[PATCH v1] ethdev: add Linux ethtool link mode conversion

[Thomas Monjalon <thomas@monjalon.net>]

Speed capabilities of a NIC may be discovered through its Linux
kernel driver. It is especially useful for bifurcated drivers,
so they don't have to duplicate the same logic in the DPDK driver.

Parsing ethtool speed capabilities is made easy thanks to
the functions added in ethdev for internal usage only.
Of course these functions work only on Linux,
so they are not compiled in other environments.

In order to ease parsing, the ethtool macro names are parsed
externally in a shell command which generates a C array
included in this patch.
It also avoids to depend on a kernel version.
This C array should be updated in future to get latest ethtool bits.
Note it is easier to update this array than adding new cases
in a parsing code.

The types in the functions are following the ethtool type:
uint32_t for bitmaps, and int8_t for the number of 32-bitmaps.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---

A follow-up patch will be sent to use these functions in mlx5.
I suspect mana could use this parsing as well.

---
 lib/ethdev/ethdev_linux_ethtool.c | 162 ++++++++++++++++++++++++++++++
 lib/ethdev/ethdev_linux_ethtool.h |  41 ++++++++
 lib/ethdev/meson.build            |   9 ++
 lib/ethdev/version.map            |   3 +
 4 files changed, 215 insertions(+)
 create mode 100644 lib/ethdev/ethdev_linux_ethtool.c
 create mode 100644 lib/ethdev/ethdev_linux_ethtool.h

