Jaehoon,
On Tue, Dec 2, 2014 at 4:17 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
>> @@ -1245,27 +1246,37 @@ static int dw_mci_get_cd(struct mmc_host *mmc)
>> return present;
>> }
>>
>> -/*
>> - * Disable lower power mode.
>> - *
>> - * Low power mode will stop the card clock when idle. According to the
>> - * description of the CLKENA register we should disable low power mode
>> - * for SDIO cards if we need SDIO interrupts to work.
>> - *
>> - * This function is fast if low power mode is already disabled.
>> - */
>> -static void dw_mci_disable_low_power(struct dw_mci_slot *slot)
>> +static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card)
>> {
>> + struct dw_mci_slot *slot = mmc_priv(mmc);
>> struct dw_mci *host = slot->host;
>> - u32 clk_en_a;
>> - const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id;
>>
>> - clk_en_a = mci_readl(host, CLKENA);
>> + /*
>> + * Low power mode will stop the card clock when idle. According to the
>> + * description of the CLKENA register we should disable low power mode
>> + * for SDIO cards if we need SDIO interrupts to work.
>> + */
>> + if (mmc->caps & MMC_CAP_SDIO_IRQ) {
>> + const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id;
>> + u32 clk_en_a_old;
>> + u32 clk_en_a;
>>
>> - if (clk_en_a & clken_low_pwr) {
>> - mci_writel(host, CLKENA, clk_en_a & ~clken_low_pwr);
>> - mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |
>> - SDMMC_CMD_PRV_DAT_WAIT, 0);
>> + clk_en_a_old = mci_readl(host, CLKENA);
>> +
>> + if (card->type == MMC_TYPE_SDIO ||
>> + card->type == MMC_TYPE_SD_COMBO) {
>> + set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);
>> + clk_en_a = clk_en_a_old & ~clken_low_pwr;
>> + } else {
>
> I wonder this point. When entered at this point?
>
> MMC_CAP_SDIO_IRQ is sdio capability. and card->type is also related with SDIO, isn't?
Right. As I understand it:
* You can certainly add MMC_CAP_SDIO_IRQ to an external card slot that
might have an MMC card, and SD card, or an SDIO card. You still want
the LOW_PWR mode for MMC/SD cards but don't want it for SDIO cards in
that case.
* If you don't set MMC_CAP_SDIO_IRQ then presumably you've got some
problem where the SDIO interrupt is broken on your board. That means
you're using polling mode to find interrupts. As I understand it that
would allow you to use LOW_PWR since you don't need to detect SDIO
interrupts. I know on Marvell WiFi modules I tested this seemed to
work OK, but I doubt anyone is really running a production device in
this way.
Basically I was trying to mirror the functionality of the old code as
closely as possible. In the old code if you were using polling mode
then dw_mci_enable_sdio_irq() should never be called and you'd never
go out of low power mode.
-Doug
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