[RFC PATCH v4 4/7] PCI: rockchip: idle the inactive PHY(s)

[Shawn Lin <shawn.lin@rock-chips.com>]

Check the status of all lanes and idle the inactive one(s).

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Jeffy Chen <jeffy.chen@rock-chips.com>
---

Changes in v4:
- return u8 for rockchip_pcie_lane_map

Changes in v3:
- use cached lanes_map to avoid powering off inactive
  lanes twice

Changes in v2: None

 drivers/pci/host/pcie-rockchip.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
index f510349..a8c51b0 100644
--- a/drivers/pci/host/pcie-rockchip.c
+++ b/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)
@@ -229,6 +233,7 @@ 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;
@@ -301,6 +306,18 @@ static int rockchip_pcie_valid_device(struct rockchip_pcie *rockchip,
 	return 1;
 }
 
+static u8 rockchip_pcie_lane_map(struct rockchip_pcie *rockchip)
+{
+	u32 val = rockchip_pcie_read(rockchip, PCIE_CORE_LANE_MAP);
+	u8 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)
 {
@@ -697,6 +714,18 @@ 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);
 
+	if (!rockchip->legacy_phy) {
+		/*  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))
+				continue;
+
+			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,
@@ -1329,7 +1358,9 @@ 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 lane is already powered off */
+		if (rockchip->lanes_map & BIT(i))
+			phy_power_off(rockchip->phys[i]);
 		phy_exit(rockchip->phys[i]);
 	}
 
@@ -1575,7 +1606,9 @@ 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 lane is already powered off */
+		if (rockchip->lanes_map & BIT(i))
+			phy_power_off(rockchip->phys[i]);
 		phy_exit(rockchip->phys[i]);
 	}
 
-- 
1.9.1