// SPDX-License-Identifier: GPL-2.0-or-later
/*

  Broadcom B43legacy wireless driver

  PIO Transmission

  Copyright (c) 2005 Michael Buesch <m@bues.ch>


*/

#include "b43legacy.h"
#include "pio.h"
#include "main.h"
#include "xmit.h"

#include <linux/delay.h>
#include <linux/slab.h>


static void tx_start(struct b43legacy_pioqueue *queue)
{
        b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                            B43legacy_PIO_TXCTL_INIT);
}

static void tx_octet(struct b43legacy_pioqueue *queue,
                     u8 octet)
{
        if (queue->need_workarounds) {
                b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, octet);
                b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                                    B43legacy_PIO_TXCTL_WRITELO);
        } else {
                b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                                    B43legacy_PIO_TXCTL_WRITELO);
                b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, octet);
        }
}

static u16 tx_get_next_word(const u8 *txhdr,
                            const u8 *packet,
                            size_t txhdr_size,
                            unsigned int *pos)
{
        const u8 *source;
        unsigned int i = *pos;
        u16 ret;

        if (i < txhdr_size)
                source = txhdr;
        else {
                source = packet;
                i -= txhdr_size;
        }
        ret = le16_to_cpu(*((__le16 *)(source + i)));
        *pos += 2;

        return ret;
}

static void tx_data(struct b43legacy_pioqueue *queue,
                    u8 *txhdr,
                    const u8 *packet,
                    unsigned int octets)
{
        u16 data;
        unsigned int i = 0;

        if (queue->need_workarounds) {
                data = tx_get_next_word(txhdr, packet,
                                        sizeof(struct b43legacy_txhdr_fw3), &i);
                b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, data);
        }
        b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                            B43legacy_PIO_TXCTL_WRITELO |
                            B43legacy_PIO_TXCTL_WRITEHI);
        while (i < octets - 1) {
                data = tx_get_next_word(txhdr, packet,
                                        sizeof(struct b43legacy_txhdr_fw3), &i);
                b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, data);
        }
        if (octets % 2)
                tx_octet(queue, packet[octets -
                         sizeof(struct b43legacy_txhdr_fw3) - 1]);
}

static void tx_complete(struct b43legacy_pioqueue *queue,
                        struct sk_buff *skb)
{
        if (queue->need_workarounds) {
                b43legacy_pio_write(queue, B43legacy_PIO_TXDATA,
                                    skb->data[skb->len - 1]);
                b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                                    B43legacy_PIO_TXCTL_WRITELO |
                                    B43legacy_PIO_TXCTL_COMPLETE);
        } else
                b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                                    B43legacy_PIO_TXCTL_COMPLETE);
}

static u16 generate_cookie(struct b43legacy_pioqueue *queue,
                           struct b43legacy_pio_txpacket *packet)
{
        u16 cookie = 0x0000;
        int packetindex;

        /* We use the upper 4 bits for the PIO
         * controller ID and the lower 12 bits
         * for the packet index (in the cache).
         */
        switch (queue->mmio_base) {
        case B43legacy_MMIO_PIO1_BASE:
                break;
        case B43legacy_MMIO_PIO2_BASE:
                cookie = 0x1000;
                break;
        case B43legacy_MMIO_PIO3_BASE:
                cookie = 0x2000;
                break;
        case B43legacy_MMIO_PIO4_BASE:
                cookie = 0x3000;
                break;
        default:
                B43legacy_WARN_ON(1);
        }
        packetindex = pio_txpacket_getindex(packet);
        B43legacy_WARN_ON(!(((u16)packetindex & 0xF000) == 0x0000));
        cookie |= (u16)packetindex;

        return cookie;
}

static
struct b43legacy_pioqueue *parse_cookie(struct b43legacy_wldev *dev,
                                        u16 cookie,
                                        struct b43legacy_pio_txpacket **packet)
{
        struct b43legacy_pio *pio = &dev->pio;
        struct b43legacy_pioqueue *queue = NULL;
        int packetindex;

        switch (cookie & 0xF000) {
        case 0x0000:
                queue = pio->queue0;
                break;
        case 0x1000:
                queue = pio->queue1;
                break;
        case 0x2000:
                queue = pio->queue2;
                break;
        case 0x3000:
                queue = pio->queue3;
                break;
        default:
                B43legacy_WARN_ON(1);
        }
        packetindex = (cookie & 0x0FFF);
        B43legacy_WARN_ON(!(packetindex >= 0 && packetindex
                          < B43legacy_PIO_MAXTXPACKETS));
        *packet = &(queue->tx_packets_cache[packetindex]);

