From: Neil Armstrong <narmstrong@baylibre.com>
To: Robin Murphy <robin.murphy@arm.com>, Rob Herring <robh@kernel.org>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Sudeep Holla <sudeep.holla@arm.com>,
Russell King <rmk+kernel@arm.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 02/18] dt-bindings: timer: sp804: add timer-width property
Date: Tue, 22 Mar 2016 15:29:46 +0100 [thread overview]
Message-ID: <56F156DA.3000602@baylibre.com> (raw)
In-Reply-To: <56F13458.1080401@arm.com>
On 03/22/2016 01:02 PM, Robin Murphy wrote:
> Hi Neil,
>>>>
>>>> Humm, same as integrator timers perhaps?
>>>
>>> Having had a quick look, what the Integrator/AP manual describes certainly smells like the same basic block as the "AMBA Timer" - 16 bit counters and the same control register layout - albeit in a mutant triple-timer version with a bigger offset between each register set. Integrator/CP, on the other hand, looks much more SP804-like.
>>>
>>> Robin.
>>>
>>
>> Hi,
>>
>> I will switch to oxsemi,ox810se-rps-timer since it need a specific register width that will be handled by the driver.
>
> By "needs a specific register width" do you mean the OxSemi implementation will give a bus error on a 32-bit access and requires 16-bit accessors? If so, I'd expect to see patch 1 changing readl()s to readw()s at least somewhere. Otherwise, if it's merely that the clocksource API needs to know the upper 16 bits of a word it reads are undefined, then since that's the standard behaviour I'd be inclined to add it to the driver as a canonical "arm,amba-timer" implementation, then have your implementation-specific compatible on top of that just in case.
No actually the bus access is 32bit but the counter is 24bit wide instead of 16bit, so the clocksource won't work and the system time will furiously drift. It's not the case of the clockevent since the delay fits in 24 bits.
It also seems is ignores the 32BIT config bit, so it seems based on the initial 16bit only reference design.
How do you think I should implement this ?
Neil
> Robin.
>
>>
>> Thanks,
>> Neil
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
>
next prev parent reply other threads:[~2016-03-22 14:29 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1457005210-18485-1-git-send-email-narmstrong@baylibre.com>
2016-03-03 11:39 ` [PATCH 03/17] dt-bindings: Add PLX Technology RPS IRQ Controller bindings Neil Armstrong
2016-03-03 14:53 ` Andrew Lunn
2016-03-03 14:57 ` Neil Armstrong
[not found] ` <56D850C6.1010404-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-03 15:06 ` Andrew Lunn
2016-03-03 11:39 ` [PATCH 05/17] dt-bindings: Add PLX Technology RPS Timer bindings Neil Armstrong
2016-03-03 11:40 ` [PATCH 07/17] dt-bindings: Add PLX Technology Reset Controller bindings Neil Armstrong
2016-03-03 14:21 ` Philipp Zabel
[not found] ` <1457014907.3425.56.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2016-03-03 14:24 ` Neil Armstrong
2016-03-03 14:31 ` Philipp Zabel
2016-03-03 11:40 ` [PATCH 09/17] dt-bindings: Add PLX Technology OXNAS Standard Clocks bindings Neil Armstrong
2016-03-03 11:40 ` [PATCH 11/17] dt-bindings: Add PLX Technology OXNAS pinctrl and gpio bindings Neil Armstrong
[not found] ` <1457005210-18485-12-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-15 14:30 ` Linus Walleij
[not found] ` <1457005210-18485-1-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-03 11:39 ` [PATCH 01/17] dt-bindings: vendor-prefixes: Add PLX Technology Neil Armstrong
2016-03-03 15:02 ` Philipp Zabel
2016-03-05 4:29 ` Rob Herring
2016-03-07 9:55 ` Philipp Zabel
2016-03-03 11:40 ` [PATCH 14/17] arm: boot: dts: Add PLX Technology OX810SE dtsi Neil Armstrong
2016-03-03 12:15 ` Arnd Bergmann
2016-03-03 13:39 ` Neil Armstrong
2016-03-03 11:40 ` [PATCH 15/17] dt-bindings: Add OXNAS bindings Neil Armstrong
2016-03-03 11:40 ` [PATCH 16/17] dt-bindings: Add Western Digital to vendor prefixes Neil Armstrong
2016-03-05 4:29 ` Rob Herring
2016-03-03 11:40 ` [PATCH 17/17] arm: boot: dts: Add Western Digital My Book World Edition device tree Neil Armstrong
[not found] ` <1457519060-6038-1-git-send-email-narmstrong@baylibre.com>
2016-03-09 10:24 ` [PATCH v2 02/18] dt-bindings: timer: sp804: add timer-width property Neil Armstrong
[not found] ` <1457519060-6038-3-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-17 17:09 ` Rob Herring
2016-03-17 18:06 ` Robin Murphy
2016-03-17 19:00 ` Rob Herring
[not found] ` <CAL_JsqKRjFDNmGjkPfJ-BKXG8ekNzUgear3uLzsFYbZU7Zph7w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-03-17 19:21 ` Robin Murphy
2016-03-22 9:21 ` Neil Armstrong
2016-03-22 12:02 ` Robin Murphy
2016-03-22 14:29 ` Neil Armstrong [this message]
2016-03-09 10:24 ` [PATCH v2 04/18] dt-bindings: irq: arm,versatile-fpga: add arm,rps-irq compatible string Neil Armstrong
[not found] ` <1457519060-6038-5-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-17 17:15 ` Rob Herring
2016-03-09 10:24 ` [PATCH v2 05/18] dt-bindings: vendor-prefixes: Add PLX Technology Neil Armstrong
[not found] ` <1457519060-6038-6-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-17 17:15 ` Rob Herring
2016-03-09 10:24 ` [PATCH v2 06/18] dt-bindings: Add Oxford Semiconductors to vendor prefixes Neil Armstrong
2016-03-17 17:16 ` Rob Herring
2016-03-09 10:24 ` [PATCH v2 08/18] dt-bindings: Add PLX Technology Reset Controller bindings Neil Armstrong
[not found] ` <1457519060-6038-9-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-17 17:18 ` Rob Herring
2016-03-09 10:24 ` [PATCH v2 10/18] dt-bindings: Add PLX Technology OXNAS Standard Clocks bindings Neil Armstrong
2016-03-17 17:19 ` Rob Herring
2016-03-09 10:24 ` [PATCH v2 12/18] dt-bindings: Add PLX Technology OXNAS pinctrl and gpio bindings Neil Armstrong
2016-03-17 17:25 ` Rob Herring
2016-03-09 10:24 ` [PATCH v2 16/18] dt-bindings: Add OXNAS bindings Neil Armstrong
[not found] ` <1457519060-6038-17-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-17 17:27 ` Rob Herring
2016-03-23 8:37 ` Neil Armstrong
2016-03-09 10:24 ` [PATCH v2 17/18] dt-bindings: Add Western Digital to vendor prefixes Neil Armstrong
[not found] ` <1457519060-6038-1-git-send-email-narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2016-03-09 10:24 ` [PATCH v2 15/18] arm: boot: dts: Add PLX Technology OX810SE dtsi Neil Armstrong
2016-03-09 10:24 ` [PATCH v2 18/18] arm: boot: dts: Add Western Digital My Book World Edition device tree Neil Armstrong
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