Hi, On Tue, Jan 19, 2016 at 10:17 PM, P L Sai Krishna <lakshmi.sai.krishna.potthuri@xxxxxxxxxx> wrote: > During the auto tuning mode of SDR104, a couple of transactions > on rx_tap_value which are not incremental or decremental by 1. > Since the DLL supports only increment/decrement by 1 during > dynamic change, observed unexpected delays during both these > transactions. > The first transaction occurs when the tap value > reached 0x1F, it will reset to 0x0 and go till 0x7. This > transaction can be avoided by changing the corecfg_dis1p5xtuningcnt > to 1'b1 which is currently tied to 1'b0 in the RTL. > The second transaction occurs after the tuning is completed. > Once the tuning is done, the tuning fsm in the host controller > calculates the average pattern match and will write the value > on the rx tap value. Therefore observed a transaction from 0x7 to > the final value which need not be a increment/decrement value. > Because of this issue DLL tuning will not be accurate and SDR50, > SDR104 & HS200 modes may not work. > > This patch adds workaround to change the SD clock after > tuning done to provide accurate DLL tuning for SDR50, > SD104 & HS200 modes. > > After receiving the tuning done, program "SDCLK Frequency Select" > of clock control register with a value different from the desired > value. Wait for the "Internal Clock Stable" bit of the clock > control register and program the desired frequency. Does this series apply to any non-Arasan or non-sdhci mmc hosts? The subject does not indicate a specific platform. Thanks ChenYu > Signed-off-by: P L Sai Krishna <lakshmis@xxxxxxxxxx> > --- > drivers/mmc/host/sdhci-of-arasan.c | 18 ++++++++++++++++++ > drivers/mmc/host/sdhci-pltfm.c | 3 +++ > drivers/mmc/host/sdhci.c | 5 +++++ > drivers/mmc/host/sdhci.h | 4 ++++ > 4 files changed, 30 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
