Am 09.11.2017 um 11:04 schrieb Sascha Hauer:
> On Wed, Nov 08, 2017 at 04:33:08PM +0100, Oleksij Rempel wrote:
>> this part of code is executed at least 4 times in eMMC probe sequence.
>> Optimizing it is reducing 20-30 msec of boot time.
>>
>> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
>> ---
>> drivers/mci/imx-esdhc.c | 14 ++++++++++----
>> 1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/mci/imx-esdhc.c b/drivers/mci/imx-esdhc.c
>> index 141d715c90..5c2a3a36e3 100644
>> --- a/drivers/mci/imx-esdhc.c
>> +++ b/drivers/mci/imx-esdhc.c
>> @@ -95,6 +95,7 @@ struct fsl_esdhc_host {
>> struct device_d *dev;
>> struct clk *clk;
>> const struct esdhc_soc_data *socdata;
>> + u32 last_clock;
>> };
>>
>> #define to_fsl_esdhc(mci) container_of(mci, struct fsl_esdhc_host, mci)
>> @@ -408,7 +409,7 @@ esdhc_send_cmd(struct mci_host *mci, struct mci_cmd *cmd, struct mci_data *data)
>>
>> static void set_sysctl(struct mci_host *mci, u32 clock)
>> {
>> - int div, pre_div;
>> + int div, pre_div, i;
>> struct fsl_esdhc_host *host = to_fsl_esdhc(mci);
>> void __iomem *regs = host->regs;
>> int sdhc_clk = clk_get_rate(host->clk);
>> @@ -453,13 +454,17 @@ static void set_sysctl(struct mci_host *mci, u32 clock)
>> esdhc_clrsetbits32(regs + SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET,
>> SYSCTL_CLOCK_MASK, clk);
>>
>> - wait_on_timeout(10 * MSECOND,
>> - !(esdhc_read32(regs + SDHCI_PRESENT_STATE) & PRSSTAT_SDSTB));
>> + for (i = 0; i < 1000; i++) {
>> + if (esdhc_read32(regs + SDHCI_PRESENT_STATE) & PRSSTAT_SDSTB)
>> + break;
>> + udelay(10);
>> + }
>
> I hope this hunk doesn't make anything better. If yes, we have a
> problem.
this is the part which need most of the time. Some times it will pass
immediately or will take exactly 10ms.
>>
>> clk = SYSCTL_PEREN | SYSCTL_CKEN;
>>
>> esdhc_setbits32(regs + SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET,
>> clk);
>> + host->last_clock = clock;
>
> Instead of storing the desired clock I would rather store the clock we
> actually make from the desired clock. This way we could optimze for
> multiple input frequencies that result in the same actual frequency.
>
> Also please rename the variable from last_clock to cur_clock.
ok.
--
Regards,
Oleksij
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