Date:	Thu, 26 Mar 2015 20:20:15 +0000
From:	"Tantilov, Emil S" <emil.s.tantilov@...el.com>
To:	Vlad Zolotarov <vladz@...udius-systems.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:	"avi@...udius-systems.com" <avi@...udius-systems.com>,
	"intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>,
	"gleb@...udius-systems.com" <gleb@...udius-systems.com>
Subject: RE: [Intel-wired-lan] [PATCH net-next v1 1/2] ixgbe: Refactor the
 RSS	configuration code.

>-----Original Message-----
>From: Intel-wired-lan [mailto:intel-wired-lan-bounces@...ts.osuosl.org] On Behalf Of Vlad Zolotarov
>Sent: Thursday, March 26, 2015 10:57 AM
>Subject: [Intel-wired-lan] [PATCH net-next v1 1/2] ixgbe: Refactor the RSS configuration code.
>
>This patch is a preparation for enablement of ethtool RSS indirection table
>and hash key querying. We don't want to read registers every time the RSS info
>is queried. Therefore we will store its current content in the
>arrays in the adapter struct and will read it from there (instead of from
>registers) when requested.
>
>Will change the code that writes the indirection table and hash key into the HW registers
>to take its content from these arrays. This will also simplify the indirection
>table updating ethtool callback implementation in the future.
>
>Signed-off-by: Vlad Zolotarov <vladz@...udius-systems.com>
>---
> drivers/net/ethernet/intel/ixgbe/ixgbe.h      |   2 +
> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 143 ++++++++++++++++++--------
> drivers/net/ethernet/intel/ixgbe/ixgbe_type.h |   7 ++
> 3 files changed, 109 insertions(+), 43 deletions(-)
>
>diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>index 5e44e48..402d182 100644
>--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>@@ -766,6 +766,8 @@ struct ixgbe_adapter {
> 
> 	u8 default_up;
> 	unsigned long fwd_bitmask; /* Bitmask indicating in use pools */
>+	u8 rss_indir_tbl[IXGBE_MAX_RETA_ENTRIES];
>+	u32 rss_key[IXGBE_RSS_KEY_SIZE / sizeof(u32)];
> };
> 
> static inline u8 ixgbe_max_rss_indices(struct ixgbe_adapter *adapter)
>diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>index 8853d52..e3de0c9 100644
>--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>@@ -3228,51 +3228,54 @@ static void ixgbe_configure_srrctl(struct ixgbe_adapter *adapter,
> 	IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(reg_idx), srrctl);
> }
> 
>-static void ixgbe_setup_reta(struct ixgbe_adapter *adapter, const u32 *seed)
>+/**
>+ * Return a number of entries in the RSS indirection table

The preferred style for multiline comments is to not start with an empty "/*" checkpatch would generally 
catch those.

>+ *
>+ * @adapter: device handle
>+ *
>+ *  - 82598/82599/X540:     128
>+ *  - X550(non-SRIOV mode): 512
>+ *  - X550(SRIOV mode):     64
>+ */
>+static u32 ixgbe_rss_indir_tbl_entries(struct ixgbe_adapter *adapter)
>+{
>+	if (adapter->hw.mac.type < ixgbe_mac_X550)
>+		return 128;
>+	else if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)
>+		return 64;
>+	else
>+		return 512;
>+}
>+
>+/**
>+ * Write the RETA table to HW
>+ *
>+ * @adapter: device handle
>+ *
>+ * Write the RSS redirection table stored in adapter.rss_indir_tbl[] to HW.
>+ */
>+static void ixgbe_store_reta(struct ixgbe_adapter *adapter)

What is the point of having separate functions for writing the registers? Unless you intend to use
them in other parts of the code, those can be folded inside ixgbe_setupvf/reta().

