[PATCH 13/30] PCI: tegra: Update flow control threshold in Tegra210

[Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>]

Recommended update FC threshold in Tegra210 is 0x60 for best performance
of x1 link. Setting this to 0x60 provides the best balance between number
of UpdateFC and read data sent over the link.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
---
 drivers/pci/controller/pci-tegra.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index b74408eeb367..7dc728cc5f51 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -319,6 +319,7 @@ struct tegra_pcie_soc {
 	bool update_clamp_threshold;
 	bool program_deskew_time;
 	bool raw_violation_fixup;
+	bool update_fc_threshold;
 	struct {
 		struct {
 			u32 rp_ectl_2_r1;
@@ -662,6 +663,13 @@ static void tegra_pcie_apply_sw_fixup(struct tegra_pcie_port *port)
 		value |= soc->update_fc_val;
 		writel(value, port->base + RP_VEND_XP);
 	}
+
+	if (soc->update_fc_threshold) {
+		value = readl(port->base + RP_VEND_XP);
+		value &= ~RP_VEND_XP_UPDATE_FC_THRESHOLD_MASK;
+		value |= soc->update_fc_val;
+		writel(value, port->base + RP_VEND_XP);
+	}
 }
 
 static void tegra_pcie_port_enable(struct tegra_pcie_port *port)
@@ -2409,6 +2417,7 @@ static const struct tegra_pcie_soc tegra20_pcie = {
 	.update_clamp_threshold = false,
 	.program_deskew_time = false,
 	.raw_violation_fixup = false,
+	.update_fc_threshold = false,
 	.ectl.enable = false,
 };
 
@@ -2436,6 +2445,7 @@ static const struct tegra_pcie_soc tegra30_pcie = {
 	.update_clamp_threshold = false,
 	.program_deskew_time = false,
 	.raw_violation_fixup = false,
+	.update_fc_threshold = false,
 	.ectl.enable = false,
 };
 
@@ -2458,6 +2468,7 @@ static const struct tegra_pcie_soc tegra124_pcie = {
 	.update_clamp_threshold = true,
 	.program_deskew_time = false,
 	.raw_violation_fixup = true,
+	.update_fc_threshold = false,
 	.ectl.enable = false,
 };
 
@@ -2468,6 +2479,8 @@ static const struct tegra_pcie_soc tegra210_pcie = {
 	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
 	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
 	.pads_refclk_cfg0 = 0x90b890b8,
+	/* FC threshold is bit[25:18] */
+	.update_fc_val = 0x01800000,
 	.has_pex_clkreq_en = true,
 	.has_pex_bias_ctrl = true,
 	.has_intr_prsnt_sense = true,
@@ -2478,6 +2491,7 @@ static const struct tegra_pcie_soc tegra210_pcie = {
 	.update_clamp_threshold = true,
 	.program_deskew_time = true,
 	.raw_violation_fixup = false,
+	.update_fc_threshold = true,
 	.ectl.regs.rp_ectl_2_r1 = 0x0000000f,
 	.ectl.regs.rp_ectl_4_r1 = 0x00000067,
 	.ectl.regs.rp_ectl_5_r1 = 0x55010000,
@@ -2513,6 +2527,7 @@ static const struct tegra_pcie_soc tegra186_pcie = {
 	.update_clamp_threshold = false,
 	.program_deskew_time = false,
 	.raw_violation_fixup = false,
+	.update_fc_threshold = false,
 	.ectl.enable = false,
 };
 
-- 
2.17.1