treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / net / wireless / ath / ath5k / dma.c

/*
 * Copyright (c) 2004-2008 Reyk Floeter <reyk@openbsd.org>
 * Copyright (c) 2006-2008 Nick Kossifidis <mickflemm@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

/*************************************\
* DMA and interrupt masking functions *
\*************************************/

/**
 * DOC: DMA and interrupt masking functions
 *
 * Here we setup descriptor pointers (rxdp/txdp) start/stop dma engine and
 * handle queue setup for 5210 chipset (rest are handled on qcu.c).
 * Also we setup interrupt mask register (IMR) and read the various interrupt
 * status registers (ISR).
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "ath5k.h"
#include "reg.h"
#include "debug.h"


/*********\
* Receive *
\*********/

/**
 * ath5k_hw_start_rx_dma() - Start DMA receive
 * @ah: The &struct ath5k_hw
 */
void
ath5k_hw_start_rx_dma(struct ath5k_hw *ah)
{
        ath5k_hw_reg_write(ah, AR5K_CR_RXE, AR5K_CR);
        ath5k_hw_reg_read(ah, AR5K_CR);
}

/**
 * ath5k_hw_stop_rx_dma() - Stop DMA receive
 * @ah: The &struct ath5k_hw
 */
static int
ath5k_hw_stop_rx_dma(struct ath5k_hw *ah)
{
        unsigned int i;

        ath5k_hw_reg_write(ah, AR5K_CR_RXD, AR5K_CR);

        /*
         * It may take some time to disable the DMA receive unit
         */
        for (i = 1000; i > 0 &&
                        (ath5k_hw_reg_read(ah, AR5K_CR) & AR5K_CR_RXE) != 0;
                        i--)
                udelay(100);

        if (!i)
                ATH5K_DBG(ah, ATH5K_DEBUG_DMA,
                                "failed to stop RX DMA !\n");

        return i ? 0 : -EBUSY;
}

/**
 * ath5k_hw_get_rxdp() - Get RX Descriptor's address
 * @ah: The &struct ath5k_hw
 */
u32
ath5k_hw_get_rxdp(struct ath5k_hw *ah)
{
        return ath5k_hw_reg_read(ah, AR5K_RXDP);
}

/**
 * ath5k_hw_set_rxdp() - Set RX Descriptor's address
 * @ah: The &struct ath5k_hw
 * @phys_addr: RX descriptor address
 *
 * Returns -EIO if rx is active
 */
int
ath5k_hw_set_rxdp(struct ath5k_hw *ah, u32 phys_addr)
{
        if (ath5k_hw_reg_read(ah, AR5K_CR) & AR5K_CR_RXE) {
                ATH5K_DBG(ah, ATH5K_DEBUG_DMA,
                                "tried to set RXDP while rx was active !\n");
                return -EIO;
        }

        ath5k_hw_reg_write(ah, phys_addr, AR5K_RXDP);
        return 0;
}


/**********\
* Transmit *
\**********/

/**
 * ath5k_hw_start_tx_dma() - Start DMA transmit for a specific queue
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Start DMA transmit for a specific queue and since 5210 doesn't have
 * QCU/DCU, set up queue parameters for 5210 here based on queue type (one
 * queue for normal data and one queue for beacons). For queue setup
 * on newer chips check out qcu.c. Returns -EINVAL if queue number is out
 * of range or if queue is already disabled.
 *
 * NOTE: Must be called after setting up tx control descriptor for that
 * queue (see below).
 */
int
ath5k_hw_start_tx_dma(struct ath5k_hw *ah, unsigned int queue)
{
        u32 tx_queue;

        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        /* Return if queue is declared inactive */
        if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
                return -EINVAL;

        if (ah->ah_version == AR5K_AR5210) {
                tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);