> {
>+	u32 i, reta_entries = ixgbe_rss_indir_tbl_entries(adapter);
> 	struct ixgbe_hw *hw = &adapter->hw;
> 	u32 reta = 0;
>-	int i, j;
>-	int reta_entries = 128;
>-	u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
> 	int indices_multi;
>-
>-	/*
>-	 * Program table for at least 2 queues w/ SR-IOV so that VFs can
>-	 * make full use of any rings they may have.  We will use the
>-	 * PSRTYPE register to control how many rings we use within the PF.
>-	 */
>-	if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) && (rss_i < 2))
>-		rss_i = 2;
>-
>-	/* Fill out hash function seeds */
>-	for (i = 0; i < 10; i++)
>-		IXGBE_WRITE_REG(hw, IXGBE_RSSRK(i), seed[i]);
>+	u8 *indir_tbl = adapter->rss_indir_tbl;
> 
> 	/* Fill out the redirection table as follows:
>-	 * 82598: 128 (8 bit wide) entries containing pair of 4 bit RSS indices
>-	 * 82599/X540: 128 (8 bit wide) entries containing 4 bit RSS index
>-	 * X550: 512 (8 bit wide) entries containing 6 bit RSS index
>+	 *  - 82598:      8 bit wide entries containing pair of 4 bit RSS
>+	 *    indices.
>+	 *  - 82599/X540: 8 bit wide entries containing 4 bit RSS index
>+	 *  - X550:       8 bit wide entries containing 6 bit RSS index
> 	 */
> 	if (adapter->hw.mac.type == ixgbe_mac_82598EB)
> 		indices_multi = 0x11;
> 	else
> 		indices_multi = 0x1;
> 
>-	switch (adapter->hw.mac.type) {
>-	case ixgbe_mac_X550:
>-	case ixgbe_mac_X550EM_x:
>-		if (!(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED))
>-			reta_entries = 512;
>-	default:
>-		break;
>-	}
>-
>-	/* Fill out redirection table */
>-	for (i = 0, j = 0; i < reta_entries; i++, j++) {
>-		if (j == rss_i)
>-			j = 0;
>-		reta = (reta << 8) | (j * indices_multi);
>+	/* Write redirection table to HW */
>+	for (i = 0; i < reta_entries; i++) {
>+		reta = (reta << 8) | (indices_multi * indir_tbl[i]);
> 		if ((i & 3) == 3) {
> 			if (i < 128)
> 				IXGBE_WRITE_REG(hw, IXGBE_RETA(i >> 2), reta);
>@@ -3283,34 +3286,88 @@ static void ixgbe_setup_reta(struct ixgbe_adapter *adapter, const u32 *seed)
> 	}
> }
> 
>-static void ixgbe_setup_vfreta(struct ixgbe_adapter *adapter, const u32 *seed)
>+/**
>+ * Write the RETA table to HW (for x550 devices in SRIOV mode)
>+ *
>+ * @adapter: device handle
>+ *
>+ * Write the RSS redirection table stored in adapter.rss_indir_tbl[] to HW.
>+ */
>+static void ixgbe_store_vfreta(struct ixgbe_adapter *adapter)
> {
>+	u32 i, reta_entries = ixgbe_rss_indir_tbl_entries(adapter);
> 	struct ixgbe_hw *hw = &adapter->hw;
> 	u32 vfreta = 0;
>+	unsigned int pf_pool = adapter->num_vfs;
>+
>+	/* Write redirection table to HW */
>+	for (i = 0; i < reta_entries; i++) {
>+		vfreta = (vfreta << 8) | adapter->rss_indir_tbl[i];
>+		if ((i & 3) == 3)
>+			IXGBE_WRITE_REG(hw, IXGBE_PFVFRETA(i >> 2, pf_pool),
>+					vfreta);
>+	}
>+}
>+
>+static void ixgbe_setup_reta(struct ixgbe_adapter *adapter)
>+{
>+	struct ixgbe_hw *hw = &adapter->hw;
>+	u32 i, j;
>+	u32 reta_entries = ixgbe_rss_indir_tbl_entries(adapter);
>+	u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
>+
>+	/*
>+	 * Program table for at least 2 queues w/ SR-IOV so that VFs can
>+	 * make full use of any rings they may have.  We will use the
>+	 * PSRTYPE register to control how many rings we use within the PF.
>+	 */
>+	if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) && (rss_i < 2))
>+		rss_i = 2;
