[PATCH v4 12/16] mtd: onenand: omap2: Enable DMA by default

[Roger Quadros]

Hi,

On 11/11/17 23:24, Ladislav Michl wrote:
> DMA and R/B pin are independent on each other. Use DMA by default.

Is there a R/B pin on Onenand? It looks more like it has a RDY pin and
an INT pin (which is used for command completion interrupt).

I think the subject and message are a bit misleading.

It should be something like

mtd: onenand: omap2: decouple DMA enabling from INT pin availability

INT pin (gpio_irq) is not really needed for DMA but only for notification
when a command that needs wait has completed. We can still have DMA
even without gpio_irq available.

> 
> Signed-off-by: Ladislav Michl <ladis at linux-mips.org>
> ---
>  Changes:
>  -v4: new patch
> 
>  drivers/mtd/onenand/omap2.c | 41 +++++++++++++++++------------------------
>  1 file changed, 17 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/mtd/onenand/omap2.c b/drivers/mtd/onenand/omap2.c
> index e4857a41760d..62e4ede918c4 100644
> --- a/drivers/mtd/onenand/omap2.c
> +++ b/drivers/mtd/onenand/omap2.c
> @@ -152,17 +152,13 @@ static int omap2_onenand_wait(struct mtd_info *mtd, int state)
>  		}
>  
>  		reinit_completion(&c->irq_done);
> -		if (c->gpio_irq) {
> -			result = gpio_get_value(c->gpio_irq);
> -			if (result == -1) {
> -				ctrl = read_reg(c, ONENAND_REG_CTRL_STATUS);
> -				intr = read_reg(c, ONENAND_REG_INTERRUPT);
> -				wait_err("gpio error", state, ctrl, intr);
> -				return -EIO;
> -			}
> -		} else
> -			result = 0;
> -		if (result == 0) {
> +		result = gpio_get_value(c->gpio_irq);
> +		if (result < 0) {
> +			ctrl = read_reg(c, ONENAND_REG_CTRL_STATUS);
> +			intr = read_reg(c, ONENAND_REG_INTERRUPT);
> +			wait_err("gpio error", state, ctrl, intr);
> +			return -EIO;
> +		} else if (result == 0) {
>  			int retry_cnt = 0;
>  retry:
>  			if (!wait_for_completion_io_timeout(&c->irq_done,
> @@ -513,13 +509,15 @@ static int omap2_onenand_probe(struct platform_device *pdev)

We need to get rid if this code from probe.

        if (pdata->dma_channel < 0) {
                /* if -1, don't use DMA */
                c->gpio_irq = 0;
        }

>  			dev_err(&pdev->dev,  "Failed to request GPIO%d for "
>  				"OneNAND\n", c->gpio_irq);
>  			goto err_iounmap;
> -	}
> -	gpio_direction_input(c->gpio_irq);
> +		}
> +		gpio_direction_input(c->gpio_irq);
> +
> +		if ((r = request_irq(gpio_to_irq(c->gpio_irq),
> +				     omap2_onenand_interrupt, IRQF_TRIGGER_RISING,
> +				     pdev->dev.driver->name, c)) < 0)
> +			goto err_release_gpio;
>  
> -	if ((r = request_irq(gpio_to_irq(c->gpio_irq),
> -			     omap2_onenand_interrupt, IRQF_TRIGGER_RISING,
> -			     pdev->dev.driver->name, c)) < 0)
> -		goto err_release_gpio;
> +		this->wait = omap2_onenand_wait;
>  	}
>  
>  	if (pdata->dma_channel >= 0) {
> @@ -529,15 +527,11 @@ static int omap2_onenand_probe(struct platform_device *pdev)
>  		dma_cap_set(DMA_MEMCPY, mask);
>  
>  		c->dma_chan = dma_request_channel(mask, NULL, NULL);
> -		if (!c->dma_chan)
> -			dev_info(&pdev->dev,
> -				 "failed to allocate DMA for OneNAND, "
> -				 "using PIO instead\n");

Why get rid of the print message? Instead we could choose to error out completely
if a DMA channel was provided and we couldn't get it.

>  	}
>  
>  	dev_info(&pdev->dev, "initializing on CS%d, phys base 0x%08lx, virtual "
> -		 "base %p, freq %d MHz\n", c->gpmc_cs, c->phys_base,
> -		 c->onenand.base, c->freq);
> +		 "base %p, freq %d MHz, %s mode\n", c->gpmc_cs, c->phys_base,
> +		 c->onenand.base, c->freq, c->dma_chan ? "DMA" : "PIO");
>  
>  	c->pdev = pdev;
>  	c->mtd.priv = &c->onenand;
> @@ -547,7 +541,6 @@ static int omap2_onenand_probe(struct platform_device *pdev)
>  
>  	this = &c->onenand;
>  	if (c->dma_chan) {
> -		this->wait = omap2_onenand_wait;
>  		this->read_bufferram = omap2_onenand_read_bufferram;
>  		this->write_bufferram = omap2_onenand_write_bufferram;
>  	}
> 

-- 
cheers,
-roger

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