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[v7,00/30] Add support for QMC HDLC, framer infrastructure and PEF2256 framer

Message ID 20230928070652.330429-1-herve.codina@bootlin.com
Headers show
Series Add support for QMC HDLC, framer infrastructure and PEF2256 framer | expand

Message

Herve Codina Sept. 28, 2023, 7:06 a.m. UTC 
Hi,

I have a system where I need to handle an HDLC interface and some audio
data.

The HDLC data are transferred using a TDM bus on which a PEF2256
(E1/T1 framer) is present. The PEF2256 transfers data from/to the TDM
bus to/from the E1 line. This PEF2256 is connected to a PowerQUICC SoC
for the control path and the TDM is connected to the SoC (QMC component)
for the data path.

Comments

Jakub Kicinski Oct. 6, 2023, 10:08 p.m. UTC | #1 
On Thu, 28 Sep 2023 09:06:42 +0200 Herve Codina wrote:
> +menu "Framer Subsystem"
> +
> +config GENERIC_FRAMER
> +	bool "Framer Core"
> +	help
> +	  Generic Framer support.
> +	  A framer is a component in charge of an E1/T1 line interface.
> +	  Connected usually to a TDM bus, it converts TDM frames to/from E1/T1
> +	  frames. It also provides information related to the E1/T1 line.
> +	  Used with HDLC, the network can be reached through the E1/T1 line.
> +
> +	  This framework is designed to provide a generic interface for framer
> +	  devices present in the kernel. This layer will have the generic
> +	  API by which framer drivers can create framer using the framer
> +	  framework and framer users can obtain reference to the framer.
> +	  All the users of this framework should select this config.

maybe make the menu a menuconfig with info about framers but hide 
the GENERIC_FRAMER symbol? The driver 'select' it anyway, what's
the point of prompting the user..

> +	if (WARN_ON(!dev))
> +		return ERR_PTR(-EINVAL);

no defensive programming, let the kernel crash

> +	ret = framer_pm_runtime_get_sync(framer);
> +	if (ret < 0 && ret != -EOPNOTSUPP)
> +		goto err_pm_sync;
> +
> +	ret = 0; /* Override possible ret == -EOPNOTSUPP */

This looks pointless given that ret is either overwritten or not used
later on

> +	mutex_lock(&framer->mutex);
> +	if (framer->power_count == 0 && framer->ops->power_on) {
> +		ret = framer->ops->power_on(framer);
> +		if (ret < 0) {
> +			dev_err(&framer->dev, "framer poweron failed --> %d\n", ret);
> +			goto err_pwr_on;
> +		}
> +	}
> +	++framer->power_count;
> +	mutex_unlock(&framer->mutex);
> +	return 0;