ice: move interrupt related code to separate file

Keep interrupt handling code in a dedicated file. This helps keep driver
structured better and prepares for more functionality added to this file.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Piotr Raczynski <piotr.raczynski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 226 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_irq.c b/drivers/net/ethernet/intel/ice/ice_irq.c
new file mode 100644
index 000000000000..1fc7daec9732
--- /dev/null
+++ b/drivers/net/ethernet/intel/ice/ice_irq.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023, Intel Corporation. */
+
+#include "ice.h"
+#include "ice_lib.h"
+#include "ice_irq.h"
+
+/**
+ * ice_reduce_msix_usage - Reduce usage of MSI-X vectors
+ * @pf: board private structure
+ * @v_remain: number of remaining MSI-X vectors to be distributed
+ *
+ * Reduce the usage of MSI-X vectors when entire request cannot be fulfilled.
+ * pf->num_lan_msix and pf->num_rdma_msix values are set based on number of
+ * remaining vectors.
+ */
+static void ice_reduce_msix_usage(struct ice_pf *pf, int v_remain)
+{
+	int v_rdma;
+
+	if (!ice_is_rdma_ena(pf)) {
+		pf->num_lan_msix = v_remain;
+		return;
+	}
+
+	/* RDMA needs at least 1 interrupt in addition to AEQ MSIX */
+	v_rdma = ICE_RDMA_NUM_AEQ_MSIX + 1;
+
+	if (v_remain < ICE_MIN_LAN_TXRX_MSIX + ICE_MIN_RDMA_MSIX) {
+		dev_warn(ice_pf_to_dev(pf), "Not enough MSI-X vectors to support RDMA.\n");
+		clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);
+
+		pf->num_rdma_msix = 0;
+		pf->num_lan_msix = ICE_MIN_LAN_TXRX_MSIX;
+	} else if ((v_remain < ICE_MIN_LAN_TXRX_MSIX + v_rdma) ||
+		   (v_remain - v_rdma < v_rdma)) {
+		/* Support minimum RDMA and give remaining vectors to LAN MSIX
+		 */
+		pf->num_rdma_msix = ICE_MIN_RDMA_MSIX;
+		pf->num_lan_msix = v_remain - ICE_MIN_RDMA_MSIX;
+	} else {
+		/* Split remaining MSIX with RDMA after accounting for AEQ MSIX
+		 */
+		pf->num_rdma_msix = (v_remain - ICE_RDMA_NUM_AEQ_MSIX) / 2 +
+				    ICE_RDMA_NUM_AEQ_MSIX;
+		pf->num_lan_msix = v_remain - pf->num_rdma_msix;
+	}
+}
+
+/**
+ * ice_ena_msix_range - Request a range of MSIX vectors from the OS
+ * @pf: board private structure
+ *
+ * Compute the number of MSIX vectors wanted and request from the OS. Adjust
+ * device usage if there are not enough vectors. Return the number of vectors
+ * reserved or negative on failure.
+ */
+static int ice_ena_msix_range(struct ice_pf *pf)
+{
+	int num_cpus, hw_num_msix, v_other, v_wanted, v_actual;
+	struct device *dev = ice_pf_to_dev(pf);
+	int err, i;
+
+	hw_num_msix = pf->hw.func_caps.common_cap.num_msix_vectors;
+	num_cpus = num_online_cpus();
+
+	/* LAN miscellaneous handler */
+	v_other = ICE_MIN_LAN_OICR_MSIX;
+
+	/* Flow Director */
+	if (test_bit(ICE_FLAG_FD_ENA, pf->flags))
+		v_other += ICE_FDIR_MSIX;
+
+	/* switchdev */
+	v_other += ICE_ESWITCH_MSIX;
+
+	v_wanted = v_other;
+
+	/* LAN traffic */
+	pf->num_lan_msix = num_cpus;
+	v_wanted += pf->num_lan_msix;
+
+	/* RDMA auxiliary driver */
+	if (ice_is_rdma_ena(pf)) {
+		pf->num_rdma_msix = num_cpus + ICE_RDMA_NUM_AEQ_MSIX;
+		v_wanted += pf->num_rdma_msix;
+	}
+
+	if (v_wanted > hw_num_msix) {
+		int v_remain;
+
+		dev_warn(dev, "not enough device MSI-X vectors. wanted = %d, available = %d\n",
