From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Lee Jones <lee.jones@linaro.org>,
Jean Delvare <jdelvare@suse.com>,
Guenter Roeck <linux@roeck-us.net>,
Mark Rutland <mark.rutland@arm.com>,
Joel Stanley <joel@jms.id.au>, Andrew Jeffery <andrew@aj.id.au>,
Jonathan Corbet <corbet@lwn.net>,
Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
Kishon Vijay Abraham I <kishon@ti.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
Eric Sandeen <sandeen@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
Wu Hao <hao.wu@intel.com>,
Tomohiro Kusumi <kusumi.tomohiro@gmail.com>,
"Bryant G . Ly" <bryantly@linux.vnet.ibm.com>,
Frederic Barrat <fbarrat@linux.vnet.ibm.com>,
"David S . Miller" <davem@davemloft.net>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Randy Dunlap <rdunlap@infradead.org>,
Philippe Ombredanne <pombredanne@nexb.com>,
Vinod Koul <vkoul@kernel.org>,
Stephen Boyd <sboyd@codeaurora.org>,
David Kershner <david.kershner@unisys.com>,
Uwe Kleine-Konig <u.kleine-koenig@pengutronix.de>,
Sagar Dharia <sdharia@codeaurora.org>,
Johan Hovold <johan@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Juergen Gross <jgross@suse.com>,
Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
Tomer Maimon <tmaimon77@gmail.com>,
linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
openbmc@lists.ozlabs.org, Robin Murphy <robin.murphy@arm.com>,
Ryan Chen <ryan_chen@aspeedtech.com>
Subject: Re: [PATCH v11 06/14] peci: Add Aspeed PECI adapter driver
Date: Wed, 11 Dec 2019 22:28:18 +0200 [thread overview]
Message-ID: <20191211202818.GD32742@smile.fi.intel.com> (raw)
In-Reply-To: <20191211194624.2872-7-jae.hyun.yoo@linux.intel.com>
On Wed, Dec 11, 2019 at 11:46:16AM -0800, Jae Hyun Yoo wrote:
> This commit adds Aspeed PECI adapter driver for Aspeed
> AST24xx/25xx/26xx SoCs.
...
> +#define ASPEED_PECI_CMD_IDLE_MASK (ASPEED_PECI_CMD_STS_MASK | \
> + ASPEED_PECI_CMD_PIN_MON)
Better looking when the value completely occupies second line without touching
the first.
...
> +static int aspeed_peci_check_idle(struct aspeed_peci *priv)
> +{
> + ulong timeout = jiffies + usecs_to_jiffies(ASPEED_PECI_IDLE_CHECK_TIMEOUT_USEC);
> + u32 cmd_sts;
Like in the previous patch this one has hard to read timeout loops with inefficient code.
> + for (;;) {
> + cmd_sts = readl(priv->base + ASPEED_PECI_CMD);
> + if (!(cmd_sts & ASPEED_PECI_CMD_IDLE_MASK))
> + break;
> + if (time_after(jiffies, timeout)) {
This is actually main exit condition (vs. infinite loop).
> + cmd_sts = readl(priv->base + ASPEED_PECI_CMD);
This make no sense. If you would like to have one more iteration, just spell it
explicitly.
> + break;
> + }
> + usleep_range((ASPEED_PECI_IDLE_CHECK_INTERVAL_USEC >> 2) + 1,
> + ASPEED_PECI_IDLE_CHECK_INTERVAL_USEC);
> + }
> +
> + return !(cmd_sts & ASPEED_PECI_CMD_IDLE_MASK) ? 0 : -ETIMEDOUT;
Ditto.
> +}
Now look at the other variant:
do {
...do something...
if (success)
return 0;
usleep(...);
} while (time_before(...));
return -ETIMEDOUT;
* Easy
* less LOCs
* guaranteed always to be at least one iteration
* has explicitly spelled exit condition
BUT!
In this very case you may do even better if you read iopoll.h, i.e
readl_poll_timeout() has this functionality embedded in the macro.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2019-12-11 20:28 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 19:46 [PATCH v11 00/14] PECI device driver introduction Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 01/14] dt-bindings: Add PECI subsystem document Jae Hyun Yoo
2019-12-18 2:52 ` Rob Herring
2019-12-18 23:12 ` Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 02/14] Documentation: ioctl: Add ioctl numbers for PECI subsystem Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 04/14] dt-bindings: Add bindings document of Aspeed PECI adapter Jae Hyun Yoo
2019-12-18 2:57 ` Rob Herring
2019-12-18 23:21 ` Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 05/14] ARM: dts: aspeed: Add PECI node Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 06/14] peci: Add Aspeed PECI adapter driver Jae Hyun Yoo
2019-12-11 20:28 ` Andy Shevchenko [this message]
2019-12-12 0:50 ` Jae Hyun Yoo
2019-12-12 8:47 ` Andy Shevchenko
2019-12-12 18:51 ` Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 07/14] dt-bindings: peci: add NPCM PECI documentation Jae Hyun Yoo
2019-12-18 14:42 ` Rob Herring
2019-12-18 23:30 ` Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 08/14] ARM: dts: npcm7xx: Add PECI node Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 09/14] peci: npcm: add NPCM PECI driver Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 10/14] dt-bindings: mfd: Add Intel PECI client bindings document Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 11/14] mfd: intel-peci-client: Add Intel PECI client driver Jae Hyun Yoo
2019-12-16 16:01 ` Lee Jones
2019-12-16 21:57 ` Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 12/14] Documentation: hwmon: Add documents for PECI hwmon drivers Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 13/14] hwmon: Add PECI cputemp driver Jae Hyun Yoo
2019-12-13 6:24 ` Guenter Roeck
2019-12-16 20:43 ` Jae Hyun Yoo
2019-12-11 19:46 ` [PATCH v11 14/14] hwmon: Add PECI dimmtemp driver Jae Hyun Yoo
2019-12-13 6:32 ` Guenter Roeck
2019-12-16 21:04 ` Jae Hyun Yoo
2019-12-16 21:21 ` Guenter Roeck
2019-12-16 22:17 ` Jae Hyun Yoo
2019-12-16 23:27 ` Guenter Roeck
2019-12-16 23:31 ` Jae Hyun Yoo
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