diff --git a/lib/ethdev/ethdev_linux_ethtool.c b/lib/ethdev/ethdev_linux_ethtool.c
new file mode 100644
index 0000000000..fe98882b8a
--- /dev/null
+++ b/lib/ethdev/ethdev_linux_ethtool.c
@@ -0,0 +1,162 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2024 NVIDIA Corporation & Affiliates
+ */
+
+#include <rte_bitops.h>
+
+#include "rte_ethdev.h"
+#include "ethdev_linux_ethtool.h"
+
+/*
+Link modes sorted with index as defined in ethtool.
+Values are speed in Mbps with LSB indicating duplex.
+
+The ethtool bits definition should not change as it is a kernel API.
+Using raw numbers directly avoids checking API availability
+and allows to compile with new bits included even on an old kernel.
+
+The array below is built from bit definitions with this shell command:
+	sed -rn 's;.*(ETHTOOL_LINK_MODE_)([0-9]+)([0-9a-zA-Z_]*).*= *([0-9]*).*;'\
+		'[\4] = \2, /\* \1\2\3 *\/;p' /usr/include/linux/ethtool.h |
+	awk '/_Half_/{$3=$3+1","}1'
+*/
+static uint32_t link_modes[] = {
+	[  0] =      11, /* ETHTOOL_LINK_MODE_10baseT_Half_BIT */
+	[  1] =      10, /* ETHTOOL_LINK_MODE_10baseT_Full_BIT */
+	[  2] =     101, /* ETHTOOL_LINK_MODE_100baseT_Half_BIT */
+	[  3] =     100, /* ETHTOOL_LINK_MODE_100baseT_Full_BIT */
+	[  4] =    1001, /* ETHTOOL_LINK_MODE_1000baseT_Half_BIT */
+	[  5] =    1000, /* ETHTOOL_LINK_MODE_1000baseT_Full_BIT */
+	[ 12] =   10000, /* ETHTOOL_LINK_MODE_10000baseT_Full_BIT */
+	[ 15] =    2500, /* ETHTOOL_LINK_MODE_2500baseX_Full_BIT */
+	[ 17] =    1000, /* ETHTOOL_LINK_MODE_1000baseKX_Full_BIT */
+	[ 18] =   10000, /* ETHTOOL_LINK_MODE_10000baseKX4_Full_BIT */
+	[ 19] =   10000, /* ETHTOOL_LINK_MODE_10000baseKR_Full_BIT */
+	[ 20] =   10000, /* ETHTOOL_LINK_MODE_10000baseR_FEC_BIT */
+	[ 21] =   20000, /* ETHTOOL_LINK_MODE_20000baseMLD2_Full_BIT */
+	[ 22] =   20000, /* ETHTOOL_LINK_MODE_20000baseKR2_Full_BIT */
+	[ 23] =   40000, /* ETHTOOL_LINK_MODE_40000baseKR4_Full_BIT */
+	[ 24] =   40000, /* ETHTOOL_LINK_MODE_40000baseCR4_Full_BIT */
+	[ 25] =   40000, /* ETHTOOL_LINK_MODE_40000baseSR4_Full_BIT */
+	[ 26] =   40000, /* ETHTOOL_LINK_MODE_40000baseLR4_Full_BIT */
+	[ 27] =   56000, /* ETHTOOL_LINK_MODE_56000baseKR4_Full_BIT */
+	[ 28] =   56000, /* ETHTOOL_LINK_MODE_56000baseCR4_Full_BIT */
+	[ 29] =   56000, /* ETHTOOL_LINK_MODE_56000baseSR4_Full_BIT */
+	[ 30] =   56000, /* ETHTOOL_LINK_MODE_56000baseLR4_Full_BIT */
+	[ 31] =   25000, /* ETHTOOL_LINK_MODE_25000baseCR_Full_BIT */
+	[ 32] =   25000, /* ETHTOOL_LINK_MODE_25000baseKR_Full_BIT */
+	[ 33] =   25000, /* ETHTOOL_LINK_MODE_25000baseSR_Full_BIT */
+	[ 34] =   50000, /* ETHTOOL_LINK_MODE_50000baseCR2_Full_BIT */
+	[ 35] =   50000, /* ETHTOOL_LINK_MODE_50000baseKR2_Full_BIT */
+	[ 36] =  100000, /* ETHTOOL_LINK_MODE_100000baseKR4_Full_BIT */
+	[ 37] =  100000, /* ETHTOOL_LINK_MODE_100000baseSR4_Full_BIT */
+	[ 38] =  100000, /* ETHTOOL_LINK_MODE_100000baseCR4_Full_BIT */
+	[ 39] =  100000, /* ETHTOOL_LINK_MODE_100000baseLR4_ER4_Full_BIT */
+	[ 40] =   50000, /* ETHTOOL_LINK_MODE_50000baseSR2_Full_BIT */
+	[ 41] =    1000, /* ETHTOOL_LINK_MODE_1000baseX_Full_BIT */
+	[ 42] =   10000, /* ETHTOOL_LINK_MODE_10000baseCR_Full_BIT */
+	[ 43] =   10000, /* ETHTOOL_LINK_MODE_10000baseSR_Full_BIT */
+	[ 44] =   10000, /* ETHTOOL_LINK_MODE_10000baseLR_Full_BIT */
