// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) Meta Platforms, Inc. and affiliates. */

#include <linux/pci.h>
#include <linux/types.h>

#include "fbnic.h"
#include "fbnic_netdev.h"
#include "fbnic_txrx.h"

static irqreturn_t fbnic_fw_msix_intr(int __always_unused irq, void *data)
{
        struct fbnic_dev *fbd = (struct fbnic_dev *)data;

        fbnic_mbx_poll(fbd);

        fbnic_wr32(fbd, FBNIC_INTR_MASK_CLEAR(0), 1u << FBNIC_FW_MSIX_ENTRY);

        return IRQ_HANDLED;
}

static int __fbnic_fw_enable_mbx(struct fbnic_dev *fbd, int vector)
{
        int err;

        /* Initialize mailbox and attempt to poll it into ready state */
        fbnic_mbx_init(fbd);
        err = fbnic_mbx_poll_tx_ready(fbd);
        if (err) {
                dev_warn(fbd->dev, "FW mailbox did not enter ready state\n");
                return err;
        }

        /* Enable interrupt and unmask the vector */
        enable_irq(vector);
        fbnic_wr32(fbd, FBNIC_INTR_MASK_CLEAR(0), 1u << FBNIC_FW_MSIX_ENTRY);

        return 0;
}

/**
 * fbnic_fw_request_mbx - Configure and initialize Firmware Mailbox
 * @fbd: Pointer to device to initialize
 *
 * This function will allocate the IRQ and then reinitialize the mailbox
 * starting communication between the host and firmware.
 *
 * Return: non-zero on failure.
 **/
int fbnic_fw_request_mbx(struct fbnic_dev *fbd)
{
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        int vector, err;

        WARN_ON(fbd->fw_msix_vector);

        vector = pci_irq_vector(pdev, FBNIC_FW_MSIX_ENTRY);
        if (vector < 0)
                return vector;

        /* Request the IRQ for FW Mailbox vector. */
        err = request_threaded_irq(vector, NULL, &fbnic_fw_msix_intr,
                                   IRQF_ONESHOT | IRQF_NO_AUTOEN,
                                   dev_name(fbd->dev), fbd);
        if (err)
                return err;

        /* Initialize mailbox and attempt to poll it into ready state */
        err = __fbnic_fw_enable_mbx(fbd, vector);
        if (err)
                free_irq(vector, fbd);

        fbd->fw_msix_vector = vector;

        return err;
}

/**
 * fbnic_fw_disable_mbx - Temporarily place mailbox in standby state
 * @fbd: Pointer to device
 *
 * Shutdown the mailbox by notifying the firmware to stop sending us logs, mask
 * and synchronize the IRQ, and then clean up the rings.
 **/
static void fbnic_fw_disable_mbx(struct fbnic_dev *fbd)
{
        /* Disable interrupt and synchronize the IRQ */
        disable_irq(fbd->fw_msix_vector);

        /* Mask the vector */
        fbnic_wr32(fbd, FBNIC_INTR_MASK_SET(0), 1u << FBNIC_FW_MSIX_ENTRY);

        /* Make sure disabling logs message is sent, must be done here to
         * avoid risk of completing without a running interrupt.
         */
        fbnic_mbx_flush_tx(fbd);
        fbnic_mbx_clean(fbd);
}

/**
 * fbnic_fw_free_mbx - Disable mailbox and place it in standby state
 * @fbd: Pointer to device to disable
 *
 * This function will disable the mailbox interrupt, free any messages still
 * in the mailbox and place it into a disabled state. The firmware is
 * expected to see the update and assume that the host is in the reset state.
 **/
void fbnic_fw_free_mbx(struct fbnic_dev *fbd)
{
        /* Vector has already been freed */
        if (!fbd->fw_msix_vector)
                return;

        fbnic_fw_disable_mbx(fbd);

