Re: [PATCH v7 3/5] PCI: j721e: Add PCIe 4x lane selection support

From: Roger Quadros
Date: Fri Nov 25 2022 - 07:31:24 EST




On 24/11/2022 10:12, Matt Ranostay wrote:
> Add support for setting of two-bit field that allows selection of 4x lane
> PCIe which was previously limited to only 2x lanes.
>
> Signed-off-by: Matt Ranostay <mranostay@xxxxxx>
> Reviewed-by: Vignesh Raghavendra <vigneshr@xxxxxx>
> ---
> drivers/pci/controller/cadence/pci-j721e.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
> index 8990f58d64d5..dab3db9be6d8 100644
> --- a/drivers/pci/controller/cadence/pci-j721e.c
> +++ b/drivers/pci/controller/cadence/pci-j721e.c
> @@ -42,7 +42,6 @@ enum link_status {
> };
>
> #define J721E_MODE_RC BIT(7)
> -#define LANE_COUNT_MASK BIT(8)
> #define LANE_COUNT(n) ((n) << 8)
>
> #define GENERATION_SEL_MASK GENMASK(1, 0)
> @@ -52,6 +51,7 @@ struct j721e_pcie {
> struct clk *refclk;
> u32 mode;
> u32 num_lanes;
> + u32 max_lanes;
> void __iomem *user_cfg_base;
> void __iomem *intd_cfg_base;
> u32 linkdown_irq_regfield;
> @@ -205,11 +205,15 @@ static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie,
> {
> struct device *dev = pcie->cdns_pcie->dev;
> u32 lanes = pcie->num_lanes;
> + u32 mask = GENMASK(8, 8);

u32 mask = BIT(8);

> u32 val = 0;
> int ret;
>
> + if (pcie->max_lanes == 4)
> + mask = GENMASK(9, 8);
> +
> val = LANE_COUNT(lanes - 1);
> - ret = regmap_update_bits(syscon, offset, LANE_COUNT_MASK, val);
> + ret = regmap_update_bits(syscon, offset, mask, val);
> if (ret)
> dev_err(dev, "failed to set link count\n");
>
> @@ -439,6 +443,8 @@ static int j721e_pcie_probe(struct platform_device *pdev)
> ret = of_property_read_u32(node, "num-lanes", &num_lanes);
> if (ret || num_lanes > data->max_lanes)
> num_lanes = 1;
> +
> + pcie->max_lanes = data->max_lanes;
> pcie->num_lanes = num_lanes;
>
> if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48)))

Reviewed-by: Roger Quadros <rogerq@xxxxxxxxxx>

cheers,
-roger