// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2015 MediaTek Inc.
 * Author:
 *  Zhigang.Wei <zhigang.wei@mediatek.com>
 *  Chunfeng.Yun <chunfeng.yun@mediatek.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "xhci.h"
#include "xhci-mtk.h"

#define SS_BW_BOUNDARY  51000
/* table 5-5. High-speed Isoc Transaction Limits in usb_20 spec */
#define HS_BW_BOUNDARY  6144
/* usb2 spec section11.18.1: at most 188 FS bytes per microframe */
#define FS_PAYLOAD_MAX 188

/* mtk scheduler bitmasks */
#define EP_BPKTS(p)     ((p) & 0x3f)
#define EP_BCSCOUNT(p)  (((p) & 0x7) << 8)
#define EP_BBM(p)       ((p) << 11)
#define EP_BOFFSET(p)   ((p) & 0x3fff)
#define EP_BREPEAT(p)   (((p) & 0x7fff) << 16)

static int is_fs_or_ls(enum usb_device_speed speed)
{
        return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
}

/*
* get the index of bandwidth domains array which @ep belongs to.
*
* the bandwidth domain array is saved to @sch_array of struct xhci_hcd_mtk,
* each HS root port is treated as a single bandwidth domain,
* but each SS root port is treated as two bandwidth domains, one for IN eps,
* one for OUT eps.
* @real_port value is defined as follow according to xHCI spec:
* 1 for SSport0, ..., N+1 for SSportN, N+2 for HSport0, N+3 for HSport1, etc
* so the bandwidth domain array is organized as follow for simplification:
* SSport0-OUT, SSport0-IN, ..., SSportX-OUT, SSportX-IN, HSport0, ..., HSportY
*/
static int get_bw_index(struct xhci_hcd *xhci, struct usb_device *udev,
        struct usb_host_endpoint *ep)
{
        struct xhci_virt_device *virt_dev;
        int bw_index;

        virt_dev = xhci->devs[udev->slot_id];

        if (udev->speed == USB_SPEED_SUPER) {
                if (usb_endpoint_dir_out(&ep->desc))
                        bw_index = (virt_dev->real_port - 1) * 2;
                else
                        bw_index = (virt_dev->real_port - 1) * 2 + 1;
        } else {
                /* add one more for each SS port */
                bw_index = virt_dev->real_port + xhci->usb3_rhub.num_ports - 1;
        }

        return bw_index;
}

static void setup_sch_info(struct usb_device *udev,
                struct xhci_ep_ctx *ep_ctx, struct mu3h_sch_ep_info *sch_ep)
{
        u32 ep_type;
        u32 ep_interval;
        u32 max_packet_size;
        u32 max_burst;
        u32 mult;
        u32 esit_pkts;

        ep_type = CTX_TO_EP_TYPE(le32_to_cpu(ep_ctx->ep_info2));
        ep_interval = CTX_TO_EP_INTERVAL(le32_to_cpu(ep_ctx->ep_info));
        max_packet_size = MAX_PACKET_DECODED(le32_to_cpu(ep_ctx->ep_info2));
        max_burst = CTX_TO_MAX_BURST(le32_to_cpu(ep_ctx->ep_info2));
        mult = CTX_TO_EP_MULT(le32_to_cpu(ep_ctx->ep_info));

        sch_ep->esit = 1 << ep_interval;
        sch_ep->offset = 0;
        sch_ep->burst_mode = 0;

        if (udev->speed == USB_SPEED_HIGH) {
                sch_ep->cs_count = 0;

                /*
                 * usb_20 spec section5.9
                 * a single microframe is enough for HS synchromous endpoints
                 * in a interval
                 */
                sch_ep->num_budget_microframes = 1;
                sch_ep->repeat = 0;

                /*
                 * xHCI spec section6.2.3.4
                 * @max_burst is the number of additional transactions
                 * opportunities per microframe
                 */
                sch_ep->pkts = max_burst + 1;
                sch_ep->bw_cost_per_microframe = max_packet_size * sch_ep->pkts;
        } else if (udev->speed == USB_SPEED_SUPER) {
                /* usb3_r1 spec section4.4.7 & 4.4.8 */
                sch_ep->cs_count = 0;
                esit_pkts = (mult + 1) * (max_burst + 1);
                if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
                        sch_ep->pkts = esit_pkts;
                        sch_ep->num_budget_microframes = 1;
                        sch_ep->repeat = 0;
                }

                if (ep_type == ISOC_IN_EP || ep_type == ISOC_OUT_EP) {
                        if (esit_pkts <= sch_ep->esit)
                                sch_ep->pkts = 1;
                        else
                                sch_ep->pkts = roundup_pow_of_two(esit_pkts)
                                        / sch_ep->esit;

                        sch_ep->num_budget_microframes =
                                DIV_ROUND_UP(esit_pkts, sch_ep->pkts);

                        if (sch_ep->num_budget_microframes > 1)
                                sch_ep->repeat = 1;
                        else
                                sch_ep->repeat = 0;
                }
                sch_ep->bw_cost_per_microframe = max_packet_size * sch_ep->pkts;
        } else if (is_fs_or_ls(udev->speed)) {

