From: Tony Lindgren <tony@atomide.com>
To: Ohad Ben-Cohen <ohad@wizery.com>
Cc: linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH 04/10] hwspinlock/core/omap: fix id issues on multiple hwspinlock devices
Date: Wed, 21 Sep 2011 09:14:06 -0700 [thread overview]
Message-ID: <20110921161406.GF2937@atomide.com> (raw)
In-Reply-To: <1315846025-11453-5-git-send-email-ohad@wizery.com>
* Ohad Ben-Cohen <ohad@wizery.com> [110912 09:14]:
> hwspinlock devices provide system-wide hardware locks that are used
> by remote processors that have no other way to achieve synchronization.
>
> For that to work, each physical lock must have a system-wide unique id
> number that all processors are familiar with, otherwise they can't
> possibly assume they're using the same hardware lock.
>
> Usually SoCs have a single hwspinlock device, which provides several
> hwspinlocks, and in this case, they can be trivially numbered 0 to
> (num-of-locks - 1).
>
> In case boards have several hwspinlocks devices (each of which
> providing numerous hardware spinlocks) a different base id should be
> used for each hwspinlock device (they can't all use 0 as a starting
> id!).
>
> While this is certainly not common, it's just plain wrong to just
> silently use 0 as a base id whenever the hwspinlock driver is probed.
>
> This patch provides a hwspinlock_pdata structure, that boards can use
> to set a different base id for each of the hwspinlock devices they may
> have, and demonstrates how to use it with the omap hwspinlock driver
> (ultimately it will be DT which will supply this base_id information).
>
> While we're at it, make sure the hwspinlock core prints an explicit
> error message in case an hwspinlock is registered with an id number
> that already exists; this will help users catch such base id issues.
>
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Tony Lindgren <tony@atomide.com>
WARNING: multiple messages have this Message-ID (diff)
From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 04/10] hwspinlock/core/omap: fix id issues on multiple hwspinlock devices
Date: Wed, 21 Sep 2011 09:14:06 -0700 [thread overview]
Message-ID: <20110921161406.GF2937@atomide.com> (raw)
In-Reply-To: <1315846025-11453-5-git-send-email-ohad@wizery.com>
* Ohad Ben-Cohen <ohad@wizery.com> [110912 09:14]:
> hwspinlock devices provide system-wide hardware locks that are used
> by remote processors that have no other way to achieve synchronization.
>
> For that to work, each physical lock must have a system-wide unique id
> number that all processors are familiar with, otherwise they can't
> possibly assume they're using the same hardware lock.
>
> Usually SoCs have a single hwspinlock device, which provides several
> hwspinlocks, and in this case, they can be trivially numbered 0 to
> (num-of-locks - 1).
>
> In case boards have several hwspinlocks devices (each of which
> providing numerous hardware spinlocks) a different base id should be
> used for each hwspinlock device (they can't all use 0 as a starting
> id!).
>
> While this is certainly not common, it's just plain wrong to just
> silently use 0 as a base id whenever the hwspinlock driver is probed.
>
> This patch provides a hwspinlock_pdata structure, that boards can use
> to set a different base id for each of the hwspinlock devices they may
> have, and demonstrates how to use it with the omap hwspinlock driver
> (ultimately it will be DT which will supply this base_id information).
>
> While we're at it, make sure the hwspinlock core prints an explicit
> error message in case an hwspinlock is registered with an id number
> that already exists; this will help users catch such base id issues.
>
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Tony Lindgren <tony@atomide.com>
next prev parent reply other threads:[~2011-09-21 16:14 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-12 16:46 [PATCH 00/10] hwspinlock-next Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` [PATCH 01/10] hwspinlock/core: simplify Kconfig Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` [PATCH 02/10] hwspinlock/core: simplify 'owner' handling Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` [PATCH 03/10] hwspinlock/omap: simplify allocation scheme Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` [PATCH 04/10] hwspinlock/core/omap: fix id issues on multiple hwspinlock devices Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-12 16:46 ` Ohad Ben-Cohen
2011-09-21 16:14 ` Tony Lindgren [this message]
2011-09-21 16:14 ` Tony Lindgren
2011-09-12 16:47 ` [PATCH 05/10] hwspinlock/core: use a mutex to protect the radix tree Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` [PATCH 06/10] hwspinlock/core: remove stubs for register/unregister Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` [PATCH 07/10] hwspinlock/core: register a bank of hwspinlocks in a single API call Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` [PATCH 08/10] hwspinlock/u8500: add hwspinlock driver Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` [PATCH 09/10] hwspinlock/omap: omap_hwspinlock_remove should be __devexit Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` [PATCH 10/10] hwspinlock: add MAINTAINERS entries Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:47 ` Ohad Ben-Cohen
2011-09-12 16:58 ` Joe Perches
2011-09-12 16:58 ` Joe Perches
2011-09-12 16:58 ` Joe Perches
2011-09-12 17:01 ` Ohad Ben-Cohen
2011-09-12 17:01 ` Ohad Ben-Cohen
2011-09-12 17:01 ` Ohad Ben-Cohen
2011-09-20 9:07 ` [PATCH 00/10] hwspinlock-next Ohad Ben-Cohen
2011-09-20 9:07 ` Ohad Ben-Cohen
2011-09-20 9:07 ` Ohad Ben-Cohen
2011-09-20 23:13 ` Tony Lindgren
2011-09-20 23:13 ` Tony Lindgren
2011-09-20 23:45 ` Greg KH
2011-09-20 23:45 ` Greg KH
2011-09-21 15:24 ` Tony Lindgren
2011-09-21 15:24 ` Tony Lindgren
2011-09-21 14:12 ` Arnd Bergmann
2011-09-21 14:12 ` Arnd Bergmann
2011-09-21 15:28 ` Tony Lindgren
2011-09-21 15:28 ` Tony Lindgren
2011-09-21 15:56 ` Ohad Ben-Cohen
2011-09-21 15:56 ` Ohad Ben-Cohen
2011-09-21 15:56 ` Ohad Ben-Cohen
2011-09-21 16:07 ` Ohad Ben-Cohen
2011-09-21 16:07 ` Ohad Ben-Cohen
2011-09-21 16:14 ` Tony Lindgren
2011-09-21 16:14 ` Tony Lindgren
2011-09-21 16:16 ` Ohad Ben-Cohen
2011-09-21 16:16 ` Ohad Ben-Cohen
2011-09-21 15:53 ` Linus Walleij
2011-09-21 15:53 ` Linus Walleij
2011-09-21 16:21 ` Arnd Bergmann
2011-09-21 16:21 ` Arnd Bergmann
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