On Fri, January 10, 2014, Zhangfei Gao wrote:
> On 01/10/2014 09:39 PM, Seungwon Jeon wrote:
> >> +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> >> +{
> >> + struct dw_mci_k3_priv_data *priv = host->priv;
> >> + u32 rate = priv->clk_table[ios->timing];
> >
> > First, sorry for quick review even though your effort.
> > But I still worry about this change.
> > Currently k3 host's clock table depends on value number of SD/MMC mode value.
> > It seems close to identifier for eachg mode. I think it's not good way to use as table's index.
> > Can you modify to mmc_clk_determine_rate() in your another patch-set?
> > I guess required actual target rate could be determined depending on ios->clock.
> >
>
> No, it can not get input clock source rate simply from ios->clock, also
> requied info like which controller, which mode etc.
> Here is setting clock source rate, not the working clock rate.
>
> For example, emmc init clock source rate is 13M, while sd init clock
> source is 25M, it can not simply get such info from ios->clock.
> And for HS200, emmc may have to set clock source rate to 104M since the
> controller limitation and can not work stable as 208M.
Yes, clock table is source clock rate, not actual working clock rate.
I was not saying that 'ios->clock' would be used for source clock directly.
I meant that you can adjust the source clock rate depending on 'ios->clock'.
You've already done with clock table similarly in mmc_clk_determine_rate().
For example, in case of HS200, 'ios->clock' will be passed with 200MHz.
And then, mmc_clk_determine_rate() can set the 'rate & best' to 100000000 and 720000000 respectively.
Also, 'ios->clock' with 400KHz or less may be passed for init clock.
If clock id is HI3620_SD_CIUCLK, 'rate & best' can be selected with 13000000 and 26000000.
If not and it's case of MMC, 'rate & best' can be selected with 25000000 and 180000000.
If it should be considered with other conditions, please let me know.
Thanks,
Seungwon Jeon
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