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Date:   Fri, 24 Nov 2023 17:41:36 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     shravan chippa <shravan.chippa@microchip.com>
Cc:     green.wan@sifive.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, palmer@dabbelt.com,
        paul.walmsley@sifive.com, conor+dt@kernel.org,
        dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        nagasuresh.relli@microchip.com, praveen.kumar@microchip.com,
        Emil Renner Berthing <emil.renner.berthing@canonical.com>
Subject: Re: [PATCH v4 3/4] dmaengine: sf-pdma: add mpfs-pdma compatible name
Message-ID: <ZWCS+ECGTgwVPR1u@matsya>
References: <20231031052753.3430169-1-shravan.chippa@microchip.com>
 <20231031052753.3430169-4-shravan.chippa@microchip.com>
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On 31-10-23, 10:57, shravan chippa wrote:
> From: Shravan Chippa <shravan.chippa@microchip.com>
> 
> Sifive platform dma does not allow out-of-order transfers,
> Add a PolarFire SoC specific compatible and code to support
> for out-of-order dma transfers

By default dma xtions are not supposed to be out of order, so why does
it make sense specifying that here?

> 
> Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
> Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com>
> ---
>  drivers/dma/sf-pdma/sf-pdma.c | 27 ++++++++++++++++++++++++---
>  drivers/dma/sf-pdma/sf-pdma.h |  8 +++++++-
>  2 files changed, 31 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c
> index 4c456bdef882..82ab12c40743 100644
> --- a/drivers/dma/sf-pdma/sf-pdma.c
> +++ b/drivers/dma/sf-pdma/sf-pdma.c
> @@ -25,6 +25,8 @@
>  
>  #include "sf-pdma.h"
>  
> +#define PDMA_QUIRK_NO_STRICT_ORDERING   BIT(0)
> +
>  #ifndef readq
>  static inline unsigned long long readq(void __iomem *addr)
>  {
> @@ -66,7 +68,7 @@ static struct sf_pdma_desc *sf_pdma_alloc_desc(struct sf_pdma_chan *chan)
>  static void sf_pdma_fill_desc(struct sf_pdma_desc *desc,
>  			      u64 dst, u64 src, u64 size)
>  {
> -	desc->xfer_type = PDMA_FULL_SPEED;
> +	desc->xfer_type =  desc->chan->pdma->transfer_type;
>  	desc->xfer_size = size;
>  	desc->dst_addr = dst;
>  	desc->src_addr = src;
> @@ -520,6 +522,7 @@ static struct dma_chan *sf_pdma_of_xlate(struct of_phandle_args *dma_spec,
>  
>  static int sf_pdma_probe(struct platform_device *pdev)
>  {
> +	const struct sf_pdma_driver_platdata *ddata;
>  	struct sf_pdma *pdma;
>  	int ret, n_chans;
>  	const enum dma_slave_buswidth widths =
> @@ -545,6 +548,14 @@ static int sf_pdma_probe(struct platform_device *pdev)
>  
>  	pdma->n_chans = n_chans;
>  
> +	pdma->transfer_type = PDMA_FULL_SPEED | PDMA_STRICT_ORDERING;
> +
> +	ddata  = device_get_match_data(&pdev->dev);
> +	if (ddata) {
> +		if (ddata->quirks & PDMA_QUIRK_NO_STRICT_ORDERING)
> +			pdma->transfer_type &= ~PDMA_STRICT_ORDERING;
> +	}
> +
>  	pdma->membase = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(pdma->membase))
>  		return PTR_ERR(pdma->membase);
> @@ -632,9 +643,19 @@ static int sf_pdma_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct sf_pdma_driver_platdata mpfs_pdma = {
> +	.quirks = PDMA_QUIRK_NO_STRICT_ORDERING,
> +};
> +
>  static const struct of_device_id sf_pdma_dt_ids[] = {
> -	{ .compatible = "sifive,fu540-c000-pdma" },
> -	{ .compatible = "sifive,pdma0" },
> +	{
> +		.compatible = "sifive,fu540-c000-pdma",
> +	}, {
> +		.compatible = "sifive,pdma0",
> +	}, {
> +		.compatible = "microchip,mpfs-pdma",
> +		.data	    = &mpfs_pdma,
> +	},
>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, sf_pdma_dt_ids);
> diff --git a/drivers/dma/sf-pdma/sf-pdma.h b/drivers/dma/sf-pdma/sf-pdma.h
> index 5c398a83b491..267e79a5e0a5 100644
> --- a/drivers/dma/sf-pdma/sf-pdma.h
> +++ b/drivers/dma/sf-pdma/sf-pdma.h
> @@ -48,7 +48,8 @@
>  #define PDMA_ERR_STATUS_MASK				GENMASK(31, 31)
>  
>  /* Transfer Type */
> -#define PDMA_FULL_SPEED					0xFF000008
> +#define PDMA_FULL_SPEED					0xFF000000
> +#define PDMA_STRICT_ORDERING				BIT(3)
>  
>  /* Error Recovery */
>  #define MAX_RETRY					1
> @@ -112,8 +113,13 @@ struct sf_pdma {
>  	struct dma_device       dma_dev;
>  	void __iomem            *membase;
>  	void __iomem            *mappedbase;
> +	u32			transfer_type;
>  	u32			n_chans;
>  	struct sf_pdma_chan	chans[];
>  };
>  
> +struct sf_pdma_driver_platdata {
> +	u32 quirks;
> +};
> +
>  #endif /* _SF_PDMA_H */
> -- 
> 2.34.1

-- 
~Vinod