        return queue;
}

union txhdr_union {
        struct b43legacy_txhdr_fw3 txhdr_fw3;
};

static int pio_tx_write_fragment(struct b43legacy_pioqueue *queue,
                                  struct sk_buff *skb,
                                  struct b43legacy_pio_txpacket *packet,
                                  size_t txhdr_size)
{
        union txhdr_union txhdr_data;
        u8 *txhdr = NULL;
        unsigned int octets;
        int err;

        txhdr = (u8 *)(&txhdr_data.txhdr_fw3);

        B43legacy_WARN_ON(skb_shinfo(skb)->nr_frags != 0);
        err = b43legacy_generate_txhdr(queue->dev,
                                 txhdr, skb->data, skb->len,
                                 IEEE80211_SKB_CB(skb),
                                 generate_cookie(queue, packet));
        if (err)
                return err;

        tx_start(queue);
        octets = skb->len + txhdr_size;
        if (queue->need_workarounds)
                octets--;
        tx_data(queue, txhdr, (u8 *)skb->data, octets);
        tx_complete(queue, skb);

        return 0;
}

static void free_txpacket(struct b43legacy_pio_txpacket *packet,
                          int irq_context)
{
        struct b43legacy_pioqueue *queue = packet->queue;

        if (packet->skb) {
                if (irq_context)
                        dev_kfree_skb_irq(packet->skb);
                else
                        dev_kfree_skb(packet->skb);
        }
        list_move(&packet->list, &queue->txfree);
        queue->nr_txfree++;
}

static int pio_tx_packet(struct b43legacy_pio_txpacket *packet)
{
        struct b43legacy_pioqueue *queue = packet->queue;
        struct sk_buff *skb = packet->skb;
        u16 octets;
        int err;

        octets = (u16)skb->len + sizeof(struct b43legacy_txhdr_fw3);
        if (queue->tx_devq_size < octets) {
                b43legacywarn(queue->dev->wl, "PIO queue too small. "
                        "Dropping packet.\n");
                /* Drop it silently (return success) */
                free_txpacket(packet, 1);
                return 0;
        }
        B43legacy_WARN_ON(queue->tx_devq_packets >
                          B43legacy_PIO_MAXTXDEVQPACKETS);
        B43legacy_WARN_ON(queue->tx_devq_used > queue->tx_devq_size);
        /* Check if there is sufficient free space on the device
         * TX queue. If not, return and let the TX tasklet
         * retry later.
         */
        if (queue->tx_devq_packets == B43legacy_PIO_MAXTXDEVQPACKETS)
                return -EBUSY;
        if (queue->tx_devq_used + octets > queue->tx_devq_size)
                return -EBUSY;
        /* Now poke the device. */
        err = pio_tx_write_fragment(queue, skb, packet,
                              sizeof(struct b43legacy_txhdr_fw3));
        if (unlikely(err == -ENOKEY)) {
                /* Drop this packet, as we don't have the encryption key
                 * anymore and must not transmit it unencrypted. */
                free_txpacket(packet, 1);
                return 0;
        }

        /* Account for the packet size.
         * (We must not overflow the device TX queue)
         */
        queue->tx_devq_packets++;
        queue->tx_devq_used += octets;

        /* Transmission started, everything ok, move the
         * packet to the txrunning list.
         */
        list_move_tail(&packet->list, &queue->txrunning);

        return 0;
}

static void tx_tasklet(struct tasklet_struct *t)
{
        struct b43legacy_pioqueue *queue = from_tasklet(queue, t, txtask);
        struct b43legacy_wldev *dev = queue->dev;
        unsigned long flags;
        struct b43legacy_pio_txpacket *packet, *tmp_packet;
        int err;
        u16 txctl;

        spin_lock_irqsave(&dev->wl->irq_lock, flags);
        if (queue->tx_frozen)
                goto out_unlock;
        txctl = b43legacy_pio_read(queue, B43legacy_PIO_TXCTL);
        if (txctl & B43legacy_PIO_TXCTL_SUSPEND)
                goto out_unlock;

        list_for_each_entry_safe(packet, tmp_packet, &queue->txqueue, list) {
                /* Try to transmit the packet. This can fail, if
                 * the device queue is full. In case of failure, the
                 * packet is left in the txqueue.
                 * If transmission succeed, the packet is moved to txrunning.
                 * If it is impossible to transmit the packet, it
                 * is dropped.
                 */
                err = pio_tx_packet(packet);
                if (err)
                        break;
        }
out_unlock:
        spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
}