        /* Free the vector */
        free_irq(fbd->fw_msix_vector, fbd);
        fbd->fw_msix_vector = 0;
}

static irqreturn_t fbnic_mac_msix_intr(int __always_unused irq, void *data)
{
        struct fbnic_dev *fbd = data;
        struct fbnic_net *fbn;

        if (fbd->mac->get_link_event(fbd) == FBNIC_LINK_EVENT_NONE) {
                fbnic_wr32(fbd, FBNIC_INTR_MASK_CLEAR(0),
                           1u << FBNIC_PCS_MSIX_ENTRY);
                return IRQ_HANDLED;
        }

        fbn = netdev_priv(fbd->netdev);

        /* Record link down events */
        if (!fbd->mac->get_link(fbd, fbn->aui, fbn->fec))
                phylink_pcs_change(fbn->pcs, false);

        return IRQ_HANDLED;
}

/**
 * fbnic_mac_request_irq - Configure the MAC to enable it to advertise link
 * @fbd: Pointer to device to initialize
 *
 * This function provides basic bringup for the MAC/PHY IRQ. For now the IRQ
 * will remain disabled until we start the MAC/PCS/PHY logic via phylink.
 *
 * Return: non-zero on failure.
 **/
int fbnic_mac_request_irq(struct fbnic_dev *fbd)
{
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        int vector, err;

        WARN_ON(fbd->mac_msix_vector);

        vector = pci_irq_vector(pdev, FBNIC_PCS_MSIX_ENTRY);
        if (vector < 0)
                return vector;

        /* Request the IRQ for PCS link vector.
         * Map PCS cause to it, and unmask it
         */
        err = request_irq(vector, &fbnic_mac_msix_intr, 0,
                          fbd->netdev->name, fbd);
        if (err)
                return err;

        /* Map and enable interrupt, unmask vector after link is configured */
        fbnic_wr32(fbd, FBNIC_INTR_MSIX_CTRL(FBNIC_INTR_MSIX_CTRL_PCS_IDX),
                   FBNIC_PCS_MSIX_ENTRY | FBNIC_INTR_MSIX_CTRL_ENABLE);

        fbnic_wr32(fbd, FBNIC_INTR_MSIX_CTRL(FBNIC_INTR_MSIX_CTRL_RXB_IDX), 0);

        fbd->mac_msix_vector = vector;

        return 0;
}

/**
 * fbnic_mac_free_irq - Teardown the MAC IRQ to prepare for stopping
 * @fbd: Pointer to device that is stopping
 *
 * This function undoes the work done in fbnic_mac_request_irq and prepares
 * the device to no longer receive traffic on the host interface.
 **/
void fbnic_mac_free_irq(struct fbnic_dev *fbd)
{
        /* Vector has already been freed */
        if (!fbd->mac_msix_vector)
                return;

        /* Disable interrupt */
        fbnic_wr32(fbd, FBNIC_INTR_MSIX_CTRL(FBNIC_INTR_MSIX_CTRL_PCS_IDX),
                   FBNIC_PCS_MSIX_ENTRY);
        fbnic_wrfl(fbd);

        /* Synchronize IRQ to prevent race that would unmask vector */
        synchronize_irq(fbd->mac_msix_vector);

        /* Mask the vector */
        fbnic_wr32(fbd, FBNIC_INTR_MASK_SET(0), 1u << FBNIC_PCS_MSIX_ENTRY);

        /* Free the vector */
        free_irq(fbd->mac_msix_vector, fbd);
        fbd->mac_msix_vector = 0;
}

void fbnic_synchronize_irq(struct fbnic_dev *fbd, int nr)
{
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        int irq = pci_irq_vector(pdev, nr);

        if (irq < 0)
                return;

        synchronize_irq(irq);
}

int fbnic_request_irq(struct fbnic_dev *fbd, int nr, irq_handler_t handler,
                      unsigned long flags, const char *name, void *data)
{
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        int irq = pci_irq_vector(pdev, nr);

        if (irq < 0)
                return irq;

        return request_irq(irq, handler, flags, name, data);
}

void fbnic_free_irq(struct fbnic_dev *fbd, int nr, void *data)
{
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        int irq = pci_irq_vector(pdev, nr);

        if (irq < 0)
                return;