                /*
                 * Set the queue by type on 5210
                 */
                switch (ah->ah_txq[queue].tqi_type) {
                case AR5K_TX_QUEUE_DATA:
                        tx_queue |= AR5K_CR_TXE0 & ~AR5K_CR_TXD0;
                        break;
                case AR5K_TX_QUEUE_BEACON:
                        tx_queue |= AR5K_CR_TXE1 & ~AR5K_CR_TXD1;
                        ath5k_hw_reg_write(ah, AR5K_BCR_TQ1V | AR5K_BCR_BDMAE,
                                        AR5K_BSR);
                        break;
                case AR5K_TX_QUEUE_CAB:
                        tx_queue |= AR5K_CR_TXE1 & ~AR5K_CR_TXD1;
                        ath5k_hw_reg_write(ah, AR5K_BCR_TQ1FV | AR5K_BCR_TQ1V |
                                AR5K_BCR_BDMAE, AR5K_BSR);
                        break;
                default:
                        return -EINVAL;
                }
                /* Start queue */
                ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
                ath5k_hw_reg_read(ah, AR5K_CR);
        } else {
                /* Return if queue is disabled */
                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXD, queue))
                        return -EIO;

                /* Start queue */
                AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXE, queue);
        }

        return 0;
}

/**
 * ath5k_hw_stop_tx_dma() - Stop DMA transmit on a specific queue
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Stop DMA transmit on a specific hw queue and drain queue so we don't
 * have any pending frames. Returns -EBUSY if we still have pending frames,
 * -EINVAL if queue number is out of range or inactive.
 */
static int
ath5k_hw_stop_tx_dma(struct ath5k_hw *ah, unsigned int queue)
{
        unsigned int i = 40;
        u32 tx_queue, pending;

        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        /* Return if queue is declared inactive */
        if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
                return -EINVAL;

        if (ah->ah_version == AR5K_AR5210) {
                tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);

                /*
                 * Set by queue type
                 */
                switch (ah->ah_txq[queue].tqi_type) {
                case AR5K_TX_QUEUE_DATA:
                        tx_queue |= AR5K_CR_TXD0 & ~AR5K_CR_TXE0;
                        break;
                case AR5K_TX_QUEUE_BEACON:
                case AR5K_TX_QUEUE_CAB:
                        /* XXX Fix me... */
                        tx_queue |= AR5K_CR_TXD1 & ~AR5K_CR_TXD1;
                        ath5k_hw_reg_write(ah, 0, AR5K_BSR);
                        break;
                default:
                        return -EINVAL;
                }

                /* Stop queue */
                ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
                ath5k_hw_reg_read(ah, AR5K_CR);
        } else {

                /*
                 * Enable DCU early termination to quickly
                 * flush any pending frames from QCU
                 */
                AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_DCU_EARLY);

                /*
                 * Schedule TX disable and wait until queue is empty
                 */
                AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXD, queue);

                /* Wait for queue to stop */
                for (i = 1000; i > 0 &&
                (AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue) != 0);
                i--)
                        udelay(100);

                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue))
                        ATH5K_DBG(ah, ATH5K_DEBUG_DMA,
                                "queue %i didn't stop !\n", queue);

                /* Check for pending frames */
                i = 1000;
                do {
                        pending = ath5k_hw_reg_read(ah,
                                AR5K_QUEUE_STATUS(queue)) &
                                AR5K_QCU_STS_FRMPENDCNT;
                        udelay(100);
                } while (--i && pending);

                /* For 2413+ order PCU to drop packets using
                 * QUIET mechanism */
                if (ah->ah_mac_version >= (AR5K_SREV_AR2414 >> 4) &&
                    pending) {
                        /* Set periodicity and duration */
                        ath5k_hw_reg_write(ah,
                                AR5K_REG_SM(100, AR5K_QUIET_CTL2_QT_PER)|
                                AR5K_REG_SM(10, AR5K_QUIET_CTL2_QT_DUR),
                                AR5K_QUIET_CTL2);

                        /* Enable quiet period for current TSF */
                        ath5k_hw_reg_write(ah,
                                AR5K_QUIET_CTL1_QT_EN |
                                AR5K_REG_SM(ath5k_hw_reg_read(ah,
                                                AR5K_TSF_L32_5211) >> 10,
                                                AR5K_QUIET_CTL1_NEXT_QT_TSF),
                                AR5K_QUIET_CTL1);

                        /* Force channel idle high */
                        AR5K_REG_ENABLE_BITS(ah, AR5K_DIAG_SW_5211,
                                        AR5K_DIAG_SW_CHANNEL_IDLE_HIGH);

