ath6kl: add a timeout to ath6kl_hif_intr_bh_handler()

[linux-2.6.git] / drivers / net / wireless / ath / ath6kl / hif.c

/*
 * Copyright (c) 2007-2011 Atheros Communications Inc.
 *
 * Permission to use, copy, modify, and/or 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.
 */
#include "hif.h"

#include "core.h"
#include "target.h"
#include "hif-ops.h"
#include "debug.h"

#define MAILBOX_FOR_BLOCK_SIZE          1

#define ATH6KL_TIME_QUANTUM     10  /* in ms */

static int ath6kl_hif_cp_scat_dma_buf(struct hif_scatter_req *req,
                                      bool from_dma)
{
        u8 *buf;
        int i;

        buf = req->virt_dma_buf;

        for (i = 0; i < req->scat_entries; i++) {

                if (from_dma)
                        memcpy(req->scat_list[i].buf, buf,
                               req->scat_list[i].len);
                else
                        memcpy(buf, req->scat_list[i].buf,
                               req->scat_list[i].len);

                buf += req->scat_list[i].len;
        }

        return 0;
}

int ath6kl_hif_rw_comp_handler(void *context, int status)
{
        struct htc_packet *packet = context;

        ath6kl_dbg(ATH6KL_DBG_HIF, "hif rw completion pkt 0x%p status %d\n",
                   packet, status);

        packet->status = status;
        packet->completion(packet->context, packet);

        return 0;
}

static int ath6kl_hif_proc_dbg_intr(struct ath6kl_device *dev)
{
        u32 dummy;
        int status;

        ath6kl_err("target debug interrupt\n");

        ath6kl_target_failure(dev->ar);

        /*
         * read counter to clear the interrupt, the debug error interrupt is
         * counter 0.
         */
        status = hif_read_write_sync(dev->ar, COUNT_DEC_ADDRESS,
                                     (u8 *)&dummy, 4, HIF_RD_SYNC_BYTE_INC);
        if (status)
                WARN_ON(1);

        return status;
}

/* mailbox recv message polling */
int ath6kl_hif_poll_mboxmsg_rx(struct ath6kl_device *dev, u32 *lk_ahd,
                              int timeout)
{
        struct ath6kl_irq_proc_registers *rg;
        int status = 0, i;
        u8 htc_mbox = 1 << HTC_MAILBOX;

        for (i = timeout / ATH6KL_TIME_QUANTUM; i > 0; i--) {
                /* this is the standard HIF way, load the reg table */
                status = hif_read_write_sync(dev->ar, HOST_INT_STATUS_ADDRESS,
                                             (u8 *) &dev->irq_proc_reg,
                                             sizeof(dev->irq_proc_reg),
                                             HIF_RD_SYNC_BYTE_INC);

                if (status) {
                        ath6kl_err("failed to read reg table\n");
                        return status;
                }

                /* check for MBOX data and valid lookahead */
                if (dev->irq_proc_reg.host_int_status & htc_mbox) {
                        if (dev->irq_proc_reg.rx_lkahd_valid &
                            htc_mbox) {
                                /*
                                 * Mailbox has a message and the look ahead
                                 * is valid.
                                 */
                                rg = &dev->irq_proc_reg;
                                *lk_ahd =
                                        le32_to_cpu(rg->rx_lkahd[HTC_MAILBOX]);
                                break;
                        }
                }

                /* delay a little  */
                mdelay(ATH6KL_TIME_QUANTUM);
                ath6kl_dbg(ATH6KL_DBG_HIF, "hif retry mbox poll try %d\n", i);
        }

        if (i == 0) {
                ath6kl_err("timeout waiting for recv message\n");
                status = -ETIME;
                /* check if the target asserted */
                if (dev->irq_proc_reg.counter_int_status &
                    ATH6KL_TARGET_DEBUG_INTR_MASK)
                        /*
                         * Target failure handler will be called in case of
                         * an assert.
                         */
                        ath6kl_hif_proc_dbg_intr(dev);
        }

        return status;
}

/*
 * Disable packet reception (used in case the host runs out of buffers)
 * using the interrupt enable registers through the host I/F
 */
int ath6kl_hif_rx_control(struct ath6kl_device *dev, bool enable_rx)
{
        struct ath6kl_irq_enable_reg regs;
        int status = 0;

        ath6kl_dbg(ATH6KL_DBG_HIF, "hif rx %s\n",
                   enable_rx ? "enable" : "disable");