        free_irq(irq, data);
}

struct fbnic_msix_test_data {
        struct fbnic_dev *fbd;
        unsigned long test_msix_status[BITS_TO_LONGS(FBNIC_MAX_MSIX_VECS)];
        int irq_vector[FBNIC_MAX_MSIX_VECS];
};

static irqreturn_t fbnic_irq_test(int irq, void *data)
{
        struct fbnic_msix_test_data *test_data = data;
        struct fbnic_dev *fbd = test_data->fbd;
        int i;

        for (i = fbd->num_irqs; i--;) {
                if (test_data->irq_vector[i] == irq) {
                        set_bit(i, test_data->test_msix_status);
                        break;
                }
        }

        return IRQ_HANDLED;
}

/**
 * fbnic_msix_test - Verify behavior of NIC interrupts
 * @fbd: device to test
 *
 * This function is meant to test the global interrupt registers and the
 * PCIe IP MSI-X functionality. It essentially goes through and tests
 * various combinations of the set, clear, and mask bits in order to
 * verify the behavior is as we expect it to be from the driver.
 *
 * Return: See enum fbnic_msix_self_test_codes
 **/
enum fbnic_msix_self_test_codes fbnic_msix_test(struct fbnic_dev *fbd)
{
        enum fbnic_msix_self_test_codes result = FBNIC_TEST_MSIX_SUCCESS;
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        struct fbnic_msix_test_data *test_data;
        u32 mask = 0;
        int i;

        /* Allocate bitmap and IRQ vector table */
        test_data = kzalloc_obj(*test_data, GFP_KERNEL);

        /* memory allocation failure */
        if (!test_data)
                return FBNIC_TEST_MSIX_NOMEM;

        /* Initialize test data */
        test_data->fbd = fbd;

        for (i = FBNIC_NON_NAPI_VECTORS; i < fbd->num_irqs; i++) {
                /* Add IRQ to vector table so it can be found */
                test_data->irq_vector[i] = pci_irq_vector(pdev, i);

                /* Enable the interrupt */
                if (!fbnic_request_irq(fbd, i, fbnic_irq_test, 0,
                                       fbd->netdev->name, test_data))
                        continue;

                while (i-- > FBNIC_NON_NAPI_VECTORS)
                        fbnic_free_irq(fbd, i, test_data);
                kfree(test_data);

                /* IRQ request failure */
                return FBNIC_TEST_MSIX_IRQ_REQ_FAIL;
        }

        /* Test each bit individually */
        for (i = FBNIC_NON_NAPI_VECTORS; i < fbd->num_irqs; i++) {
                mask = 1U << (i % 32);

                /* Start with mask set and interrupt cleared */
                fbnic_wr32(fbd, FBNIC_INTR_MASK_SET(i / 32), mask);
                fbnic_wrfl(fbd);
                fbnic_wr32(fbd, FBNIC_INTR_CLEAR(i / 32), mask);
                fbnic_wrfl(fbd);

                /* masking failure to prevent interrupt */
                result = FBNIC_TEST_MSIX_MASK;

                fbnic_wr32(fbd, FBNIC_INTR_SET(i / 32), mask);
                fbnic_wrfl(fbd);
                usleep_range(10000, 11000);

                if (test_bit(i, test_data->test_msix_status))
                        break;

                /* unmasking failure w/ sw status set */
                result = FBNIC_TEST_MSIX_UNMASK;

                fbnic_wr32(fbd, FBNIC_INTR_MASK_CLEAR(i / 32), mask);
                fbnic_wrfl(fbd);
                usleep_range(10000, 11000);

                if (!test_bit(i, test_data->test_msix_status))
                        break;

                /* interrupt when clearing mask */
                result = FBNIC_TEST_MSIX_IRQ_CLEAR;

                clear_bit(i, test_data->test_msix_status);
                fbnic_wr32(fbd, FBNIC_INTR_MASK_CLEAR(i / 32), mask);
                fbnic_wrfl(fbd);
                usleep_range(10000, 11000);

                if (test_bit(i, test_data->test_msix_status))
                        break;

