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Subject[PATCH v3 4/5] mailbox: bcm-flexrm-mailbox: Use bitmap instead of IDA
Date
Currently, we are using IDA library for managing IDs
on a FlexRM ring. The IDA library dynamically allocates
memory for underlying data structures which can cause
potential locking issue when allocating/free IDs from
flexrm_new_request() and flexrm_process_completions().

To tackle this, we replace use of IDA with bitmap for
each FlexRM ring and also protect the bitmap with FlexRM
ring lock.

Signed-off-by: Anup Patel <anup.patel@broadcom.com>
---
drivers/mailbox/bcm-flexrm-mailbox.c | 36 +++++++++++++++++++-----------------
1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c
index 46ad305..9873818 100644
--- a/drivers/mailbox/bcm-flexrm-mailbox.c
+++ b/drivers/mailbox/bcm-flexrm-mailbox.c
@@ -18,13 +18,13 @@
#include <asm/barrier.h>
#include <asm/byteorder.h>
#include <linux/atomic.h>
+#include <linux/bitmap.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/err.h>
-#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mailbox_controller.h>
@@ -265,7 +265,6 @@ struct flexrm_ring {
cpumask_t irq_aff_hint;
unsigned int msi_timer_val;
unsigned int msi_count_threshold;
- struct ida requests_ida;
struct brcm_message *requests[RING_MAX_REQ_COUNT];
void *bd_base;
dma_addr_t bd_dma_base;
@@ -277,6 +276,7 @@ struct flexrm_ring {
atomic_t msg_cmpl_count;
/* Protected members */
spinlock_t lock;
+ DECLARE_BITMAP(requests_bmap, RING_MAX_REQ_COUNT);
struct brcm_message *last_pending_msg;
u32 cmpl_read_offset;
};
@@ -994,10 +994,10 @@ static int flexrm_new_request(struct flexrm_ring *ring,
msg->error = 0;

/* If no requests possible then save data pointer and goto done. */
- reqid = ida_simple_get(&ring->requests_ida, 0,
- RING_MAX_REQ_COUNT, GFP_KERNEL);
+ spin_lock_irqsave(&ring->lock, flags);
+ reqid = bitmap_find_free_region(ring->requests_bmap,
+ RING_MAX_REQ_COUNT, 0);
if (reqid < 0) {
- spin_lock_irqsave(&ring->lock, flags);
if (batch_msg)
ring->last_pending_msg = batch_msg;
else
@@ -1005,13 +1005,16 @@ static int flexrm_new_request(struct flexrm_ring *ring,
spin_unlock_irqrestore(&ring->lock, flags);
return 0;
}
+ spin_unlock_irqrestore(&ring->lock, flags);
ring->requests[reqid] = msg;

/* Do DMA mappings for the message */
ret = flexrm_dma_map(ring->mbox->dev, msg);
if (ret < 0) {
ring->requests[reqid] = NULL;
- ida_simple_remove(&ring->requests_ida, reqid);
+ spin_lock_irqsave(&ring->lock, flags);
+ bitmap_release_region(ring->requests_bmap, reqid, 0);
+ spin_unlock_irqrestore(&ring->lock, flags);
return ret;
}

@@ -1088,7 +1091,9 @@ static int flexrm_new_request(struct flexrm_ring *ring,
if (exit_cleanup) {
flexrm_dma_unmap(ring->mbox->dev, msg);
ring->requests[reqid] = NULL;
- ida_simple_remove(&ring->requests_ida, reqid);
+ spin_lock_irqsave(&ring->lock, flags);
+ bitmap_release_region(ring->requests_bmap, reqid, 0);
+ spin_unlock_irqrestore(&ring->lock, flags);
}

return ret;
@@ -1163,7 +1168,9 @@ static int flexrm_process_completions(struct flexrm_ring *ring)

/* Release reqid for recycling */
ring->requests[reqid] = NULL;
- ida_simple_remove(&ring->requests_ida, reqid);
+ spin_lock_irqsave(&ring->lock, flags);
+ bitmap_release_region(ring->requests_bmap, reqid, 0);
+ spin_unlock_irqrestore(&ring->lock, flags);

/* Unmap DMA mappings */
flexrm_dma_unmap(ring->mbox->dev, msg);
@@ -1414,7 +1421,6 @@ static void flexrm_shutdown(struct mbox_chan *chan)

/* Release reqid for recycling */
ring->requests[reqid] = NULL;
- ida_simple_remove(&ring->requests_ida, reqid);

/* Unmap DMA mappings */
flexrm_dma_unmap(ring->mbox->dev, msg);
@@ -1424,6 +1430,9 @@ static void flexrm_shutdown(struct mbox_chan *chan)
mbox_chan_received_data(chan, msg);
}

+ /* Clear requests bitmap */
+ bitmap_zero(ring->requests_bmap, RING_MAX_REQ_COUNT);
+
/* Release IRQ */
if (ring->irq_requested) {
irq_set_affinity_hint(ring->irq, NULL);
@@ -1581,7 +1590,6 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
ring->irq_requested = false;
ring->msi_timer_val = MSI_TIMER_VAL_MASK;
ring->msi_count_threshold = 0x1;
- ida_init(&ring->requests_ida);
memset(ring->requests, 0, sizeof(ring->requests));
ring->bd_base = NULL;
ring->bd_dma_base = 0;
@@ -1590,6 +1598,7 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
atomic_set(&ring->msg_send_count, 0);
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;
}
@@ -1701,9 +1710,7 @@ static int flexrm_mbox_probe(struct platform_device *pdev)

static int flexrm_mbox_remove(struct platform_device *pdev)
{
- int index;
struct device *dev = &pdev->dev;
- struct flexrm_ring *ring;
struct flexrm_mbox *mbox = platform_get_drvdata(pdev);

mbox_controller_unregister(&mbox->controller);
@@ -1715,11 +1722,6 @@ static int flexrm_mbox_remove(struct platform_device *pdev)
dma_pool_destroy(mbox->cmpl_pool);
dma_pool_destroy(mbox->bd_pool);

- for (index = 0; index < mbox->num_rings; index++) {
- ring = &mbox->rings[index];
- ida_destroy(&ring->requests_ida);
- }
-
return 0;
}

--
2.7.4
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