From: Artem Bityutskiy <dedekind1@gmail.com>
To: Josh Wu <josh.wu@atmel.com>
Cc: hongxu.cn@gmail.com, nicolas.ferre@atmel.com,
linux-mtd@lists.infradead.org, ivan.djelic@parrot.com,
plagnioj@jcrosoft.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v9 3/3] MTD: at91: atmel_nand: Update driver to support Programmable Multibit ECC controller
Date: Sun, 27 May 2012 15:50:53 +0300 [thread overview]
Message-ID: <1338123053.19389.9.camel@koala> (raw)
In-Reply-To: <1338038677-6752-4-git-send-email-josh.wu@atmel.com>
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On Sat, 2012-05-26 at 21:24 +0800, Josh Wu wrote:
> + while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) {
> + if (unlikely(timeout_count++ > PMECC_MAX_TIMEOUT_COUNT)) {
> + dev_err(host->dev, "PMECC: Timeout to get ECC value.\n");
> + return; /* Time out */
How this error is communicated then up the the user?
> + }
> + cpu_relax();
> + }
I see this pattern all over the place - why people consider it reliable?
Is this code guaranteed to run on the same CPU?
Why not to use loops_per_jiffie * msecs_to_jiffies(TIMOUT) instead to
calculate how many iterations to do? Yes, due to HW register reading and
cpu_relax() the real timeout will be larger, but this is about error
anyway, so it does not hurt to iterate longer?
--
Best Regards,
Artem Bityutskiy
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next prev parent reply other threads:[~2012-05-27 12:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-26 13:24 [PATCH v9 0/3] MTD: at91: Add PMECC support for at91 nand flash driver Josh Wu
2012-05-26 13:24 ` [PATCH v9 1/3] MTD: at91: extract hw ecc initialization to one function and use relaxed read/write Josh Wu
2012-05-27 12:44 ` Artem Bityutskiy
2012-05-28 8:50 ` Josh Wu
2012-05-26 13:24 ` [PATCH v9 2/3] MTD: at91: add dt parameters for PMECC Josh Wu
2012-05-26 13:24 ` [PATCH v9 3/3] MTD: at91: atmel_nand: Update driver to support Programmable Multibit ECC controller Josh Wu
2012-05-27 12:50 ` Artem Bityutskiy [this message]
2012-05-28 8:43 ` Josh Wu
2012-05-28 6:58 ` Jean-Christophe PLAGNIOL-VILLARD
2012-05-28 8:34 ` Josh Wu
2012-05-29 16:01 ` Jean-Christophe PLAGNIOL-VILLARD
2012-05-28 6:39 ` [PATCH v9 0/3] MTD: at91: Add PMECC support for at91 nand flash driver Jean-Christophe PLAGNIOL-VILLARD
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