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Date:   Thu, 12 May 2022 09:13:48 +0200
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Subject: Re: [PATCH v3 22/23] ata: ahci-dwc: Add Baikal-T1 AHCI SATA interface
 support
Content-Language: en-US
To:     Serge Semin <Sergey.Semin@baikalelectronics.ru>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Jens Axboe <axboe@kernel.dk>,
        Serge Semin <fancer.lancer@gmail.com>
Cc:     Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
        Rob Herring <robh+dt@kernel.org>, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
References: <20220511231810.4928-1-Sergey.Semin@baikalelectronics.ru>
 <20220511231810.4928-23-Sergey.Semin@baikalelectronics.ru>
From:   Hannes Reinecke <hare@suse.de>
In-Reply-To: <20220511231810.4928-23-Sergey.Semin@baikalelectronics.ru>
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On 5/12/22 01:18, Serge Semin wrote:
> It's almost fully compatible DWC AHCI SATA IP-core derivative except the
> reference clocks source, which need to be very carefully selected. In
> particular the DWC AHCI SATA PHY can be clocked either from the pads
> ref_pad_clk_{m,p} or from the internal wires ref_alt_clk_{m,n}. In the
> later case the clock signal is generated from the Baikal-T1 CCU SATA PLL.
> The clocks source is selected by means of the ref_use_pad wire connected
> to the CCU SATA reference clock CSR.
> 
> In normal situation it would be much more handy to use the internal
> reference clock source, but alas we haven't managed to make the AHCI
> controller working well with it so far. So it's preferable to have the
> controller clocked from the external clock generator and fallback to the
> internal clock source only as a last resort. Other than that the
> controller is full compatible with the DWC AHCI SATA IP-core.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> 
> ---
> 
> Changelog v2:
> - Rename 'syscon' property to 'baikal,bt1-syscon'.
> - Change the local objects prefix from 'dwc_ahci_' to 'ahci_dwc_',
>    from 'bt1_ahci_' to 'ahci_bt1_'. (@Damien)
> ---
>   drivers/ata/Kconfig    |  1 +
>   drivers/ata/ahci_dwc.c | 87 ++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 88 insertions(+)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes


-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
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