[dpdk-dev] [PATCH 3/7] net/sfc/base: honour packed stream RSS restriction

[Andrew Rybchenko <arybchenko@solarflare.com>]

From: Ivan Malov <ivan.malov@oktetlabs.ru>

Packed stream firmware variant on EF10 adapters has a
number of properties which must be taken into account:

 - Only one exclusive RSS context is available per port.
 - Only IP addresses can contribute to the hash value.

Huntington and Medford have one more limitation which
is important for the drivers capable of packed stream:

 - Hash algorithm is non-standard (i.e. non-Toeplitz).
   This implies XORing together source + destination
   IP addresses (or last four bytes in the case of IPv6)
   and using the result as the input to a Toeplitz hash.

This patch provides a number of improvements in order
to treat the mentioned limitations in the common code.

If the firmware variant is packed stream, the list of
supported hash tuples will include less variants, and
the maximum number of RSS contexts will be set to one.

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 drivers/net/sfc/base/ef10_nic.c  | 59 +++++++++++++++++++++++++++++++++++-----
 drivers/net/sfc/base/ef10_rx.c   |  6 ++--
 drivers/net/sfc/base/efx.h       | 14 +++++++++-
 drivers/net/sfc/base/efx_rx.c    | 17 +++++++++---
 drivers/net/sfc/base/siena_nic.c |  9 ++++++
 5 files changed, 91 insertions(+), 14 deletions(-)

diff --git a/drivers/net/sfc/base/ef10_nic.c b/drivers/net/sfc/base/ef10_nic.c
index f0b6039..0ad367c 100644
--- a/drivers/net/sfc/base/ef10_nic.c
+++ b/drivers/net/sfc/base/ef10_nic.c
@@ -1233,11 +1233,63 @@ ef10_get_datapath_caps(
 	else
 		encp->enc_fec_counters = B_FALSE;
 
+	if (CAP_FLAGS1(req, RX_RSS_LIMITED)) {
+		/* Only one exclusive RSS context is available per port. */
+		encp->enc_rx_scale_max_exclusive_contexts = 1;
+
+		switch (enp->en_family) {
+		case EFX_FAMILY_MEDFORD2:
+			encp->enc_rx_scale_hash_alg_mask =
+			    (1U << EFX_RX_HASHALG_TOEPLITZ);
+			break;
+
+		case EFX_FAMILY_MEDFORD:
+		case EFX_FAMILY_HUNTINGTON:
+			/*
+			 * Packed stream firmware variant maintains a
+			 * non-standard algorithm for hash computation.
+			 * It implies explicit XORing together
+			 * source + destination IP addresses (or last
+			 * four bytes in the case of IPv6) and using the
+			 * resulting value as the input to a Toeplitz hash.
+			 */
+			encp->enc_rx_scale_hash_alg_mask =
+			    (1U << EFX_RX_HASHALG_PACKED_STREAM);
+			break;
+
+		default:
+			rc = EINVAL;
+			goto fail5;
+		}
+
+		/* Port numbers cannot contribute to the hash value */
+		encp->enc_rx_scale_l4_hash_supported = B_FALSE;
+	} else {
+		/*
+		 * Maximum number of exclusive RSS contexts.
+		 * EF10 hardware supports 64 in total, but 6 are reserved
+		 * for shared contexts. They are a global resource so
+		 * not all may be available.
+		 */
+		encp->enc_rx_scale_max_exclusive_contexts = 64 - 6;
+
+		encp->enc_rx_scale_hash_alg_mask =
+		    (1U << EFX_RX_HASHALG_TOEPLITZ);
+
+		/*
+		 * It is possible to use port numbers as
+		 * the input data for hash computation.
+		 */
+		encp->enc_rx_scale_l4_hash_supported = B_TRUE;
+	}
+
 #undef CAP_FLAGS1
 #undef CAP_FLAGS2
 
 	return (0);
 
+fail5:
+	EFSYS_PROBE(fail5);
 fail4:
 	EFSYS_PROBE(fail4);
 fail3:
@@ -1707,13 +1759,6 @@ ef10_nic_board_cfg(
 	/* Alignment for WPTR updates */
 	encp->enc_rx_push_align = EF10_RX_WPTR_ALIGN;
 
-	/*
-	 * Maximum number of exclusive RSS contexts. EF10 hardware supports 64
-	 * in total, but 6 are reserved for shared contexts. They are a global
-	 * resource so not all may be available.
-	 */
-	encp->enc_rx_scale_max_exclusive_contexts = 64 - 6;
-
 	encp->enc_tx_dma_desc_size_max = EFX_MASK32(ESF_DZ_RX_KER_BYTE_CNT);
 	/* No boundary crossing limits */
 	encp->enc_tx_dma_desc_boundary = 0;
diff --git a/drivers/net/sfc/base/ef10_rx.c b/drivers/net/sfc/base/ef10_rx.c
index fc9e342..70e451f 100644
--- a/drivers/net/sfc/base/ef10_rx.c
+++ b/drivers/net/sfc/base/ef10_rx.c
@@ -609,12 +609,13 @@ ef10_rx_scale_mode_set(
 	__in		efx_rx_hash_type_t type,
 	__in		boolean_t insert)
 {
+	efx_nic_cfg_t *encp = &enp->en_nic_cfg;
 	efx_rc_t rc;
 
-	EFSYS_ASSERT3U(alg, ==, EFX_RX_HASHALG_TOEPLITZ);
 	EFSYS_ASSERT3U(insert, ==, B_TRUE);
 
