linux-kernel - Re: [PATCH v5 09/13] soc: mediatek: cmdq: add write

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Date:   Sun, 24 May 2020 20:13:56 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Dennis-YC Hsieh <dennis-yc.hsieh@...iatek.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Jassi Brar <jassisinghbrar@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, devicetree@...r.kernel.org,
        wsd_upstream@...iatek.com, dri-devel@...ts.freedesktop.org,
        Bibby Hsieh <bibby.hsieh@...iatek.com>,
        CK Hu <ck.hu@...iatek.com>,
        Houlong Wei <houlong.wei@...iatek.com>,
        linux-arm-kernel@...ts.infradead.org,
        HS Liao <hs.liao@...iatek.com>
Subject: Re: [PATCH v5 09/13] soc: mediatek: cmdq: add write_s value function



On 24/05/2020 19:31, Dennis-YC Hsieh wrote:
> Hi Matthias,
> 
> Thanks for your comment.
> 
> On Sat, 2020-05-16 at 20:20 +0200, Matthias Brugger wrote:
>>
>> On 08/03/2020 11:52, Dennis YC Hsieh wrote:
>>> add write_s function in cmdq helper functions which
>>> writes a constant value to address with large dma
>>> access support.
>>>
>>> Signed-off-by: Dennis YC Hsieh <dennis-yc.hsieh@...iatek.com>
>>> Reviewed-by: CK Hu <ck.hu@...iatek.com>
>>> ---
>>>  drivers/soc/mediatek/mtk-cmdq-helper.c | 26 ++++++++++++++++++++++++++
>>>  include/linux/soc/mediatek/mtk-cmdq.h  | 14 ++++++++++++++
>>>  2 files changed, 40 insertions(+)
>>>
>>> diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
>>> index 03c129230cd7..a9ebbabb7439 100644
>>> --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
>>> +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
>>> @@ -269,6 +269,32 @@ int cmdq_pkt_write_s(struct cmdq_pkt *pkt, u16 high_addr_reg_idx,
>>>  }
>>>  EXPORT_SYMBOL(cmdq_pkt_write_s);
>>>  
>>> +int cmdq_pkt_write_s_value(struct cmdq_pkt *pkt, u16 high_addr_reg_idx,
>>> +			   u16 addr_low, u32 value, u32 mask)
>>> +{
>>> +	struct cmdq_instruction inst = { {0} };
>>> +	int err;
>>> +
>>> +	if (mask != U32_MAX) {
>>> +		inst.op = CMDQ_CODE_MASK;
>>> +		inst.mask = ~mask;
>>> +		err = cmdq_pkt_append_command(pkt, inst);
>>> +		if (err < 0)
>>> +			return err;
>>> +
>>> +		inst.op = CMDQ_CODE_WRITE_S_MASK;
>>> +	} else {
>>> +		inst.op = CMDQ_CODE_WRITE_S;
>>> +	}
>>> +
>>> +	inst.sop = high_addr_reg_idx;
>>
>> Writing u16 value in a 5 bit wide variable?
> 
> We need only 5 bits in this case. I'll change high_addr_reg_idx
> parameter to u8.
> 

Ok, please make sure to mask the value, so that it's explicit in the code that
we only use the lowest 5 bits of high_addr_reg_idx.

Regards,
Matthias

>>
>>> +	inst.offset = addr_low;
>>> +	inst.value = value;
>>> +
>>> +	return cmdq_pkt_append_command(pkt, inst);
>>> +}
>>> +EXPORT_SYMBOL(cmdq_pkt_write_s_value);
>>> +
>>>  int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u16 event)
>>>  {
>>>  	struct cmdq_instruction inst = { {0} };
>>> diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/mediatek/mtk-cmdq.h
>>> index 01b4184af310..fec292aac83c 100644
>>> --- a/include/linux/soc/mediatek/mtk-cmdq.h
>>> +++ b/include/linux/soc/mediatek/mtk-cmdq.h
>>> @@ -135,6 +135,20 @@ int cmdq_pkt_read_s(struct cmdq_pkt *pkt, u16 high_addr_reg_idx, u16 addr_low,
>>>  int cmdq_pkt_write_s(struct cmdq_pkt *pkt, u16 high_addr_reg_idx,
>>>  		     u16 addr_low, u16 src_reg_idx, u32 mask);
>>>  
>>> +/**
>>> + * cmdq_pkt_write_s_value() - append write_s command with mask to the CMDQ
>>> + *			      packet which write value to a physical address
>>> + * @pkt:	the CMDQ packet
>>> + * @high_addr_reg_idx:	internal regisger ID which contains high address of pa
>>
>> register
> 
> will fix
> 
> 
> Regards,
> Dennis
> 
>>
>>> + * @addr_low:	low address of pa
>>> + * @value:	the specified target value
>>> + * @mask:	the specified target mask
>>> + *
>>> + * Return: 0 for success; else the error code is returned
>>> + */
>>> +int cmdq_pkt_write_s_value(struct cmdq_pkt *pkt, u16 high_addr_reg_idx,
>>> +			   u16 addr_low, u32 value, u32 mask);
>>> +
>>>  /**
>>>   * cmdq_pkt_wfe() - append wait for event command to the CMDQ packet
>>>   * @pkt:	the CMDQ packet
>>>
>