+			 v_wanted, hw_num_msix);
+
+		if (hw_num_msix < ICE_MIN_MSIX) {
+			err = -ERANGE;
+			goto exit_err;
+		}
+
+		v_remain = hw_num_msix - v_other;
+		if (v_remain < ICE_MIN_LAN_TXRX_MSIX) {
+			v_other = ICE_MIN_MSIX - ICE_MIN_LAN_TXRX_MSIX;
+			v_remain = ICE_MIN_LAN_TXRX_MSIX;
+		}
+
+		ice_reduce_msix_usage(pf, v_remain);
+		v_wanted = pf->num_lan_msix + pf->num_rdma_msix + v_other;
+
+		dev_notice(dev, "Reducing request to %d MSI-X vectors for LAN traffic.\n",
+			   pf->num_lan_msix);
+		if (ice_is_rdma_ena(pf))
+			dev_notice(dev, "Reducing request to %d MSI-X vectors for RDMA.\n",
+				   pf->num_rdma_msix);
+	}
+
+	pf->msix_entries = devm_kcalloc(dev, v_wanted,
+					sizeof(*pf->msix_entries), GFP_KERNEL);
+	if (!pf->msix_entries) {
+		err = -ENOMEM;
+		goto exit_err;
+	}
+
+	for (i = 0; i < v_wanted; i++)
+		pf->msix_entries[i].entry = i;
+
+	/* actually reserve the vectors */
+	v_actual = pci_enable_msix_range(pf->pdev, pf->msix_entries,
+					 ICE_MIN_MSIX, v_wanted);
+	if (v_actual < 0) {
+		dev_err(dev, "unable to reserve MSI-X vectors\n");
+		err = v_actual;
+		goto msix_err;
+	}
+
+	if (v_actual < v_wanted) {
+		dev_warn(dev, "not enough OS MSI-X vectors. requested = %d, obtained = %d\n",
+			 v_wanted, v_actual);
+
+		if (v_actual < ICE_MIN_MSIX) {
+			/* error if we can't get minimum vectors */
+			pci_disable_msix(pf->pdev);
+			err = -ERANGE;
+			goto msix_err;
+		} else {
+			int v_remain = v_actual - v_other;
+
+			if (v_remain < ICE_MIN_LAN_TXRX_MSIX)
+				v_remain = ICE_MIN_LAN_TXRX_MSIX;
+
+			ice_reduce_msix_usage(pf, v_remain);
+
+			dev_notice(dev, "Enabled %d MSI-X vectors for LAN traffic.\n",
+				   pf->num_lan_msix);
+
+			if (ice_is_rdma_ena(pf))
+				dev_notice(dev, "Enabled %d MSI-X vectors for RDMA.\n",
+					   pf->num_rdma_msix);
+		}
+	}
+
+	return v_actual;
+
+msix_err:
+	devm_kfree(dev, pf->msix_entries);
+
+exit_err:
+	pf->num_rdma_msix = 0;
+	pf->num_lan_msix = 0;
+	return err;
+}
+
+/**
+ * ice_dis_msix - Disable MSI-X interrupt setup in OS
+ * @pf: board private structure
+ */
+static void ice_dis_msix(struct ice_pf *pf)
+{
+	pci_disable_msix(pf->pdev);
+	devm_kfree(ice_pf_to_dev(pf), pf->msix_entries);
+	pf->msix_entries = NULL;
+}
+
+/**
+ * ice_clear_interrupt_scheme - Undo things done by ice_init_interrupt_scheme
+ * @pf: board private structure
+ */
+void ice_clear_interrupt_scheme(struct ice_pf *pf)
+{
+	ice_dis_msix(pf);
+
+	if (pf->irq_tracker) {
+		devm_kfree(ice_pf_to_dev(pf), pf->irq_tracker);
+		pf->irq_tracker = NULL;
+	}
+}
+
+/**
+ * ice_init_interrupt_scheme - Determine proper interrupt scheme
+ * @pf: board private structure to initialize
+ */
+int ice_init_interrupt_scheme(struct ice_pf *pf)
+{
+	int vectors;
+
+	vectors = ice_ena_msix_range(pf);
+
+	if (vectors < 0)
+		return vectors;
+
+	/* set up vector assignment tracking */
+	pf->irq_tracker = devm_kzalloc(ice_pf_to_dev(pf),
+				       struct_size(pf->irq_tracker, list,
+						   vectors),
+				       GFP_KERNEL);
+	if (!pf->irq_tracker) {
+		ice_dis_msix(pf);
+		return -ENOMEM;
+	}
+
+	/* populate SW interrupts pool with number of OS granted IRQs. */
+	pf->num_avail_sw_msix = (u16)vectors;
+	pf->irq_tracker->num_entries = (u16)vectors;
+	pf->irq_tracker->end = pf->irq_tracker->num_entries;
+
+	return 0;
+}