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dmaengine: mv_xor_v2: implement proper interrupt coalescing 

Until now, the driver was not using interrupt coalescing: one interrupt
was generated for each descriptor processed by the XOR engine. This
commit changes that by using the interrupt coalescing features of the
hardware, by setting both a number of descriptors processed before an
interrupt is generated and a timeout before an interrupt is generated.

Signed-off-by: Hanna Hawa <hannah@marvell.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
hifive-unleashed-5.1
Hanna Hawa 2017-05-05 11:57:51 +02:00 committed by Vinod Koul
parent b2d3c270f9
commit d793327fac
1 changed files with 36 additions and 0 deletions
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36
drivers/dma/mv_xor_v2.c
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@ -42,6 +42,7 @@
#define MV_XOR_V2_DMA_IMSG_THRD_OFF 0x018
#define MV_XOR_V2_DMA_IMSG_THRD_MASK 0x7FFF
#define MV_XOR_V2_DMA_IMSG_THRD_SHIFT 0x0
#define MV_XOR_V2_DMA_IMSG_TIMER_EN BIT(18)
#define MV_XOR_V2_DMA_DESQ_AWATTR_OFF 0x01C
/* Same flags as MV_XOR_V2_DMA_DESQ_ARATTR_OFF */
#define MV_XOR_V2_DMA_DESQ_ALLOC_OFF 0x04C
@ -55,6 +56,9 @@
#define MV_XOR_V2_DMA_DESQ_STOP_OFF 0x800
#define MV_XOR_V2_DMA_DESQ_DEALLOC_OFF 0x804
#define MV_XOR_V2_DMA_DESQ_ADD_OFF 0x808
#define MV_XOR_V2_DMA_IMSG_TMOT 0x810
#define MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK 0x1FFF
#define MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT 0
/* XOR Global registers */
#define MV_XOR_V2_GLOB_BW_CTRL 0x4
@ -90,6 +94,13 @@
*/
#define MV_XOR_V2_DESC_NUM 1024
/*
* Threshold values for descriptors and timeout, determined by
* experimentation as giving a good level of performance.
*/
#define MV_XOR_V2_DONE_IMSG_THRD 0x14
#define MV_XOR_V2_TIMER_THRD 0xB0
/**
* struct mv_xor_v2_descriptor - DMA HW descriptor
* @desc_id: used by S/W and is not affected by H/W.
@ -246,6 +257,29 @@ static int mv_xor_v2_set_desc_size(struct mv_xor_v2_device *xor_dev)
return MV_XOR_V2_EXT_DESC_SIZE;
}
/*
* Set the IMSG threshold
*/
static inline
void mv_xor_v2_enable_imsg_thrd(struct mv_xor_v2_device *xor_dev)
{
u32 reg;
/* Configure threshold of number of descriptors, and enable timer */
reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << MV_XOR_V2_DMA_IMSG_THRD_SHIFT);
reg |= (MV_XOR_V2_DONE_IMSG_THRD << MV_XOR_V2_DMA_IMSG_THRD_SHIFT);
reg |= MV_XOR_V2_DMA_IMSG_TIMER_EN;
writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
/* Configure Timer Threshold */
reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT);
reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK <<
MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT);
reg |= (MV_XOR_V2_TIMER_THRD << MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT);
writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT);
}
static irqreturn_t mv_xor_v2_interrupt_handler(int irq, void *data)
{
struct mv_xor_v2_device *xor_dev = data;
@ -795,6 +829,8 @@ static int mv_xor_v2_probe(struct platform_device *pdev)
list_add_tail(&xor_dev->dmachan.device_node,
&dma_dev->channels);
mv_xor_v2_enable_imsg_thrd(xor_dev);
mv_xor_v2_descq_init(xor_dev);
ret = dma_async_device_register(dma_dev);