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From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Sergey Suloev <ssuloev@orpaltech.com>
Cc: Mark Brown <broonie@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] spi: sun4i: restrict transfer length in PIO-mode
Date: Tue, 3 Apr 2018 10:10:41 +0200	[thread overview]
Message-ID: <20180403081041.3ully6bcyfwx2cx6@flea> (raw)
In-Reply-To: <20180329185907.27281-3-ssuloev@orpaltech.com>

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On Thu, Mar 29, 2018 at 09:59:03PM +0300, Sergey Suloev wrote:
> There is no need to handle 3/4 empty/full interrupts as the maximum
> supported transfer length in PIO mode is 64 bytes for sun4i-family
> SoCs.

That assumes that you'll be able to treat the FIFO full interrupt and
drain the FIFO before we have the next byte coming in. This would
require a real time system, and we're not in one of them.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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WARNING: multiple messages have this Message-ID (diff)
From: maxime.ripard@bootlin.com (Maxime Ripard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/6] spi: sun4i: restrict transfer length in PIO-mode
Date: Tue, 3 Apr 2018 10:10:41 +0200	[thread overview]
Message-ID: <20180403081041.3ully6bcyfwx2cx6@flea> (raw)
In-Reply-To: <20180329185907.27281-3-ssuloev@orpaltech.com>

On Thu, Mar 29, 2018 at 09:59:03PM +0300, Sergey Suloev wrote:
> There is no need to handle 3/4 empty/full interrupts as the maximum
> supported transfer length in PIO mode is 64 bytes for sun4i-family
> SoCs.

That assumes that you'll be able to treat the FIFO full interrupt and
drain the FIFO before we have the next byte coming in. This would
require a real time system, and we're not in one of them.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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  reply	other threads:[~2018-04-03  8:10 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-29 18:59 [PATCH 0/6] spi: Add support for DMA transfers in sun4i SPI driver Sergey Suloev
2018-03-29 18:59 ` Sergey Suloev
2018-03-29 18:59 ` Sergey Suloev
2018-03-29 18:59 ` [PATCH 1/6] spi: core: handle timeout error from transfer_one() Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-03-29 18:59 ` [PATCH 2/6] spi: sun4i: restrict transfer length in PIO-mode Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-04-03  8:10   ` Maxime Ripard [this message]
2018-04-03  8:10     ` Maxime Ripard
2018-04-03 10:26     ` Sergey Suloev
2018-04-03 10:26       ` Sergey Suloev
2018-04-03 11:08     ` Sergey Suloev
2018-04-03 11:08       ` Sergey Suloev
2018-04-03 11:08       ` Sergey Suloev
2018-04-03 11:40       ` Maxime Ripard
2018-04-03 11:40         ` Maxime Ripard
2018-04-03 12:12         ` Sergey Suloev
2018-04-03 12:12           ` Sergey Suloev
2018-03-29 18:59 ` [PATCH 3/6] spi: sun4i: coding style/readability improvements Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-03-29 18:59 ` [PATCH 4/6] spi: sun4i: use completion provided by SPI core driver Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-03-29 18:59 ` [PATCH 5/6] spi: sun4i: introduce register set/unset helpers Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-04-03  8:14   ` Maxime Ripard
2018-04-03  8:14     ` Maxime Ripard
2018-04-03 10:27     ` Sergey Suloev
2018-04-03 10:27       ` Sergey Suloev
2018-03-29 18:59 ` [PATCH 6/6] spi: sun4i: add DMA transfers support Sergey Suloev
2018-03-29 18:59   ` Sergey Suloev
2018-04-03  8:17   ` Maxime Ripard
2018-04-03  8:17     ` Maxime Ripard
2018-04-03 13:03     ` Sergey Suloev
2018-04-03 13:03       ` Sergey Suloev
2018-04-04  6:27       ` Maxime Ripard
2018-04-04  6:27         ` Maxime Ripard

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