+	[ 45] =   10000, /* ETHTOOL_LINK_MODE_10000baseLRM_Full_BIT */
+	[ 46] =   10000, /* ETHTOOL_LINK_MODE_10000baseER_Full_BIT */
+	[ 47] =    2500, /* ETHTOOL_LINK_MODE_2500baseT_Full_BIT */
+	[ 48] =    5000, /* ETHTOOL_LINK_MODE_5000baseT_Full_BIT */
+	[ 52] =   50000, /* ETHTOOL_LINK_MODE_50000baseKR_Full_BIT */
+	[ 53] =   50000, /* ETHTOOL_LINK_MODE_50000baseSR_Full_BIT */
+	[ 54] =   50000, /* ETHTOOL_LINK_MODE_50000baseCR_Full_BIT */
+	[ 55] =   50000, /* ETHTOOL_LINK_MODE_50000baseLR_ER_FR_Full_BIT */
+	[ 56] =   50000, /* ETHTOOL_LINK_MODE_50000baseDR_Full_BIT */
+	[ 57] =  100000, /* ETHTOOL_LINK_MODE_100000baseKR2_Full_BIT */
+	[ 58] =  100000, /* ETHTOOL_LINK_MODE_100000baseSR2_Full_BIT */
+	[ 59] =  100000, /* ETHTOOL_LINK_MODE_100000baseCR2_Full_BIT */
+	[ 60] =  100000, /* ETHTOOL_LINK_MODE_100000baseLR2_ER2_FR2_Full_BIT */
+	[ 61] =  100000, /* ETHTOOL_LINK_MODE_100000baseDR2_Full_BIT */
+	[ 62] =  200000, /* ETHTOOL_LINK_MODE_200000baseKR4_Full_BIT */
+	[ 63] =  200000, /* ETHTOOL_LINK_MODE_200000baseSR4_Full_BIT */
+	[ 64] =  200000, /* ETHTOOL_LINK_MODE_200000baseLR4_ER4_FR4_Full_BIT */
+	[ 65] =  200000, /* ETHTOOL_LINK_MODE_200000baseDR4_Full_BIT */
+	[ 66] =  200000, /* ETHTOOL_LINK_MODE_200000baseCR4_Full_BIT */
+	[ 67] =     100, /* ETHTOOL_LINK_MODE_100baseT1_Full_BIT */
+	[ 68] =    1000, /* ETHTOOL_LINK_MODE_1000baseT1_Full_BIT */
+	[ 69] =  400000, /* ETHTOOL_LINK_MODE_400000baseKR8_Full_BIT */
+	[ 70] =  400000, /* ETHTOOL_LINK_MODE_400000baseSR8_Full_BIT */
+	[ 71] =  400000, /* ETHTOOL_LINK_MODE_400000baseLR8_ER8_FR8_Full_BIT */
+	[ 72] =  400000, /* ETHTOOL_LINK_MODE_400000baseDR8_Full_BIT */
+	[ 73] =  400000, /* ETHTOOL_LINK_MODE_400000baseCR8_Full_BIT */
+	[ 75] =  100000, /* ETHTOOL_LINK_MODE_100000baseKR_Full_BIT */
+	[ 76] =  100000, /* ETHTOOL_LINK_MODE_100000baseSR_Full_BIT */
+	[ 77] =  100000, /* ETHTOOL_LINK_MODE_100000baseLR_ER_FR_Full_BIT */
+	[ 78] =  100000, /* ETHTOOL_LINK_MODE_100000baseCR_Full_BIT */
+	[ 79] =  100000, /* ETHTOOL_LINK_MODE_100000baseDR_Full_BIT */
+	[ 80] =  200000, /* ETHTOOL_LINK_MODE_200000baseKR2_Full_BIT */
+	[ 81] =  200000, /* ETHTOOL_LINK_MODE_200000baseSR2_Full_BIT */
+	[ 82] =  200000, /* ETHTOOL_LINK_MODE_200000baseLR2_ER2_FR2_Full_BIT */
+	[ 83] =  200000, /* ETHTOOL_LINK_MODE_200000baseDR2_Full_BIT */
+	[ 84] =  200000, /* ETHTOOL_LINK_MODE_200000baseCR2_Full_BIT */
+	[ 85] =  400000, /* ETHTOOL_LINK_MODE_400000baseKR4_Full_BIT */
+	[ 86] =  400000, /* ETHTOOL_LINK_MODE_400000baseSR4_Full_BIT */
+	[ 87] =  400000, /* ETHTOOL_LINK_MODE_400000baseLR4_ER4_FR4_Full_BIT */
+	[ 88] =  400000, /* ETHTOOL_LINK_MODE_400000baseDR4_Full_BIT */
+	[ 89] =  400000, /* ETHTOOL_LINK_MODE_400000baseCR4_Full_BIT */
+	[ 90] =     101, /* ETHTOOL_LINK_MODE_100baseFX_Half_BIT */
+	[ 91] =     100, /* ETHTOOL_LINK_MODE_100baseFX_Full_BIT */
+	[ 92] =      10, /* ETHTOOL_LINK_MODE_10baseT1L_Full_BIT */
+	[ 93] =  800000, /* ETHTOOL_LINK_MODE_800000baseCR8_Full_BIT */
+	[ 94] =  800000, /* ETHTOOL_LINK_MODE_800000baseKR8_Full_BIT */
+	[ 95] =  800000, /* ETHTOOL_LINK_MODE_800000baseDR8_Full_BIT */
+	[ 96] =  800000, /* ETHTOOL_LINK_MODE_800000baseDR8_2_Full_BIT */
+	[ 97] =  800000, /* ETHTOOL_LINK_MODE_800000baseSR8_Full_BIT */
+	[ 98] =  800000, /* ETHTOOL_LINK_MODE_800000baseVR8_Full_BIT */