        /* take the lock to protect interrupt enable shadows */
        spin_lock_bh(&dev->lock);

        if (enable_rx)
                dev->irq_en_reg.int_status_en |=
                        SM(INT_STATUS_ENABLE_MBOX_DATA, 0x01);
        else
                dev->irq_en_reg.int_status_en &=
                    ~SM(INT_STATUS_ENABLE_MBOX_DATA, 0x01);

        memcpy(&regs, &dev->irq_en_reg, sizeof(regs));

        spin_unlock_bh(&dev->lock);

        status = hif_read_write_sync(dev->ar, INT_STATUS_ENABLE_ADDRESS,
                                     &regs.int_status_en,
                                     sizeof(struct ath6kl_irq_enable_reg),
                                     HIF_WR_SYNC_BYTE_INC);

        return status;
}

int ath6kl_hif_submit_scat_req(struct ath6kl_device *dev,
                              struct hif_scatter_req *scat_req, bool read)
{
        int status = 0;

        if (read) {
                scat_req->req = HIF_RD_SYNC_BLOCK_FIX;
                scat_req->addr = dev->ar->mbox_info.htc_addr;
        } else {
                scat_req->req = HIF_WR_ASYNC_BLOCK_INC;

                scat_req->addr =
                        (scat_req->len > HIF_MBOX_WIDTH) ?
                        dev->ar->mbox_info.htc_ext_addr :
                        dev->ar->mbox_info.htc_addr;
        }

        ath6kl_dbg(ATH6KL_DBG_HIF,
                   "hif submit scatter request entries %d len %d mbox 0x%x %s %s\n",
                   scat_req->scat_entries, scat_req->len,
                   scat_req->addr, !read ? "async" : "sync",
                   (read) ? "rd" : "wr");

        if (!read && scat_req->virt_scat) {
                status = ath6kl_hif_cp_scat_dma_buf(scat_req, false);
                if (status) {
                        scat_req->status = status;
                        scat_req->complete(dev->ar->htc_target, scat_req);
                        return 0;
                }
        }

        status = ath6kl_hif_scat_req_rw(dev->ar, scat_req);

        if (read) {
                /* in sync mode, we can touch the scatter request */
                scat_req->status = status;
                if (!status && scat_req->virt_scat)
                        scat_req->status =
                                ath6kl_hif_cp_scat_dma_buf(scat_req, true);
        }

        return status;
}

static int ath6kl_hif_proc_counter_intr(struct ath6kl_device *dev)
{
        u8 counter_int_status;

        ath6kl_dbg(ATH6KL_DBG_IRQ, "counter interrupt\n");

        counter_int_status = dev->irq_proc_reg.counter_int_status &
                             dev->irq_en_reg.cntr_int_status_en;

        ath6kl_dbg(ATH6KL_DBG_IRQ,
                "valid interrupt source(s) in COUNTER_INT_STATUS: 0x%x\n",
                counter_int_status);

        /*
         * NOTE: other modules like GMBOX may use the counter interrupt for
         * credit flow control on other counters, we only need to check for
         * the debug assertion counter interrupt.
         */
        if (counter_int_status & ATH6KL_TARGET_DEBUG_INTR_MASK)
                return ath6kl_hif_proc_dbg_intr(dev);

        return 0;
}

static int ath6kl_hif_proc_err_intr(struct ath6kl_device *dev)
{
        int status;
        u8 error_int_status;
        u8 reg_buf[4];

        ath6kl_dbg(ATH6KL_DBG_IRQ, "error interrupt\n");

        error_int_status = dev->irq_proc_reg.error_int_status & 0x0F;
        if (!error_int_status) {
                WARN_ON(1);
                return -EIO;
        }

        ath6kl_dbg(ATH6KL_DBG_IRQ,
                   "valid interrupt source(s) in ERROR_INT_STATUS: 0x%x\n",
                   error_int_status);

        if (MS(ERROR_INT_STATUS_WAKEUP, error_int_status))
                ath6kl_dbg(ATH6KL_DBG_IRQ, "error : wakeup\n");

        if (MS(ERROR_INT_STATUS_RX_UNDERFLOW, error_int_status))
                ath6kl_err("rx underflow\n");

        if (MS(ERROR_INT_STATUS_TX_OVERFLOW, error_int_status))
                ath6kl_err("tx overflow\n");

        /* Clear the interrupt */
        dev->irq_proc_reg.error_int_status &= ~error_int_status;