                        /* Wait a while and disable mechanism */
                        udelay(400);
                        AR5K_REG_DISABLE_BITS(ah, AR5K_QUIET_CTL1,
                                                AR5K_QUIET_CTL1_QT_EN);

                        /* Re-check for pending frames */
                        i = 100;
                        do {
                                pending = ath5k_hw_reg_read(ah,
                                        AR5K_QUEUE_STATUS(queue)) &
                                        AR5K_QCU_STS_FRMPENDCNT;
                                udelay(100);
                        } while (--i && pending);

                        AR5K_REG_DISABLE_BITS(ah, AR5K_DIAG_SW_5211,
                                        AR5K_DIAG_SW_CHANNEL_IDLE_HIGH);

                        if (pending)
                                ATH5K_DBG(ah, ATH5K_DEBUG_DMA,
                                        "quiet mechanism didn't work q:%i !\n",
                                        queue);
                }

                /*
                 * Disable DCU early termination
                 */
                AR5K_REG_DISABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
                                        AR5K_QCU_MISC_DCU_EARLY);

                /* Clear register */
                ath5k_hw_reg_write(ah, 0, AR5K_QCU_TXD);
                if (pending) {
                        ATH5K_DBG(ah, ATH5K_DEBUG_DMA,
                                        "tx dma didn't stop (q:%i, frm:%i) !\n",
                                        queue, pending);
                        return -EBUSY;
                }
        }

        /* TODO: Check for success on 5210 else return error */
        return 0;
}

/**
 * ath5k_hw_stop_beacon_queue() - Stop beacon queue
 * @ah: The &struct ath5k_hw
 * @queue: The queue number
 *
 * Returns -EIO if queue didn't stop
 */
int
ath5k_hw_stop_beacon_queue(struct ath5k_hw *ah, unsigned int queue)
{
        int ret;
        ret = ath5k_hw_stop_tx_dma(ah, queue);
        if (ret) {
                ATH5K_DBG(ah, ATH5K_DEBUG_DMA,
                                "beacon queue didn't stop !\n");
                return -EIO;
        }
        return 0;
}

/**
 * ath5k_hw_get_txdp() - Get TX Descriptor's address for a specific queue
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Get TX descriptor's address for a specific queue. For 5210 we ignore
 * the queue number and use tx queue type since we only have 2 queues.
 * We use TXDP0 for normal data queue and TXDP1 for beacon queue.
 * For newer chips with QCU/DCU we just read the corresponding TXDP register.
 *
 * XXX: Is TXDP read and clear ?
 */
u32
ath5k_hw_get_txdp(struct ath5k_hw *ah, unsigned int queue)
{
        u16 tx_reg;

        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        /*
         * Get the transmit queue descriptor pointer from the selected queue
         */
        /*5210 doesn't have QCU*/
        if (ah->ah_version == AR5K_AR5210) {
                switch (ah->ah_txq[queue].tqi_type) {
                case AR5K_TX_QUEUE_DATA:
                        tx_reg = AR5K_NOQCU_TXDP0;
                        break;
                case AR5K_TX_QUEUE_BEACON:
                case AR5K_TX_QUEUE_CAB:
                        tx_reg = AR5K_NOQCU_TXDP1;
                        break;
                default:
                        return 0xffffffff;
                }
        } else {
                tx_reg = AR5K_QUEUE_TXDP(queue);
        }

        return ath5k_hw_reg_read(ah, tx_reg);
}

/**
 * ath5k_hw_set_txdp() - Set TX Descriptor's address for a specific queue
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 * @phys_addr: The physical address
 *
 * Set TX descriptor's address for a specific queue. For 5210 we ignore
 * the queue number and we use tx queue type since we only have 2 queues
 * so as above we use TXDP0 for normal data queue and TXDP1 for beacon queue.
 * For newer chips with QCU/DCU we just set the corresponding TXDP register.
 * Returns -EINVAL if queue type is invalid for 5210 and -EIO if queue is still
 * active.
 */
int
ath5k_hw_set_txdp(struct ath5k_hw *ah, unsigned int queue, u32 phys_addr)
{
        u16 tx_reg;

        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);

