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From: Arnd Bergmann <arnd@arndb.de>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Robin Murphy <robin.murphy@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Arnd Bergmann <arnd@arndb.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Christoph Hellwig <hch@infradead.org>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	USB list <linux-usb@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] ARM: sa1100/assabet: move dmabounce hack to ohci driver
Date: Wed, 2 Feb 2022 09:05:24 +0100	[thread overview]
Message-ID: <CAK8P3a1cnQ=uJ84tGxfPi8km_qmOY9=iUuV1NKBqKevTAbWVCg@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a0jFMhtajAA9L6u56fbFRxBXhhsfMrfGisHdoP8qCFKMg@mail.gmail.com>

On Wed, Feb 2, 2022 at 12:10 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> while this part would not work if dma_alloc_flags() ends up getting
> memory that is not accessible. At the minimum I need to drop the
> machine_is_assabet() check and always allocate a safe buffer to
> back hcd->local_mem regardless of the machine.

I double-checked this to ensure we don't have to check for sa1100
vs pxa instead, and I found that all three sa1100 platforms with sa1111
(assabet/neponset, badge4, jornada720) enable DMA, but the one
pxa machine (lubbock) has the DMA mask set to 0 and won't
be able to use OHCI anyway.

       Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Robin Murphy <robin.murphy@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	 Alan Stern <stern@rowland.harvard.edu>,
	Arnd Bergmann <arnd@arndb.de>,
	 Linus Walleij <linus.walleij@linaro.org>,
	Christoph Hellwig <hch@infradead.org>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	USB list <linux-usb@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] ARM: sa1100/assabet: move dmabounce hack to ohci driver
Date: Wed, 2 Feb 2022 09:05:24 +0100	[thread overview]
Message-ID: <CAK8P3a1cnQ=uJ84tGxfPi8km_qmOY9=iUuV1NKBqKevTAbWVCg@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a0jFMhtajAA9L6u56fbFRxBXhhsfMrfGisHdoP8qCFKMg@mail.gmail.com>

On Wed, Feb 2, 2022 at 12:10 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> while this part would not work if dma_alloc_flags() ends up getting
> memory that is not accessible. At the minimum I need to drop the
> machine_is_assabet() check and always allocate a safe buffer to
> back hcd->local_mem regardless of the machine.

I double-checked this to ensure we don't have to check for sa1100
vs pxa instead, and I found that all three sa1100 platforms with sa1111
(assabet/neponset, badge4, jornada720) enable DMA, but the one
pxa machine (lubbock) has the DMA mask set to 0 and won't
be able to use OHCI anyway.

       Arnd

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-02-02  8:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-01 15:02 [RFC] ARM: sa1100/assabet: move dmabounce hack to ohci driver Arnd Bergmann
2022-02-01 15:02 ` Arnd Bergmann
2022-02-01 15:31 ` Alan Stern
2022-02-01 15:31   ` Alan Stern
2022-02-01 16:08   ` Arnd Bergmann
2022-02-01 16:08     ` Arnd Bergmann
2022-02-01 17:10 ` Robin Murphy
2022-02-01 17:10   ` Robin Murphy
2022-02-01 17:48   ` Russell King (Oracle)
2022-02-01 17:48     ` Russell King (Oracle)
2022-02-01 23:10     ` Arnd Bergmann
2022-02-01 23:10       ` Arnd Bergmann
2022-02-02  8:05       ` Arnd Bergmann [this message]
2022-02-02  8:05         ` Arnd Bergmann

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