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Message-ID: <d127c7ff-8883-4069-9cc9-407be1b6feaf@starfivetech.com>
Date: Mon, 16 Oct 2023 17:27:10 +0800
From: Xingyu Wu <xingyu.wu@...rfivetech.com>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>
CC: <aou@...s.berkeley.edu>, <conor@...nel.org>,
<daniel.lezcano@...aro.org>, <devicetree@...r.kernel.org>,
<emil.renner.berthing@...onical.com>,
<krzysztof.kozlowski+dt@...aro.org>,
<linux-kernel@...r.kernel.org>, <linux-riscv@...ts.infradead.org>,
<p.zabel@...gutronix.de>, <palmer@...belt.com>,
<paul.walmsley@...ive.com>, <robh+dt@...nel.org>,
<samin.guo@...rfivetech.com>, <tglx@...utronix.de>,
<walker.chen@...rfivetech.com>
Subject: Re: [PATCH v6 2/3] clocksource: Add JH7110 timer driver
On 2023/10/14 2:02, Christophe JAILLET wrote:
> Le 13/10/2023 à 11:34, Xingyu Wu a écrit :
>> On 2023/10/13 1:53, Christophe JAILLET wrote:
>>> Le 12/10/2023 à 10:10, Xingyu Wu a écrit :
>>>> Add timer driver for the StarFive JH7110 SoC.
>>>>
>>>> Signed-off-by: Xingyu Wu <xingyu.wu-bONrM45KWFOXmMXjJBpWqg-XMD5yJDbdMStu3cLTcvVIw@...lic.gmane.orge.org>
>>>
>>> ...
>>
>> It looks normal in my email and the web. Is this due to some settings?
>
> Hi,
>
> I use gmane.org and a news reader (Thunderbird).
> Gmane sometimes (not always!) obfuscate e-mail addresses.
>
> Do not pay attantion to these strange rewritten addresses.
>
>>
>>>
>>>> +static int jh7110_timer_probe(struct platform_device *pdev)
>>>> +{
>>>> + struct jh7110_clkevt *clkevt[JH7110_TIMER_CH_MAX];
>>>> + char name[4];
>>>> + struct clk *pclk;
>>>> + struct reset_control *rst;
>>>> + int ch;
>>>> + int ret;
>>>> + void __iomem *base;
>>>> +
>>>> + base = devm_platform_ioremap_resource(pdev, 0);
>>>> + if (IS_ERR(base))
>>>> + return dev_err_probe(&pdev->dev, PTR_ERR(base),
>>>> + "failed to map registers\n");
>>>> +
>>>> + rst = devm_reset_control_get_exclusive(&pdev->dev, "apb");
>>>> + if (IS_ERR(rst))
>>>> + return dev_err_probe(&pdev->dev, PTR_ERR(rst), "failed to get apb reset\n");
>>>> +
>>>> + pclk = devm_clk_get_enabled(&pdev->dev, "apb");
>>>> + if (IS_ERR(pclk))
>>>> + return dev_err_probe(&pdev->dev, PTR_ERR(pclk),
>>>> + "failed to get & enable apb clock\n");
>>>> +
>>>> + ret = reset_control_deassert(rst);
>>>> + if (ret)
>>>> + return dev_err_probe(&pdev->dev, ret, "failed to deassert apb reset\n");
>>>
>>> Hi,
>>>
>>> I'm not very familiar with the reset_control_[de]assert() functions, but shouldn't this be undone by a reset_control_assert() call if an error occurs later?
>>
>> In this case, the reset controller is set from 'assert' state to 'deassert' state. If it is failed and still 'assert' state, I don't think it need to call reset_control_assert().
>
> Emil already explained what I meaned (sorry for not being clear enough).
> I do agree with his proposed approach.
