2011/10/27 Shawn.Dong <shawn.dong...@gmail.com>: > sdhci_set_clock or sdhci_reset or sdhci_send_command may be used in > critical region which is protected by spin_lock_irqsave. Thus, these > functions will delay the responsing of the kernel interrupts. > > So in this case, using a mdelay will cause unnecessary latency. Our > hardware, in most case will not cause 1ms to finish its job. Using > udelay instead can reduce it. > > By default, sdhci_do_set_ios will need about 1ms to finish in my platform. > After using udelay instead, sdhci_do_set_ios only need a few microseconds. > > Signed-off-by: Shawn.Dong <shawn.dong...@gmail.com>
ACK, see my patch as well: http://www.spinics.net/lists/linux-mmc/msg10257.html > --- > drivers/mmc/host/sdhci.c | 12 ++++++------ > 1 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 6d8eea3..9314cd1 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -195,7 +195,7 @@ static void sdhci_reset(struct sdhci_host *host, u8 mask) > host->clock = 0; > > /* Wait max 100 ms */ > - timeout = 100; > + timeout = 10000; > > /* hw clears the bit when it's done */ > while (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) { > @@ -206,7 +206,7 @@ static void sdhci_reset(struct sdhci_host *host, u8 mask) > return; > } > timeout--; > - mdelay(1); > + udelay(10); > } > > if (host->ops->platform_reset_exit) > @@ -959,7 +959,7 @@ static void sdhci_send_command(struct sdhci_host *host, > struct mmc_command *cmd) > WARN_ON(host->cmd); > > /* Wait max 10 ms */ > - timeout = 10; > + timeout = 1000; > > mask = SDHCI_CMD_INHIBIT; > if ((cmd->data != NULL) || (cmd->flags & MMC_RSP_BUSY)) > @@ -980,7 +980,7 @@ static void sdhci_send_command(struct sdhci_host *host, > struct mmc_command *cmd) > return; > } > timeout--; > - mdelay(1); > + udelay(10); > } > > mod_timer(&host->timer, jiffies + 10 * HZ); > @@ -1140,7 +1140,7 @@ static void sdhci_set_clock(struct sdhci_host *host, > unsigned int clock) > sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); > > /* Wait max 20 ms */ > - timeout = 20; > + timeout = 2000; > while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL)) > & SDHCI_CLOCK_INT_STABLE)) { > if (timeout == 0) { > @@ -1150,7 +1150,7 @@ static void sdhci_set_clock(struct sdhci_host *host, > unsigned int clock) > return; > } > timeout--; > - mdelay(1); > + udelay(10); > } > > clk |= SDHCI_CLOCK_CARD_EN; > -- > 1.7.3.4 -barry -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
