From d793327fac3a9292edfdcee0ab6c29e4fdd08d65 Mon Sep 17 00:00:00 2001 From: Hanna Hawa Date: Fri, 5 May 2017 11:57:51 +0200 Subject: [PATCH] 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 Signed-off-by: Thomas Petazzoni Signed-off-by: Vinod Koul --- 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 f3e211f8f6c5..5292ff2d5380 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);