                /* interrupt not triggering when not masked */
                result = FBNIC_TEST_MSIX_NO_INTERRUPT;

                fbnic_wr32(fbd, FBNIC_INTR_SET(i / 32), mask);
                fbnic_wrfl(fbd);
                usleep_range(10000, 11000);

                if (!test_bit(i, test_data->test_msix_status))
                        break;

                /* status not cleared, or mask not set */
                result = FBNIC_TEST_MSIX_NO_CLEAR_OR_MASK;
                if (mask & fbnic_rd32(fbd, FBNIC_INTR_STATUS(i / 32)))
                        break;
                if (!(mask & fbnic_rd32(fbd, FBNIC_INTR_MASK(i / 32))))
                        break;

                /* Result = 0 - Success */
                result = FBNIC_TEST_MSIX_SUCCESS;

                clear_bit(i, test_data->test_msix_status);
        }

        if (i < fbd->num_irqs) {
                fbnic_wr32(fbd, FBNIC_INTR_MASK_SET(i / 32), mask);
                fbnic_wrfl(fbd);
                fbnic_wr32(fbd, FBNIC_INTR_CLEAR(i / 32), mask);
                fbnic_wrfl(fbd);
                clear_bit(i, test_data->test_msix_status);
        }

        for (i = FBNIC_NON_NAPI_VECTORS; i < fbd->num_irqs; i++) {
                /* Test for bits set after testing */
                if (test_bit(i, test_data->test_msix_status))
                        result = FBNIC_TEST_MSIX_BITS_SET_AFTER_TEST;

                /* Free IRQ */
                fbnic_free_irq(fbd, i, test_data);
        }

        kfree(test_data);

        return result;
}

void fbnic_napi_name_irqs(struct fbnic_dev *fbd)
{
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(fbd->napi_irq); i++)
                snprintf(fbd->napi_irq[i].name,
                         sizeof(fbd->napi_irq[i].name),
                         "%s-TxRx-%u", fbd->netdev->name, i);
}

int fbnic_napi_request_irq(struct fbnic_dev *fbd,
                           struct fbnic_napi_vector *nv)
{
        struct fbnic_net *fbn = netdev_priv(fbd->netdev);
        int i = fbnic_napi_idx(nv);
        int err;

        if (!fbd->napi_irq[i].users) {
                err = fbnic_request_irq(fbd, nv->v_idx,
                                        fbnic_msix_clean_rings, 0,
                                        fbd->napi_irq[i].name,
                                        &fbn->napi[i]);
                if (err)
                        return err;
        }

        fbd->napi_irq[i].users++;
        return 0;
}

void fbnic_napi_free_irq(struct fbnic_dev *fbd,
                         struct fbnic_napi_vector *nv)
{
        struct fbnic_net *fbn = netdev_priv(fbd->netdev);
        int i = fbnic_napi_idx(nv);

        if (--fbd->napi_irq[i].users)
                return;

        fbnic_free_irq(fbd, nv->v_idx, &fbn->napi[i]);
}

void fbnic_free_irqs(struct fbnic_dev *fbd)
{
        struct pci_dev *pdev = to_pci_dev(fbd->dev);

        fbd->num_irqs = 0;

        pci_free_irq_vectors(pdev);
}

int fbnic_alloc_irqs(struct fbnic_dev *fbd)
{
        unsigned int wanted_irqs = FBNIC_NON_NAPI_VECTORS;
        struct pci_dev *pdev = to_pci_dev(fbd->dev);
        int num_irqs;

        wanted_irqs += min_t(unsigned int, num_online_cpus(), FBNIC_MAX_RXQS);
        num_irqs = pci_alloc_irq_vectors(pdev, FBNIC_NON_NAPI_VECTORS + 1,
                                         wanted_irqs, PCI_IRQ_MSIX);
        if (num_irqs < 0) {
                dev_err(fbd->dev, "Failed to allocate MSI-X entries\n");
                return num_irqs;
        }

        if (num_irqs < wanted_irqs)
                dev_warn(fbd->dev, "Allocated %d IRQs, expected %d\n",
                         num_irqs, wanted_irqs);

        fbd->num_irqs = num_irqs;

        return 0;
}