[PATCH 08/12] PCI: tegra: Wait for DLLP to finish before entering L1 or L2

Manikanta Maddireddy
2017-10-27T19:29:25Z

Set required bit to have LTSSM wait for DLLP to finish before entering L1
or L2. This avoids truncation of PM messages which results in receiver
errors.

Signed-off-by: Manikanta Maddireddy <mmaddireddy-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
drivers/pci/host/pci-tegra.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index b8cac871712b..6028d5f3d5bb 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -217,6 +217,9 @@
#define RP_VEND_CTL1 0xf48
#define RP_VEND_CTL1_ERPT (1 << 13)

+#define RP_VEND_XP_BIST 0xf4c
+#define RP_VEND_XP_BIST_GOTO_L1_L2_AFTER_DLLP_DONE (1 << 28)
+
#define RP_VEND_CTL2 0x00000fa8
#define RP_VEND_CTL2_PCA_ENABLE (1 << 7)

@@ -2160,6 +2163,13 @@ static void tegra_pcie_apply_sw_fixup(struct tegra_pcie_port *port)
value |= RP_VEND_XP_OPPORTUNISTIC_ACK;
value |= RP_VEND_XP_OPPORTUNISTIC_UPDATEFC;
writel(value, port->base + RP_VEND_XP);
+
+ /* LTSSM will wait for DLLP to finish before entering L1 or L2,
+ * to avoid truncation of PM messages which results in receiver errors
+ */
+ value = readl(port->base + RP_VEND_XP_BIST);
+ value |= RP_VEND_XP_BIST_GOTO_L1_L2_AFTER_DLLP_DONE;
+ writel(value, port->base + RP_VEND_XP_BIST);
}
/*
* FIXME: If there are no PCIe cards attached, then calling this function
--
2.1.4