static void setup_txqueues(struct b43legacy_pioqueue *queue)
{
        struct b43legacy_pio_txpacket *packet;
        int i;

        queue->nr_txfree = B43legacy_PIO_MAXTXPACKETS;
        for (i = 0; i < B43legacy_PIO_MAXTXPACKETS; i++) {
                packet = &(queue->tx_packets_cache[i]);

                packet->queue = queue;
                INIT_LIST_HEAD(&packet->list);

                list_add(&packet->list, &queue->txfree);
        }
}

static
struct b43legacy_pioqueue *b43legacy_setup_pioqueue(struct b43legacy_wldev *dev,
                                                    u16 pio_mmio_base)
{
        struct b43legacy_pioqueue *queue;
        u32 value;
        u16 qsize;

        queue = kzalloc_obj(*queue);
        if (!queue)
                goto out;

        queue->dev = dev;
        queue->mmio_base = pio_mmio_base;
        queue->need_workarounds = (dev->dev->id.revision < 3);

        INIT_LIST_HEAD(&queue->txfree);
        INIT_LIST_HEAD(&queue->txqueue);
        INIT_LIST_HEAD(&queue->txrunning);
        tasklet_setup(&queue->txtask, tx_tasklet);

        value = b43legacy_read32(dev, B43legacy_MMIO_MACCTL);
        value &= ~B43legacy_MACCTL_BE;
        b43legacy_write32(dev, B43legacy_MMIO_MACCTL, value);

        qsize = b43legacy_read16(dev, queue->mmio_base
                                 + B43legacy_PIO_TXQBUFSIZE);
        if (qsize == 0) {
                b43legacyerr(dev->wl, "This card does not support PIO "
                       "operation mode. Please use DMA mode "
                       "(module parameter pio=0).\n");
                goto err_freequeue;
        }
        if (qsize <= B43legacy_PIO_TXQADJUST) {
                b43legacyerr(dev->wl, "PIO tx device-queue too small (%u)\n",
                       qsize);
                goto err_freequeue;
        }
        qsize -= B43legacy_PIO_TXQADJUST;
        queue->tx_devq_size = qsize;

        setup_txqueues(queue);

out:
        return queue;

err_freequeue:
        kfree(queue);
        queue = NULL;
        goto out;
}

static void cancel_transfers(struct b43legacy_pioqueue *queue)
{
        struct b43legacy_pio_txpacket *packet, *tmp_packet;

        tasklet_kill(&queue->txtask);

        list_for_each_entry_safe(packet, tmp_packet, &queue->txrunning, list)
                free_txpacket(packet, 0);
        list_for_each_entry_safe(packet, tmp_packet, &queue->txqueue, list)
                free_txpacket(packet, 0);
}

static void b43legacy_destroy_pioqueue(struct b43legacy_pioqueue *queue)
{
        if (!queue)
                return;

        cancel_transfers(queue);
        kfree(queue);
}

void b43legacy_pio_free(struct b43legacy_wldev *dev)
{
        struct b43legacy_pio *pio;

        if (!b43legacy_using_pio(dev))
                return;
        pio = &dev->pio;

        b43legacy_destroy_pioqueue(pio->queue3);
        pio->queue3 = NULL;
        b43legacy_destroy_pioqueue(pio->queue2);
        pio->queue2 = NULL;
        b43legacy_destroy_pioqueue(pio->queue1);
        pio->queue1 = NULL;
        b43legacy_destroy_pioqueue(pio->queue0);
        pio->queue0 = NULL;
}

int b43legacy_pio_init(struct b43legacy_wldev *dev)
{
        struct b43legacy_pio *pio = &dev->pio;
        struct b43legacy_pioqueue *queue;
        int err = -ENOMEM;

        queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO1_BASE);
        if (!queue)
                goto out;
        pio->queue0 = queue;

        queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO2_BASE);
        if (!queue)
                goto err_destroy0;
        pio->queue1 = queue;

        queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO3_BASE);
        if (!queue)
                goto err_destroy1;
        pio->queue2 = queue;

        queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO4_BASE);
        if (!queue)
                goto err_destroy2;
        pio->queue3 = queue;

        if (dev->dev->id.revision < 3)
                dev->irq_mask |= B43legacy_IRQ_PIO_WORKAROUND;

