From: Stephen Warren <swarren@xxxxxxxxxx>
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 mays 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@xxxxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/host/pci-tegra.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 75607c7..ad95c40 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;
--
1.8.3.4
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