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Subject[PATCH v3 5/5] mailbox: bcm-flexrm-mailbox: Use txdone_ack instead of txdone_poll
Date
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>
---
drivers/mailbox/bcm-flexrm-mailbox.c | 61 +++---------------------------------
1 file changed, 4 insertions(+), 57 deletions(-)

diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c
index 9873818..ae61463 100644
--- 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 @@ static int flexrm_mbox_probe(struct platform_device *pdev)

/* 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;
--
2.7.4
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