PCI: rockchip: Provide captured slot power limit and scale

If vpcie3v3 is available, we could provide these information via RC's
configure register to make EP able to know the power limit.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
index e04f69beb42d0f8ef04de5da85702f238ff2a8a5..36f5eeb530f5287c8b506c3a8ca47cdc4e749d67 100644 (file)
--- a/drivers/pci/host/pcie-rockchip.c
+++ b/drivers/pci/host/pcie-rockchip.c
@@ -135,6 +135,10 @@
 #define PCIE_RC_CONFIG_VENDOR          (PCIE_RC_CONFIG_BASE + 0x00)
 #define PCIE_RC_CONFIG_RID_CCR         (PCIE_RC_CONFIG_BASE + 0x08)
 #define   PCIE_RC_CONFIG_SCC_SHIFT             16
+#define PCIE_RC_CONFIG_DCR             (PCIE_RC_CONFIG_BASE + 0xc4)
+#define   PCIE_RC_CONFIG_DCR_CSPL_SHIFT                18
+#define   PCIE_RC_CONFIG_DCR_CSPL_LIMIT                0xff
+#define   PCIE_RC_CONFIG_DCR_CPLS_SHIFT                26
 #define PCIE_RC_CONFIG_LCS             (PCIE_RC_CONFIG_BASE + 0xd0)
 #define   PCIE_RC_CONFIG_LCS_RETRAIN_LINK      BIT(5)
 #define   PCIE_RC_CONFIG_LCS_LBMIE             BIT(10)
@@ -398,6 +402,40 @@ static struct pci_ops rockchip_pcie_ops = {
        .write = rockchip_pcie_wr_conf,
 };
 
+static void rockchip_pcie_set_power_limit(struct rockchip_pcie *rockchip)
+{
+       u32 status, curr, scale, power;
+
+       if (IS_ERR(rockchip->vpcie3v3))
+               return;
+
+       /*
+        * Set RC's captured slot power limit and scale if
+        * vpcie3v3 available. The default values are both zero
+        * which means the software should set these two according
+        * to the actual power supply.
+        */
+       curr = regulator_get_current_limit(rockchip->vpcie3v3);
+       if (curr > 0) {
+               scale = 3; /* 0.001x */
+               curr = curr / 1000; /* convert to mA */
+               power = (curr * 3300) / 1000; /* milliwatt */
+               while (power > PCIE_RC_CONFIG_DCR_CSPL_LIMIT) {
+                       if (!scale) {
+                               dev_warn(rockchip->dev, "invalid power supply\n");
+                               return;
+                       }
+                       scale--;
+                       power = power / 10;
+               }
+
+               status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_DCR);
+               status |= (power << PCIE_RC_CONFIG_DCR_CSPL_SHIFT) |
+                         (scale << PCIE_RC_CONFIG_DCR_CPLS_SHIFT);
+               rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_DCR);
+       }
+}
+
 /**
  * rockchip_pcie_init_port - Initialize hardware
  * @rockchip: PCIe port information
@@ -537,6 +575,8 @@ static int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
                 (PCIE_CORE_CTRL_PLC1_FTS_CNT << PCIE_CORE_CTRL_PLC1_FTS_SHIFT);
        rockchip_pcie_write(rockchip, status, PCIE_CORE_CTRL_PLC1);
 
+       rockchip_pcie_set_power_limit(rockchip);
+
        /* Enable Gen1 training */
        rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
                            PCIE_CLIENT_CONFIG);