From: jh80.chung@samsung•com (Jaehoon Chung)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/3] mmc: dw_mmc: simplify the SDMMC_CLKEN_LOW_PWR logic
Date: Mon, 17 Aug 2015 20:26:05 +0900 [thread overview]
Message-ID: <55D1C4CD.4040200@samsung.com> (raw)
In-Reply-To: <CAOMqctQ8DHj6qPg8zR93OGRHXAZDd0yUmG_J8Vz7dGFuDpCgRQ@mail.gmail.com>
On 08/17/2015 02:52 PM, Michal Suchanek wrote:
> Hello,
>
> On 17 August 2015 at 03:55, Jaehoon Chung <jh80.chung@samsung•com> wrote:
>> Hi, Michal.
>>
>> On 08/12/2015 09:23 PM, Michal Suchanek wrote:
>>> The driver has open-coded test for SDIO cards. Use the mmc core provided
>>> MMC_QUIRK_BROKEN_CLK_GATING flag instead.
>>
>> Did you use the clock-gating for SDIO cards?
>> Doesn't MMC_CAP_SDIO_IRQ bit set? Which case is broken?
>> Could you explain to me more?
>
> The core flag for disabling power saving is MMC_QUIRK_BROKEN_CLK_GATING.
I understood your intention. And i read the comment into mmc/core/quirks.c
I will test SDIO card with this patch. Thanks.
Best Regards,
Jaehoon Chung
>
> It may coincide with MMC_CAP_SDIO_IRQ but that's different flag for
> different purpose.
>
> MMC_QUIRK_BROKEN_CLK_GATING is currently set for all SDIO cards except
> for cards on a whitelist.
>
> I don't know any particular SDIO card that has problems when the clock
> is off and does not use an IRQ.
>
> Thanks
>
> Michal
>
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>> As a bonus this may enable clock gating on SDIO cards that are known to
>>> work with it.
>>>
>>> Signed-off-by: Michal Suchanek <hramrach@gmail•com>
>>> ---
>>> drivers/mmc/host/dw_mmc.c | 33 +++++++++++++++------------------
>>> 1 file changed, 15 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>> index 40e9d8e..3bc9fd7 100644
>>> --- a/drivers/mmc/host/dw_mmc.c
>>> +++ b/drivers/mmc/host/dw_mmc.c
>>> @@ -1335,27 +1335,24 @@ static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card)
>>> * 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;
>>> + const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id;
>>> + u32 clk_en_a_old;
>>> + u32 clk_en_a;
>>>
>>> - clk_en_a_old = mci_readl(host, CLKENA);
>>> + 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 {
>>> - clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);
>>> - clk_en_a = clk_en_a_old | clken_low_pwr;
>>> - }
>>> + if (card->quirks & MMC_QUIRK_BROKEN_CLK_GATING) {
>>> + set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);
>>> + clk_en_a = clk_en_a_old & ~clken_low_pwr;
>>> + } else {
>>> + clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);
>>> + clk_en_a = clk_en_a_old | clken_low_pwr;
>>> + }
>>>
>>> - if (clk_en_a != clk_en_a_old) {
>>> - mci_writel(host, CLKENA, clk_en_a);
>>> - mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |
>>> - SDMMC_CMD_PRV_DAT_WAIT, 0);
>>> - }
>>> + if (clk_en_a != clk_en_a_old) {
>>> + mci_writel(host, CLKENA, clk_en_a);
>>> + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |
>>> + SDMMC_CMD_PRV_DAT_WAIT, 0);
>>> }
>>> }
>>>
>>>
>>
> --
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next prev parent reply other threads:[~2015-08-17 11:26 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-12 12:10 [PATCH 0/3] misc MMC fixes Michal Suchanek
2015-08-12 12:23 ` [PATCH resend 1/3] mmc: sunxi: fix timeout in sunxi_mmc_oclk_onoff michal.suchanek at ruk.cuni.cz
2015-08-12 12:32 ` Hans de Goede
2015-08-12 12:40 ` [linux-sunxi] " Olliver Schinagl
2015-08-12 13:04 ` Michal Suchanek
2015-08-12 13:29 ` [PATCH v3 " Michal Suchanek
2015-08-12 14:49 ` [linux-sunxi] " Hans de Goede
2015-08-25 12:06 ` Ulf Hansson
2015-08-12 12:23 ` [PATCH 2/3] mmc: dw_mmc: simplify the SDMMC_CLKEN_LOW_PWR logic Michal Suchanek
2015-08-17 1:55 ` Jaehoon Chung
2015-08-17 5:52 ` Michal Suchanek
2015-08-17 11:26 ` Jaehoon Chung [this message]
2015-08-17 14:42 ` Alim Akhtar
2015-08-17 14:55 ` Michal Suchanek
2015-08-17 16:21 ` Alim Akhtar
2015-08-12 12:23 ` [PATCH 3/3] mmc: sunxi: use controller automatic clock gating Michal Suchanek
2015-08-12 12:35 ` [linux-sunxi] " Hans de Goede
2015-08-12 12:53 ` Michal Suchanek
2015-08-12 13:19 ` Olliver Schinagl
2015-08-12 13:37 ` Michal Suchanek
2015-08-12 14:57 ` Olliver Schinagl
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