In case of "host->bus_hz < slot->clock", divider value is miscalculated. And clock divider register value is multiple of 2. If calculated divider value is odd number, result can be over-clocking.
Signed-off-by: Seungwon Jeon <[email protected]> --- drivers/mmc/host/dw_mmc.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index f2f8463..c87745e 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -617,14 +617,16 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot) u32 div; if (slot->clock != host->current_speed) { - if (host->bus_hz % slot->clock) + div = host->bus_hz / slot->clock; + if (host->bus_hz % slot->clock && + host->bus_hz > slot->clock) /* * move the + 1 after the divide to prevent * over-clocking the card. */ - div = ((host->bus_hz / slot->clock) >> 1) + 1; - else - div = (host->bus_hz / slot->clock) >> 1; + div += 1; + + div = (host->bus_hz != slot->clock) ? DIV_ROUND_UP(div, 2) : 0; dev_info(&slot->mmc->class_dev, "Bus speed (slot %d) = %dHz (slot req %dHz, actual %dHZ" -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
