ethtool: Add forced speed to supported link modes maps

The need to map Ethtool forced speeds to Ethtool supported link modes is
common among drivers. To support this, add a common structure for forced
speed maps and a function to init them.  This is solution was originally
introduced in commit 1d4e4ecccb11 ("qede: populate supported link modes
maps on module init") for qede driver.

ethtool_forced_speed_maps_init() should be called during driver init
with an array of struct ethtool_forced_speed_map to populate the mapping.

Definitions for maps themselves are left in the driver code, as the sets
of supported link modes may vary between the devices.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Pawel Chmielewski <pawel.chmielewski@intel.com>
Signed-off-by: Paul Greenwalt <paul.greenwalt@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 62b61527bcc4..8e91e8b8a693 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -13,6 +13,7 @@
 #ifndef _LINUX_ETHTOOL_H
 #define _LINUX_ETHTOOL_H
 
+#include <linux/linkmode.h>
 #include <linux/bitmap.h>
 #include <linux/compat.h>
 #include <linux/if_ether.h>
@@ -1052,4 +1053,40 @@ static inline int ethtool_mm_frag_size_min_to_add(u32 val_min, u32 *val_add,
  * next string.
  */
 extern __printf(2, 3) void ethtool_sprintf(u8 **data, const char *fmt, ...);
+
+/* Link mode to forced speed capabilities maps */
+struct ethtool_forced_speed_map {
+	u32		speed;
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(caps);
+
+	const u32	*cap_arr;
+	u32		arr_size;
+};
+
+#define ETHTOOL_FORCED_SPEED_MAP(prefix, value)				\
+{									\
+	.speed		= SPEED_##value,				\
+	.cap_arr	= prefix##_##value,				\
+	.arr_size	= ARRAY_SIZE(prefix##_##value),			\
+}
+
+/**
+ * ethtool_forced_speed_maps_init
+ * @maps: Pointer to an array of Ethtool forced speed map
+ * @size: Array size
+ *
+ * Initialize an array of Ethtool forced speed map to Ethtool link modes. This
+ * should be called during driver module init.
+ */
+static inline void
+ethtool_forced_speed_maps_init(struct ethtool_forced_speed_map *maps, u32 size)
+{
+	for (u32 i = 0; i < size; i++) {
+		struct ethtool_forced_speed_map *map = &maps[i];
+
+		linkmode_set_bit_array(map->cap_arr, map->arr_size, map->caps);
+		map->cap_arr = NULL;
+		map->arr_size = 0;
+	}
+}
 #endif /* _LINUX_ETHTOOL_H */