PCI: tegra: set up PADS_REFCLK_CFG1

The registers PADS_REFCLK_CFG are an array of 16-bit data, one entry per
PCIe root port. For Tegra30, we therefore need to write a 3rd entry in
this array. Doing so makes the mini-PCIe slot on Beaver operate correctly.

While we're at it, add some #defines to partially document the fields
within these 16-bit values.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

1 files changed, 24 insertions, 5 deletions

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 75607c788ff6..ad95c406a6d0 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -195,6 +195,25 @@
 #define PADS_REFCLK_CFG0                        0x000000C8
 #define PADS_REFCLK_CFG1                        0x000000CC
 
+/*
+ * Fields in PADS_REFCLK_CFG*. Those registers form an array of 16-bit
+ * entries, one entry per PCIe port. These field definitions and desired
+ * values aren't in the TRM, but do come from NVIDIA.
+ */
+#define PADS_REFCLK_CFG_TERM_SHIFT              2  /* 6:2 */
+#define PADS_REFCLK_CFG_E_TERM_SHIFT            7
+#define PADS_REFCLK_CFG_PREDI_SHIFT             8  /* 11:8 */
+#define PADS_REFCLK_CFG_DRVI_SHIFT              12 /* 15:12 */
+
+/* Default value provided by HW engineering is 0xfa5c */
+#define PADS_REFCLK_CFG_VALUE \
+        ( \
+                (0x17 << PADS_REFCLK_CFG_TERM_SHIFT)   | \
+                (0    << PADS_REFCLK_CFG_E_TERM_SHIFT) | \
+                (0xa  << PADS_REFCLK_CFG_PREDI_SHIFT)  | \
+                (0xf  << PADS_REFCLK_CFG_DRVI_SHIFT)     \
+        )
+
 struct tegra_msi {
         struct msi_chip chip;
         DECLARE_BITMAP(used, INT_PCI_MSI_NR);
@@ -808,11 +827,11 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie)
         value |= PADS_PLL_CTL_RST_B4SM;
         pads_writel(pcie, value, soc->pads_pll_ctl);
 
-        /*
-         * Hack, set the clock voltage to the DEFAULT provided by hw folks.
-         * This doesn't exist in the documentation.
-         */
-        pads_writel(pcie, 0xfa5cfa5c, PADS_REFCLK_CFG0);
+        /* Configure the reference clock driver */
+        value = PADS_REFCLK_CFG_VALUE | (PADS_REFCLK_CFG_VALUE << 16);
+        pads_writel(pcie, value, PADS_REFCLK_CFG0);
+        if (soc->num_ports > 2)
+                pads_writel(pcie, PADS_REFCLK_CFG_VALUE, PADS_REFCLK_CFG1);
 
         /* wait for the PLL to lock */
         timeout = 300;