                /*
                 * usb_20 spec section11.18.4
                 * assume worst cases
                 */
                sch_ep->repeat = 0;
                sch_ep->pkts = 1; /* at most one packet for each microframe */
                if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
                        sch_ep->cs_count = 3; /* at most need 3 CS*/
                        /* one for SS and one for budgeted transaction */
                        sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
                        sch_ep->bw_cost_per_microframe = max_packet_size;
                }
                if (ep_type == ISOC_OUT_EP) {

                        /*
                         * the best case FS budget assumes that 188 FS bytes
                         * occur in each microframe
                         */
                        sch_ep->num_budget_microframes = DIV_ROUND_UP(
                                max_packet_size, FS_PAYLOAD_MAX);
                        sch_ep->bw_cost_per_microframe = FS_PAYLOAD_MAX;
                        sch_ep->cs_count = sch_ep->num_budget_microframes;
                }
                if (ep_type == ISOC_IN_EP) {
                        /* at most need additional two CS. */
                        sch_ep->cs_count = DIV_ROUND_UP(
                                max_packet_size, FS_PAYLOAD_MAX) + 2;
                        sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
                        sch_ep->bw_cost_per_microframe = FS_PAYLOAD_MAX;
                }
        }
}

/* Get maximum bandwidth when we schedule at offset slot. */
static u32 get_max_bw(struct mu3h_sch_bw_info *sch_bw,
        struct mu3h_sch_ep_info *sch_ep, u32 offset)
{
        u32 num_esit;
        u32 max_bw = 0;
        int i;
        int j;

        num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
        for (i = 0; i < num_esit; i++) {
                u32 base = offset + i * sch_ep->esit;

                for (j = 0; j < sch_ep->num_budget_microframes; j++) {
                        if (sch_bw->bus_bw[base + j] > max_bw)
                                max_bw = sch_bw->bus_bw[base + j];
                }
        }
        return max_bw;
}

static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
        struct mu3h_sch_ep_info *sch_ep, int bw_cost)
{
        u32 num_esit;
        u32 base;
        int i;
        int j;

        num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
        for (i = 0; i < num_esit; i++) {
                base = sch_ep->offset + i * sch_ep->esit;
                for (j = 0; j < sch_ep->num_budget_microframes; j++)
                        sch_bw->bus_bw[base + j] += bw_cost;
        }
}

static int check_sch_bw(struct usb_device *udev,
        struct mu3h_sch_bw_info *sch_bw, struct mu3h_sch_ep_info *sch_ep)
{
        u32 offset;
        u32 esit;
        u32 num_budget_microframes;
        u32 min_bw;
        u32 min_index;
        u32 worst_bw;
        u32 bw_boundary;

        if (sch_ep->esit > XHCI_MTK_MAX_ESIT)
                sch_ep->esit = XHCI_MTK_MAX_ESIT;

        esit = sch_ep->esit;
        num_budget_microframes = sch_ep->num_budget_microframes;

        /*
         * Search through all possible schedule microframes.
         * and find a microframe where its worst bandwidth is minimum.
         */
        min_bw = ~0;
        min_index = 0;
        for (offset = 0; offset < esit; offset++) {
                if ((offset + num_budget_microframes) > sch_ep->esit)
                        break;

                /*
                 * usb_20 spec section11.18:
                 * must never schedule Start-Split in Y6
                 */
                if (is_fs_or_ls(udev->speed) && (offset % 8 == 6))
                        continue;

                worst_bw = get_max_bw(sch_bw, sch_ep, offset);
                if (min_bw > worst_bw) {
                        min_bw = worst_bw;
                        min_index = offset;
                }
                if (min_bw == 0)
                        break;
        }
        sch_ep->offset = min_index;

        bw_boundary = (udev->speed == USB_SPEED_SUPER)
                                ? SS_BW_BOUNDARY : HS_BW_BOUNDARY;

        /* check bandwidth */
        if (min_bw + sch_ep->bw_cost_per_microframe > bw_boundary)
                return -ERANGE;

        /* update bus bandwidth info */
        update_bus_bw(sch_bw, sch_ep, sch_ep->bw_cost_per_microframe);

        return 0;
}

static bool need_bw_sch(struct usb_host_endpoint *ep,
        enum usb_device_speed speed, int has_tt)
{
        /* only for periodic endpoints */
        if (usb_endpoint_xfer_control(&ep->desc)
                || usb_endpoint_xfer_bulk(&ep->desc))
                return false;

        /*
         * for LS & FS periodic endpoints which its device is not behind
         * a TT are also ignored, root-hub will schedule them directly,
         * but need set @bpkts field of endpoint context to 1.
         */
        if (is_fs_or_ls(speed) && !has_tt)
                return false;

        return true;
}

int xhci_mtk_sch_init(struct xhci_hcd_mtk *mtk)
{
        struct xhci_hcd *xhci = hcd_to_xhci(mtk->hcd);
        struct mu3h_sch_bw_info *sch_array;
        int num_usb_bus;
        int i;

