Re: [PATCH v9 16/16] PCI: imx6: Add iMX95 Endpoint (EP) support

[Lorenzo Pieralisi <lpieralisi@kernel.org>]

[+Christoph, Robin - just checking with you if the DMA mask handling is
what you expect from drivers, don't want to merge code that breaks your
expectations]

On Fri, Jan 19, 2024 at 12:11:22PM -0500, Frank Li wrote:
> Add iMX95 EP support and add 64bit address support. Internal bus bridge for
> PCI support 64bit dma address in iMX95. Hence, call
> dma_set_mask_and_coherent() to set 64 bit DMA mask.
> 
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> 
> Notes:
>     Change from v8 to v9
>     - update fixme comments
>     - update BAR1 comments
>     - Add mani's review tag
>     Change from v7 to v8
>     - Update commit message
>     - Using Fixme
>     - Update clks_cnts by ARRAY_SIZE
>     
>     Change from v4 to v7
>     - none
>     Change from v3 to v4
>     - change align to 4k for imx95
>     Change from v1 to v3
>     - new patches at v3
> 
>  drivers/pci/controller/dwc/pci-imx6.c | 47 +++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index bbaa45c08323b..7889318f6555a 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -75,6 +75,7 @@ enum imx6_pcie_variants {
>  	IMX8MQ_EP,
>  	IMX8MM_EP,
>  	IMX8MP_EP,
> +	IMX95_EP,
>  };
>  
>  #define IMX6_PCIE_FLAG_IMX6_PHY			BIT(0)
> @@ -84,6 +85,7 @@ enum imx6_pcie_variants {
>  #define IMX6_PCIE_FLAG_HAS_APP_RESET		BIT(4)
>  #define IMX6_PCIE_FLAG_HAS_PHY_RESET		BIT(5)
>  #define IMX6_PCIE_FLAG_HAS_SERDES		BIT(6)
> +#define IMX6_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
>  
>  #define imx6_check_flag(pci, val)     (pci->drvdata->flags & val)
>  
> @@ -616,6 +618,7 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
>  		break;
>  	case IMX7D:
>  	case IMX95:
> +	case IMX95_EP:
>  		break;
>  	case IMX8MM:
>  	case IMX8MM_EP:
> @@ -1050,6 +1053,23 @@ static const struct pci_epc_features imx8m_pcie_epc_features = {
>  	.align = SZ_64K,
>  };
>  
> +/*
> + * BAR#	| Default BAR enable	| Default BAR Type	| Default BAR Size	| BAR Sizing Scheme
> + * ================================================================================================
> + * BAR0	| Enable		| 64-bit		| 1 MB			| Programmable Size
> + * BAR1	| Disable		| 32-bit		| 64 KB			| Fixed Size
> + *        BAR1 should be disabled if BAR0 is 64bit.
> + * BAR2	| Enable		| 32-bit		| 1 MB			| Programmable Size
> + * BAR3	| Enable		| 32-bit		| 64 KB			| Programmable Size
> + * BAR4	| Enable		| 32-bit		| 1M			| Programmable Size
> + * BAR5	| Enable		| 32-bit		| 64 KB			| Programmable Size
> + */
> +static const struct pci_epc_features imx95_pcie_epc_features = {
> +	.msi_capable = true,
> +	.bar_fixed_size[1] = SZ_64K,
> +	.align = SZ_4K,
> +};
> +
>  static const struct pci_epc_features*
>  imx6_pcie_ep_get_features(struct dw_pcie_ep *ep)
>  {
> @@ -1092,6 +1112,15 @@ static int imx6_add_pcie_ep(struct imx6_pcie *imx6_pcie,
>  
>  	pci->dbi_base2 = pci->dbi_base + pcie_dbi2_offset;
>  
> +	/*
> +	 * FIXME: Ideally, dbi2 base address should come from DT. But since only IMX95 is defining
> +	 * "dbi2" in DT, "dbi_base2" is set to NULL here for that platform alone so that the DWC
> +	 * core code can fetch that from DT. But once all platform DTs were fixed, this and the
> +	 * above "dbi_base2" setting should be removed.
> +	 */
> +	if (imx6_pcie->drvdata->variant == IMX95_EP)
> +		pci->dbi_base2 = NULL;
> +
>  	ret = dw_pcie_ep_init(ep);
>  	if (ret) {
>  		dev_err(dev, "failed to initialize endpoint\n");
> @@ -1345,6 +1374,9 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  					     "unable to find iomuxc registers\n");
>  	}
>  
> +	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_SUPPORT_64BIT))
> +		dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
> +
>  	/* Grab PCIe PHY Tx Settings */
>  	if (of_property_read_u32(node, "fsl,tx-deemph-gen1",
>  				 &imx6_pcie->tx_deemph_gen1))
> @@ -1563,6 +1595,20 @@ static const struct imx6_pcie_drvdata drvdata[] = {
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.epc_features = &imx8m_pcie_epc_features,
>  	},
> +	[IMX95_EP] = {
> +		.variant = IMX95_EP,
> +		.flags = IMX6_PCIE_FLAG_HAS_SERDES |
> +			 IMX6_PCIE_FLAG_SUPPORT_64BIT,
> +		.clk_names = imx8mq_clks,
> +		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
> +		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
> +		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
> +		.mode_off[0]  = IMX95_PE0_GEN_CTRL_1,
> +		.mode_mask[0] = IMX95_PCIE_DEVICE_TYPE,
> +		.init_phy = imx95_pcie_init_phy,
> +		.epc_features = &imx95_pcie_epc_features,
> +		.mode = DW_PCIE_EP_TYPE,
> +	},
>  };
>  
>  static const struct of_device_id imx6_pcie_of_match[] = {
> @@ -1577,6 +1623,7 @@ static const struct of_device_id imx6_pcie_of_match[] = {
>  	{ .compatible = "fsl,imx8mq-pcie-ep", .data = &drvdata[IMX8MQ_EP], },
>  	{ .compatible = "fsl,imx8mm-pcie-ep", .data = &drvdata[IMX8MM_EP], },
>  	{ .compatible = "fsl,imx8mp-pcie-ep", .data = &drvdata[IMX8MP_EP], },
> +	{ .compatible = "fsl,imx95-pcie-ep", .data = &drvdata[IMX95_EP], },
>  	{},
>  };
>  
> -- 
> 2.34.1
>