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dmaengine: mv_xor_v2: fix tx_submit() implementation

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The mv_xor_v2_tx_submit() gets the next available HW descriptor by
calling mv_xor_v2_get_desq_write_ptr(), which reads a HW register
telling the next available HW descriptor. This was working fine when HW
descriptors were issued for processing directly in tx_submit().

However, as part of the review process of the driver, a change was
requested to move the actual kick-off of HW descriptors processing to
->issue_pending(). Due to this, reading the HW register to know the next
available HW descriptor no longer works.

So instead of using this HW register, we implemented a software index
pointing to the next available HW descriptor.

Fixes: 19a340b1a8 ("dmaengine: mv_xor_v2: new driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Thomas Petazzoni 2017-05-05 11:57:48 +02:00 committed by Vinod Koul
parent ab2c5f0a77
commit 44d5887a8b
1 changed files with 5 additions and 17 deletions
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22
drivers/dma/mv_xor_v2.c
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@ -161,6 +161,7 @@ struct mv_xor_v2_device {
struct mv_xor_v2_sw_desc *sw_desq;
int desc_size;
unsigned int npendings;
unsigned int hw_queue_idx;
};
/**
@ -213,18 +214,6 @@ static void mv_xor_v2_set_data_buffers(struct mv_xor_v2_device *xor_dev,
}
}
/*
* Return the next available index in the DESQ.
*/
static int mv_xor_v2_get_desq_write_ptr(struct mv_xor_v2_device *xor_dev)
{
/* read the index for the next available descriptor in the DESQ */
u32 reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ALLOC_OFF);
return ((reg >> MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_SHIFT)
& MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_MASK);
}
/*
* notify the engine of new descriptors, and update the available index.
*/
@ -306,7 +295,6 @@ static irqreturn_t mv_xor_v2_interrupt_handler(int irq, void *data)
static dma_cookie_t
mv_xor_v2_tx_submit(struct dma_async_tx_descriptor *tx)
{
int desq_ptr;
void *dest_hw_desc;
dma_cookie_t cookie;
struct mv_xor_v2_sw_desc *sw_desc =
@ -322,15 +310,15 @@ mv_xor_v2_tx_submit(struct dma_async_tx_descriptor *tx)
spin_lock_bh(&xor_dev->lock);
cookie = dma_cookie_assign(tx);
/* get the next available slot in the DESQ */
desq_ptr = mv_xor_v2_get_desq_write_ptr(xor_dev);
/* copy the HW descriptor from the SW descriptor to the DESQ */
dest_hw_desc = xor_dev->hw_desq_virt + desq_ptr;
dest_hw_desc = xor_dev->hw_desq_virt + xor_dev->hw_queue_idx;
memcpy(dest_hw_desc, &sw_desc->hw_desc, xor_dev->desc_size);
xor_dev->npendings++;
xor_dev->hw_queue_idx++;
if (xor_dev->hw_queue_idx >= MV_XOR_V2_DESC_NUM)
xor_dev->hw_queue_idx = 0;
spin_unlock_bh(&xor_dev->lock);