        /* set W1C value to clear the interrupt, this hits the register first */
        reg_buf[0] = error_int_status;
        reg_buf[1] = 0;
        reg_buf[2] = 0;
        reg_buf[3] = 0;

        status = hif_read_write_sync(dev->ar, ERROR_INT_STATUS_ADDRESS,
                                     reg_buf, 4, HIF_WR_SYNC_BYTE_FIX);

        if (status)
                WARN_ON(1);

        return status;
}

static int ath6kl_hif_proc_cpu_intr(struct ath6kl_device *dev)
{
        int status;
        u8 cpu_int_status;
        u8 reg_buf[4];

        ath6kl_dbg(ATH6KL_DBG_IRQ, "cpu interrupt\n");

        cpu_int_status = dev->irq_proc_reg.cpu_int_status &
                         dev->irq_en_reg.cpu_int_status_en;
        if (!cpu_int_status) {
                WARN_ON(1);
                return -EIO;
        }

        ath6kl_dbg(ATH6KL_DBG_IRQ,
                "valid interrupt source(s) in CPU_INT_STATUS: 0x%x\n",
                cpu_int_status);

        /* Clear the interrupt */
        dev->irq_proc_reg.cpu_int_status &= ~cpu_int_status;

        /*
         * Set up the register transfer buffer to hit the register 4 times ,
         * this is done to make the access 4-byte aligned to mitigate issues
         * with host bus interconnects that restrict bus transfer lengths to
         * be a multiple of 4-bytes.
         */

        /* set W1C value to clear the interrupt, this hits the register first */
        reg_buf[0] = cpu_int_status;
        /* the remaining are set to zero which have no-effect  */
        reg_buf[1] = 0;
        reg_buf[2] = 0;
        reg_buf[3] = 0;

        status = hif_read_write_sync(dev->ar, CPU_INT_STATUS_ADDRESS,
                                     reg_buf, 4, HIF_WR_SYNC_BYTE_FIX);

        if (status)
                WARN_ON(1);

        return status;
}

/* process pending interrupts synchronously */
static int proc_pending_irqs(struct ath6kl_device *dev, bool *done)
{
        struct ath6kl_irq_proc_registers *rg;
        int status = 0;
        u8 host_int_status = 0;
        u32 lk_ahd = 0;
        u8 htc_mbox = 1 << HTC_MAILBOX;

        ath6kl_dbg(ATH6KL_DBG_IRQ, "proc_pending_irqs: (dev: 0x%p)\n", dev);

        /*
         * NOTE: HIF implementation guarantees that the context of this
         * call allows us to perform SYNCHRONOUS I/O, that is we can block,
         * sleep or call any API that can block or switch thread/task
         * contexts. This is a fully schedulable context.
         */

        /*
         * Process pending intr only when int_status_en is clear, it may
         * result in unnecessary bus transaction otherwise. Target may be
         * unresponsive at the time.
         */
        if (dev->irq_en_reg.int_status_en) {
                /*
                 * Read the first 28 bytes of the HTC register table. This
                 * will yield us the value of different int status
                 * registers and the lookahead registers.
                 *
                 *    length = sizeof(int_status) + sizeof(cpu_int_status)
                 *             + sizeof(error_int_status) +
                 *             sizeof(counter_int_status) +
                 *             sizeof(mbox_frame) + sizeof(rx_lkahd_valid)
                 *             + sizeof(hole) + sizeof(rx_lkahd) +
                 *             sizeof(int_status_en) +
                 *             sizeof(cpu_int_status_en) +
                 *             sizeof(err_int_status_en) +
                 *             sizeof(cntr_int_status_en);
                 */
                status = hif_read_write_sync(dev->ar, HOST_INT_STATUS_ADDRESS,
                                             (u8 *) &dev->irq_proc_reg,
                                             sizeof(dev->irq_proc_reg),
                                             HIF_RD_SYNC_BYTE_INC);
                if (status)
                        goto out;

                if (AR_DBG_LVL_CHECK(ATH6KL_DBG_IRQ))
                        ath6kl_dump_registers(dev, &dev->irq_proc_reg,
                                         &dev->irq_en_reg);

                /* Update only those registers that are enabled */
                host_int_status = dev->irq_proc_reg.host_int_status &
                                  dev->irq_en_reg.int_status_en;