        b43legacydbg(dev->wl, "PIO initialized\n");
        err = 0;
out:
        return err;

err_destroy2:
        b43legacy_destroy_pioqueue(pio->queue2);
        pio->queue2 = NULL;
err_destroy1:
        b43legacy_destroy_pioqueue(pio->queue1);
        pio->queue1 = NULL;
err_destroy0:
        b43legacy_destroy_pioqueue(pio->queue0);
        pio->queue0 = NULL;
        goto out;
}

int b43legacy_pio_tx(struct b43legacy_wldev *dev,
                     struct sk_buff *skb)
{
        struct b43legacy_pioqueue *queue = dev->pio.queue1;
        struct b43legacy_pio_txpacket *packet;

        B43legacy_WARN_ON(queue->tx_suspended);
        B43legacy_WARN_ON(list_empty(&queue->txfree));

        packet = list_entry(queue->txfree.next, struct b43legacy_pio_txpacket,
                            list);
        packet->skb = skb;

        list_move_tail(&packet->list, &queue->txqueue);
        queue->nr_txfree--;
        B43legacy_WARN_ON(queue->nr_txfree >= B43legacy_PIO_MAXTXPACKETS);

        tasklet_schedule(&queue->txtask);

        return 0;
}

void b43legacy_pio_handle_txstatus(struct b43legacy_wldev *dev,
                                   const struct b43legacy_txstatus *status)
{
        struct b43legacy_pioqueue *queue;
        struct b43legacy_pio_txpacket *packet;
        struct ieee80211_tx_info *info;
        int retry_limit;

        queue = parse_cookie(dev, status->cookie, &packet);
        B43legacy_WARN_ON(!queue);

        if (!packet->skb)
                return;

        queue->tx_devq_packets--;
        queue->tx_devq_used -= (packet->skb->len +
                                sizeof(struct b43legacy_txhdr_fw3));

        info = IEEE80211_SKB_CB(packet->skb);

        /* preserve the confiured retry limit before clearing the status
         * The xmit function has overwritten the rc's value with the actual
         * retry limit done by the hardware */
        retry_limit = info->status.rates[0].count;
        ieee80211_tx_info_clear_status(info);

        if (status->acked)
                info->flags |= IEEE80211_TX_STAT_ACK;

        if (status->rts_count > dev->wl->hw->conf.short_frame_max_tx_count) {
                /*
                 * If the short retries (RTS, not data frame) have exceeded
                 * the limit, the hw will not have tried the selected rate,
                 * but will have used the fallback rate instead.
                 * Don't let the rate control count attempts for the selected
                 * rate in this case, otherwise the statistics will be off.
                 */
                info->status.rates[0].count = 0;
                info->status.rates[1].count = status->frame_count;
        } else {
                if (status->frame_count > retry_limit) {
                        info->status.rates[0].count = retry_limit;
                        info->status.rates[1].count = status->frame_count -
                                        retry_limit;

                } else {
                        info->status.rates[0].count = status->frame_count;
                        info->status.rates[1].idx = -1;
                }
        }
        ieee80211_tx_status_irqsafe(dev->wl->hw, packet->skb);
        packet->skb = NULL;

        free_txpacket(packet, 1);
        /* If there are packets on the txqueue, poke the tasklet
         * to transmit them.
         */
        if (!list_empty(&queue->txqueue))
                tasklet_schedule(&queue->txtask);
}

static void pio_rx_error(struct b43legacy_pioqueue *queue,
                         int clear_buffers,
                         const char *error)
{
        int i;

        b43legacyerr(queue->dev->wl, "PIO RX error: %s\n", error);
        b43legacy_pio_write(queue, B43legacy_PIO_RXCTL,
                            B43legacy_PIO_RXCTL_READY);
        if (clear_buffers) {
                B43legacy_WARN_ON(queue->mmio_base != B43legacy_MMIO_PIO1_BASE);
                for (i = 0; i < 15; i++) {
                        /* Dummy read. */
                        b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
                }
        }
}

void b43legacy_pio_rx(struct b43legacy_pioqueue *queue)
{
        __le16 preamble[21] = { 0 };
        struct b43legacy_rxhdr_fw3 *rxhdr;
        u16 tmp;
        u16 len;
        u16 macstat;
        int i;
        int preamble_readwords;
        struct sk_buff *skb;

        tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXCTL);
        if (!(tmp & B43legacy_PIO_RXCTL_DATAAVAILABLE))
                return;
        b43legacy_pio_write(queue, B43legacy_PIO_RXCTL,
                            B43legacy_PIO_RXCTL_DATAAVAILABLE);

        for (i = 0; i < 10; i++) {
                tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXCTL);
                if (tmp & B43legacy_PIO_RXCTL_READY)
                        goto data_ready;
                udelay(10);
        }
        b43legacydbg(queue->dev->wl, "PIO RX timed out\n");
        return;
data_ready:

        len = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
        if (unlikely(len > 0x700)) {
                pio_rx_error(queue, 0, "len > 0x700");
                return;
        }
        if (unlikely(len == 0 && queue->mmio_base !=
                     B43legacy_MMIO_PIO4_BASE)) {
                pio_rx_error(queue, 0, "len == 0");
                return;
        }
        preamble[0] = cpu_to_le16(len);
        if (queue->mmio_base == B43legacy_MMIO_PIO4_BASE)
                preamble_readwords = 14 / sizeof(u16);
        else
                preamble_readwords = 18 / sizeof(u16);
        for (i = 0; i < preamble_readwords; i++) {
                tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
                preamble[i + 1] = cpu_to_le16(tmp);
        }
        rxhdr = (struct b43legacy_rxhdr_fw3 *)preamble;
        macstat = le16_to_cpu(rxhdr->mac_status);
        if (macstat & B43legacy_RX_MAC_FCSERR) {
                pio_rx_error(queue,
                             (queue->mmio_base == B43legacy_MMIO_PIO1_BASE),
                             "Frame FCS error");
                return;
        }
        if (queue->mmio_base == B43legacy_MMIO_PIO4_BASE) {
                /* We received an xmit status. */
                struct b43legacy_hwtxstatus *hw;

                hw = (struct b43legacy_hwtxstatus *)(preamble + 1);
                b43legacy_handle_hwtxstatus(queue->dev, hw);

                return;
        }

        skb = dev_alloc_skb(len);
        if (unlikely(!skb)) {
                pio_rx_error(queue, 1, "OOM");
                return;
        }
        skb_put(skb, len);
        for (i = 0; i < len - 1; i += 2) {
                tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
                *((__le16 *)(skb->data + i)) = cpu_to_le16(tmp);
        }
        if (len % 2) {
                tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
                skb->data[len - 1] = (tmp & 0x00FF);
        }
        b43legacy_rx(queue->dev, skb, rxhdr);
}

void b43legacy_pio_tx_suspend(struct b43legacy_pioqueue *queue)
{
        b43legacy_power_saving_ctl_bits(queue->dev, -1, 1);
        b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                            b43legacy_pio_read(queue, B43legacy_PIO_TXCTL)
                            | B43legacy_PIO_TXCTL_SUSPEND);
}

void b43legacy_pio_tx_resume(struct b43legacy_pioqueue *queue)
{
        b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                            b43legacy_pio_read(queue, B43legacy_PIO_TXCTL)
                            & ~B43legacy_PIO_TXCTL_SUSPEND);
        b43legacy_power_saving_ctl_bits(queue->dev, -1, -1);
        tasklet_schedule(&queue->txtask);
}

void b43legacy_pio_freeze_txqueues(struct b43legacy_wldev *dev)
{
        struct b43legacy_pio *pio;

        B43legacy_WARN_ON(!b43legacy_using_pio(dev));
        pio = &dev->pio;
        pio->queue0->tx_frozen = 1;
        pio->queue1->tx_frozen = 1;
        pio->queue2->tx_frozen = 1;
        pio->queue3->tx_frozen = 1;
}

void b43legacy_pio_thaw_txqueues(struct b43legacy_wldev *dev)
{
        struct b43legacy_pio *pio;

        B43legacy_WARN_ON(!b43legacy_using_pio(dev));
        pio = &dev->pio;
        pio->queue0->tx_frozen = 0;
        pio->queue1->tx_frozen = 0;
        pio->queue2->tx_frozen = 0;
        pio->queue3->tx_frozen = 0;
        if (!list_empty(&pio->queue0->txqueue))
                tasklet_schedule(&pio->queue0->txtask);
        if (!list_empty(&pio->queue1->txqueue))
                tasklet_schedule(&pio->queue1->txtask);
        if (!list_empty(&pio->queue2->txqueue))
                tasklet_schedule(&pio->queue2->txtask);
        if (!list_empty(&pio->queue3->txqueue))
                tasklet_schedule(&pio->queue3->txtask);
}