Previously the dw_mmc driver would ignore any requests to disable the card's clock. This doesn't seem like a good thing in general, but had one extra bad side effect in the following situtation: * mmc core would set clk to 400kHz at boot time while initting * mmc core would set clk to 0 since no card, but it would be ignored. * suspend to ram and resume; clocks in the dw_mmc IP block are now 0 but dw_mmc thinks that they're 400kHz (it ignored the set to 0). * insert card * mmc core would set clk to 400kHz which would be considered a no-op.
Note that if there is no card in the slot and we do a suspend/resume cycle, we _do_ still end up with differences in a dw_mmc register dump, but the differences are clock related and we've got the clock disabled both before and after, so this should be OK. Signed-off-by: Doug Anderson <[email protected]> --- Changes in v7: - Avoid printing the same clock over and over again w/ MMC_CLKGATE. Changes in v6: - Replaces previous pathes that ensured saving/restoring clocks. drivers/mmc/host/dw_mmc.c | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index ee5f167..1584705 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -88,6 +88,8 @@ struct idmac_desc { * @queue_node: List node for placing this node in the @queue list of * &struct dw_mci. * @clock: Clock rate configured by set_ios(). Protected by host->lock. + * @last_printed_clock: The last clock we printed. Keeping track of this helps + * us to avoid spamming the console with CONFIG_MMC_CLKGATE. * @flags: Random state bits associated with the slot. * @id: Number of this slot. * @last_detect_state: Most recently observed card detect state. @@ -105,6 +107,7 @@ struct dw_mci_slot { struct list_head queue_node; unsigned int clock; + unsigned int last_printed_clock; unsigned long flags; #define DW_MMC_CARD_PRESENT 0 #define DW_MMC_CARD_NEED_INIT 1 @@ -635,7 +638,11 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) u32 div; u32 clk_en_a; - if (slot->clock != host->current_speed || force_clkinit) { + if (slot->clock == 0) { + mci_writel(host, CLKENA, 0); + mci_send_cmd(slot, + SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); + } else if (slot->clock != host->current_speed || force_clkinit) { div = host->bus_hz / slot->clock; if (host->bus_hz % slot->clock && host->bus_hz > slot->clock) /* @@ -646,10 +653,14 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) 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" - " div = %d)\n", slot->id, host->bus_hz, slot->clock, - div ? ((host->bus_hz / div) >> 1) : host->bus_hz, div); + if (slot->clock != slot->last_printed_clock || force_clkinit) { + dev_info(&slot->mmc->class_dev, + "Bus speed (slot %d) = %dHz (slot req %dHz, actual %dHZ div = %d)\n", + slot->id, host->bus_hz, slot->clock, + div ? ((host->bus_hz / div) >> 1) : + host->bus_hz, div); + slot->last_printed_clock = slot->clock; + } /* disable clock */ mci_writel(host, CLKENA, 0); @@ -675,9 +686,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) /* inform CIU */ mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); - - host->current_speed = slot->clock; } + host->current_speed = slot->clock; /* Set the current slot bus width */ mci_writel(host, CTYPE, (slot->ctype << slot->id)); @@ -807,13 +817,11 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) mci_writel(slot->host, UHS_REG, regs); - if (ios->clock) { - /* - * Use mirror of ios->clock to prevent race with mmc - * core ios update when finding the minimum. - */ - slot->clock = ios->clock; - } + /* + * Use mirror of ios->clock to prevent race with mmc + * core ios update when finding the minimum. + */ + slot->clock = ios->clock; if (drv_data && drv_data->set_ios) drv_data->set_ios(slot->host, ios); -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
