ixgbe: Add a RETA query command to VF-PF channel API

Add this new command for 82599 and x540 devices only. Support for other
devices will be added later.

82599 and x540 VFs and PF share the same RSS redirection table (RETA).
Therefore we just return it for all VFs.

For 82599 and x540 RETA table is an array of 32 registers (128 bytes) and
the maximum number of registers that may be delivered in a single VF-PF
channel command is 15. On the other hand VFs of these devices can be
configured to have up to 4 RSS queues. Therefore we will "compress" the
RETA by transferring only 2 bits per entry and thereby it will take only 8
registers (DWORDS) to transfer the whole VF RETA.

Thus this patch does the following:

  - Adds a new API version (to specify a new commands set).
  - Adds the IXGBE_VF_GET_RETA command to the VF-PF commands set.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h

@@ -73,6 +73,7 @@ enum ixgbe_pfvf_api_rev {
 	ixgbe_mbox_api_10,	/* API version 1.0, linux/freebsd VF driver */
 	ixgbe_mbox_api_20,	/* API version 2.0, solaris Phase1 VF driver */
 	ixgbe_mbox_api_11,	/* API version 1.1, linux/freebsd VF driver */
+	ixgbe_mbox_api_12,	/* API version 1.2, linux/freebsd VF driver */
 	/* This value should always be last */
 	ixgbe_mbox_api_unknown,	/* indicates that API version is not known */
 };
@@ -97,6 +98,9 @@ enum ixgbe_pfvf_api_rev {
 #define IXGBE_VF_TRANS_VLAN	3	/* Indication of port vlan */
 #define IXGBE_VF_DEF_QUEUE	4	/* Default queue offset */
 
+/* mailbox API, version 1.2 VF requests */
+#define IXGBE_VF_GET_RETA	0x0a	/* VF request for RETA */
+
 /* length of permanent address message returned from PF */
 #define IXGBE_VF_PERMADDR_MSG_LEN 4
 /* word in permanent address message with the current multicast type */

drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c

@@ -434,6 +434,7 @@ static s32 ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
 #endif /* CONFIG_FCOE */
 		switch (adapter->vfinfo[vf].vf_api) {
 		case ixgbe_mbox_api_11:
+		case ixgbe_mbox_api_12:
 			/*
 			 * Version 1.1 supports jumbo frames on VFs if PF has
 			 * jumbo frames enabled which means legacy VFs are
@@ -901,6 +902,7 @@ static int ixgbe_negotiate_vf_api(struct ixgbe_adapter *adapter,
 	switch (api) {
 	case ixgbe_mbox_api_10:
 	case ixgbe_mbox_api_11:
+	case ixgbe_mbox_api_12:
 		adapter->vfinfo[vf].vf_api = api;
 		return 0;
 	default:
@@ -924,6 +926,7 @@ static int ixgbe_get_vf_queues(struct ixgbe_adapter *adapter,
 	switch (adapter->vfinfo[vf].vf_api) {
 	case ixgbe_mbox_api_20:
 	case ixgbe_mbox_api_11:
+	case ixgbe_mbox_api_12:
 		break;
 	default:
 		return -1;
@@ -951,6 +954,35 @@ static int ixgbe_get_vf_queues(struct ixgbe_adapter *adapter,
 	return 0;
 }
 
+static int ixgbe_get_vf_reta(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
+{
+	u32 i, j;
+	u32 *out_buf = &msgbuf[1];
+	const u8 *reta = adapter->rss_indir_tbl;
+	u32 reta_size = ixgbe_rss_indir_tbl_entries(adapter);
+
+	/* Check if operation is permitted */
+	if (!adapter->vfinfo[vf].rss_query_enabled)
+		return -EPERM;
+
+	/* verify the PF is supporting the correct API */
+	if (adapter->vfinfo[vf].vf_api != ixgbe_mbox_api_12)
+		return -EOPNOTSUPP;
+
+	/* This mailbox command is supported (required) only for 82599 and x540
+	 * VFs which support up to 4 RSS queues. Therefore we will compress the
+	 * RETA by saving only 2 bits from each entry. This way we will be able
+	 * to transfer the whole RETA in a single mailbox operation.
+	 */
+	for (i = 0; i < reta_size / 16; i++) {
+		out_buf[i] = 0;
+		for (j = 0; j < 16; j++)
+			out_buf[i] |= (u32)(reta[16 * i + j] & 0x3) << (2 * j);
+	}
+
+	return 0;
+}
+
 static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
 {
 	u32 mbx_size = IXGBE_VFMAILBOX_SIZE;
@@ -1007,6 +1039,9 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
 	case IXGBE_VF_GET_QUEUES:
 		retval = ixgbe_get_vf_queues(adapter, msgbuf, vf);
 		break;
+	case IXGBE_VF_GET_RETA:
+		retval = ixgbe_get_vf_reta(adapter, msgbuf, vf);
+		break;
 	default:
 		e_err(drv, "Unhandled Msg %8.8x\n", msgbuf[0]);
 		retval = IXGBE_ERR_MBX;