        /*
         * Set the transmit queue descriptor pointer register by type
         * on 5210
         */
        if (ah->ah_version == AR5K_AR5210) {
                switch (ah->ah_txq[queue].tqi_type) {
                case AR5K_TX_QUEUE_DATA:
                        tx_reg = AR5K_NOQCU_TXDP0;
                        break;
                case AR5K_TX_QUEUE_BEACON:
                case AR5K_TX_QUEUE_CAB:
                        tx_reg = AR5K_NOQCU_TXDP1;
                        break;
                default:
                        return -EINVAL;
                }
        } else {
                /*
                 * Set the transmit queue descriptor pointer for
                 * the selected queue on QCU for 5211+
                 * (this won't work if the queue is still active)
                 */
                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue))
                        return -EIO;

                tx_reg = AR5K_QUEUE_TXDP(queue);
        }

        /* Set descriptor pointer */
        ath5k_hw_reg_write(ah, phys_addr, tx_reg);

        return 0;
}

/**
 * ath5k_hw_update_tx_triglevel() - Update tx trigger level
 * @ah: The &struct ath5k_hw
 * @increase: Flag to force increase of trigger level
 *
 * This function increases/decreases the tx trigger level for the tx fifo
 * buffer (aka FIFO threshold) that is used to indicate when PCU flushes
 * the buffer and transmits its data. Lowering this results sending small
 * frames more quickly but can lead to tx underruns, raising it a lot can
 * result other problems. Right now we start with the lowest possible
 * (64Bytes) and if we get tx underrun we increase it using the increase
 * flag. Returns -EIO if we have reached maximum/minimum.
 *
 * XXX: Link this with tx DMA size ?
 * XXX2: Use it to save interrupts ?
 */
int
ath5k_hw_update_tx_triglevel(struct ath5k_hw *ah, bool increase)
{
        u32 trigger_level, imr;
        int ret = -EIO;

        /*
         * Disable interrupts by setting the mask
         */
        imr = ath5k_hw_set_imr(ah, ah->ah_imr & ~AR5K_INT_GLOBAL);

        trigger_level = AR5K_REG_MS(ath5k_hw_reg_read(ah, AR5K_TXCFG),
                        AR5K_TXCFG_TXFULL);

        if (!increase) {
                if (--trigger_level < AR5K_TUNE_MIN_TX_FIFO_THRES)
                        goto done;
        } else
                trigger_level +=
                        ((AR5K_TUNE_MAX_TX_FIFO_THRES - trigger_level) / 2);

        /*
         * Update trigger level on success
         */
        if (ah->ah_version == AR5K_AR5210)
                ath5k_hw_reg_write(ah, trigger_level, AR5K_TRIG_LVL);
        else
                AR5K_REG_WRITE_BITS(ah, AR5K_TXCFG,
                                AR5K_TXCFG_TXFULL, trigger_level);

        ret = 0;

done:
        /*
         * Restore interrupt mask
         */
        ath5k_hw_set_imr(ah, imr);

        return ret;
}


/*******************\
* Interrupt masking *
\*******************/

/**
 * ath5k_hw_is_intr_pending() - Check if we have pending interrupts
 * @ah: The &struct ath5k_hw
 *
 * Check if we have pending interrupts to process. Returns 1 if we
 * have pending interrupts and 0 if we haven't.
 */
bool
ath5k_hw_is_intr_pending(struct ath5k_hw *ah)
{
        return ath5k_hw_reg_read(ah, AR5K_INTPEND) == 1 ? 1 : 0;
}

/**
 * ath5k_hw_get_isr() - Get interrupt status
 * @ah: The @struct ath5k_hw
 * @interrupt_mask: Driver's interrupt mask used to filter out
 * interrupts in sw.
 *
 * This function is used inside our interrupt handler to determine the reason
 * for the interrupt by reading Primary Interrupt Status Register. Returns an
 * abstract interrupt status mask which is mostly ISR with some uncommon bits
 * being mapped on some standard non hw-specific positions
 * (check out &ath5k_int).
 *
 * NOTE: We do write-to-clear, so the active PISR/SISR bits at the time this
 * function gets called are cleared on return.
 */
int
ath5k_hw_get_isr(struct ath5k_hw *ah, enum ath5k_int *interrupt_mask)
{
        u32 data = 0;

