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 <[email protected]> >> --- >> 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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