>+
>+	/* Fill out hash function seeds */
>+	for (i = 0; i < 10; i++)
>+		IXGBE_WRITE_REG(hw, IXGBE_RSSRK(i), adapter->rss_key[i]);
>+
>+	/* Fill out redirection table */
>+	memset(adapter->rss_indir_tbl, 0, sizeof(adapter->rss_indir_tbl));
>+
>+	for (i = 0, j = 0; i < reta_entries; i++, j++) {
>+		if (j == rss_i)
>+			j = 0;
>+
>+		adapter->rss_indir_tbl[i] = j;
>+	}
>+
>+	ixgbe_store_reta(adapter);
>+}
>+
>+static void ixgbe_setup_vfreta(struct ixgbe_adapter *adapter)
>+{
>+	struct ixgbe_hw *hw = &adapter->hw;
> 	u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
> 	unsigned int pf_pool = adapter->num_vfs;
> 	int i, j;
> 
> 	/* Fill out hash function seeds */
> 	for (i = 0; i < 10; i++)
>-		IXGBE_WRITE_REG(hw, IXGBE_PFVFRSSRK(i, pf_pool), seed[i]);
>+		IXGBE_WRITE_REG(hw, IXGBE_PFVFRSSRK(i, pf_pool),
>+				adapter->rss_key[i]);
> 
> 	/* Fill out the redirection table */
> 	for (i = 0, j = 0; i < 64; i++, j++) {
> 		if (j == rss_i)
> 			j = 0;
>-		vfreta = (vfreta << 8) | j;
>-		if ((i & 3) == 3)
>-			IXGBE_WRITE_REG(hw, IXGBE_PFVFRETA(i >> 2, pf_pool),
>-					vfreta);
>+
>+		adapter->rss_indir_tbl[i] = j;
> 	}
>+
>+	ixgbe_store_vfreta(adapter);
> }
> 
> static void ixgbe_setup_mrqc(struct ixgbe_adapter *adapter)
> {
> 	struct ixgbe_hw *hw = &adapter->hw;
> 	u32 mrqc = 0, rss_field = 0, vfmrqc = 0;
>-	u32 rss_key[10];
> 	u32 rxcsum;
> 
> 	/* Disable indicating checksum in descriptor, enables RSS hash */
>@@ -3354,7 +3411,7 @@ static void ixgbe_setup_mrqc(struct ixgbe_adapter *adapter)
> 	if (adapter->flags2 & IXGBE_FLAG2_RSS_FIELD_IPV6_UDP)
> 		rss_field |= IXGBE_MRQC_RSS_FIELD_IPV6_UDP;
> 
>-	netdev_rss_key_fill(rss_key, sizeof(rss_key));
>+	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter->rss_key));
> 	if ((hw->mac.type >= ixgbe_mac_X550) &&
> 	    (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)) {
> 		unsigned int pf_pool = adapter->num_vfs;
>@@ -3364,12 +3421,12 @@ static void ixgbe_setup_mrqc(struct ixgbe_adapter *adapter)
> 		IXGBE_WRITE_REG(hw, IXGBE_MRQC, mrqc);
> 
> 		/* Setup RSS through the VF registers */
>-		ixgbe_setup_vfreta(adapter, rss_key);
>+		ixgbe_setup_vfreta(adapter);
> 		vfmrqc = IXGBE_MRQC_RSSEN;
> 		vfmrqc |= rss_field;
> 		IXGBE_WRITE_REG(hw, IXGBE_PFVFMRQC(pf_pool), vfmrqc);
> 	} else {
>-		ixgbe_setup_reta(adapter, rss_key);
>+		ixgbe_setup_reta(adapter);
> 		mrqc |= rss_field;
> 		IXGBE_WRITE_REG(hw, IXGBE_MRQC, mrqc);
> 	}
>diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
>index c3ddc94..0c671b1 100644
>--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
>+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
>@@ -311,6 +311,13 @@ struct ixgbe_thermal_sensor_data {
> #define IXGBE_ERETA(_i)	(0x0EE80 + ((_i) * 4))  /* 96 of these (0-95) */
> #define IXGBE_RSSRK(_i) (0x05C80 + ((_i) * 4))  /* 10 of these (0-9) */
> 
>+/* maximum number of RETA entries among all devices supported by ixgbe
>+ * driver: currently it's x550 device in non-SRIOV mode
>+ */
>+#define IXGBE_MAX_RETA_ENTRIES 512
>+
>+#define IXGBE_RSS_KEY_SIZE     40  /* size of RSS Hash Key in bytes */
>+

These defines should be in ixgbe.h

> /* Registers for setting up RSS on X550 with SRIOV
>  * _p - pool number (0..63)
>  * _i - index (0..10 for PFVFRSSRK, 0..15 for PFVFRETA)

Thanks,
Emil

-- 
2.1.0

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