[Skiboot] [PATCH 3/4] p8i2c: Use calculated poll_interval when booting OPAL

[Claudio Carvalho]

Tested-by: Claudio Carvalho <cclaudio at linux.vnet.ibm.com>

On 11/23/2016 03:46 AM, Stewart Smith wrote:
> Otherwise we'd default to 2seconds (TIMER_POLL) during boot on
> chips with a functional i2c interrupt, leading to slow i2c
> during boot (or hitting timeouts instead).
> 
> Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>
> ---
>  hw/p8-i2c.c       | 23 +++++++++++++----------
>  include/skiboot.h |  5 +++++
>  2 files changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/p8-i2c.c b/hw/p8-i2c.c
> index 12a4d1a..718f6db 100644
> --- a/hw/p8-i2c.c
> +++ b/hw/p8-i2c.c
> @@ -870,7 +870,7 @@ static int p8_i2c_start_request(struct p8_i2c_master *master,
>  	struct p8_i2c_master_port *port;
>  	struct p8_i2c_request *request =
>  		container_of(req, struct p8_i2c_request, req);
> -	uint64_t cmd, now;
> +	uint64_t cmd, now, poll_interval;
>  	int64_t rc, tbytes;
>  
>  	DBG("Starting req %d len=%d addr=%02x (offset=%x)\n",
> @@ -975,7 +975,11 @@ static int p8_i2c_start_request(struct p8_i2c_master *master,
>  	/* Run a poll timer for boot cases or non-working interrupts
>  	 * cases
>  	 */
> -	now = schedule_timer(&master->poller, master->poll_interval);
> +	if (!opal_booting() && master->irq_ok)
> +		poll_interval = TIMER_POLL;
> +	else
> +		poll_interval = master->poll_interval;
> +	now = schedule_timer(&master->poller, poll_interval);
>  
>  	/* Calculate and start timeout */
>  	if (request->timeout) {
> @@ -1428,15 +1432,14 @@ static void p8_i2c_init_one(struct dt_node *i2cm, enum p8_i2c_master_type type)
>  		port++;
>  	}
>  
> -	/* If we have no interrupt, calculate a poll interval,
> -	 * otherwise just use a TIMER_POLL timer which will tick
> -	 * on OPAL pollers only (which allows us to operate
> -	 * during boot before interrupts are functional etc...
> +	/* When at runtime and we have the i2c irq, we just use it
> +	 * (see p8_i2c_start_request), but in the situation where
> +	 * one of those isn't the case (e.g. during boot), we need
> +	 * a better poll interval to efficiently crank the i2c machine.
> +	 * poll_interval is that interval.
>  	 */
> -	if (master->irq_ok)
> -		master->poll_interval = TIMER_POLL;
> -	else
> -		master->poll_interval = p8_i2c_get_poll_interval(max_bus_speed);
> +	master->poll_interval = p8_i2c_get_poll_interval(max_bus_speed);
> +
>  	master->byte_timeout = master->irq_ok ?
>  		msecs_to_tb(I2C_TIMEOUT_IRQ_MS) :
>  		msecs_to_tb(I2C_TIMEOUT_POLL_MS);
> diff --git a/include/skiboot.h b/include/skiboot.h
> index 97bdce7..3f7c077 100644
> --- a/include/skiboot.h
> +++ b/include/skiboot.h
> @@ -86,6 +86,11 @@ struct debug_descriptor {
>  };
>  extern struct debug_descriptor debug_descriptor;
>  
> +static inline bool opal_booting(void)
> +{
> +	return !(debug_descriptor.state_flags & OPAL_BOOT_COMPLETE);
> +}
> +
>  /* Console logging */
>  #define PR_EMERG	0
>  #define PR_ALERT	1
>