From: Mark Brown <broonie@kernel.org>
To: Trent Piepho <tpiepho@impinj.com>
Cc: linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Gustavo A . R . Silva" <garsilva@embeddedor.com>,
Eric Anholt <eric@anholt.net>,
Stefan Wahren <stefan.wahren@i2se.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Ray Jui <rjui@broadcom.com>
Subject: Re: [PATCH] spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc
Date: Wed, 14 Feb 2018 16:04:24 +0000 [thread overview]
Message-ID: <20180214160424.GF12658@sirena.org.uk> (raw)
In-Reply-To: <20180212193814.17644-1-tpiepho@impinj.com>
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On Mon, Feb 12, 2018 at 11:38:14AM -0800, Trent Piepho wrote:
> We want to check for xfers that are over 30 microseconds. Rather than
> find how many µs a xfer will take, instead find how many bytes can be
> transferred in 30 µs. The latter must be less than 32 bits (since our
> clock speed is limited to 32 bits), while the former involves 64 bit
> quantities and more arithmetic operations.
Please don't bury patches in the middle of existing threads, it makes it
much harder to find them.
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From: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Trent Piepho <tpiepho-cgc2CodaaHDQT0dZR+AlfA@public.gmane.org>
Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Gustavo A . R . Silva"
<garsilva-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>,
Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>,
Stefan Wahren <stefan.wahren-eS4NqCHxEME@public.gmane.org>,
Florian Fainelli
<f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Ray Jui <rjui-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
Subject: Re: [PATCH] spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc
Date: Wed, 14 Feb 2018 16:04:24 +0000 [thread overview]
Message-ID: <20180214160424.GF12658@sirena.org.uk> (raw)
In-Reply-To: <20180212193814.17644-1-tpiepho-cgc2CodaaHDQT0dZR+AlfA@public.gmane.org>
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On Mon, Feb 12, 2018 at 11:38:14AM -0800, Trent Piepho wrote:
> We want to check for xfers that are over 30 microseconds. Rather than
> find how many µs a xfer will take, instead find how many bytes can be
> transferred in 30 µs. The latter must be less than 32 bits (since our
> clock speed is limited to 32 bits), while the former involves 64 bit
> quantities and more arithmetic operations.
Please don't bury patches in the middle of existing threads, it makes it
much harder to find them.
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From: broonie@kernel.org (Mark Brown)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc
Date: Wed, 14 Feb 2018 16:04:24 +0000 [thread overview]
Message-ID: <20180214160424.GF12658@sirena.org.uk> (raw)
In-Reply-To: <20180212193814.17644-1-tpiepho@impinj.com>
On Mon, Feb 12, 2018 at 11:38:14AM -0800, Trent Piepho wrote:
> We want to check for xfers that are over 30 microseconds. Rather than
> find how many ?s a xfer will take, instead find how many bytes can be
> transferred in 30 ?s. The latter must be less than 32 bits (since our
> clock speed is limited to 32 bits), while the former involves 64 bit
> quantities and more arithmetic operations.
Please don't bury patches in the middle of existing threads, it makes it
much harder to find them.
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next prev parent reply other threads:[~2018-02-14 16:04 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-07 16:00 [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit Gustavo A. R. Silva
2018-02-07 16:00 ` Gustavo A. R. Silva
2018-02-08 8:22 ` Eric Anholt
2018-02-08 8:22 ` Eric Anholt
2018-02-12 17:57 ` Gustavo A. R. Silva
2018-02-12 17:57 ` Gustavo A. R. Silva
2018-02-08 9:54 ` Ard Biesheuvel
2018-02-08 9:54 ` Ard Biesheuvel
2018-02-08 9:54 ` Ard Biesheuvel
2018-02-12 18:04 ` Gustavo A. R. Silva
2018-02-12 18:04 ` Gustavo A. R. Silva
2018-02-12 18:45 ` Ard Biesheuvel
2018-02-12 18:45 ` Ard Biesheuvel
2018-02-12 19:10 ` Florian Fainelli
2018-02-12 19:10 ` Florian Fainelli
2018-02-12 19:10 ` Florian Fainelli
2018-02-12 19:11 ` Ard Biesheuvel
2018-02-12 19:11 ` Ard Biesheuvel
2018-02-12 19:11 ` Ard Biesheuvel
2018-02-12 19:14 ` Florian Fainelli
2018-02-12 19:14 ` Florian Fainelli
2018-02-12 19:14 ` Florian Fainelli
2018-02-12 19:31 ` Trent Piepho
2018-02-12 19:31 ` Trent Piepho
2018-02-12 19:31 ` Trent Piepho
2018-02-12 19:38 ` [PATCH] spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc Trent Piepho
2018-02-12 19:38 ` Trent Piepho
2018-02-14 16:04 ` Mark Brown [this message]
2018-02-14 16:04 ` Mark Brown
2018-02-14 16:04 ` Mark Brown
2018-02-14 16:28 ` Applied "spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc" to the spi tree Mark Brown
2018-02-14 16:28 ` Mark Brown
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