linux-kernel - Re: [PATCH v6 2/4] dmaengine: dw-axi-dmac: Add support for StarFive JH7110 DMA

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Message-ID: <ZCbMRdSCf5vKUk/c@matsya>
Date:   Fri, 31 Mar 2023 17:34:21 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Walker Chen <walker.chen@...rfivetech.com>
Cc:     Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Emil Renner Berthing <emil.renner.berthing@...onical.com>,
        dmaengine@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v6 2/4] dmaengine: dw-axi-dmac: Add support for StarFive
 JH7110 DMA

On 22-03-23, 17:48, Walker Chen wrote:
> Add DMA reset operation in device probe and use different configuration
> on CH_CFG registers according to match data. Update all uses of
> of_device_is_compatible with of_device_get_match_data.
> 
> Signed-off-by: Walker Chen <walker.chen@...rfivetech.com>
> ---
>  .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 38 ++++++++++++++++---
>  drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  1 +
>  2 files changed, 34 insertions(+), 5 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 4169e1d7d5ca..6cfcb541d8c3 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -21,10 +21,12 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/of_dma.h>
>  #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>
>  
> @@ -46,6 +48,10 @@
>  	DMA_SLAVE_BUSWIDTH_32_BYTES	| \
>  	DMA_SLAVE_BUSWIDTH_64_BYTES)
>  
> +#define AXI_DMA_FLAG_HAS_APB_REGS	BIT(0)
> +#define AXI_DMA_FLAG_HAS_RESETS		BIT(1)
> +#define AXI_DMA_FLAG_USE_CFG2		BIT(2)
> +
>  static inline void
>  axi_dma_iowrite32(struct axi_dma_chip *chip, u32 reg, u32 val)
>  {
> @@ -86,7 +92,8 @@ 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) {

I think this will break existing users.. 

This is set for reg_map_8_channels && use_cfg2, latter being set only
for new controller, so what about existing users of these bits?

>  		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 |
> @@ -1367,10 +1374,11 @@ static int parse_device_properties(struct axi_dma_chip *chip)
>  
>  static int dw_probe(struct platform_device *pdev)
>  {
> -	struct device_node *node = pdev->dev.of_node;
>  	struct axi_dma_chip *chip;
>  	struct dw_axi_dma *dw;
>  	struct dw_axi_dma_hcfg *hdata;
> +	struct reset_control *resets;
> +	unsigned int flags;
>  	u32 i;
>  	int ret;
>  
> @@ -1398,12 +1406,25 @@ static int dw_probe(struct platform_device *pdev)
>  	if (IS_ERR(chip->regs))
>  		return PTR_ERR(chip->regs);
>  
> -	if (of_device_is_compatible(node, "intel,kmb-axi-dma")) {
> +	flags = (uintptr_t)of_device_get_match_data(&pdev->dev);
> +	if (flags & AXI_DMA_FLAG_HAS_APB_REGS) {
>  		chip->apb_regs = devm_platform_ioremap_resource(pdev, 1);
>  		if (IS_ERR(chip->apb_regs))
>  			return PTR_ERR(chip->apb_regs);
>  	}
>  
> +	if (flags & AXI_DMA_FLAG_HAS_RESETS) {
> +		resets = devm_reset_control_array_get_exclusive(&pdev->dev);
> +		if (IS_ERR(resets))
> +			return PTR_ERR(resets);
> +
> +		ret = reset_control_deassert(resets);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	chip->dw->hdata->use_cfg2 = !!(flags & AXI_DMA_FLAG_USE_CFG2);
> +
>  	chip->core_clk = devm_clk_get(chip->dev, "core-clk");
>  	if (IS_ERR(chip->core_clk))
>  		return PTR_ERR(chip->core_clk);
> @@ -1554,8 +1575,15 @@ static const struct dev_pm_ops dw_axi_dma_pm_ops = {
>  };
>  
>  static const struct of_device_id dw_dma_of_id_table[] = {
> -	{ .compatible = "snps,axi-dma-1.01a" },
> -	{ .compatible = "intel,kmb-axi-dma" },
> +	{
> +		.compatible = "snps,axi-dma-1.01a"
> +	}, {
> +		.compatible = "intel,kmb-axi-dma",
> +		.data = (void *)AXI_DMA_FLAG_HAS_APB_REGS,
> +	}, {
> +		.compatible = "starfive,jh7110-axi-dma",
> +		.data = (void *)(AXI_DMA_FLAG_HAS_RESETS | AXI_DMA_FLAG_USE_CFG2),
> +	},
>  	{}
>  };
>  MODULE_DEVICE_TABLE(of, dw_dma_of_id_table);
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> index e9d5eb0fd594..eb267cb24f67 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> @@ -33,6 +33,7 @@ struct dw_axi_dma_hcfg {
>  	/* Register map for DMAX_NUM_CHANNELS <= 8 */
>  	bool	reg_map_8_channels;
>  	bool	restrict_axi_burst_len;
> +	bool	use_cfg2;
>  };
>  
>  struct axi_dma_chan {
> -- 
> 2.17.1

-- 
~Vinod