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List:       linux-tegra
Subject:    [PATCH V3 08/12] PCI: tegra: Wait for DLLP to finish before entering L1 or L2
From:       Manikanta Maddireddy <mmaddireddy () nvidia ! com>
Date:       2017-10-30 13:59:24
Message-ID: 1509371843-22931-9-git-send-email-mmaddireddy () nvidia ! com
[Download RAW message or body]

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@nvidia.com>
---
V3:
* no change in this patch
V2:
* no change in this patch

 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 c264037112cb..34740a7033f7 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -219,6 +219,9 @@
 #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)
 
@@ -2162,6 +2165,13 @@ 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

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