From: Marek Vasut <marex@denx•de>
To: Joachim Eastwood <manabian@gmail•com>
Cc: netdev <netdev@vger•kernel.org>,
"peppe.cavallaro" <peppe.cavallaro@st•com>,
alexandre.torgue@st•com,
Matthew Gerlach <mgerlach@opensource•altera.com>,
Dinh Nguyen <dinguyen@opensource•altera.com>,
"David S . Miller" <davem@davemloft•net>
Subject: Re: [PATCH V3] net: stmmac: socfpga: Remove re-registration of reset controller
Date: Tue, 26 Apr 2016 00:55:27 +0200 [thread overview]
Message-ID: <571EA05F.3070200@denx.de> (raw)
In-Reply-To: <CAGhQ9VzpZcP23DC0LZ95YggtsBDsUCe-NHEtna7hY9Yvdr=ZGg@mail.gmail.com>
On 04/25/2016 08:11 PM, Joachim Eastwood wrote:
> Hi Marek,
Hi!
> On 21 April 2016 at 14:11, Marek Vasut <marex@denx•de> wrote:
>> Both socfpga_dwmac_parse_data() in dwmac-socfpga.c and stmmac_dvr_probe()
>> in stmmac_main.c functions call devm_reset_control_get() to register an
>> reset controller for the stmmac. This results in an attempt to register
>> two reset controllers for the same non-shared reset line.
>>
>> The first attempt to register the reset controller works fine. The second
>> attempt fails with warning from the reset controller core, see below.
>> The warning is produced because the reset line is non-shared and thus
>> it is allowed to have only up-to one reset controller associated with
>> that reset line, not two or more.
>>
>> The solution has multiple parts. First, the original socfpga_dwmac_init()
>> is tweaked to use reset controller pointer from the stmmac_priv (private
>> data of the stmmac core) instead of the local instance, which was used
>> before. The local re-registration of the reset controller is removed.
>>
>> Next, the socfpga_dwmac_init() is moved after stmmac_dvr_probe() in the
>> probe function. This order is legal according to Altera and it makes the
>> code much easier, since there is no need to temporarily register and
>> unregister the reset controller ; the reset controller is already registered
>> by the stmmac_dvr_probe().
>>
>> Finally, plat_dat->exit and socfpga_dwmac_exit() is no longer necessary,
>> since the functionality is already performed by the stmmac core.
>
> I am trying to rebase my changes on top of your two patches and
> noticed a couple of things.
>
>> static int socfpga_dwmac_init(struct platform_device *pdev, void *priv)
>> {
>> - struct socfpga_dwmac *dwmac = priv;
>> + struct socfpga_dwmac *dwmac = priv;
>> struct net_device *ndev = platform_get_drvdata(pdev);
>> struct stmmac_priv *stpriv = NULL;
>> int ret = 0;
>>
>> - if (ndev)
>> - stpriv = netdev_priv(ndev);
>> + if (!ndev)
>> + return -EINVAL;
>
> ndev can never be NULL here. socfpga_dwmac_init() is only called if
> stmmac_dvr_probe() succeeds or we are running the resume callback. So
> I don't see how this could ever be NULL.
That's a good point, this check can indeed be removed. While you're at
the patching, can you remove this one ?
>> +
>> + stpriv = netdev_priv(ndev);
>
> It's not really nice to access 'stmmac_priv' as it should be private
> to the core driver, but I don't see any other good solution right now.
I guess some stmmac_reset_assert() wrapper would be nicer, yes. What do
you think ?
>> + if (!stpriv)
>> + return -EINVAL;
>>
>> /* Assert reset to the enet controller before changing the phy mode */
>> - if (dwmac->stmmac_rst)
>> - reset_control_assert(dwmac->stmmac_rst);
>> + if (stpriv->stmmac_rst)
>> + reset_control_assert(stpriv->stmmac_rst);
>>
>> /* Setup the phy mode in the system manager registers according to
>> * devicetree configuration
>> @@ -227,8 +210,8 @@ static int socfpga_dwmac_init(struct platform_device *pdev, void *priv)
>> /* Deassert reset for the phy configuration to be sampled by
>> * the enet controller, and operation to start in requested mode
>> */
>> - if (dwmac->stmmac_rst)
>> - reset_control_deassert(dwmac->stmmac_rst);
>> + if (stpriv->stmmac_rst)
>> + reset_control_deassert(stpriv->stmmac_rst);
>>
>> /* Before the enet controller is suspended, the phy is suspended.
>> * This causes the phy clock to be gated. The enet controller is
>> @@ -245,7 +228,7 @@ static int socfpga_dwmac_init(struct platform_device *pdev, void *priv)
>> * control register 0, and can be modified by the phy driver
>> * framework.
>> */
>> - if (stpriv && stpriv->phydev)
>> + if (stpriv->phydev)
>> phy_resume(stpriv->phydev);
>
> Before this change phy_resume() was only called during driver resume
> when , but your patches cause phy_resume() to called at probe time as
> well. Is this okey?
I _hope_ it's OK. The cryptic comment above is not very helpful in this
aspect. Dinh ? :)
> regards,
> Joachim Eastwood
>
btw I wish you reviewed my patch a bit earlier to catch these bits.
--
Best regards,
Marek Vasut
next prev parent reply other threads:[~2016-04-25 22:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-21 12:11 [PATCH V3] net: stmmac: socfpga: Remove re-registration of reset controller Marek Vasut
2016-04-21 14:39 ` Dinh Nguyen
2016-04-24 18:40 ` David Miller
2016-04-25 18:11 ` Joachim Eastwood
2016-04-25 22:55 ` Marek Vasut [this message]
2016-04-26 12:26 ` Joachim Eastwood
2016-04-26 12:47 ` Marek Vasut
2016-04-26 21:22 ` Joachim Eastwood
2016-04-26 22:33 ` Marek Vasut
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