Hi Stephen, On Thu, 21 Mar 2013 22:02:18 -0600, Stephen Warren <[email protected]> wrote:
> The back-to-back-writes workaround in the BCM2835 MMC driver assumed > that get_timer() returned uS. Now that it returns mS, the delay is far > too long. Use udelay() directly to avoid this. Dispense with the > "last_write" code since we now have no way of recording an absolute > time in uS. The difference between two un-averaged tests loading a > zImage is 445 mS vs the original 412 mS, so the difference doesn't > appear too relevant. I don't entirely get the 'we have no way of recording an absolute time in us': doesn't get_timer_us() precisely provide this absolute us time just like 'old' get_timer(base) did? IOW, could you not simply turn every get_timer(X) into (get_timer_us()-X)? > Signed-off-by: Stephen Warren <[email protected]> > --- > drivers/mmc/bcm2835_sdhci.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/mmc/bcm2835_sdhci.c b/drivers/mmc/bcm2835_sdhci.c > index b0afc3c..240b5ec 100644 > --- a/drivers/mmc/bcm2835_sdhci.c > +++ b/drivers/mmc/bcm2835_sdhci.c > @@ -46,7 +46,6 @@ > struct bcm2835_sdhci_host { > struct sdhci_host host; > uint twoticks_delay; > - ulong last_write; > }; > > static inline struct bcm2835_sdhci_host *to_bcm(struct sdhci_host *host) > @@ -67,11 +66,9 @@ static inline void bcm2835_sdhci_raw_writel(struct > sdhci_host *host, u32 val, > * (Which is just as well - otherwise we'd have to nobble the DMA engine > * too) > */ > - while (get_timer(bcm_host->last_write) < bcm_host->twoticks_delay) > - ; > + udelay(bcm_host->twoticks_delay); > > writel(val, host->ioaddr + reg); > - bcm_host->last_write = get_timer(0); > } > > static inline u32 bcm2835_sdhci_raw_readl(struct sdhci_host *host, int reg) > @@ -172,7 +169,6 @@ int bcm2835_sdhci_init(u32 regbase, u32 emmc_freq) > * +1 for hack rounding. > */ > bcm_host->twoticks_delay = ((2 * 1000000) / MIN_FREQ) + 1; > - bcm_host->last_write = 0; > > host = &bcm_host->host; > host->name = "bcm2835_sdhci"; Amicalement, -- Albert. _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
