From: marc_gonzalez@sigmadesigns•com (Marc Gonzalez)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3] arm-soc: Add support for Sigma Designs Tango4
Date: Mon, 19 Oct 2015 13:09:22 +0200 [thread overview]
Message-ID: <5624CF62.6020001@sigmadesigns.com> (raw)
In-Reply-To: <CAL_JsqKa4trfpLY_DPsjBrfH-7SSUQMACYVW7DNN1=Pv3B4FrA@mail.gmail.com>
On 13/10/2015 19:55, Rob Herring wrote:
> Marc Gonzalez wrote:
>> On 09/10/2015 16:08, Rob Herring wrote:
>>
>>> No cpus node?
>>
>> Is this used to document the CPU?
>> I didn't see any code making use of that information.
>
> The SMP code uses it: arch/arm/kernel/devtree.c
Now I see arm_dt_init_cpu_maps()
<confused> I thought DT was used to specify things that cannot be
dynamically discovered? Isn't it possible for the OS to discover at
run-time how many cores and/or CPUs are present?
On a related topic, I have a DTS for my board, which includes the
DTS for the architecture. However, there are single-core SoCs and
dual-core SoCs. Where is the cpus node supposed to appear?
Or should I specify in the architecture DTS the maximum number
of cores, as in
cpus {
#address-cells = <1>;
#size-cells = <0>;
cpu at 0 {
compatible = "arm,cortex-a9";
reg = <0>;
};
cpu at 1 {
compatible = "arm,cortex-a9";
reg = <1>;
};
};
>>> No pl310? A9 performance mon?
Found "arm,cortex-a9-pmu" in arch/arm/kernel/perf_event_v7.c
Are the PMU registers available from non-secure mode, or is TrustZone
going to get in the way?
About the cache controller, I was confused by this comment:
/*
* Always enable non-secure access to the lockdown registers -
* we write to them as part of the L2C enable sequence so they
* need to be accessible.
*/
l2x0_saved_regs.aux_ctrl = aux | L310_AUX_CTRL_NS_LOCKDOWN;
I see no lock() function, only unlock().
But the unlock function merely writes 0 to the relevant registers,
and 0 is the value at reset for those registers. Since nothing ever
sets the registers to non-zero, why is the unlock needed at all?
Regards.
next prev parent reply other threads:[~2015-10-19 11:09 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 16:02 [PATCH] arm-soc: Add Sigma Designs Tango4 port Mason
2015-10-02 16:10 ` Måns Rullgård
2015-10-02 16:33 ` Mason
2015-10-02 16:55 ` Måns Rullgård
2015-10-02 18:00 ` Mason
2015-10-02 17:13 ` Russell King - ARM Linux
2015-10-02 18:09 ` Mason
2015-10-02 18:53 ` Russell King - ARM Linux
2015-10-02 19:25 ` Mason
2015-10-02 19:56 ` Arnd Bergmann
2015-10-02 20:53 ` Mason
2015-10-02 21:11 ` Arnd Bergmann
2015-10-02 21:57 ` Mason
2015-10-02 22:12 ` Arnd Bergmann
2015-10-05 16:25 ` [PATCH v2] arm-soc: Add support for Sigma Designs Tango4 Marc Gonzalez
2015-10-06 15:57 ` [PATCH v3] " Marc Gonzalez
2015-10-09 13:18 ` Arnd Bergmann
2015-10-09 13:30 ` Marc Gonzalez
2015-10-09 14:40 ` Måns Rullgård
2015-10-09 19:01 ` Mason
2015-10-09 20:24 ` Måns Rullgård
2015-10-09 21:12 ` Mason
2015-10-09 14:08 ` Rob Herring
2015-10-09 14:16 ` Marc Gonzalez
2015-10-09 14:48 ` Rob Herring
2015-10-13 15:54 ` Marc Gonzalez
2015-10-13 17:55 ` Rob Herring
2015-10-19 11:09 ` Marc Gonzalez [this message]
2015-10-19 16:39 ` Rob Herring
2015-10-19 17:32 ` Mark Rutland
2015-10-20 9:20 ` Marc Gonzalez
2015-10-20 9:50 ` Marc Gonzalez
2015-10-20 10:04 ` Russell King - ARM Linux
2015-10-20 10:54 ` Marc Gonzalez
2015-10-09 14:12 ` [PATCH v2] " Rob Herring
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