                /* Look at mbox status */
                if (host_int_status & htc_mbox) {
                        /*
                         * Mask out pending mbox value, we use "lookAhead as
                         * the real flag for mbox processing.
                         */
                        host_int_status &= ~htc_mbox;
                        if (dev->irq_proc_reg.rx_lkahd_valid &
                            htc_mbox) {
                                rg = &dev->irq_proc_reg;
                                lk_ahd = le32_to_cpu(rg->rx_lkahd[HTC_MAILBOX]);
                                if (!lk_ahd)
                                        ath6kl_err("lookAhead is zero!\n");
                        }
                }
        }

        if (!host_int_status && !lk_ahd) {
                *done = true;
                goto out;
        }

        if (lk_ahd) {
                int fetched = 0;

                ath6kl_dbg(ATH6KL_DBG_IRQ,
                           "pending mailbox msg, lk_ahd: 0x%X\n", lk_ahd);
                /*
                 * Mailbox Interrupt, the HTC layer may issue async
                 * requests to empty the mailbox. When emptying the recv
                 * mailbox we use the async handler above called from the
                 * completion routine of the callers read request. This can
                 * improve performance by reducing context switching when
                 * we rapidly pull packets.
                 */
                status = ath6kl_htc_rxmsg_pending_handler(dev->htc_cnxt,
                                                          lk_ahd, &fetched);
                if (status)
                        goto out;

                if (!fetched)
                        /*
                         * HTC could not pull any messages out due to lack
                         * of resources.
                         */
                        dev->htc_cnxt->chk_irq_status_cnt = 0;
        }

        /* now handle the rest of them */
        ath6kl_dbg(ATH6KL_DBG_IRQ,
                   "valid interrupt source(s) for other interrupts: 0x%x\n",
                   host_int_status);

        if (MS(HOST_INT_STATUS_CPU, host_int_status)) {
                /* CPU Interrupt */
                status = ath6kl_hif_proc_cpu_intr(dev);
                if (status)
                        goto out;
        }

        if (MS(HOST_INT_STATUS_ERROR, host_int_status)) {
                /* Error Interrupt */
                status = ath6kl_hif_proc_err_intr(dev);
                if (status)
                        goto out;
        }

        if (MS(HOST_INT_STATUS_COUNTER, host_int_status))
                /* Counter Interrupt */
                status = ath6kl_hif_proc_counter_intr(dev);

out:
        /*
         * An optimization to bypass reading the IRQ status registers
         * unecessarily which can re-wake the target, if upper layers
         * determine that we are in a low-throughput mode, we can rely on
         * taking another interrupt rather than re-checking the status
         * registers which can re-wake the target.
         *
         * NOTE : for host interfaces that makes use of detecting pending
         * mbox messages at hif can not use this optimization due to
         * possible side effects, SPI requires the host to drain all
         * messages from the mailbox before exiting the ISR routine.
         */

        ath6kl_dbg(ATH6KL_DBG_IRQ,
                   "bypassing irq status re-check, forcing done\n");

        if (!dev->htc_cnxt->chk_irq_status_cnt)
                *done = true;

        ath6kl_dbg(ATH6KL_DBG_IRQ,
                   "proc_pending_irqs: (done:%d, status=%d\n", *done, status);

        return status;
}

/* interrupt handler, kicks off all interrupt processing */
int ath6kl_hif_intr_bh_handler(struct ath6kl *ar)
{
        struct ath6kl_device *dev = ar->htc_target->dev;
        unsigned long timeout;
        int status = 0;
        bool done = false;

        /*
         * Reset counter used to flag a re-scan of IRQ status registers on
         * the target.
         */
        dev->htc_cnxt->chk_irq_status_cnt = 0;

        /*
         * IRQ processing is synchronous, interrupt status registers can be
         * re-read.
         */
        timeout = jiffies + msecs_to_jiffies(ATH6KL_HIF_COMMUNICATION_TIMEOUT);
        while (time_before(jiffies, timeout) && !done) {
                status = proc_pending_irqs(dev, &done);
                if (status)
                        break;
        }

        return status;
}

static int ath6kl_hif_enable_intrs(struct ath6kl_device *dev)
{
        struct ath6kl_irq_enable_reg regs;
        int status;

        spin_lock_bh(&dev->lock);

        /* Enable all but ATH6KL CPU interrupts */
        dev->irq_en_reg.int_status_en =
                        SM(INT_STATUS_ENABLE_ERROR, 0x01) |
                        SM(INT_STATUS_ENABLE_CPU, 0x01) |
                        SM(INT_STATUS_ENABLE_COUNTER, 0x01);