        /*
         * Read interrupt status from Primary Interrupt
         * Register.
         *
         * Note: PISR/SISR Not available on 5210
         */
        if (ah->ah_version == AR5K_AR5210) {
                u32 isr = 0;
                isr = ath5k_hw_reg_read(ah, AR5K_ISR);
                if (unlikely(isr == AR5K_INT_NOCARD)) {
                        *interrupt_mask = isr;
                        return -ENODEV;
                }

                /*
                 * Filter out the non-common bits from the interrupt
                 * status.
                 */
                *interrupt_mask = (isr & AR5K_INT_COMMON) & ah->ah_imr;

                /* Hanlde INT_FATAL */
                if (unlikely(isr & (AR5K_ISR_SSERR | AR5K_ISR_MCABT
                                                | AR5K_ISR_DPERR)))
                        *interrupt_mask |= AR5K_INT_FATAL;

                /*
                 * XXX: BMISS interrupts may occur after association.
                 * I found this on 5210 code but it needs testing. If this is
                 * true we should disable them before assoc and re-enable them
                 * after a successful assoc + some jiffies.
                        interrupt_mask &= ~AR5K_INT_BMISS;
                 */

                data = isr;
        } else {
                u32 pisr = 0;
                u32 pisr_clear = 0;
                u32 sisr0 = 0;
                u32 sisr1 = 0;
                u32 sisr2 = 0;
                u32 sisr3 = 0;
                u32 sisr4 = 0;

                /* Read PISR and SISRs... */
                pisr = ath5k_hw_reg_read(ah, AR5K_PISR);
                if (unlikely(pisr == AR5K_INT_NOCARD)) {
                        *interrupt_mask = pisr;
                        return -ENODEV;
                }

                sisr0 = ath5k_hw_reg_read(ah, AR5K_SISR0);
                sisr1 = ath5k_hw_reg_read(ah, AR5K_SISR1);
                sisr2 = ath5k_hw_reg_read(ah, AR5K_SISR2);
                sisr3 = ath5k_hw_reg_read(ah, AR5K_SISR3);
                sisr4 = ath5k_hw_reg_read(ah, AR5K_SISR4);

                /*
                 * PISR holds the logical OR of interrupt bits
                 * from SISR registers:
                 *
                 * TXOK and TXDESC  -> Logical OR of TXOK and TXDESC
                 *                      per-queue bits on SISR0
                 *
                 * TXERR and TXEOL -> Logical OR of TXERR and TXEOL
                 *                      per-queue bits on SISR1
                 *
                 * TXURN -> Logical OR of TXURN per-queue bits on SISR2
                 *
                 * HIUERR -> Logical OR of MCABT, SSERR and DPER bits on SISR2
                 *
                 * BCNMISC -> Logical OR of TIM, CAB_END, DTIM_SYNC
                 *              BCN_TIMEOUT, CAB_TIMEOUT and DTIM
                 *              (and TSFOOR ?) bits on SISR2
                 *
                 * QCBRORN and QCBRURN -> Logical OR of QCBRORN and
                 *                      QCBRURN per-queue bits on SISR3
                 * QTRIG -> Logical OR of QTRIG per-queue bits on SISR4
                 *
                 * If we clean these bits on PISR we 'll also clear all
                 * related bits from SISRs, e.g. if we write the TXOK bit on
                 * PISR we 'll clean all TXOK bits from SISR0 so if a new TXOK
                 * interrupt got fired for another queue while we were reading
                 * the interrupt registers and we write back the TXOK bit on
                 * PISR we 'll lose it. So make sure that we don't write back
                 * on PISR any bits that come from SISRs. Clearing them from
                 * SISRs will also clear PISR so no need to worry here.
                 */

                /* XXX: There seems to be  an issue on some cards
                 *      with tx interrupt flags not being updated
                 *      on PISR despite that all Tx interrupt bits
                 *      are cleared on SISRs. Since we handle all
                 *      Tx queues all together it shouldn't be an
                 *      issue if we clear Tx interrupt flags also
                 *      on PISR to avoid that.
                 */
                pisr_clear = (pisr & ~AR5K_ISR_BITS_FROM_SISRS) |
                                        (pisr & AR5K_INT_TX_ALL);

