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Re: [PATCH v3 4/4] dmaengine: xilinx_vdma: Use readl_poll_timeout instead of do while loop's

From Vinod Koul <vinod.koul@intel.com>
Newsgroups linux.kernel
Subject Re: [PATCH v3 4/4] dmaengine: xilinx_vdma: Use readl_poll_timeout instead of do while loop's
Date 2016-03-03 16:30 +0100
Message-ID <r8Dmp-ux-3@gated-at.bofh.it> (permalink)
References <r6rfH-4re-3@gated-at.bofh.it> <r6rfI-4re-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Fri, Feb 26, 2016 at 07:33:54PM +0530, Kedareswara rao Appana wrote:

>  static void xilinx_vdma_halt(struct xilinx_vdma_chan *chan)
>  {
> -	int loop = XILINX_VDMA_LOOP_COUNT;
> +	int err = 0;
> +	u32 val;
>  
>  	vdma_ctrl_clr(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);
>  
>  	/* Wait for the hardware to halt */
> -	do {
> -		if (vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
> -		    XILINX_VDMA_DMASR_HALTED)
> -			break;
> -	} while (loop--);
> +	err = xilinx_vdma_poll_timeout(chan, XILINX_VDMA_REG_DMASR, val,
> +				      (val & XILINX_VDMA_DMASR_HALTED), 0,
> +				      XILINX_VDMA_LOOP_COUNT);
>  
> -	if (!loop) {
> +	if (err) {
>  		dev_err(chan->dev, "Cannot stop channel %p: %x\n",
>  			chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
>  		chan->err = true;
> @@ -576,18 +579,17 @@ static void xilinx_vdma_halt(struct xilinx_vdma_chan *chan)
>   */
>  static void xilinx_vdma_start(struct xilinx_vdma_chan *chan)
>  {
> -	int loop = XILINX_VDMA_LOOP_COUNT;
> +	int err = 0;

why is this initialization required here and other places?

> +	u32 val;
>  
>  	vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);
>  
>  	/* Wait for the hardware to start */
> -	do {
> -		if (!(vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
> -		      XILINX_VDMA_DMASR_HALTED))
> -			break;
> -	} while (loop--);
> +	err = xilinx_vdma_poll_timeout(chan, XILINX_VDMA_REG_DMASR, val,
> +				      !(val & XILINX_VDMA_DMASR_HALTED), 0,
> +				      XILINX_VDMA_LOOP_COUNT);
>  
> -	if (!loop) {
> +	if (err) {
>  		dev_err(chan->dev, "Cannot start channel %p: %x\n",
>  			chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
>  
> @@ -754,21 +756,17 @@ static void xilinx_vdma_complete_descriptor(struct xilinx_vdma_chan *chan)
>   */
>  static int xilinx_vdma_reset(struct xilinx_vdma_chan *chan)
>  {
> -	int loop = XILINX_VDMA_LOOP_COUNT;
> +	int err = 0;
>  	u32 tmp;
>  
>  	vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RESET);
>  
> -	tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
> -		XILINX_VDMA_DMACR_RESET;
> -
>  	/* Wait for the hardware to finish reset */
> -	do {
> -		tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
> -			XILINX_VDMA_DMACR_RESET;
> -	} while (loop-- && tmp);
> +	err = xilinx_vdma_poll_timeout(chan, XILINX_VDMA_REG_DMACR, tmp,
> +				      !(tmp & XILINX_VDMA_DMACR_RESET), 0,
> +				      XILINX_VDMA_LOOP_COUNT);
>  
> -	if (!loop) {
> +	if (err) {



-- 
~Vinod

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Thread

[PATCH v3 4/4] dmaengine: xilinx_vdma: Use readl_poll_timeout instead of do while loop's Kedareswara rao Appana <appana.durga.rao@xilinx.com> - 2016-02-26 15:10 +0100
  Re: [PATCH v3 4/4] dmaengine: xilinx_vdma: Use readl_poll_timeout  instead of do while loop's Vinod Koul <vinod.koul@intel.com> - 2016-03-03 16:30 +0100
    RE: [PATCH v3 4/4] dmaengine: xilinx_vdma: Use readl_poll_timeout  instead of do while loop's Appana Durga Kedareswara Rao <appana.durga.rao@xilinx.com> - 2016-03-03 18:30 +0100

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