>
>>
>>>
>>>> +
>>>> + for (ch = 0; ch < JH7110_TIMER_CH_MAX; ch++) {
>>>> + clkevt[ch] = devm_kzalloc(&pdev->dev, sizeof(*clkevt[ch]), GFP_KERNEL);
>>>> + if (!clkevt[ch])
>>>> + return -ENOMEM;
>>>> +
>>>> + snprintf(name, sizeof(name), "ch%d", ch);
>>>> +
>>>> + clkevt[ch]->base = base + JH7110_TIMER_CH_BASE(ch);
>>>> + /* Ensure timer is disabled */
>>>> + jh7110_timer_disable(clkevt[ch]);
>>>> +
>>>> + rst = devm_reset_control_get_exclusive(&pdev->dev, name);
>>>> + if (IS_ERR(rst))
>>>> + return PTR_ERR(rst);
>>>> +
>>>> + clkevt[ch]->clk = devm_clk_get_enabled(&pdev->dev, name);
>>>> + if (IS_ERR(clkevt[ch]->clk))
>>>> + return PTR_ERR(clkevt[ch]->clk);
>>>> +
>>>> + ret = reset_control_deassert(rst);
>>>> + if (ret)
>>>> + return ret;
>>>
>>> Same here.
>>>
>>>> +
>>>> + clkevt[ch]->evt.irq = platform_get_irq(pdev, ch);
>>>> + if (clkevt[ch]->evt.irq < 0)
>>>> + return clkevt[ch]->evt.irq;
>>>> +
>>>> + snprintf(clkevt[ch]->name, sizeof(clkevt[ch]->name), "%s.ch%d", pdev->name, ch);
>>>> + jh7110_clockevents_register(clkevt[ch]);
>>>> +
>>>> + ret = devm_request_irq(&pdev->dev, clkevt[ch]->evt.irq, jh7110_timer_interrupt,
>>>> + IRQF_TIMER | IRQF_IRQPOLL,
>>>> + clkevt[ch]->name, &clkevt[ch]->evt);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + ret = jh7110_clocksource_init(clkevt[ch]);
>>>
>>> Does something should be done if this fails?
>>>
>>> CJ
>>
>> Yes, it should be call reset_control_assert() here and I will add it in next version.
>
> My point was for the above reset_control_assert() but also for the resources allocated within this for loop.
>
> I have not checked all paths, but in case of error in the probe:
> - There is another reset_control_deassert()
>
> - jh7110_clocksource_init() --> jh7110_timer_int_init_enable() --> jh7110_timer_enable()
> Should jh7110_timer_disable() be called?
>
> - jh7110_clocksource_init() --> clocksource_register_hz().
> Should clocksource_unregister() be called?
>
> If I'm correct and depending on how you update the code, a .remove function may be needed as well.
>
> CJ
>
Great. I'm going to add a action which Emil had said to do this job when remove or make the error in the loop.
Thanks,
Xingyu Wu
>>
>>>
>>>> + if (ret)
>>>> + return ret;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static const struct of_device_id jh7110_timer_match[] = {
>>>> + { .compatible = "starfive,jh7110-timer", },
>>>> + { /* sentinel */ }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, jh7110_timer_match);
>>>> +
>>>> +static struct platform_driver jh7110_timer_driver = {
>>>> + .probe = jh7110_timer_probe,
>>>> + .driver = {
>>>> + .name = "jh7110-timer",
>>>> + .of_match_table = jh7110_timer_match,
>>>> + },
>>>> +};
>>>> +module_platform_driver(jh7110_timer_driver);
>>>> +
>>>> +MODULE_AUTHOR("Xingyu Wu <xingyu.wu-bONrM45KWFOXmMXjJBpWqg-XMD5yJDbdMRS5n6/RkiaJA@...lic.gmane.orgne.org>");
>>>> +MODULE_DESCRIPTION("StarFive JH7110 timer driver");
>>>> +MODULE_LICENSE("GPL");
>>>
>>
>> Thanks,
>> Xingyu Wu
>>
>>
>>
>
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