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From: Arnd Bergmann <arnd@arndb.de>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	Russell King <linux@armlinux.org.uk>,
	Linus Walleij <linus.walleij@linaro.org>,
	Vinod Koul <vkoul@kernel.org>, Haibo Chen <haibo.chen@nxp.com>,
	Ludovic Barre <ludovic.barre@st.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	dmaengine@vger.kernel.org, "# 3.4.x" <stable@vger.kernel.org>
Subject: Re: [PATCH 2/2] amba: Initialize dma_parms for amba devices
Date: Thu, 26 Mar 2020 12:07:18 +0100	[thread overview]
Message-ID: <CAK8P3a39JrMrYrNeLCr-R6y-ivkVqRkxey_Z7R4N3++MA_qqCg@mail.gmail.com> (raw)
In-Reply-To: <20200325113407.26996-3-ulf.hansson@linaro.org>

On Wed, Mar 25, 2020 at 12:34 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> It's currently the amba driver's responsibility to initialize the pointer,
> dma_parms, for its corresponding struct device. The benefit with this
> approach allows us to avoid the initialization and to not waste memory for
> the struct device_dma_parameters, as this can be decided on a case by case
> basis.
>
> However, it has turned out that this approach is not very practical. Not
> only does it lead to open coding, but also to real errors. In principle
> callers of dma_set_max_seg_size() doesn't check the error code, but just
> assumes it succeeds.
>
> For these reasons, let's do the initialization from the common amba bus at
> the device registration point. This also follows the way the PCI devices
> are being managed, see pci_device_add().
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Acked-by: Arnd Bergmann <arnd@arndb.de>

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Russell King <linux@armlinux.org.uk>,
	Haibo Chen <haibo.chen@nxp.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Vinod Koul <vkoul@kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	dmaengine@vger.kernel.org, "# 3.4.x" <stable@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	Ludovic Barre <ludovic.barre@st.com>
Subject: Re: [PATCH 2/2] amba: Initialize dma_parms for amba devices
Date: Thu, 26 Mar 2020 12:07:18 +0100	[thread overview]
Message-ID: <CAK8P3a39JrMrYrNeLCr-R6y-ivkVqRkxey_Z7R4N3++MA_qqCg@mail.gmail.com> (raw)
In-Reply-To: <20200325113407.26996-3-ulf.hansson@linaro.org>

On Wed, Mar 25, 2020 at 12:34 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> It's currently the amba driver's responsibility to initialize the pointer,
> dma_parms, for its corresponding struct device. The benefit with this
> approach allows us to avoid the initialization and to not waste memory for
> the struct device_dma_parameters, as this can be decided on a case by case
> basis.
>
> However, it has turned out that this approach is not very practical. Not
> only does it lead to open coding, but also to real errors. In principle
> callers of dma_set_max_seg_size() doesn't check the error code, but just
> assumes it succeeds.
>
> For these reasons, let's do the initialization from the common amba bus at
> the device registration point. This also follows the way the PCI devices
> are being managed, see pci_device_add().
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Acked-by: Arnd Bergmann <arnd@arndb.de>

_______________________________________________
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  parent reply	other threads:[~2020-03-26 11:07 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 11:34 [PATCH 0/2] amba/platform: Initialize dma_parms at the bus level Ulf Hansson
2020-03-25 11:34 ` Ulf Hansson
2020-03-25 11:34 ` [PATCH 1/2] driver core: platform: Initialize dma_parms for platform devices Ulf Hansson
2020-03-25 11:34   ` Ulf Hansson
2020-03-25 15:23   ` Ludovic BARRE
2020-03-25 15:23     ` Ludovic BARRE
2020-03-26 11:01   ` Linus Walleij
2020-03-26 11:01     ` Linus Walleij
2020-03-26 11:06   ` Arnd Bergmann
2020-03-26 11:06     ` Arnd Bergmann
2020-03-27 15:03   ` Sasha Levin
2020-03-25 11:34 ` [PATCH 2/2] amba: Initialize dma_parms for amba devices Ulf Hansson
2020-03-25 11:34   ` Ulf Hansson
2020-03-25 15:24   ` Ludovic BARRE
2020-03-25 15:24     ` Ludovic BARRE
2020-03-26 11:02   ` Linus Walleij
2020-03-26 11:02     ` Linus Walleij
2020-03-26 11:07   ` Arnd Bergmann [this message]
2020-03-26 11:07     ` Arnd Bergmann
2020-03-26  4:41 ` [PATCH 0/2] amba/platform: Initialize dma_parms at the bus level BOUGH CHEN
2020-03-26  4:41   ` BOUGH CHEN
2020-03-27  3:02   ` BOUGH CHEN
2020-03-27  3:02     ` BOUGH CHEN
2020-03-27 15:34     ` Ulf Hansson
2020-03-27 15:34       ` Ulf Hansson
2020-03-27 19:15       ` Robin Murphy
2020-03-27 19:15         ` Robin Murphy
2020-03-31 18:08         ` Ulf Hansson
2020-03-31 18:08           ` Ulf Hansson

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