[PATCH ethtool 8/8] cmis: Fix printing of link length

[Ido Schimmel <idosch@nvidia.com>]

The CMIS parser only supports link length multipliers of 0.1 and 1, but
revision 5.0 of the specification (May 2021) added a multiplier of 10
and revision 5.3 (September 2024) added multipliers of 50, 100, 200 and
500.

Add support for the missing multipliers.

Fixes: 88ca347ef35a ("Add QSFP-DD support")
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 cmis.c | 8 +++++++-
 cmis.h | 1 +
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/cmis.c b/cmis.c
index 351e18484854..7a7e928ebb2f 100644
--- a/cmis.c
+++ b/cmis.c
@@ -188,6 +188,7 @@ static void cmis_show_cbl_asm_len(const struct cmis_memory_map *map)
  */
 static void cmis_print_smf_cbl_len(const struct cmis_memory_map *map)
 {
+	static const float smf_mul2[] = { 50.0f, 100.0f, 200.0f, 500.0f };
 	static const char *fn = "Length (SMF)";
 	float mul = 1.0f;
 	float val = 0.0f;
@@ -203,7 +204,12 @@ static void cmis_print_smf_cbl_len(const struct cmis_memory_map *map)
 	case CMIS_MULTIPLIER_01:
 		mul = 1.0f;
 		break;
-	default:
+	case CMIS_MULTIPLIER_10:
+		mul = 10.0f;
+		break;
+	case CMIS_MULTIPLIER_11:
+		mul = smf_mul2[(map->page_01h[CMIS_SMF_LEN_MUL2_OFFSET] &
+				CMIS_LEN_MUL_MASK) >> 6];
 		break;
 	}
 
diff --git a/cmis.h b/cmis.h
index 82fd2456a3ec..387809e00cd5 100644
--- a/cmis.h
+++ b/cmis.h
@@ -120,6 +120,7 @@
 #define CMIS_OM4_LEN_OFFSET			0x86
 #define CMIS_OM3_LEN_OFFSET			0x87
 #define CMIS_OM2_LEN_OFFSET			0x88
+#define CMIS_SMF_LEN_MUL2_OFFSET		0x89
 
 /* Wavelength (Page 1) */
 #define CMIS_NOM_WAVELENGTH_MSB			0x8A
-- 
2.55.0