Re: [PATCH] i2c-pxa: fix scheduling while atomic in i2c_pxa_abort()

[Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>]

On Tue, Aug 05, 2008 at 03:17:11PM +0400, Dmitry Baryshkov wrote:
> i2c_pxa_abort can be called from the atomic context.
> Change it to use mdelay and counted loop.

if this can be called from an atomic context, is there a distinct
possibility you are going to stop execution of the entire cpu for
the time it takes to sort this out? Is it possible to disable the
interrupt request, fire a work-struct to deal with this and then
re-enabled the controller once it is finished?
 
> Signed-off-by: Dmitry Baryshkov <dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/i2c/busses/i2c-pxa.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index dde6ce9..9a0f788 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -188,14 +188,14 @@ static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
>  
>  static void i2c_pxa_abort(struct pxa_i2c *i2c)
>  {
> -	unsigned long timeout = jiffies + HZ/4;
> +	int i = 250;
>  
>  	if (i2c_pxa_is_slavemode(i2c)) {
>  		dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
>  		return;
>  	}
>  
> -	while (time_before(jiffies, timeout) && (readl(_IBMR(i2c)) & 0x1) == 0) {
> +	while ((i > 0) && (readl(_IBMR(i2c)) & 0x1) == 0) {
>  		unsigned long icr = readl(_ICR(i2c));
>  
>  		icr &= ~ICR_START;
> @@ -205,7 +205,8 @@ static void i2c_pxa_abort(struct pxa_i2c *i2c)
>  
>  		show_state(i2c);
>  
> -		msleep(1);
> +		mdelay(1);
> +		i --;
>  	}
>  
>  	writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP),
> -- 
> 1.5.6.3
> 
> 
> -- 
> With best wishes
> Dmitry
> 
> 
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-- 
Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

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