net: ethtool: mm: extract stmmac verification logic into common library

It appears that stmmac is not the only hardware which requires a
software-driven verification state machine for the MAC Merge layer.

While on the one hand it's good to encourage hardware implementations,
on the other hand it's quite difficult to tolerate multiple drivers
implementing independently fairly non-trivial logic.

Extract the hardware-independent logic from stmmac into library code and
put it in ethtool. Name the state structure "mmsv" for MAC Merge
Software Verification. Let this expose an operations structure for
executing the hardware stuff: sync hardware with the tx_active boolean
(result of verification process), enable/disable the pMAC, send mPackets,
notify library of external events (reception of mPackets), as well as
link state changes.

Note that it is assumed that the external events are received in hardirq
context. If they are not, it is probably a good idea to disable hardirqs
when calling ethtool_mmsv_event_handle(), because the library does not
do so.

Also, the MM software verification process has no business with the
tx_min_frag_size, that is all the driver's to handle.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Co-developed-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
Signed-off-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
Tested-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
Tested-by: Furong Xu <0x1207@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 7edb5f5e7134..117718c24814 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -17,9 +17,13 @@
 #include <linux/compat.h>
 #include <linux/if_ether.h>
 #include <linux/netlink.h>
+#include <linux/timer_types.h>
 #include <uapi/linux/ethtool.h>
 #include <uapi/linux/net_tstamp.h>
 
+#define ETHTOOL_MM_MAX_VERIFY_TIME_MS		128
+#define ETHTOOL_MM_MAX_VERIFY_RETRIES		3
+
 struct compat_ethtool_rx_flow_spec {
 	u32		flow_type;
 	union ethtool_flow_union h_u;
@@ -718,6 +722,75 @@ struct ethtool_mm_stats {
 	u64 MACMergeHoldCount;
 };
 
+enum ethtool_mmsv_event {
+	ETHTOOL_MMSV_LP_SENT_VERIFY_MPACKET,
+	ETHTOOL_MMSV_LD_SENT_VERIFY_MPACKET,
+	ETHTOOL_MMSV_LP_SENT_RESPONSE_MPACKET,
+};
+
+/* MAC Merge verification mPacket type */
+enum ethtool_mpacket {
+	ETHTOOL_MPACKET_VERIFY,
+	ETHTOOL_MPACKET_RESPONSE,
+};
+
+struct ethtool_mmsv;
+
+/**
+ * struct ethtool_mmsv_ops - Operations for MAC Merge Software Verification
+ * @configure_tx: Driver callback for the event where the preemptible TX
+ *		  becomes active or inactive. Preemptible traffic
+ *		  classes must be committed to hardware only while
+ *		  preemptible TX is active.
+ * @configure_pmac: Driver callback for the event where the pMAC state
+ *		    changes as result of an administrative setting
+ *		    (ethtool) or a call to ethtool_mmsv_link_state_handle().
+ * @send_mpacket: Driver-provided method for sending a Verify or a Response
+ *		  mPacket.
+ */
+struct ethtool_mmsv_ops {
+	void (*configure_tx)(struct ethtool_mmsv *mmsv, bool tx_active);
+	void (*configure_pmac)(struct ethtool_mmsv *mmsv, bool pmac_enabled);
+	void (*send_mpacket)(struct ethtool_mmsv *mmsv, enum ethtool_mpacket mpacket);
+};
+
+/**
+ * struct ethtool_mmsv - MAC Merge Software Verification
+ * @ops: operations for MAC Merge Software Verification
+ * @dev: pointer to net_device structure
+ * @lock: serialize access to MAC Merge state between
+ *	  ethtool requests and link state updates.
+ * @status: current verification FSM state
+ * @verify_timer: timer for verification in local TX direction
+ * @verify_enabled: indicates if verification is enabled
+ * @verify_retries: number of retries for verification
+ * @pmac_enabled: indicates if the preemptible MAC is enabled
+ * @verify_time: time for verification in milliseconds
+ * @tx_enabled: indicates if transmission is enabled
+ */
+struct ethtool_mmsv {
+	const struct ethtool_mmsv_ops *ops;
+	struct net_device *dev;
+	spinlock_t lock;
+	enum ethtool_mm_verify_status status;
+	struct timer_list verify_timer;
+	bool verify_enabled;
+	int verify_retries;
+	bool pmac_enabled;
+	u32 verify_time;
+	bool tx_enabled;
+};
+
+void ethtool_mmsv_stop(struct ethtool_mmsv *mmsv);
+void ethtool_mmsv_link_state_handle(struct ethtool_mmsv *mmsv, bool up);
+void ethtool_mmsv_event_handle(struct ethtool_mmsv *mmsv,
+			       enum ethtool_mmsv_event event);
+void ethtool_mmsv_get_mm(struct ethtool_mmsv *mmsv,
+			 struct ethtool_mm_state *state);
+void ethtool_mmsv_set_mm(struct ethtool_mmsv *mmsv, struct ethtool_mm_cfg *cfg);
+void ethtool_mmsv_init(struct ethtool_mmsv *mmsv, struct net_device *dev,
+		       const struct ethtool_mmsv_ops *ops);
+
 /**
  * struct ethtool_rxfh_param - RXFH (RSS) parameters
  * @hfunc: Defines the current RSS hash function used by HW (or to be set to).