                /*
                 * Write to clear them...
                 * Note: This means that each bit we write back
                 * to the registers will get cleared, leaving the
                 * rest unaffected. So this won't affect new interrupts
                 * we didn't catch while reading/processing, we 'll get
                 * them next time get_isr gets called.
                 */
                ath5k_hw_reg_write(ah, sisr0, AR5K_SISR0);
                ath5k_hw_reg_write(ah, sisr1, AR5K_SISR1);
                ath5k_hw_reg_write(ah, sisr2, AR5K_SISR2);
                ath5k_hw_reg_write(ah, sisr3, AR5K_SISR3);
                ath5k_hw_reg_write(ah, sisr4, AR5K_SISR4);
                ath5k_hw_reg_write(ah, pisr_clear, AR5K_PISR);
                /* Flush previous write */
                ath5k_hw_reg_read(ah, AR5K_PISR);

                /*
                 * Filter out the non-common bits from the interrupt
                 * status.
                 */
                *interrupt_mask = (pisr & AR5K_INT_COMMON) & ah->ah_imr;


                /* We treat TXOK,TXDESC, TXERR and TXEOL
                 * the same way (schedule the tx tasklet)
                 * so we track them all together per queue */
                if (pisr & AR5K_ISR_TXOK)
                        ah->ah_txq_isr_txok_all |= AR5K_REG_MS(sisr0,
                                                AR5K_SISR0_QCU_TXOK);

                if (pisr & AR5K_ISR_TXDESC)
                        ah->ah_txq_isr_txok_all |= AR5K_REG_MS(sisr0,
                                                AR5K_SISR0_QCU_TXDESC);

                if (pisr & AR5K_ISR_TXERR)
                        ah->ah_txq_isr_txok_all |= AR5K_REG_MS(sisr1,
                                                AR5K_SISR1_QCU_TXERR);

                if (pisr & AR5K_ISR_TXEOL)
                        ah->ah_txq_isr_txok_all |= AR5K_REG_MS(sisr1,
                                                AR5K_SISR1_QCU_TXEOL);

                /* Currently this is not much useful since we treat
                 * all queues the same way if we get a TXURN (update
                 * tx trigger level) but we might need it later on*/
                if (pisr & AR5K_ISR_TXURN)
                        ah->ah_txq_isr_txurn |= AR5K_REG_MS(sisr2,
                                                AR5K_SISR2_QCU_TXURN);

                /* Misc Beacon related interrupts */

                /* For AR5211 */
                if (pisr & AR5K_ISR_TIM)
                        *interrupt_mask |= AR5K_INT_TIM;

                /* For AR5212+ */
                if (pisr & AR5K_ISR_BCNMISC) {
                        if (sisr2 & AR5K_SISR2_TIM)
                                *interrupt_mask |= AR5K_INT_TIM;
                        if (sisr2 & AR5K_SISR2_DTIM)
                                *interrupt_mask |= AR5K_INT_DTIM;
                        if (sisr2 & AR5K_SISR2_DTIM_SYNC)
                                *interrupt_mask |= AR5K_INT_DTIM_SYNC;
                        if (sisr2 & AR5K_SISR2_BCN_TIMEOUT)
                                *interrupt_mask |= AR5K_INT_BCN_TIMEOUT;
                        if (sisr2 & AR5K_SISR2_CAB_TIMEOUT)
                                *interrupt_mask |= AR5K_INT_CAB_TIMEOUT;
                }

                /* Below interrupts are unlikely to happen */

                /* HIU = Host Interface Unit (PCI etc)
                 * Can be one of MCABT, SSERR, DPERR from SISR2 */
                if (unlikely(pisr & (AR5K_ISR_HIUERR)))
                        *interrupt_mask |= AR5K_INT_FATAL;

                /*Beacon Not Ready*/
                if (unlikely(pisr & (AR5K_ISR_BNR)))
                        *interrupt_mask |= AR5K_INT_BNR;