        /* ss IN and OUT are separated */
        num_usb_bus = xhci->usb3_rhub.num_ports * 2 + xhci->usb2_rhub.num_ports;

        sch_array = kcalloc(num_usb_bus, sizeof(*sch_array), GFP_KERNEL);
        if (sch_array == NULL)
                return -ENOMEM;

        for (i = 0; i < num_usb_bus; i++)
                INIT_LIST_HEAD(&sch_array[i].bw_ep_list);

        mtk->sch_array = sch_array;

        return 0;
}
EXPORT_SYMBOL_GPL(xhci_mtk_sch_init);

void xhci_mtk_sch_exit(struct xhci_hcd_mtk *mtk)
{
        kfree(mtk->sch_array);
}
EXPORT_SYMBOL_GPL(xhci_mtk_sch_exit);

int xhci_mtk_add_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
        struct xhci_hcd *xhci;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_slot_ctx *slot_ctx;
        struct xhci_virt_device *virt_dev;
        struct mu3h_sch_bw_info *sch_bw;
        struct mu3h_sch_ep_info *sch_ep;
        struct mu3h_sch_bw_info *sch_array;
        unsigned int ep_index;
        int bw_index;
        int ret = 0;

        xhci = hcd_to_xhci(hcd);
        virt_dev = xhci->devs[udev->slot_id];
        ep_index = xhci_get_endpoint_index(&ep->desc);
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
        sch_array = mtk->sch_array;

        xhci_dbg(xhci, "%s() type:%d, speed:%d, mpkt:%d, dir:%d, ep:%p\n",
                __func__, usb_endpoint_type(&ep->desc), udev->speed,
                usb_endpoint_maxp(&ep->desc),
                usb_endpoint_dir_in(&ep->desc), ep);

        if (!need_bw_sch(ep, udev->speed, slot_ctx->tt_info & TT_SLOT)) {
                /*
                 * set @bpkts to 1 if it is LS or FS periodic endpoint, and its
                 * device does not connected through an external HS hub
                 */
                if (usb_endpoint_xfer_int(&ep->desc)
                        || usb_endpoint_xfer_isoc(&ep->desc))
                        ep_ctx->reserved[0] |= cpu_to_le32(EP_BPKTS(1));

                return 0;
        }

        bw_index = get_bw_index(xhci, udev, ep);
        sch_bw = &sch_array[bw_index];

        sch_ep = kzalloc(sizeof(struct mu3h_sch_ep_info), GFP_NOIO);
        if (!sch_ep)
                return -ENOMEM;

        setup_sch_info(udev, ep_ctx, sch_ep);

        ret = check_sch_bw(udev, sch_bw, sch_ep);
        if (ret) {
                xhci_err(xhci, "Not enough bandwidth!\n");
                kfree(sch_ep);
                return -ENOSPC;
        }

        list_add_tail(&sch_ep->endpoint, &sch_bw->bw_ep_list);
        sch_ep->ep = ep;

        ep_ctx->reserved[0] |= cpu_to_le32(EP_BPKTS(sch_ep->pkts)
                | EP_BCSCOUNT(sch_ep->cs_count) | EP_BBM(sch_ep->burst_mode));
        ep_ctx->reserved[1] |= cpu_to_le32(EP_BOFFSET(sch_ep->offset)
                | EP_BREPEAT(sch_ep->repeat));

        xhci_dbg(xhci, " PKTS:%x, CSCOUNT:%x, BM:%x, OFFSET:%x, REPEAT:%x\n",
                        sch_ep->pkts, sch_ep->cs_count, sch_ep->burst_mode,
                        sch_ep->offset, sch_ep->repeat);

        return 0;
}
EXPORT_SYMBOL_GPL(xhci_mtk_add_ep_quirk);

void xhci_mtk_drop_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
        struct xhci_hcd *xhci;
        struct xhci_slot_ctx *slot_ctx;
        struct xhci_virt_device *virt_dev;
        struct mu3h_sch_bw_info *sch_array;
        struct mu3h_sch_bw_info *sch_bw;
        struct mu3h_sch_ep_info *sch_ep;
        int bw_index;

        xhci = hcd_to_xhci(hcd);
        virt_dev = xhci->devs[udev->slot_id];
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
        sch_array = mtk->sch_array;

        xhci_dbg(xhci, "%s() type:%d, speed:%d, mpks:%d, dir:%d, ep:%p\n",
                __func__, usb_endpoint_type(&ep->desc), udev->speed,
                usb_endpoint_maxp(&ep->desc),
                usb_endpoint_dir_in(&ep->desc), ep);

        if (!need_bw_sch(ep, udev->speed, slot_ctx->tt_info & TT_SLOT))
                return;

        bw_index = get_bw_index(xhci, udev, ep);
        sch_bw = &sch_array[bw_index];

        list_for_each_entry(sch_ep, &sch_bw->bw_ep_list, endpoint) {
                if (sch_ep->ep == ep) {
                        update_bus_bw(sch_bw, sch_ep,
                                -sch_ep->bw_cost_per_microframe);
                        list_del(&sch_ep->endpoint);
                        kfree(sch_ep);
                        break;
                }
        }
}
EXPORT_SYMBOL_GPL(xhci_mtk_drop_ep_quirk);