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
