Re: [PATCH 1/3] memory: mtk-smi: add larbid init routine

[Robin Murphy <robin.murphy@arm.com>]

On 28/07/17 02:15, Honghui Zhang wrote:
> On Thu, 2017-07-27 at 17:42 +0200, Matthias Brugger wrote:
>>
>> On 07/27/2017 04:01 AM, honghui.zhang@mediatek.com wrote:
>>> From: Honghui Zhang <honghui.zhang@mediatek.com>
>>>
>>> In the commit 3c8f4ad85c4b ("memory/mediatek: add support for mt2701"),
>>> the larb->larbid was added but not initialized.
>>> Mediatek's gen1 smi need this hardware larbid information to get the
>>> register offset which controls whether enable iommu for this larb.
>>> This patch add the initialize routine for larbid.
>>>
>>> Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
>>> ---
>>>   drivers/memory/mtk-smi.c | 9 +++++++++
>>>   1 file changed, 9 insertions(+)
>>>
>>> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
>>> index 2b798bb4..fe36b3e 100644
>>> --- a/drivers/memory/mtk-smi.c
>>> +++ b/drivers/memory/mtk-smi.c
>>> @@ -240,6 +240,7 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
>>>   	struct device *dev = &pdev->dev;
>>>   	struct device_node *smi_node;
>>>   	struct platform_device *smi_pdev;
>>> +	int err;
>>>   
>>>   	if (!dev->pm_domain)
>>>   		return -EPROBE_DEFER;
>>> @@ -263,6 +264,14 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
>>>   		return PTR_ERR(larb->smi.clk_smi);
>>>   	larb->smi.dev = dev;
>>>   
>>> +	err = of_property_read_u32(dev->of_node, "mediatek,larbid",
>>> +				   &larb->larbid);
>>> +	if (err && of_device_is_compatible(dev->of_node,
>>> +					   "mediatek,mt2701-smi-larb")) {
>>
>> Instead of checking hard-coded bindings you should be able to determine the 
>> generation using the smi_pdev.
>> Apart I think it would be better to check for mediatek,larbid only on 
>> MTK_SIM_GEN1, or do I miss something?
>>
> 
> Hi, Matthias,
> 	There's a new SoC of mediatek which use MTK_SMI_GEN2 hardware, but it
> has 2 iommus and 2 smi_common, and we are intend to send it's driver
> soon. It need the mediatek,larbid to identify which iommu should be
> binding to.
> 
> This patch use the hard-code bindings will make the future work easier.

In that case, might it make sense to add some indicator like "bool
need_larb_id" to struct mtk_smi_larb_gen?

Robin.

> 
> thanks.
>> Regards,
>> Matthias
>>
>>> +		dev_err(dev, "missing larbid property\n");
>>> +		return err;
>>> +	}
>>> +
>>>   	smi_node = of_parse_phandle(dev->of_node, "mediatek,smi", 0);
>>>   	if (!smi_node)
>>>   		return -EINVAL;
>>>
>>
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> 
>