From: Hanna Hawa <hannah@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
---
drivers/dma/mv_xor_v2.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c
index f3e211f..5292ff2 100644
--- a/drivers/dma/mv_xor_v2.c
+++ b/drivers/dma/mv_xor_v2.c
@@ -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);
--
2.7.4
--
To unsubscribe from this list: send the line "unsubscribe dmaengine" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
