linux-kernel - Re: [PATCH 2/3] mmc: sdhci-esdhc-imx: obtain the 'per' clock rate after its enablement

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8b5bf7d6-8dfa-463b-a2ae-fa74a3e5ba73@intel.com>
Date: Wed, 10 Jul 2024 16:18:23 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Ciprian Marian Costea <ciprianmarian.costea@....nxp.com>,
 Haibo Chen <haibo.chen@....com>, Ulf Hansson <ulf.hansson@...aro.org>,
 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>,
 Pengutronix Kernel Team <kernel@...gutronix.de>,
 Fabio Estevam <festevam@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-mmc@...r.kernel.org,
 imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, s32@....com
Subject: Re: [PATCH 2/3] mmc: sdhci-esdhc-imx: obtain the 'per' clock rate
 after its enablement

On 10/07/24 15:50, Ciprian Marian Costea wrote:
> On 7/10/2024 3:33 PM, Adrian Hunter wrote:
>> On 8/07/24 15:10, Ciprian Costea wrote:
>>> The I.MX SDHCI driver assumes that the frequency of the 'per' clock
>>> can be obtained even on disabled clocks, which is not always the case.
>>>
>>> According to 'clk_get_rate' documentation, it is only valid
>>> once the clock source has been enabled.
>>
>> The kerneldoc comment for clk_get_rate() says
>>
>>     Can be called regardless of the clock enabledness
>>
>> which sounds like the opposite.  Please clarify.
>>
> 
> Hello Adrian,
> 
> My observation was based on the following [1] 'clk_get_rate()' documentation.
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/clk.h#n720
> 
> Best Regards,
> Ciprian

Yes, that is clear.

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> 
>>>
>>> Signed-off-by: Ciprian Costea <ciprianmarian.costea@....nxp.com>
>>> ---
>>>   drivers/mmc/host/sdhci-esdhc-imx.c | 8 +++++++-
>>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
>>> index 21d984a77be8..8f0bc6dca2b0 100644
>>> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
>>> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
>>> @@ -1709,7 +1709,6 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
>>>       }
>>>         pltfm_host->clk = imx_data->clk_per;
>>> -    pltfm_host->clock = clk_get_rate(pltfm_host->clk);
>>>       err = clk_prepare_enable(imx_data->clk_per);
>>>       if (err)
>>>           goto free_sdhci;
>>> @@ -1720,6 +1719,13 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
>>>       if (err)
>>>           goto disable_ipg_clk;
>>>   +    pltfm_host->clock = clk_get_rate(pltfm_host->clk);
>>> +    if (!pltfm_host->clock) {
>>> +        dev_err(mmc_dev(host->mmc), "could not get clk rate\n");
>>> +        err = -EINVAL;
>>> +        goto disable_ahb_clk;
>>> +    }
>>> +
>>>       imx_data->pinctrl = devm_pinctrl_get(&pdev->dev);
>>>       if (IS_ERR(imx_data->pinctrl))
>>>           dev_warn(mmc_dev(host->mmc), "could not get pinctrl\n");
>>
>