coresight: tmc-etr: Add function to register catu ops

Make etr_catu_buf_ops static. Instead of directly accessing it in
etr_buf_ops[], add a function to let catu driver register the ops at
runtime. Break circular dependency between tmc-etr and catu drivers.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200928163513.70169-23-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-catu.c

@@ -358,7 +358,7 @@ static int catu_alloc_etr_buf(struct tmc_drvdata *tmc_drvdata,
 	return 0;
 }
 
-const struct etr_buf_operations etr_catu_buf_ops = {
+static const struct etr_buf_operations etr_catu_buf_ops = {
 	.alloc = catu_alloc_etr_buf,
 	.free = catu_free_etr_buf,
 	.sync = catu_sync_etr_buf,
@@ -582,4 +582,22 @@ static struct amba_driver catu_driver = {
 	.id_table			= catu_ids,
 };
 
-builtin_amba_driver(catu_driver);
+static int __init catu_init(void)
+{
+	int ret;
+
+	ret = amba_driver_register(&catu_driver);
+	if (ret)
+		pr_info("Error registering catu driver\n");
+	tmc_etr_set_catu_ops(&etr_catu_buf_ops);
+	return ret;
+}
+
+static void __exit catu_exit(void)
+{
+	tmc_etr_remove_catu_ops();
+	amba_driver_unregister(&catu_driver);
+}
+
+module_init(catu_init);
+module_exit(catu_exit);

drivers/hwtracing/coresight/coresight-catu.h

@@ -108,6 +108,4 @@ static inline bool coresight_is_catu_device(struct coresight_device *csdev)
 	return true;
 }
 
-extern const struct etr_buf_operations etr_catu_buf_ops;
-
 #endif

drivers/hwtracing/coresight/coresight-tmc-etr.c

@@ -794,10 +794,21 @@ static inline void tmc_etr_disable_catu(struct tmc_drvdata *drvdata)
 static const struct etr_buf_operations *etr_buf_ops[] = {
 	[ETR_MODE_FLAT] = &etr_flat_buf_ops,
 	[ETR_MODE_ETR_SG] = &etr_sg_buf_ops,
-	[ETR_MODE_CATU] = IS_ENABLED(CONFIG_CORESIGHT_CATU)
-						? &etr_catu_buf_ops : NULL,
+	[ETR_MODE_CATU] = NULL,
 };
 
+void tmc_etr_set_catu_ops(const struct etr_buf_operations *catu)
+{
+	etr_buf_ops[ETR_MODE_CATU] = catu;
+}
+EXPORT_SYMBOL_GPL(tmc_etr_set_catu_ops);
+
+void tmc_etr_remove_catu_ops(void)
+{
+	etr_buf_ops[ETR_MODE_CATU] = NULL;
+}
+EXPORT_SYMBOL_GPL(tmc_etr_remove_catu_ops);
+
 static inline int tmc_etr_mode_alloc_buf(int mode,
 					 struct tmc_drvdata *drvdata,
 					 struct etr_buf *etr_buf, int node,

drivers/hwtracing/coresight/coresight-tmc.h

@@ -326,4 +326,7 @@ tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
 
 struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);
 
+void tmc_etr_set_catu_ops(const struct etr_buf_operations *catu);
+void tmc_etr_remove_catu_ops(void);
+
 #endif