linux-kernel - Re: [PATCH v2] mmc: sdhci-of-arasan: fix set

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Date:	Wed, 4 May 2016 09:48:55 +0800
From:	Shawn Lin <shawn.lin@...k-chips.com>
To:	Ulf Hansson <ulf.hansson@...aro.org>
Cc:	shawn.lin@...k-chips.com, Adrian Hunter <adrian.hunter@...el.com>,
	Michal Simek <michal.simek@...inx.com>,
	Sören Brinkmann <soren.brinkmann@...inx.com>,
	linux-mmc <linux-mmc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Doug Anderson <dianders@...omium.org>,
	Heiko Stuebner <heiko@...ech.de>,
	"open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>
Subject: Re: [PATCH v2] mmc: sdhci-of-arasan: fix set_clock when a phy is
 supported

在 2016/4/28 18:38, Ulf Hansson 写道:
> On 28 April 2016 at 10:38, Shawn Lin <shawn.lin@...k-chips.com> wrote:
>> commit 61b914eb81f8 ("mmc: sdhci-of-arasan: add phy support for
>> sdhci-of-arasan") introduce phy support for arasan. According to
>> the vendor's databook, we should make sure the phy is in poweroff
>> status before we configure the clk stuff. Otherwise it may cause
>> some IO sample timing issues from the test. And we don't need this
>> extra operation while running in low performance mode since phy
>> doesn't trigger sampling block.
>>
>> Signed-off-by: Shawn Lin <shawn.lin@...k-chips.com>
>
> Thanks, applied for next!

Thanks for applying v2 but, could you please drop it and applied v3
I just send :) .
Because v2 introduces a bug. Set_clock callback will be
called under the protection of spinlock in sdhci_do_set_ios. However
PHY APIs need mutex which fails the kernel's debug check

BUG: sleeping function called from invalid context at kernel/locking/mutex.c

>
> Kind regards
> Uffe
>
>>
>> ---
>>
>> Changes in v2:
>> - change commit msg title to indicate it's a fix
>> - fix a typo in commmit msg
>>
>>  drivers/mmc/host/sdhci-of-arasan.c | 20 +++++++++++++++++++-
>>  1 file changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>> index 2e482b1..20b859e 100644
>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>> @@ -55,8 +55,26 @@ static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host)
>>         return freq;
>>  }
>>
>> +static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
>> +{
>> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> +       struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
>> +       bool ctrl_phy = false;
>> +
>> +       if (clock > MMC_HIGH_52_MAX_DTR && (!IS_ERR(sdhci_arasan->phy)))
>> +               ctrl_phy = true;
>> +
>> +       if (ctrl_phy)
>> +               phy_power_off(sdhci_arasan->phy);
>> +
>> +       sdhci_set_clock(host, clock);
>> +
>> +       if (ctrl_phy)
>> +               phy_power_on(sdhci_arasan->phy);
>> +}
>> +
>>  static struct sdhci_ops sdhci_arasan_ops = {
>> -       .set_clock = sdhci_set_clock,
>> +       .set_clock = sdhci_arasan_set_clock,
>>         .get_max_clock = sdhci_pltfm_clk_get_max_clock,
>>         .get_timeout_clock = sdhci_arasan_get_timeout_clock,
>>         .set_bus_width = sdhci_set_bus_width,
>> --
>> 2.3.7
>>
>>
>> --
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>
>
>


-- 
Best Regards
Shawn Lin