/13] MIPS: cpu-probe: ingenic: Fix broken BUG_ON Paul Cercueil
2020-08-03 17:01 ` [PATCH 04/13] MIPS: Kconfig: add MIPS_GENERIC_KERNEL symbol Paul Cercueil
2020-08-03 17:01 ` [PATCH 05/13] MIPS: machine: Add get_system_type callback Paul Cercueil
2020-08-03 17:01 ` [PATCH 06/13] MIPS: generic: Call the machine's .get_system_type callback if provided Paul Cercueil
2020-08-11 12:43 ` Paul Cercueil
2020-08-03 17:01 ` [PATCH 07/13] MIPS: generic: Support booting with built-in or appended DTB Paul Cercueil
2020-08-03 17:01 ` [PATCH 08/13] MIPS: generic: Add support for zboot Paul Cercueil
2020-08-03 17:01 ` [PATCH 09/13] MIPS: generic: Increase NR_IRQS to 256 Paul Cercueil
2020-08-03 17:01 ` [PATCH 10/13] MIPS: generic: Add support for Ingenic SoCs Paul Cercueil
2020-08-03 17:01 ` [PATCH 11/13] MIPS: jz4740: Drop folder Paul Cercueil
2020-08-03 17:01 ` [PATCH 12/13] MIPS: configs: Regenerate configs of Ingenic boards Paul Cercueil
2020-08-03 17:01 ` [PATCH 13/13] MAINTAINERS: Update paths to Ingenic platform code Paul Cercueil
2020-08-07 17:22 ` Zhou Yanjie
2020-08-07 17:43 ` Zhou Yanjie
2020-08-07 16:23 ` [PATCH 00/13] MIPS: Convert Ingenic to a generic board Zhou Yanjie
2020-08-07 16:45 ` Paul Cercueil
2020-08-07 17:20 ` Zhou Yanjie
2020-08-08 2:39 ` Jiaxun Yang
2020-08-21 19:23 ` Maciej W. Rozycki [this message]
2020-08-21 23:19 ` Paul Cercueil
2020-08-22 2:29 ` Maciej W. Rozycki
2020-08-22 13:17 ` Paul Cercueil
2020-08-22 14:00 ` Maciej W. Rozycki
2020-10-26 14:25 ` Zhou Yanjie
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