PCI: j721e: Add PCIe 4x lane selection support

Add support for setting of two-bit field that allows selection of 4x lane
PCIe which was previously limited to only 2x lanes.

Link: https://lore.kernel.org/linux-pci/20231128054402.2155183-5-s-vadapalli@ti.com
Signed-off-by: Matt Ranostay <mranostay@ti.com>
Signed-off-by: Achal Verma <a-verma1@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>

diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index 63c758b14314d834c07656ff921a4f9759c54ffe..645597856a1d938f509c02ade8bbfb2f3859a63b 100644 (file)
--- 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 = 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");
 
@@ -441,7 +445,9 @@ static int j721e_pcie_probe(struct platform_device *pdev)
                dev_warn(dev, "num-lanes property not provided or invalid, setting num-lanes to 1\n");
                num_lanes = 1;
        }
+
        pcie->num_lanes = num_lanes;
+       pcie->max_lanes = data->max_lanes;
 
        if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48)))
                return -EINVAL;