linux-kernel - RE: [PATCH 4/7] can: mcan: enable peripheral clk to access mram

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Date:   Wed, 9 Nov 2022 15:25:01 +0530
From:   "Vivek Yadav" <vivek.2311@...sung.com>
To:     "'Marc Kleine-Budde'" <mkl@...gutronix.de>
Cc:     <rcsekar@...sung.com>, <wg@...ndegger.com>, <davem@...emloft.net>,
        <edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
        <pankaj.dubey@...sung.com>, <ravi.patel@...sung.com>,
        <alim.akhtar@...sung.com>, <linux-can@...r.kernel.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 4/7] can: mcan: enable peripheral clk to access mram



> -----Original Message-----
> From: Marc Kleine-Budde <mkl@...gutronix.de>
> Sent: 25 October 2022 13:14
> To: Vivek Yadav <vivek.2311@...sung.com>
> Cc: rcsekar@...sung.com; wg@...ndegger.com; davem@...emloft.net;
> edumazet@...gle.com; kuba@...nel.org; pabeni@...hat.com;
> pankaj.dubey@...sung.com; ravi.patel@...sung.com;
> alim.akhtar@...sung.com; linux-can@...r.kernel.org;
> netdev@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 4/7] can: mcan: enable peripheral clk to access mram
> 
> On 21.10.2022 15:28:30, Vivek Yadav wrote:
> > When we try to access the mcan message ram addresses, make sure hclk
> > is not gated by any other drivers or disabled. Enable the clock (hclk)
> > before accessing the mram and disable it after that.
> >
> > This is required in case if by-default hclk is gated.
> 
> From my point of view it makes no sense to init the RAM during probe.
> Can you move the init_ram into the m_can_chip_config() function? The
> clocks should be enabled then.
> 
As per my understanding, we should not remove message ram init from probe because if message ram init failed then there will be no 
Storing of Tx/Rx messages onto message ram, so it's better to confirm write operations onto message ram before CAN communication.

So we can kept init_ram in the probe function only, but we will shift init_ram into m_can_dev_setup function by the time clks are already enabled.
> Marc
> 
Thanks for the review.
> --
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