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Date: Mon, 26 Feb 2024 15:57:44 +0300
From: Serge Semin <fancer.lancer@gmail.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>, 
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>, Lorenzo Pieralisi <lpieralisi@kernel.org>, 
	Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>, Rob Herring <robh@kernel.org>, 
	Bjorn Helgaas <bhelgaas@google.com>, Marek Vasut <marek.vasut+renesas@gmail.com>, 
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>, Kishon Vijay Abraham I <kishon@kernel.org>, 
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, 
	linux-arm-msm@vger.kernel.org, mhi@lists.linux.dev, Siddharth Vadapalli <s-vadapalli@ti.com>
Subject: Re: [PATCH v3 3/5] PCI: dwc: Pass the eDMA mapping format flag
 directly from glue drivers
Message-ID: <p5zdbyfkmea4fev4myvwrjd7zr7vfaeymwsg5rhodu2hqkwhra@cts5cgmvetza>
References: <20240226-dw-hdma-v3-0-cfcb8171fc24@linaro.org>
 <20240226-dw-hdma-v3-3-cfcb8171fc24@linaro.org>
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In-Reply-To: <20240226-dw-hdma-v3-3-cfcb8171fc24@linaro.org>

On Mon, Feb 26, 2024 at 05:07:28PM +0530, Manivannan Sadhasivam wrote:
> Instead of maintaining a separate capability for glue drivers that cannot
> support auto detection of the eDMA mapping format, let's pass the mapping
> format directly from them.
> 
> This will simplify the code and also allow adding HDMA support that also
> doesn't support auto detection of mapping format.
> 
> Suggested-by: Serge Semin <fancer.lancer@gmail.com>
> Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Reviewed-by: Serge Semin <fancer.lancer@gmail.com>

-Serge(y)

> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 16 +++++++++-------
>  drivers/pci/controller/dwc/pcie-designware.h |  5 ++---
>  drivers/pci/controller/dwc/pcie-rcar-gen4.c  |  2 +-
>  3 files changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index ce273c3c5421..3e90b9947a13 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -894,18 +894,20 @@ static int dw_pcie_edma_find_mf(struct dw_pcie *pci)
>  {
>  	u32 val;
>  
> +	/*
> +	 * Bail out finding the mapping format if it is already set by the glue
> +	 * driver. Also ensure that the edma.reg_base is pointing to a valid
> +	 * memory region.
> +	 */
> +	if (pci->edma.mf != EDMA_MF_EDMA_LEGACY)
> +		return pci->edma.reg_base ? 0 : -ENODEV;
> +
>  	/*
>  	 * Indirect eDMA CSRs access has been completely removed since v5.40a
>  	 * thus no space is now reserved for the eDMA channels viewport and
>  	 * former DMA CTRL register is no longer fixed to FFs.
> -	 *
> -	 * Note that Renesas R-Car S4-8's PCIe controllers for unknown reason
> -	 * have zeros in the eDMA CTRL register even though the HW-manual
> -	 * explicitly states there must FFs if the unrolled mapping is enabled.
> -	 * For such cases the low-level drivers are supposed to manually
> -	 * activate the unrolled mapping to bypass the auto-detection procedure.
>  	 */
> -	if (dw_pcie_ver_is_ge(pci, 540A) || dw_pcie_cap_is(pci, EDMA_UNROLL))
> +	if (dw_pcie_ver_is_ge(pci, 540A))
>  		val = 0xFFFFFFFF;
>  	else
>  		val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL);
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 26dae4837462..995805279021 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -51,9 +51,8 @@
>  
>  /* DWC PCIe controller capabilities */
>  #define DW_PCIE_CAP_REQ_RES		0
> -#define DW_PCIE_CAP_EDMA_UNROLL		1
> -#define DW_PCIE_CAP_IATU_UNROLL		2
> -#define DW_PCIE_CAP_CDM_CHECK		3
> +#define DW_PCIE_CAP_IATU_UNROLL		1
> +#define DW_PCIE_CAP_CDM_CHECK		2
>  
>  #define dw_pcie_cap_is(_pci, _cap) \
>  	test_bit(DW_PCIE_CAP_ ## _cap, &(_pci)->caps)
> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> index e9166619b1f9..3c535ef5ea91 100644
> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> @@ -255,7 +255,7 @@ static struct rcar_gen4_pcie *rcar_gen4_pcie_alloc(struct platform_device *pdev)
>  	rcar->dw.ops = &dw_pcie_ops;
>  	rcar->dw.dev = dev;
>  	rcar->pdev = pdev;
> -	dw_pcie_cap_set(&rcar->dw, EDMA_UNROLL);
> +	rcar->dw.edma.mf = EDMA_MF_EDMA_UNROLL;
>  	dw_pcie_cap_set(&rcar->dw, REQ_RES);
>  	platform_set_drvdata(pdev, rcar);
>  
> 
> -- 
> 2.25.1
>