mailbox: bcm-flexrm-mailbox: Use txdone_ack instead of txdone_poll

Currently, FlexRM driver uses txdone_poll method of Linux Mailbox
to model the send_data() callback. To achieve this, we have introduced
"last_pending_msg" pointer for each FlexRM ring which keeps track of
the message that did not fit in the FlexRM ring.

This patch updates FlexRM driver to use txdone_ack method instead of
txdone_poll method because txdone_poll is not efficient for FlexRM
and requires additional tracking in FlexRM driver.

Also, moving to txdone_ack method helps us remove "last_pending_msg"
pointer and last_tx_done() callback.

Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c
index 9873818..ae61463 100644 (file)
--- a/drivers/mailbox/bcm-flexrm-mailbox.c
+++ b/drivers/mailbox/bcm-flexrm-mailbox.c
@@ -277,7 +277,6 @@ struct flexrm_ring {
        /* Protected members */
        spinlock_t lock;
        DECLARE_BITMAP(requests_bmap, RING_MAX_REQ_COUNT);
-       struct brcm_message *last_pending_msg;
        u32 cmpl_read_offset;
 };
 
@@ -997,15 +996,9 @@ static int flexrm_new_request(struct flexrm_ring *ring,
        spin_lock_irqsave(&ring->lock, flags);
        reqid = bitmap_find_free_region(ring->requests_bmap,
                                        RING_MAX_REQ_COUNT, 0);
-       if (reqid < 0) {
-               if (batch_msg)
-                       ring->last_pending_msg = batch_msg;
-               else
-                       ring->last_pending_msg = msg;
-               spin_unlock_irqrestore(&ring->lock, flags);
-               return 0;
-       }
        spin_unlock_irqrestore(&ring->lock, flags);
+       if (reqid < 0)
+               return -ENOSPC;
        ring->requests[reqid] = msg;
 
        /* Do DMA mappings for the message */
@@ -1018,17 +1011,6 @@ static int flexrm_new_request(struct flexrm_ring *ring,
                return ret;
        }
 
-       /* If last_pending_msg is already set then goto done with error */
-       spin_lock_irqsave(&ring->lock, flags);
-       if (ring->last_pending_msg)
-               ret = -ENOSPC;
-       spin_unlock_irqrestore(&ring->lock, flags);
-       if (ret < 0) {
-               dev_warn(ring->mbox->dev, "no space in ring %d\n", ring->num);
-               exit_cleanup = true;
-               goto exit;
-       }
-
        /* Determine current HW BD read offset */
        read_offset = readl_relaxed(ring->regs + RING_BD_READ_PTR);
        val = readl_relaxed(ring->regs + RING_BD_START_ADDR);
@@ -1055,13 +1037,7 @@ static int flexrm_new_request(struct flexrm_ring *ring,
                        break;
        }
        if (count) {
-               spin_lock_irqsave(&ring->lock, flags);
-               if (batch_msg)
-                       ring->last_pending_msg = batch_msg;
-               else
-                       ring->last_pending_msg = msg;
-               spin_unlock_irqrestore(&ring->lock, flags);
-               ret = 0;
+               ret = -ENOSPC;
                exit_cleanup = true;
                goto exit;
        }
@@ -1110,12 +1086,6 @@ static int flexrm_process_completions(struct flexrm_ring *ring)
 
        spin_lock_irqsave(&ring->lock, flags);
 
-       /* Check last_pending_msg */
-       if (ring->last_pending_msg) {
-               msg = ring->last_pending_msg;
-               ring->last_pending_msg = NULL;
-       }
-
        /*
         * Get current completion read and write offset
         *
@@ -1131,10 +1101,6 @@ static int flexrm_process_completions(struct flexrm_ring *ring)
 
        spin_unlock_irqrestore(&ring->lock, flags);
 
-       /* If last_pending_msg was set then queue it back */
-       if (msg)
-               mbox_send_message(chan, msg);
-
        /* For each completed request notify mailbox clients */
        reqid = 0;
        while (cmpl_read_offset != cmpl_write_offset) {
@@ -1345,9 +1311,6 @@ static int flexrm_startup(struct mbox_chan *chan)
        val = CMPL_START_ADDR_VALUE(ring->cmpl_dma_base);
        writel_relaxed(val, ring->regs + RING_CMPL_START_ADDR);
 
-       /* Ensure last pending message is cleared */
-       ring->last_pending_msg = NULL;
-
        /* Completion read pointer will be same as HW write pointer */
        ring->cmpl_read_offset =
                        readl_relaxed(ring->regs + RING_CMPL_WRITE_PTR);
@@ -1455,24 +1418,10 @@ static void flexrm_shutdown(struct mbox_chan *chan)
        }
 }
 
-static bool flexrm_last_tx_done(struct mbox_chan *chan)
-{
-       bool ret;
-       unsigned long flags;
-       struct flexrm_ring *ring = chan->con_priv;
-
-       spin_lock_irqsave(&ring->lock, flags);
-       ret = (ring->last_pending_msg) ? false : true;
-       spin_unlock_irqrestore(&ring->lock, flags);
-
-       return ret;
-}
-
 static const struct mbox_chan_ops flexrm_mbox_chan_ops = {
        .send_data      = flexrm_send_data,
        .startup        = flexrm_startup,
        .shutdown       = flexrm_shutdown,
-       .last_tx_done   = flexrm_last_tx_done,
        .peek_data      = flexrm_peek_data,
 };
 
@@ -1599,7 +1548,6 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
                atomic_set(&ring->msg_cmpl_count, 0);
                spin_lock_init(&ring->lock);
                bitmap_zero(ring->requests_bmap, RING_MAX_REQ_COUNT);
-               ring->last_pending_msg = NULL;
                ring->cmpl_read_offset = 0;
        }
 
@@ -1671,8 +1619,7 @@ skip_debugfs:
 
        /* Initialize mailbox controller */
        mbox->controller.txdone_irq = false;
-       mbox->controller.txdone_poll = true;
-       mbox->controller.txpoll_period = 1;
+       mbox->controller.txdone_poll = false;
        mbox->controller.ops = &flexrm_mbox_chan_ops;
        mbox->controller.dev = dev;
        mbox->controller.num_chans = mbox->num_rings;