ice: Refactor interrupt tracking

Currently we have two MSI-x (IRQ) trackers, one for OS requested MSI-x
entries (sw_irq_tracker) and one for hardware MSI-x vectors
(hw_irq_tracker). Generally the sw_irq_tracker has less entries than the
hw_irq_tracker because the hw_irq_tracker has entries equal to the max
allowed MSI-x per PF and the sw_irq_tracker is mainly the minimum (non
SR-IOV portion of the vectors, kernel granted IRQs). All of the non
SR-IOV portions of the driver (i.e. LAN queues, RDMA queues, OICR, etc.)
take at least one of each type of tracker resource. SR-IOV only grabs
entries from the hw_irq_tracker. There are a few issues with this approach
that can be seen when doing any kind of device reconfiguration (i.e.
ethtool -L, SR-IOV, etc.). One of them being, any time the driver creates
an ice_q_vector and associates it to a LAN queue pair it will grab and
use one entry from the hw_irq_tracker and one from the sw_irq_tracker.
If the indices on these does not match it will cause a Tx timeout, which
will cause a reset and then the indices will match up again and traffic
will resume. The mismatched indices come from the trackers not being the
same size and/or the search_hint in the two trackers not being equal.
Another reason for the refactor is the co-existence of features with
SR-IOV. If SR-IOV is enabled and the interrupts are taken from the end
of the sw_irq_tracker then other features can no longer use this space
because the hardware has now given the remaining interrupts to SR-IOV.

This patch reworks how we track MSI-x vectors by removing the
hw_irq_tracker completely and instead MSI-x resources needed for SR-IOV
are determined all at once instead of per VF. This can be done because
when creating VFs we know how many are wanted and how many MSI-x vectors
each VF needs. This also allows us to start using MSI-x resources from
the end of the PF's allowed MSI-x vectors so we are less likely to use
entries needed for other features (i.e. RDMA, L2 Offload, etc).

This patch also reworks the ice_res_tracker structure by removing the
search_hint and adding a new member - "end". Instead of having a
search_hint we will always search from 0. The new member, "end", will be
used to manipulate the end of the ice_res_tracker (specifically
sw_irq_tracker) during runtime based on MSI-x vectors needed by SR-IOV.
In the normal case, the end of ice_res_tracker will be equal to the
ice_res_tracker's num_entries.

The sriov_base_vector member was added to the PF structure. It is used
to represent the starting MSI-x index of all the needed MSI-x vectors
for all SR-IOV VFs. Depending on how many MSI-x are needed, SR-IOV may
have to take resources from the sw_irq_tracker. This is done by setting
the sw_irq_tracker->end equal to the pf->sriov_base_vector. When all
SR-IOV VFs are removed then the sw_irq_tracker->end is reset back to
sw_irq_tracker->num_entries. The sriov_base_vector, along with the VF's
number of MSI-x (pf->num_vf_msix), vf_id, and the base MSI-x index on
the PF (pf->hw.func_caps.common_cap.msix_vector_first_id), is used to
calculate the first HW absolute MSI-x index for each VF, which is used
to write to the VPINT_ALLOC[_PCI] and GLINT_VECT2FUNC registers to
program the VFs MSI-x PCI configuration bits. Also, the sriov_base_vector
is used along with VF's num_vf_msix, vf_id, and q_vector->v_idx to
determine the MSI-x register index (used for writing to GLINT_DYN_CTL)
within the PF's space.

Interrupt changes removed any references to hw_base_vector, hw_oicr_idx,
and hw_irq_tracker. Only sw_base_vector, sw_oicr_idx, and sw_irq_tracker
variables remain. Change all of these by removing the "sw_" prefix to
help avoid confusion with these variables and their use.

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ice/ice.h

@@ -167,7 +167,7 @@ struct ice_tc_cfg {
 
 struct ice_res_tracker {
 	u16 num_entries;
-	u16 search_hint;
+	u16 end;
 	u16 list[1];
 };
 
@@ -252,8 +252,7 @@ struct ice_vsi {
 	u32 rx_buf_failed;
 	u32 rx_page_failed;
 	int num_q_vectors;
-	int sw_base_vector;		/* Irq base for OS reserved vectors */
-	int hw_base_vector;		/* HW (absolute) index of a vector */
+	int base_vector;		/* IRQ base for OS reserved vectors */
 	enum ice_vsi_type type;
 	u16 vsi_num;			/* HW (absolute) index of this VSI */
 	u16 idx;			/* software index in pf->vsi[] */
@@ -348,10 +347,12 @@ struct ice_pf {
 
 	/* OS reserved IRQ details */
 	struct msix_entry *msix_entries;
-	struct ice_res_tracker *sw_irq_tracker;
-
-	/* HW reserved Interrupts for this PF */
-	struct ice_res_tracker *hw_irq_tracker;
+	struct ice_res_tracker *irq_tracker;
+	/* First MSIX vector used by SR-IOV VFs. Calculated by subtracting the
+	 * number of MSIX vectors needed for all SR-IOV VFs from the number of
+	 * MSIX vectors allowed on this PF.
+	 */
+	u16 sriov_base_vector;
 
 	struct ice_vsi **vsi;		/* VSIs created by the driver */
 	struct ice_sw *first_sw;	/* first switch created by firmware */
@@ -373,10 +374,8 @@ struct ice_pf {
 	struct mutex sw_mutex;		/* lock for protecting VSI alloc flow */
 	u32 msg_enable;
 	u32 hw_csum_rx_error;
-	u32 sw_oicr_idx;	/* Other interrupt cause SW vector index */
+	u32 oicr_idx;		/* Other interrupt cause MSIX vector index */
 	u32 num_avail_sw_msix;	/* remaining MSIX SW vectors left unclaimed */
-	u32 hw_oicr_idx;	/* Other interrupt cause vector HW index */
-	u32 num_avail_hw_msix;	/* remaining HW MSIX vectors left unclaimed */
 	u32 num_lan_msix;	/* Total MSIX vectors for base driver */
 	u16 num_lan_tx;		/* num LAN Tx queues setup */
 	u16 num_lan_rx;		/* num LAN Rx queues setup */
@@ -418,7 +417,7 @@ ice_irq_dynamic_ena(struct ice_hw *hw, struct ice_vsi *vsi,
 		    struct ice_q_vector *q_vector)
 {
 	u32 vector = (vsi && q_vector) ? q_vector->reg_idx :
-				((struct ice_pf *)hw->back)->hw_oicr_idx;
+				((struct ice_pf *)hw->back)->oicr_idx;
 	int itr = ICE_ITR_NONE;
 	u32 val;