linux-kernel - Re: [PATCH v1 2/3] dma: dw-axi-dmac: Add support for StarFive DMA

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Date:   Mon, 13 Feb 2023 21:08:46 +0800
From:   Walker Chen <walker.chen@...rfivetech.com>
To:     Vinod Koul <vkoul@...nel.org>
CC:     <linux-riscv@...ts.infradead.org>, <dmaengine@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor@...nel.org>,
        "Palmer Dabbelt" <palmer@...belt.com>,
        Emil Renner Berthing <kernel@...il.dk>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/3] dma: dw-axi-dmac: Add support for StarFive DMA

On 2023/2/10 16:59, Vinod Koul wrote:
> On 06-02-23, 19:38, Walker Chen wrote:
>> Adding DMA reset operation in device probe, and using different
>> registers according to the hardware handshake number.
> 
> subsystem tag is dmaengine: xxx

OK, the tag will be changed to dmaengine.

> 
>> 
>> Signed-off-by: Walker Chen <walker.chen@...rfivetech.com>
>> ---
>>  .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 25 ++++++++++++++++---
>>  drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  3 +++
>>  2 files changed, 24 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
>> index a183d93bd7e2..3581810033d2 100644
>> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
>> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
>> @@ -25,6 +25,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/pm_runtime.h>
>>  #include <linux/property.h>
>> +#include <linux/reset.h>
>>  #include <linux/slab.h>
>>  #include <linux/types.h>
>>  
>> @@ -86,7 +87,8 @@ static inline void axi_chan_config_write(struct axi_dma_chan *chan,
>>  
>>  	cfg_lo = (config->dst_multblk_type << CH_CFG_L_DST_MULTBLK_TYPE_POS |
>>  		  config->src_multblk_type << CH_CFG_L_SRC_MULTBLK_TYPE_POS);
>> -	if (chan->chip->dw->hdata->reg_map_8_channels) {
>> +	if (chan->chip->dw->hdata->reg_map_8_channels &&
>> +	    !chan->chip->dw->hdata->use_cfg2) {
> 
> what about older/other platforms that dont have use_cfg2?

The use_cfg2 variable's default value is false, the original logic will not be affected.
Rob herring gave a suggestion that it is assigned according to compatible string, like that:
if (of_device_is_compatible(node, "starfive,jh7110-axi-dma")) {
	...
	chip->dw->hdata->use_cfg2 = true;
}

> 
>>  		cfg_hi = config->tt_fc << CH_CFG_H_TT_FC_POS |
>>  			 config->hs_sel_src << CH_CFG_H_HS_SEL_SRC_POS |
>>  			 config->hs_sel_dst << CH_CFG_H_HS_SEL_DST_POS |
>> @@ -541,8 +543,6 @@ static void dw_axi_dma_set_hw_channel(struct axi_dma_chan *chan, bool set)
>>  			(chan->id * DMA_APB_HS_SEL_BIT_SIZE));
>>  	reg_value |= (val << (chan->id * DMA_APB_HS_SEL_BIT_SIZE));
>>  	lo_hi_writeq(reg_value, chip->apb_regs + DMAC_APB_HW_HS_SEL_0);
>> -
>> -	return;
>>  }
>>  

Thanks

Best regards,
Walker