Re: [PATCH] OMAP3: PM: Dynamic calculation of SDRC clock stabilization delay

[Romit Dasgupta <romit@ti.com>]

> +#ifdef CONFIG_ARCH_OMAP3
> +unsigned long (*_omap3_sram_delay)(unsigned long);
> +unsigned int  measure_sram_delay(unsigned int loop)
> +{
> +	static struct omap_dm_timer *gpt;
> +	unsigned long flags, diff = 0, gt_rate, mpurate;
> +	unsigned int delay_sram, error_gain;
> +
> +	omap_dm_timer_init();
> +	gpt = omap_dm_timer_request_specific(10);
> +	if (!gpt)
> +		pr_err("Could not get the gptimer\n");
> +	omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
> +
> +	gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
> +	omap_dm_timer_set_load_start(gpt, 0, 0);
> +
> +	local_irq_save(flags);
> +	diff = _omap3_sram_delay(loop);
> +	local_irq_restore(flags);
> +
> +	omap_dm_timer_stop(gpt);
> +	omap_dm_timer_free(gpt);
> +
> +	mpurate = clk_get_rate(clk_get(NULL, "arm_fck"));
> +
> +	/* calculate the sram delay */
> +	delay_sram = ((((mpurate/1000000) / (gt_rate/1000000)) * diff) / 20000);
Can remove the 1000000 from the denominators as they cancel out.
> +
> +	error_gain = ((mpurate/1000000) / (gt_rate/1000000));
Same as before.
> +	delay_sram = delay_sram + error_gain;
> +
> +	return delay_sram;
> +}