linux-kernel - Re: [PATCH v2 6/7] Watchdog: introduce ARM SBSA watchdog driver

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Date:	Thu, 21 May 2015 08:09:02 -0500
From:	Timur Tabi <timur@...eaurora.org>
To:	Guenter Roeck <linux@...ck-us.net>, fu.wei@...aro.org,
	Suravee.Suthikulpanit@....com, linaro-acpi@...ts.linaro.org,
	linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org
CC:	tekkamanninja@...il.com, graeme.gregory@...aro.org,
	al.stone@...aro.org, hanjun.guo@...aro.org,
	ashwin.chaugule@...aro.org, arnd@...db.de, vgandhi@...eaurora.org,
	wim@...ana.be, jcm@...hat.com, leo.duran@....com, corbet@....net,
	mark.rutland@....com
Subject: Re: [PATCH v2 6/7] Watchdog: introduce ARM SBSA watchdog driver

Guenter Roeck wrote:
>>
>> +static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd)
>> +{
>> +    struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
>> +    u64 timeleft = sbsa_gwdt_get_wcv(wdd) - arch_counter_get_cntvct();
>> +
>
> Still not happy about the use of arch_counter_get_cntvct
> instead of using the clock subsystem. I am quite sure this could be done,
> possibly through arch_sys_counter, though at this point I am getting wary
> of bringing it up, so I guess I'll just let it go.

You made the same comment with my driver, and I keep asking for 
clarification.  The clk_get_sys() API does not work on my system, 
because there are not clocks defined.  That must be an ACPI limitation 
that I can't fix.

The alternative to arch_counter_get_cntvct() is 
arch_timer_read_counter(), which is not exported.  So we have two choices,

1) Continue to use arch_counter_get_cntvct(), which works on all ARM64 
platforms that this driver supports anyway

2) Export arch_timer_read_counter()

I prefer option #1.

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the
Code Aurora Forum, hosted by The Linux Foundation.
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