                /* A queue got CBR overrun */
                if (unlikely(pisr & (AR5K_ISR_QCBRORN))) {
                        *interrupt_mask |= AR5K_INT_QCBRORN;
                        ah->ah_txq_isr_qcborn |= AR5K_REG_MS(sisr3,
                                                AR5K_SISR3_QCBRORN);
                }

                /* A queue got CBR underrun */
                if (unlikely(pisr & (AR5K_ISR_QCBRURN))) {
                        *interrupt_mask |= AR5K_INT_QCBRURN;
                        ah->ah_txq_isr_qcburn |= AR5K_REG_MS(sisr3,
                                                AR5K_SISR3_QCBRURN);
                }

                /* A queue got triggered */
                if (unlikely(pisr & (AR5K_ISR_QTRIG))) {
                        *interrupt_mask |= AR5K_INT_QTRIG;
                        ah->ah_txq_isr_qtrig |= AR5K_REG_MS(sisr4,
                                                AR5K_SISR4_QTRIG);
                }

                data = pisr;
        }

        /*
         * In case we didn't handle anything,
         * print the register value.
         */
        if (unlikely(*interrupt_mask == 0 && net_ratelimit()))
                ATH5K_PRINTF("ISR: 0x%08x IMR: 0x%08x\n", data, ah->ah_imr);

        return 0;
}

/**
 * ath5k_hw_set_imr() - Set interrupt mask
 * @ah: The &struct ath5k_hw
 * @new_mask: The new interrupt mask to be set
 *
 * Set the interrupt mask in hw to save interrupts. We do that by mapping
 * ath5k_int bits to hw-specific bits to remove abstraction and writing
 * Interrupt Mask Register.
 */
enum ath5k_int
ath5k_hw_set_imr(struct ath5k_hw *ah, enum ath5k_int new_mask)
{
        enum ath5k_int old_mask, int_mask;

        old_mask = ah->ah_imr;

        /*
         * Disable card interrupts to prevent any race conditions
         * (they will be re-enabled afterwards if AR5K_INT GLOBAL
         * is set again on the new mask).
         */
        if (old_mask & AR5K_INT_GLOBAL) {
                ath5k_hw_reg_write(ah, AR5K_IER_DISABLE, AR5K_IER);
                ath5k_hw_reg_read(ah, AR5K_IER);
        }

        /*
         * Add additional, chipset-dependent interrupt mask flags
         * and write them to the IMR (interrupt mask register).
         */
        int_mask = new_mask & AR5K_INT_COMMON;

        if (ah->ah_version != AR5K_AR5210) {
                /* Preserve per queue TXURN interrupt mask */
                u32 simr2 = ath5k_hw_reg_read(ah, AR5K_SIMR2)
                                & AR5K_SIMR2_QCU_TXURN;

                /* Fatal interrupt abstraction for 5211+ */
                if (new_mask & AR5K_INT_FATAL) {
                        int_mask |= AR5K_IMR_HIUERR;
                        simr2 |= (AR5K_SIMR2_MCABT | AR5K_SIMR2_SSERR
                                | AR5K_SIMR2_DPERR);
                }

                /* Misc beacon related interrupts */
                if (new_mask & AR5K_INT_TIM)
                        int_mask |= AR5K_IMR_TIM;

                if (new_mask & AR5K_INT_TIM)
                        simr2 |= AR5K_SISR2_TIM;
                if (new_mask & AR5K_INT_DTIM)
                        simr2 |= AR5K_SISR2_DTIM;
                if (new_mask & AR5K_INT_DTIM_SYNC)
                        simr2 |= AR5K_SISR2_DTIM_SYNC;
                if (new_mask & AR5K_INT_BCN_TIMEOUT)
                        simr2 |= AR5K_SISR2_BCN_TIMEOUT;
                if (new_mask & AR5K_INT_CAB_TIMEOUT)
                        simr2 |= AR5K_SISR2_CAB_TIMEOUT;

                /*Beacon Not Ready*/
                if (new_mask & AR5K_INT_BNR)
                        int_mask |= AR5K_INT_BNR;

                /* Note: Per queue interrupt masks
                 * are set via ath5k_hw_reset_tx_queue() (qcu.c) */
                ath5k_hw_reg_write(ah, int_mask, AR5K_PIMR);
                ath5k_hw_reg_write(ah, simr2, AR5K_SIMR2);

