[PATCH v2 7/7] thunderbolt: Add kernel param for CLx disabling

[Gil Fine <gil.fine@intel.com>]

Add a module parameter that allows user to completely disable CLx
functionality in case problems are found.

Signed-off-by: Gil Fine <gil.fine@intel.com>
---
 drivers/thunderbolt/switch.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index cd6d16417a80..7224b9aa75ed 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -13,6 +13,7 @@
 #include <linux/sched/signal.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
+#include <linux/module.h>
 
 #include "tb.h"
 
@@ -26,6 +27,10 @@ struct nvm_auth_status {
 	u32 status;
 };
 
+static bool clx_enabled = true;
+module_param_named(clx, clx_enabled, bool, 0444);
+MODULE_PARM_DESC(clx, "allow CLx on the High-Speed link (default: true)");
+
 /*
  * Hold NVM authentication failure status per switch This information
  * needs to stay around even when the switch gets power cycled so we
@@ -3482,6 +3487,9 @@ int tb_switch_enable_clx(struct tb_switch *sw, enum tb_clx clx)
 {
 	struct tb_switch *root_sw = sw->tb->root_switch;
 
+	if (!clx_enabled)
+		return 0;
+
 	/* CLx is not enabled and validated on USB4 platforms before ADL */
 	if (root_sw->generation < 4 ||
 	    tb_switch_is_tiger_lake(root_sw))
@@ -3541,6 +3549,9 @@ static int tb_switch_disable_cl0s(struct tb_switch *sw)
  */
 int tb_switch_disable_clx(struct tb_switch *sw, enum tb_clx clx)
 {
+	if (!clx_enabled)
+		return 0;
+
 	switch (clx) {
 	case TB_CL0S:
 		return tb_switch_disable_cl0s(sw);
-- 
2.17.1

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