[U-Boot] [upstream-release] [PATCH] pci: layerscape: add option to statically allocate PCI StreamIDs

[Bharat Bhushan]

> -----Original Message-----
> From: upstream-release-bounces at linux.nxdi.nxp.com <upstream-release-
> bounces at linux.nxdi.nxp.com> On Behalf Of laurentiu.tudor at nxp.com
> Sent: Wednesday, January 30, 2019 5:31 PM
> To: u-boot at lists.denx.de; Prabhakar Kushwaha
> <prabhakar.kushwaha at nxp.com>; York Sun <york.sun at nxp.com>
> Cc: Laurentiu Tudor <laurentiu.tudor at nxp.com>
> Subject: [upstream-release] [PATCH] pci: layerscape: add option to statically
> allocate PCI StreamIDs
> 
> From: Laurentiu Tudor <laurentiu.tudor at nxp.com>
> 
> Certain PCI scenarios have more dynamic requirements, e.g. endpoints are
> "hot-plugged" later in the system lifetime. Add a Kconfig option that allows
> specifying a maximum number of end-points, per PCI controller and allocate
> a StreamID for each one.
> 
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor at nxp.com>
> ---
>  arch/arm/cpu/armv8/fsl-layerscape/Kconfig | 28 +++++++++++++++++
>  drivers/pci/pcie_layerscape_fixup.c       | 38 +++++++++++++++++++++++
>  2 files changed, 66 insertions(+)
> 
> diff --git a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> index 2b086da79b..1d633d71a8 100644
> --- a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> +++ b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
> @@ -571,3 +571,31 @@ config TFABOOT
>         help
>           Enabling this will make a U-Boot binary that is capable of being
>           booted via TFA.
> +
> +menuconfig FSL_PCIE_STATIC_STREAM_IDS
> +	bool "Allocate PCI streamIDs statically"
> +	default n
> +	depends on PCIE_LAYERSCAPE
> +	help
> +	  Statically allocate a certain number of StreamIDs for each PCI
> +	  controller, instead of enumerating the connected endpoints and
> +	  allocate a StreamID for each one. This allocation method can
> +	  be used in more dynamic PCI scenarios, e.g. where endpoints are
> +	  "hot-plugged" later in the system bringup, by statically specifying
> +	  a maximum number of StreamIDs expected for each PCI controller.
> +
> +if FSL_PCIE_STATIC_STREAM_IDS
> +
> +config FSL_PCIE1_STREAM_IDS_COUNT
> +	default 3
> +	int "Maximum number of streamIDs to allocate for PCI1 controller"
> +
> +config FSL_PCIE2_STREAM_IDS_COUNT
> +	default 3
> +	int "Maximum number of streamIDs to allocate for PCI2 controller"
> +
> +config FSL_PCIE3_STREAM_IDS_COUNT
> +	default 3
> +	int "Maximum number of streamIDs to allocate for PCI3 controller"
> +
> +endif
> diff --git a/drivers/pci/pcie_layerscape_fixup.c
> b/drivers/pci/pcie_layerscape_fixup.c
> index 1a17bd98aa..32355cbf2e 100644
> --- a/drivers/pci/pcie_layerscape_fixup.c
> +++ b/drivers/pci/pcie_layerscape_fixup.c
> @@ -177,6 +177,7 @@ static void fdt_pcie_set_iommu_map_entry(void
> *blob, struct ls_pcie *pcie,
> 
>  static void fdt_fixup_pcie(void *blob)
>  {
> +#if !CONFIG_FSL_PCIE_STATIC_STREAM_IDS
>  	struct udevice *dev, *bus;
>  	struct ls_pcie *pcie;
>  	int streamid;
> @@ -215,6 +216,43 @@ static void fdt_fixup_pcie(void *blob)
>  		fdt_pcie_set_iommu_map_entry(blob, pcie, bdf >> 8,
>  					     streamid);
>  	}
> +#else
> +	static const int streamid_cnt[] = {
> +		CONFIG_FSL_PCIE1_STREAM_IDS_COUNT,
> +		CONFIG_FSL_PCIE2_STREAM_IDS_COUNT,
> +		CONFIG_FSL_PCIE3_STREAM_IDS_COUNT

Why 3 controllers?

> +	};
> +	struct ls_pcie *pcie;
> +	int i, streamid, index;
> +	pci_dev_t bdf;
> +
> +	list_for_each_entry(pcie, &ls_pcie_list, list) {
> +		for (i = 0; i < streamid_cnt[pcie->idx]; i++) {
> +			streamid = ls_pcie_next_streamid();
> +			if (streamid < 0) {
> +				debug("ERROR: no stream ids free\n");
> +				continue;

Why to continue if we are out of stream-ids?

> +			}
> +
> +			index = ls_pcie_next_lut_index(pcie);
> +			if (index < 0) {
> +				debug("ERROR: no LUT indexes free\n");
> +				continue;

We can error out when out of LUT entry

> +			}
> +
> +			bdf = PCI_BDF(i, 0, 0);
> +			/* map PCI b.d.f to streamID in LUT */
> +			ls_pcie_lut_set_mapping(pcie, index, bdf >> 8,
> +						streamid);
> +			/* update msi-map in device tree */
> +			fdt_pcie_set_msi_map_entry(blob, pcie, bdf >> 8,
> +						   streamid);
> +			/* update iommu-map in device tree */
> +			fdt_pcie_set_iommu_map_entry(blob, pcie, bdf >>
> 8,
> +						     streamid);
> +		}
> +	}
> +#endif /* !CONFIG_FSL_PCIE_STATIC_STREAM_IDS */
>  }
>  #endif
> 
> --
> 2.17.1
> 
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