        } else {
                /* Fatal interrupt abstraction for 5210 */
                if (new_mask & AR5K_INT_FATAL)
                        int_mask |= (AR5K_IMR_SSERR | AR5K_IMR_MCABT
                                | AR5K_IMR_HIUERR | AR5K_IMR_DPERR);

                /* Only common interrupts left for 5210 (no SIMRs) */
                ath5k_hw_reg_write(ah, int_mask, AR5K_IMR);
        }

        /* If RXNOFRM interrupt is masked disable it
         * by setting AR5K_RXNOFRM to zero */
        if (!(new_mask & AR5K_INT_RXNOFRM))
                ath5k_hw_reg_write(ah, 0, AR5K_RXNOFRM);

        /* Store new interrupt mask */
        ah->ah_imr = new_mask;

        /* ..re-enable interrupts if AR5K_INT_GLOBAL is set */
        if (new_mask & AR5K_INT_GLOBAL) {
                ath5k_hw_reg_write(ah, AR5K_IER_ENABLE, AR5K_IER);
                ath5k_hw_reg_read(ah, AR5K_IER);
        }

        return old_mask;
}


/********************\
 Init/Stop functions
\********************/

/**
 * ath5k_hw_dma_init() - Initialize DMA unit
 * @ah: The &struct ath5k_hw
 *
 * Set DMA size and pre-enable interrupts
 * (driver handles tx/rx buffer setup and
 * dma start/stop)
 *
 * XXX: Save/restore RXDP/TXDP registers ?
 */
void
ath5k_hw_dma_init(struct ath5k_hw *ah)
{
        /*
         * Set Rx/Tx DMA Configuration
         *
         * Set standard DMA size (128). Note that
         * a DMA size of 512 causes rx overruns and tx errors
         * on pci-e cards (tested on 5424 but since rx overruns
         * also occur on 5416/5418 with madwifi we set 128
         * for all PCI-E cards to be safe).
         *
         * XXX: need to check 5210 for this
         * TODO: Check out tx trigger level, it's always 64 on dumps but I
         * guess we can tweak it and see how it goes ;-)
         */
        if (ah->ah_version != AR5K_AR5210) {
                AR5K_REG_WRITE_BITS(ah, AR5K_TXCFG,
                        AR5K_TXCFG_SDMAMR, AR5K_DMASIZE_128B);
                AR5K_REG_WRITE_BITS(ah, AR5K_RXCFG,
                        AR5K_RXCFG_SDMAMW, AR5K_DMASIZE_128B);
        }

        /* Pre-enable interrupts on 5211/5212*/
        if (ah->ah_version != AR5K_AR5210)
                ath5k_hw_set_imr(ah, ah->ah_imr);

}

/**
 * ath5k_hw_dma_stop() - stop DMA unit
 * @ah: The &struct ath5k_hw
 *
 * Stop tx/rx DMA and interrupts. Returns
 * -EBUSY if tx or rx dma failed to stop.
 *
 * XXX: Sometimes DMA unit hangs and we have
 * stuck frames on tx queues, only a reset
 * can fix that.
 */
int
ath5k_hw_dma_stop(struct ath5k_hw *ah)
{
        int i, qmax, err;
        err = 0;

        /* Disable interrupts */
        ath5k_hw_set_imr(ah, 0);

        /* Stop rx dma */
        err = ath5k_hw_stop_rx_dma(ah);
        if (err)
                return err;

        /* Clear any pending interrupts
         * and disable tx dma */
        if (ah->ah_version != AR5K_AR5210) {
                ath5k_hw_reg_write(ah, 0xffffffff, AR5K_PISR);
                qmax = AR5K_NUM_TX_QUEUES;
        } else {
                /* PISR/SISR Not available on 5210 */
                ath5k_hw_reg_read(ah, AR5K_ISR);
                qmax = AR5K_NUM_TX_QUEUES_NOQCU;
        }

        for (i = 0; i < qmax; i++) {
                err = ath5k_hw_stop_tx_dma(ah, i);
                /* -EINVAL -> queue inactive */
                if (err && err != -EINVAL)
                        return err;
        }

        return 0;
}