        /*
         * NOTE: There are some cases where HIF can do detection of
         * pending mbox messages which is disabled now.
         */
        dev->irq_en_reg.int_status_en |= SM(INT_STATUS_ENABLE_MBOX_DATA, 0x01);

        /* Set up the CPU Interrupt status Register */
        dev->irq_en_reg.cpu_int_status_en = 0;

        /* Set up the Error Interrupt status Register */
        dev->irq_en_reg.err_int_status_en =
                SM(ERROR_STATUS_ENABLE_RX_UNDERFLOW, 0x01) |
                SM(ERROR_STATUS_ENABLE_TX_OVERFLOW, 0x1);

        /*
         * Enable Counter interrupt status register to get fatal errors for
         * debugging.
         */
        dev->irq_en_reg.cntr_int_status_en = SM(COUNTER_INT_STATUS_ENABLE_BIT,
                                                ATH6KL_TARGET_DEBUG_INTR_MASK);
        memcpy(&regs, &dev->irq_en_reg, sizeof(regs));

        spin_unlock_bh(&dev->lock);

        status = hif_read_write_sync(dev->ar, INT_STATUS_ENABLE_ADDRESS,
                                     &regs.int_status_en, sizeof(regs),
                                     HIF_WR_SYNC_BYTE_INC);

        if (status)
                ath6kl_err("failed to update interrupt ctl reg err: %d\n",
                           status);

        return status;
}

int ath6kl_hif_disable_intrs(struct ath6kl_device *dev)
{
        struct ath6kl_irq_enable_reg regs;

        spin_lock_bh(&dev->lock);
        /* Disable all interrupts */
        dev->irq_en_reg.int_status_en = 0;
        dev->irq_en_reg.cpu_int_status_en = 0;
        dev->irq_en_reg.err_int_status_en = 0;
        dev->irq_en_reg.cntr_int_status_en = 0;
        memcpy(&regs, &dev->irq_en_reg, sizeof(regs));
        spin_unlock_bh(&dev->lock);

        return hif_read_write_sync(dev->ar, INT_STATUS_ENABLE_ADDRESS,
                                   &regs.int_status_en, sizeof(regs),
                                   HIF_WR_SYNC_BYTE_INC);
}

/* enable device interrupts */
int ath6kl_hif_unmask_intrs(struct ath6kl_device *dev)
{
        int status = 0;

        /*
         * Make sure interrupt are disabled before unmasking at the HIF
         * layer. The rationale here is that between device insertion
         * (where we clear the interrupts the first time) and when HTC
         * is finally ready to handle interrupts, other software can perform
         * target "soft" resets. The ATH6KL interrupt enables reset back to an
         * "enabled" state when this happens.
         */
        ath6kl_hif_disable_intrs(dev);

        /* unmask the host controller interrupts */
        ath6kl_hif_irq_enable(dev->ar);
        status = ath6kl_hif_enable_intrs(dev);

        return status;
}

/* disable all device interrupts */
int ath6kl_hif_mask_intrs(struct ath6kl_device *dev)
{
        /*
         * Mask the interrupt at the HIF layer to avoid any stray interrupt
         * taken while we zero out our shadow registers in
         * ath6kl_hif_disable_intrs().
         */
        ath6kl_hif_irq_disable(dev->ar);

        return ath6kl_hif_disable_intrs(dev);
}

int ath6kl_hif_setup(struct ath6kl_device *dev)
{
        int status = 0;

        spin_lock_init(&dev->lock);

        /*
         * NOTE: we actually get the block size of a mailbox other than 0,
         * for SDIO the block size on mailbox 0 is artificially set to 1.
         * So we use the block size that is set for the other 3 mailboxes.
         */
        dev->htc_cnxt->block_sz = dev->ar->mbox_info.block_size;

        /* must be a power of 2 */
        if ((dev->htc_cnxt->block_sz & (dev->htc_cnxt->block_sz - 1)) != 0) {
                WARN_ON(1);
                status = -EINVAL;
                goto fail_setup;
        }

        /* assemble mask, used for padding to a block */
        dev->htc_cnxt->block_mask = dev->htc_cnxt->block_sz - 1;

        ath6kl_dbg(ATH6KL_DBG_HIF, "hif block size %d mbox addr 0x%x\n",
                   dev->htc_cnxt->block_sz, dev->ar->mbox_info.htc_addr);

        status = ath6kl_hif_disable_intrs(dev);

fail_setup:
        return status;

}