[PATCH v7 10/25] coresight: etm4x: allow etm4x to be built as a module

[Suzuki K Poulose]

On 08/05/2020 03:54 AM, Tingwei Zhang wrote:
> From: Kim Phillips <kim.phillips at arm.com>
> 
> Allow to build coresight-etm4x as a module, for ease of development.
> 
> - Kconfig becomes a tristate, to allow =m
> - append -core to source file name to allow module to
>    be called coresight-etm4x by the Makefile
> - add an etm4_remove function, for module unload
> - add a MODULE_DEVICE_TABLE for autoloading on boot
> 
> Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
> Cc: Leo Yan <leo.yan at linaro.org>
> Cc: Alexander Shishkin <alexander.shishkin at linux.intel.com>
> Cc: Randy Dunlap <rdunlap at infradead.org>
> Cc: Suzuki K Poulose <Suzuki.Poulose at arm.com>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> Cc: Russell King <linux at armlinux.org.uk>
> Signed-off-by: Kim Phillips <kim.phillips at arm.com>
> Signed-off-by: Tingwei Zhang <tingwei at codeaurora.org>
> Tested-by: Mike Leach <mike.leach at linaro.org>
> ---


>   
> +static int __exit etm4_remove(struct amba_device *adev)
> +{
> +	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);
> +
> +	etm_perf_symlink(drvdata->csdev, false);
> +
> +	etmdrvdata[drvdata->cpu] = NULL;

I think we need to explicitly make this change visible to the other
observers, to make sure that a PM notifier doesn't end up using the
stale per-cpu pointer.

> +	etm4_pm_clear();
> +
> +	coresight_unregister(drvdata->csdev);
> +
> +	return 0;
> +}
> +
> +
>   static const struct amba_id etm4_ids[] = {
>   	CS_AMBA_ID(0x000bb95d),			/* Cortex-A53 */
>   	CS_AMBA_ID(0x000bb95e),			/* Cortex-A57 */
> @@ -1590,12 +1605,21 @@ static const struct amba_id etm4_ids[] = {
>   	{},
>   };
>   
> +MODULE_DEVICE_TABLE(amba, etm4_ids);
> +
>   static struct amba_driver etm4x_driver = {
>   	.drv = {
>   		.name   = "coresight-etm4x",
> +		.owner  = THIS_MODULE,
>   		.suppress_bind_attrs = true,
>   	},
>   	.probe		= etm4_probe,
> +	.remove         = etm4_remove,
>   	.id_table	= etm4_ids,
>   };
> -builtin_amba_driver(etm4x_driver);
> +module_amba_driver(etm4x_driver);

Please note that this could conflict with the following patch :

https://lkml.kernel.org/r/20200729051310.18436-1-saiprakash.ranjan@codeaurora.org

Otherwise looks good to me.

Suzuki