-	if ((alg != EFX_RX_HASHALG_TOEPLITZ) || (insert == B_FALSE)) {
+	if ((encp->enc_rx_scale_hash_alg_mask & (1U << alg)) == 0 ||
+	    insert == B_FALSE) {
 		rc = EINVAL;
 		goto fail1;
 	}
@@ -763,6 +764,7 @@ ef10_rx_prefix_hash(
 	_NOTE(ARGUNUSED(enp))
 
 	switch (func) {
+	case EFX_RX_HASHALG_PACKED_STREAM:
 	case EFX_RX_HASHALG_TOEPLITZ:
 		return (buffer[0] |
 		    (buffer[1] << 8) |
diff --git a/drivers/net/sfc/base/efx.h b/drivers/net/sfc/base/efx.h
index 2088eb0..5d2fef7 100644
--- a/drivers/net/sfc/base/efx.h
+++ b/drivers/net/sfc/base/efx.h
@@ -1192,6 +1192,16 @@ typedef struct efx_nic_cfg_s {
 	uint32_t		enc_rx_buf_align_start;
 	uint32_t		enc_rx_buf_align_end;
 	uint32_t		enc_rx_scale_max_exclusive_contexts;
+	/*
+	 * Mask of supported hash algorithms.
+	 * Hash algorithm types are used as the bit indices.
+	 */
+	uint32_t		enc_rx_scale_hash_alg_mask;
+	/*
+	 * Indicates whether port numbers can be included to the
+	 * input data for hash computation.
+	 */
+	boolean_t		enc_rx_scale_l4_hash_supported;
 	boolean_t		enc_rx_scale_additional_modes_supported;
 #if EFSYS_OPT_LOOPBACK
 	efx_qword_t		enc_loopback_types[EFX_LINK_NMODES];
@@ -2066,7 +2076,9 @@ efx_rx_scatter_enable(
 
 typedef enum efx_rx_hash_alg_e {
 	EFX_RX_HASHALG_LFSR = 0,
-	EFX_RX_HASHALG_TOEPLITZ
+	EFX_RX_HASHALG_TOEPLITZ,
+	EFX_RX_HASHALG_PACKED_STREAM,
+	EFX_RX_NHASHALGS
 } efx_rx_hash_alg_t;
 
 /*
diff --git a/drivers/net/sfc/base/efx_rx.c b/drivers/net/sfc/base/efx_rx.c
index 840a11c..d75957f 100644
--- a/drivers/net/sfc/base/efx_rx.c
+++ b/drivers/net/sfc/base/efx_rx.c
@@ -302,6 +302,7 @@ efx_rx_scale_hash_flags_get(
 	__out					unsigned int *nflagsp)
 {
 	efx_nic_cfg_t *encp = &enp->en_nic_cfg;
+	boolean_t l4;
 	boolean_t additional_modes;
 	unsigned int *entryp = flags;
 	efx_rc_t rc;
@@ -311,6 +312,7 @@ efx_rx_scale_hash_flags_get(
 		goto fail1;
 	}
 
+	l4 = encp->enc_rx_scale_l4_hash_supported;
 	additional_modes = encp->enc_rx_scale_additional_modes_supported;
 
 #define	LIST_FLAGS(_entryp, _class, _l4_hashing, _additional_modes)	\
@@ -339,13 +341,20 @@ efx_rx_scale_hash_flags_get(
 	} while (B_FALSE)
 
 	switch (hash_alg) {
+	case EFX_RX_HASHALG_PACKED_STREAM:
+		if ((encp->enc_rx_scale_hash_alg_mask & (1U << hash_alg)) == 0)
+			break;
+		/* FALLTHRU */
 	case EFX_RX_HASHALG_TOEPLITZ:
-		LIST_FLAGS(entryp, IPV4_TCP, B_TRUE, additional_modes);
-		LIST_FLAGS(entryp, IPV6_TCP, B_TRUE, additional_modes);
+		if ((encp->enc_rx_scale_hash_alg_mask & (1U << hash_alg)) == 0)
+			break;
+
+		LIST_FLAGS(entryp, IPV4_TCP, l4, additional_modes);
+		LIST_FLAGS(entryp, IPV6_TCP, l4, additional_modes);
 
 		if (additional_modes) {
-			LIST_FLAGS(entryp, IPV4_UDP, B_TRUE, additional_modes);
-			LIST_FLAGS(entryp, IPV6_UDP, B_TRUE, additional_modes);
+			LIST_FLAGS(entryp, IPV4_UDP, l4, additional_modes);
+			LIST_FLAGS(entryp, IPV6_UDP, l4, additional_modes);
 		}
 
 		LIST_FLAGS(entryp, IPV4, B_FALSE, additional_modes);
diff --git a/drivers/net/sfc/base/siena_nic.c b/drivers/net/sfc/base/siena_nic.c
index 55e0951..f0a88a9 100644
--- a/drivers/net/sfc/base/siena_nic.c
+++ b/drivers/net/sfc/base/siena_nic.c
@@ -118,6 +118,15 @@ siena_board_cfg(
 	/* There is one RSS context per function */
 	encp->enc_rx_scale_max_exclusive_contexts = 1;
 
+	encp->enc_rx_scale_hash_alg_mask |= (1U << EFX_RX_HASHALG_LFSR);
+	encp->enc_rx_scale_hash_alg_mask |= (1U << EFX_RX_HASHALG_TOEPLITZ);
+
+	/*
+	 * It is always possible to use port numbers
+	 * as the input data for hash computation.
+	 */
+	encp->enc_rx_scale_l4_hash_supported = B_TRUE;
+
 	/* There is no support for additional RSS modes */
 	encp->enc_rx_scale_additional_modes_supported = B_FALSE;
 
-- 
2.7.4