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From: pawel.moll@arm.com (Pawel Moll)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 06/11] ARM: vexpress: use clocksource_of_init for sp804
Date: Wed, 13 Mar 2013 15:19:39 +0000
Message-ID: <1363187979.3100.93.camel@hornet> (raw)
In-Reply-To: <CAD6h2NRkS4qk+iqbWhaOpBHmjSYOB=YBbfNkn0X3jzNawzgNEA@mail.gmail.com>

On Wed, 2013-03-13 at 15:01 +0000, Haojian Zhuang wrote:
> Yes, it's possible. Since only clocksource / clockevent is using SP804 timer
> on the VE platform. If user app or something else is using other SP804
> timer, it would be mess because of resource conflict.

How would you expose this device to the app or something else? It's an
amba_bus device, so it must be bound with an amba_driver. Otherwise
you're abusing the device model and, well, you're on your own.

The devices are managed by the system. The device tree is merely a
description of the available hardware.

> >> Imagine that only TIMINT1 signal in sp804 is routed to interrupt controller.
> >> Could system still pick any one it wants?
> >
> Then we need another new property. I try to find using minim properties.

No, we don't. See the discussion with Rob. He has an idea (using the
interrupt property only), I have another one (using already defined
interrupt-names property). I see you've just came with another one
(TIMINTC treated as TIMINT1), which is fine with me. Either way you've
got what you need to make the right decision.

> As I mentioned above, system must know the behavior first. The upper layer
> software could know which timer is used in clocksource or clockevent.

I claim otherwise. The upper layer software should know what does the
hardware offer and based on this knowledge use it in a way it wants to.

> For example, your Android system could be shared on multiple platforms. It
> could parse hardware information from DTS. (Of course, it hasn't this feature
> yet). Then it could arrange apps to use other timers.

I honestly don't know what are you suggesting here other than it looks
like an abuse to the device model.

> It's like you define console on specified UART even you have multiples UART
> port.

Where do you do this? In the Device Tree? No. In the kernel command
line, which is a runtime argument (the fact it is actually being passed
through the tree is irrelevant here) You have the serialX aliases, which
- again - simply describe the hardware ("this node is connected to a
connector labeled as serial X"). The tree doesn't tell that the user
connected his serial cable to serial1 so it should be used as the
console.

Pawe?

  reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-13  5:05 [PATCH v3 00/11] add hisilicon SoC support Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 01/11] clocksource: move sp timer driver Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 02/11] clocksource: select USE_OF by default Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 03/11] clocksource: sp804: add device tree support Haojian Zhuang
2013-03-13 11:05   ` Pawel Moll
2013-03-13 11:37     ` Haojian Zhuang
2013-03-13 11:41       ` Pawel Moll
2013-03-13 14:17     ` Rob Herring
2013-03-13 14:42       ` Pawel Moll
2013-03-13 14:51         ` Rob Herring
2013-03-13 14:55           ` Pawel Moll
2013-03-13 15:11             ` Haojian Zhuang
2013-03-13 15:23               ` Pawel Moll
2013-03-13 15:25                 ` Haojian Zhuang
2013-03-13 15:29                   ` Pawel Moll
2013-03-13 15:39                     ` Rob Herring
2013-03-13 15:41                       ` Pawel Moll
2013-03-13 15:44                         ` Haojian Zhuang
2013-03-13 15:42                     ` Haojian Zhuang
2013-03-13 15:49                       ` Pawel Moll
2013-03-13 16:35                         ` Arnd Bergmann
2013-03-13 16:41                           ` Pawel Moll
2013-03-15 12:20       ` Russell King - ARM Linux
2013-03-13  5:05 ` [PATCH v3 04/11] ARM: integrator: use clocksource_of_init for sp804 Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 05/11] ARM: highbank: " Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 06/11] ARM: vexpress: " Haojian Zhuang
2013-03-13 11:10   ` Pawel Moll
2013-03-13 11:42     ` Haojian Zhuang
2013-03-13 11:46       ` Pawel Moll
2013-03-13 12:21         ` Haojian Zhuang
2013-03-13 14:48           ` Pawel Moll
2013-03-13 15:01             ` Haojian Zhuang
2013-03-13 15:19               ` Pawel Moll [this message]
2013-03-13 15:59                 ` Haojian Zhuang
2013-03-13 16:28                   ` Pawel Moll
2013-03-13 16:32                   ` Rob Herring
2013-03-15 12:34                     ` Russell King - ARM Linux
2013-03-15 12:58                       ` Pawel Moll
2013-03-15 18:10                         ` Russell King - ARM Linux
2013-03-13  5:05 ` [PATCH v3 07/11] ARM: debug: support debug ll on hisilicon soc Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 08/11] clk: hi3xxx: add clock support Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 09/11] ARM: hi3xxx: add board support with device tree Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 10/11] ARM: hi3xxx: enable hi4511 " Haojian Zhuang
2013-03-13  5:05 ` [PATCH v3 11/11] ARM: config: append arch hi3xxx into multi defconfig Haojian Zhuang

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