PCI: rockchip: Idle inactive PHY(s)

Check the status of all lanes and idle the inactive one(s).
Tested-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
[bhelgaas: always set lanes_map, even for legacy_phy case]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/pci/host/pcie-rockchip.c

@@ -15,6 +15,7 @@
  * (at your option) any later version.
  */
 
+#include <linux/bitrev.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
@@ -112,6 +113,9 @@
 #define   PCIE_CORE_TXCREDIT_CFG1_MUI_SHIFT	16
 #define   PCIE_CORE_TXCREDIT_CFG1_MUI_ENCODE(x) \
 		(((x) >> 3) << PCIE_CORE_TXCREDIT_CFG1_MUI_SHIFT)
+#define PCIE_CORE_LANE_MAP             (PCIE_CORE_CTRL_MGMT_BASE + 0x200)
+#define   PCIE_CORE_LANE_MAP_MASK              0x0000000f
+#define   PCIE_CORE_LANE_MAP_REVERSE           BIT(16)
 #define PCIE_CORE_INT_STATUS		(PCIE_CORE_CTRL_MGMT_BASE + 0x20c)
 #define   PCIE_CORE_INT_PRFPE			BIT(0)
 #define   PCIE_CORE_INT_CRFPE			BIT(1)
@@ -230,6 +234,7 @@ struct rockchip_pcie {
 	struct	regulator *vpcie0v9; /* 0.9V power supply */
 	struct	gpio_desc *ep_gpio;
 	u32	lanes;
+	u8      lanes_map;
 	u8	root_bus_nr;
 	int	link_gen;
 	struct	device *dev;
@@ -302,6 +307,24 @@ static int rockchip_pcie_valid_device(struct rockchip_pcie *rockchip,
 	return 1;
 }
 
+static u8 rockchip_pcie_lane_map(struct rockchip_pcie *rockchip)
+{
+	u32 val;
+	u8 map;
+
+	if (rockchip->legacy_phy)
+		return GENMASK(MAX_LANE_NUM - 1, 0);
+
+	val = rockchip_pcie_read(rockchip, PCIE_CORE_LANE_MAP);
+	map = val & PCIE_CORE_LANE_MAP_MASK;
+
+	/* The link may be using a reverse-indexed mapping. */
+	if (val & PCIE_CORE_LANE_MAP_REVERSE)
+		map = bitrev8(map) >> 4;
+
+	return map;
+}
+
 static int rockchip_pcie_rd_own_conf(struct rockchip_pcie *rockchip,
 				     int where, int size, u32 *val)
 {
@@ -698,6 +721,15 @@ static int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 			  PCIE_CORE_PL_CONF_LANE_SHIFT);
 	dev_dbg(dev, "current link width is x%d\n", status);
 
+	/* Power off unused lane(s) */
+	rockchip->lanes_map = rockchip_pcie_lane_map(rockchip);
+	for (i = 0; i < MAX_LANE_NUM; i++) {
+		if (!(rockchip->lanes_map & BIT(i))) {
+			dev_dbg(dev, "idling lane %d\n", i);
+			phy_power_off(rockchip->phys[i]);
+		}
+	}
+
 	rockchip_pcie_write(rockchip, ROCKCHIP_VENDOR_ID,
 			    PCIE_CORE_CONFIG_VENDOR);
 	rockchip_pcie_write(rockchip,
@@ -1349,7 +1381,9 @@ static int __maybe_unused rockchip_pcie_suspend_noirq(struct device *dev)
 	}
 
 	for (i = 0; i < MAX_LANE_NUM; i++) {
-		phy_power_off(rockchip->phys[i]);
+		/* inactive lanes are already powered off */
+		if (rockchip->lanes_map & BIT(i))
+			phy_power_off(rockchip->phys[i]);
 		phy_exit(rockchip->phys[i]);
 	}
 
@@ -1597,7 +1631,9 @@ static int rockchip_pcie_remove(struct platform_device *pdev)
 	irq_domain_remove(rockchip->irq_domain);
 
 	for (i = 0; i < MAX_LANE_NUM; i++) {
-		phy_power_off(rockchip->phys[i]);
+		/* inactive lanes are already powered off */
+		if (rockchip->lanes_map & BIT(i))
+			phy_power_off(rockchip->phys[i]);
 		phy_exit(rockchip->phys[i]);
 	}