+	[ 99] =      10, /* ETHTOOL_LINK_MODE_10baseT1S_Full_BIT */
+	[100] =      11, /* ETHTOOL_LINK_MODE_10baseT1S_Half_BIT */
+	[101] =      11, /* ETHTOOL_LINK_MODE_10baseT1S_P2MP_Half_BIT */
+};
+
+uint32_t
+rte_eth_link_speed_ethtool(enum ethtool_link_mode_bit_indices bit)
+{
+	uint32_t speed;
+	int duplex;
+
+	/* get mode from array */
+	if (bit >= RTE_DIM(link_modes))
+		return RTE_ETH_LINK_SPEED_AUTONEG;
+	speed = link_modes[bit];
+	if (speed == 0)
+		return RTE_ETH_LINK_SPEED_AUTONEG;
+	RTE_BUILD_BUG_ON(RTE_ETH_LINK_SPEED_AUTONEG != 0);
+
+	/* duplex is LSB */
+	duplex = (speed & 1)?
+			RTE_ETH_LINK_HALF_DUPLEX:
+			RTE_ETH_LINK_FULL_DUPLEX;
+	speed &= RTE_GENMASK32(31, 1);
+
+	return rte_eth_speed_bitflag(speed, duplex);
+}
+
+uint32_t
+rte_eth_link_speed_glink(const uint32_t *bitmap, int8_t nwords)
+{
+	uint8_t word, bit;
+	uint32_t ethdev_bitmap = 0;
+
+	if (nwords < 1)
+		return 0;
+
+	for (word = 0; word < nwords; word ++) {
+		for (bit = 0; bit < 32; bit ++) {
+			if ((bitmap[word] & RTE_BIT32(bit)) == 0)
+				continue;
+			ethdev_bitmap |= rte_eth_link_speed_ethtool(word * 32 + bit);
+		}
+	}
+
+	return ethdev_bitmap;
+}
+
+uint32_t
+rte_eth_link_speed_gset(uint32_t legacy_bitmap)
+{
+	return rte_eth_link_speed_glink(&legacy_bitmap, 1);
+}
diff --git a/lib/ethdev/ethdev_linux_ethtool.h b/lib/ethdev/ethdev_linux_ethtool.h
new file mode 100644
index 0000000000..de235bd5f4
--- /dev/null
+++ b/lib/ethdev/ethdev_linux_ethtool.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2024 NVIDIA Corporation & Affiliates
+ */
+
+#ifndef ETHDEV_ETHTOOL_H
+#define ETHDEV_ETHTOOL_H
+
+#include <stdint.h>
+#include <linux/ethtool.h>
+
+#include <rte_compat.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Convert bit from ETHTOOL_LINK_MODE_* to RTE_ETH_LINK_SPEED_*
+ */
+__rte_internal
+uint32_t rte_eth_link_speed_ethtool(enum ethtool_link_mode_bit_indices bit);
+
+/*
+ * Convert bitmap from ETHTOOL_GLINKSETTINGS ethtool_link_settings::link_mode_masks
+ * to bitmap RTE_ETH_LINK_SPEED_*
+ */
+__rte_internal
+uint32_t rte_eth_link_speed_glink(const uint32_t *bitmap, int8_t nwords);
+
+/*
+ * Convert bitmap from deprecated ETHTOOL_GSET ethtool_cmd::supported
+ * to bitmap RTE_ETH_LINK_SPEED_*
+ */
+__rte_internal
+uint32_t rte_eth_link_speed_gset(uint32_t legacy_bitmap);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ETHDEV_ETHTOOL_H */
diff --git a/lib/ethdev/meson.build b/lib/ethdev/meson.build
index d11f06bc88..f1d2586591 100644
--- a/lib/ethdev/meson.build
+++ b/lib/ethdev/meson.build
@@ -44,6 +44,15 @@ driver_sdk_headers += files(
         'ethdev_vdev.h',
 )
 
+if is_linux
+    driver_sdk_headers += files(
+            'ethdev_linux_ethtool.h',
+    )
+    sources += files(
+            'ethdev_linux_ethtool.c',
+    )
+endif
+
 deps += ['net', 'kvargs', 'meter', 'telemetry']
 
 if is_freebsd
diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map
index 17e4eac8a4..9a51f3a562 100644
--- a/lib/ethdev/version.map
+++ b/lib/ethdev/version.map
@@ -350,6 +350,9 @@ INTERNAL {
 	rte_eth_hairpin_queue_peer_unbind;
 	rte_eth_hairpin_queue_peer_update;
 	rte_eth_ip_reassembly_dynfield_register;
+	rte_eth_link_speed_ethtool;
+	rte_eth_link_speed_glink;
+	rte_eth_link_speed_gset;
 	rte_eth_pkt_burst_dummy;
 	rte_eth_representor_id_get;
 	rte_eth_switch_domain_alloc;
-- 
2.43.0