[RFC/RFT v2 10/11] PCI: rockchip: add a lane-map to rockchip pcie driver

[Frank Wunderlich <linux@fw-web.de>]

From: Frank Wunderlich <frank-w@public-files.de>

Add a basic lane-map to define which PCIe lanes should be
used with this controller.

Rockchip driver uses this for bifurcation (true/false) based
on lanes should be splitted across controllers or not.

On rk3568 there are 2 PCIe Controllers which share PCIe lanes.

pcie3x1: pcie@fe270000 //lane1 when using 1+1
pcie3x2: pcie@fe280000 //lane0 when using 1+1

This ends up in one Controller (pcie3x1) uses lane-map = <0 1>; and
the other lane-map = <1 0>; (pcie3x2)

This means there are 2 lanes (count of numbers), one (by position)
is mapped to the first controller, the other one is used on the other
controller.

In this driver the lane-map is simply converted to the bifurcation
bool instead of direct mapping a specific lane to a controller.

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
---
v2:
- new patch
---
 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 79e909df241c..21cb697a5be1 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -60,6 +60,7 @@ struct rockchip_pcie {
 	struct regulator                *vpcie3v3;
 	struct irq_domain		*irq_domain;
 	bool				bifurcation;
+	u32				lane_map[2];
 };
 
 static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
@@ -293,8 +294,10 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rockchip_pcie *rockchip;
+	unsigned int lanecnt = 0;
 	struct pcie_port *pp;
 	int ret;
+	int len;
 
 	rockchip = devm_kzalloc(dev, sizeof(*rockchip), GFP_KERNEL);
 	if (!rockchip)
@@ -327,8 +330,16 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 		}
 	}
 
-	if (device_property_read_bool(dev, "bifurcation"))
-		rockchip->bifurcation = true;
+	len = of_property_read_variable_u32_array(dev->of_node, "lane-map", rockchip->lane_map,
+						  2, ARRAY_SIZE(rockchip->lane_map));
+
+	for (int i = 0; i < len; i++)
+		if (rockchip->lane_map[i])
+			lanecnt++;
+
+	rockchip->bifurcation = ((lanecnt > 0) && (lanecnt != len));
+
+	dev_info(dev, "bifurcation: %s\n", rockchip->bifurcation ? "true" : "false");
 
 	ret = rockchip_pcie_phy_init(rockchip);
 	if (ret)
-- 
2.25.1