Re: [PATCH v8 16/24] coresight: cti: add function to register cti associate ops

Mathieu Poirier
2020-08-17T16:04:35Z

On Fri, Aug 07, 2020 at 07:11:45PM +0800, Tingwei Zhang wrote:
> Add static cti_assoc_ops to coresight core driver. Let cti
> driver register the add_assoc and remove_assoc call back.
> Avoid coresight core driver to depend on cti driver.
>
> Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
> Tested-by: Mike Leach <mike.leach@linaro.org>
> ---
> drivers/hwtracing/coresight/coresight-cti.c | 32 ++++++++++++++++++--
> drivers/hwtracing/coresight/coresight-priv.h | 14 ++++-----
> drivers/hwtracing/coresight/coresight.c | 21 +++++++++++--
> 3 files changed, 53 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> index 3ccc703dc940..1f470c47ba70 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti.c
> @@ -589,7 +589,6 @@ void cti_add_assoc_to_csdev(struct coresight_device *csdev)
> cti_add_done:
> mutex_unlock(&ect_mutex);
> }
> -EXPORT_SYMBOL_GPL(cti_add_assoc_to_csdev);
>
> /*
> * Removing the associated devices is easier.
> @@ -616,7 +615,15 @@ void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
> }
> mutex_unlock(&ect_mutex);
> }
> -EXPORT_SYMBOL_GPL(cti_remove_assoc_from_csdev);

Mike and Tingwei,

It seems to me that functions cti_add_assoc_to_csdev() and
cti_remote_assoc_from_csdev() don't have to be exported. They could be called
in cti_probe() and cti_device_release() with the ect_mutex held, the same way
cti_update_conn_xrefs() and cti_remove_conn_xrefs() are.

If my assessment is correct this patch would be simpler.

Thanks,
Mathieu

> +
> +/*
> + * Operations to add and remove associated CTI.
> + * Register to coresight core driver as call back function.
> + */
> +static struct cti_assoc_op cti_assoc_ops = {
> + .add = cti_add_assoc_to_csdev,
> + .remove = cti_remove_assoc_from_csdev
> +};
>
> /*
> * Update the cross references where the associated device was found
> @@ -972,4 +979,23 @@ static struct amba_driver cti_driver = {
> .probe = cti_probe,
> .id_table = cti_ids,
> };
> -builtin_amba_driver(cti_driver);
> +
> +static int __init cti_init(void)
> +{
> + int ret;
> +
> + ret = amba_driver_register(&cti_driver);
> + if (ret)
> + pr_info("Error registering cti driver\n");
> + coresight_set_cti_ops(&cti_assoc_ops);
> + return ret;
> +}
> +
> +static void __exit cti_exit(void)
> +{
> + coresight_remove_cti_ops();
> + amba_driver_unregister(&cti_driver);
> +}
> +
> +module_init(cti_init);
> +module_exit(cti_exit);
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index dcb8aeb6af62..6cde6cf42554 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -173,15 +173,13 @@ static inline int etm_readl_cp14(u32 off, unsigned int *val) { return 0; }
> static inline int etm_writel_cp14(u32 off, u32 val) { return 0; }
> #endif
>
> -#ifdef CONFIG_CORESIGHT_CTI
> -extern void cti_add_assoc_to_csdev(struct coresight_device *csdev);
> -extern void cti_remove_assoc_from_csdev(struct coresight_device *csdev);
> +struct cti_assoc_op {
> + void (*add)(struct coresight_device *csdev);
> + void (*remove)(struct coresight_device *csdev);
> +};
>
> -#else
> -static inline void cti_add_assoc_to_csdev(struct coresight_device *csdev) {}
> -static inline void
> -cti_remove_assoc_from_csdev(struct coresight_device *csdev) {}
> -#endif
> +extern void coresight_set_cti_ops(const struct cti_assoc_op *cti_op);
> +extern void coresight_remove_cti_ops(void);
>
> /*
> * Macros and inline functions to handle CoreSight UCI data and driver
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 0b0e31577b9b..31b9ec8d3b9c 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -57,6 +57,20 @@ const u32 coresight_barrier_pkt[4] = {
> 0x7fffffff, 0x7fffffff, 0x7fffffff, 0x7fffffff};
> EXPORT_SYMBOL_GPL(coresight_barrier_pkt);
>
> +static const struct cti_assoc_op *cti_assoc_ops;
> +
> +void coresight_set_cti_ops(const struct cti_assoc_op *cti_op)
> +{
> + cti_assoc_ops = cti_op;
> +}
> +EXPORT_SYMBOL_GPL(coresight_set_cti_ops);
> +
> +void coresight_remove_cti_ops(void)
> +{
> + cti_assoc_ops = NULL;
> +}
> +EXPORT_SYMBOL_GPL(coresight_remove_cti_ops);
> +
> static int coresight_id_match(struct device *dev, void *data)
> {
> int trace_id, i_trace_id;
> @@ -1242,7 +1256,8 @@ static void coresight_device_release(struct device *dev)
> {
> struct coresight_device *csdev = to_coresight_device(dev);
>
> - cti_remove_assoc_from_csdev(csdev);
> + if (cti_assoc_ops && cti_assoc_ops->remove)
> + cti_assoc_ops->remove(csdev);
> fwnode_handle_put(csdev->dev.fwnode);
> kfree(csdev->refcnt);
> kfree(csdev);
> @@ -1553,8 +1568,8 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
> ret = coresight_fixup_device_conns(csdev);
> if (!ret)
> ret = coresight_fixup_orphan_conns(csdev);
> - if (!ret)
> - cti_add_assoc_to_csdev(csdev);
> + if (!ret && cti_assoc_ops && cti_assoc_ops->add)
> + cti_assoc_ops->add(csdev);
>
> mutex_unlock(&coresight_mutex);
> if (ret) {
> --
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