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From: Manikanta Maddireddy <mmaddireddy@nvidia.com>
To: <thierry.reding@gmail.com>, <bhelgaas@google.com>,
	<robh+dt@kernel.org>, <mark.rutland@arm.com>,
	<jonathanh@nvidia.com>, <lorenzo.pieralisi@arm.com>,
	<vidyas@nvidia.com>
Cc: <linux-tegra@vger.kernel.org>, <linux-pci@vger.kernel.org>,
	<devicetree@vger.kernel.org>,
	Manikanta Maddireddy <mmaddireddy@nvidia.com>
Subject: [PATCH V5 05/27] PCI: tegra: Fix PCIe host power up sequence
Date: Mon, 17 Jun 2019 23:09:30 +0530
Message-ID: <20190617173952.29363-6-mmaddireddy@nvidia.com> (raw)
In-Reply-To: <20190617173952.29363-1-mmaddireddy@nvidia.com>

PCIe host power up sequence involves programming AFI(AXI to FPCI bridge)
registers first and then PCIe registers. Otherwise AFI register settings
may not latch to PCIe IP.

PCIe root port starts LTSSM as soon as PCIe xrst is deasserted.
So deassert PCIe xrst after programming PCIe registers.

Modify PCIe power up sequence as follows,
 - Power ungate PCIe partition
 - Enable AFI clock
 - Deassert AFI reset
 - Program AFI registers
 - Enable PCIe clock
 - Deassert PCIe reset
 - Program PCIe PHY
 - Program PCIe pad control registers
 - Program PCIe root port registers
 - Deassert PCIe xrst to start LTSSM

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
---
V5: No change

V4: No change

V3: No change

V2: Error cleanup changes are moved to new patch and only sequence
correction is done in this patch.

 drivers/pci/controller/pci-tegra.c | 52 +++++++++++++++++-------------
 1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index 0453bfb2726e..5e9fcef5f8eb 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -949,9 +949,6 @@ static void tegra_pcie_enable_controller(struct tegra_pcie *pcie)
 		afi_writel(pcie, value, AFI_FUSE);
 	}
 
-	/* take the PCIe interface module out of reset */
-	reset_control_deassert(pcie->pcie_xrst);
-
 	/* finally enable PCIe */
 	value = afi_readl(pcie, AFI_CONFIGURATION);
 	value |= AFI_CONFIGURATION_EN_FPCI;
@@ -981,13 +978,11 @@ static void tegra_pcie_power_off(struct tegra_pcie *pcie)
 	int err;
 
 	reset_control_assert(pcie->afi_rst);
-	reset_control_assert(pcie->pex_rst);
 
 	clk_disable_unprepare(pcie->pll_e);
 	if (soc->has_cml_clk)
 		clk_disable_unprepare(pcie->cml_clk);
 	clk_disable_unprepare(pcie->afi_clk);
-	clk_disable_unprepare(pcie->pex_clk);
 
 	if (!dev->pm_domain)
 		tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);
@@ -1015,25 +1010,19 @@ static int tegra_pcie_power_on(struct tegra_pcie *pcie)
 	if (err < 0)
 		dev_err(dev, "failed to enable regulators: %d\n", err);
 
-	if (dev->pm_domain) {
-		err = clk_prepare_enable(pcie->pex_clk);
+	if (!dev->pm_domain) {
+		err = tegra_powergate_power_on(TEGRA_POWERGATE_PCIE);
 		if (err) {
-			dev_err(dev, "failed to enable PEX clock: %d\n", err);
+			dev_err(dev, "failed to power ungate: %d\n", err);
 			goto regulator_disable;
 		}
-		reset_control_deassert(pcie->pex_rst);
-	} else {
-		err = tegra_powergate_sequence_power_up(TEGRA_POWERGATE_PCIE,
-							pcie->pex_clk,
-							pcie->pex_rst);
+		err = tegra_powergate_remove_clamping(TEGRA_POWERGATE_PCIE);
 		if (err) {
-			dev_err(dev, "powerup sequence failed: %d\n", err);
-			goto regulator_disable;
+			dev_err(dev, "failed to remove clamp: %d\n", err);
+			goto powergate;
 		}
 	}
 
-	reset_control_deassert(pcie->afi_rst);
-
 	err = clk_prepare_enable(pcie->afi_clk);
 	if (err < 0) {
 		dev_err(dev, "failed to enable AFI clock: %d\n", err);
@@ -1054,6 +1043,8 @@ static int tegra_pcie_power_on(struct tegra_pcie *pcie)
 		goto disable_cml_clk;
 	}
 
+	reset_control_deassert(pcie->afi_rst);
+
 	return 0;
 
 disable_cml_clk:
@@ -1062,9 +1053,6 @@ static int tegra_pcie_power_on(struct tegra_pcie *pcie)
 disable_afi_clk:
 	clk_disable_unprepare(pcie->afi_clk);
 powergate:
-	reset_control_assert(pcie->afi_rst);
-	reset_control_assert(pcie->pex_rst);
-	clk_disable_unprepare(pcie->pex_clk);
 	if (!dev->pm_domain)
 		tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);
 regulator_disable:
@@ -2111,7 +2099,12 @@ static void tegra_pcie_enable_ports(struct tegra_pcie *pcie)
 			 port->index, port->lanes);
 
 		tegra_pcie_port_enable(port);
+	}
 
+	/* Start LTSSM from Tegra side */
+	reset_control_deassert(pcie->pcie_xrst);
+
+	list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
 		if (tegra_pcie_port_check_link(port))
 			continue;
 
@@ -2126,6 +2119,8 @@ static void tegra_pcie_disable_ports(struct tegra_pcie *pcie)
 {
 	struct tegra_pcie_port *port, *tmp;
 
+	reset_control_assert(pcie->pcie_xrst);
+
 	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
 		tegra_pcie_port_disable(port);
 }
@@ -2488,10 +2483,12 @@ static int __maybe_unused tegra_pcie_pm_suspend(struct device *dev)
 			dev_err(dev, "failed to power off PHY(s): %d\n", err);
 	}
 
+	reset_control_assert(pcie->pex_rst);
+	clk_disable_unprepare(pcie->pex_clk);
+
 	if (IS_ENABLED(CONFIG_PCI_MSI))
 		tegra_pcie_disable_msi(pcie);
 
-	reset_control_assert(pcie->pcie_xrst);
 	tegra_pcie_power_off(pcie);
 
 	return 0;
@@ -2513,11 +2510,19 @@ static int __maybe_unused tegra_pcie_pm_resume(struct device *dev)
 	if (IS_ENABLED(CONFIG_PCI_MSI))
 		tegra_pcie_enable_msi(pcie);
 
+	err = clk_prepare_enable(pcie->pex_clk);
+	if (err) {
+		dev_err(dev, "failed to enable PEX clock: %d\n", err);
+		goto poweroff;
+	}
+
+	reset_control_deassert(pcie->pex_rst);
+
 	if (pcie->soc->program_uphy) {
 		err = tegra_pcie_phy_power_on(pcie);
 		if (err < 0) {
 			dev_err(dev, "failed to power on PHY(s): %d\n", err);
-			goto poweroff;
+			goto disable_pex_clk;
 		}
 	}
 
@@ -2526,6 +2531,9 @@ static int __maybe_unused tegra_pcie_pm_resume(struct device *dev)
 
 	return 0;
 
+disable_pex_clk:
+	reset_control_assert(pcie->pex_rst);
+	clk_disable_unprepare(pcie->pex_clk);
 poweroff:
 	tegra_pcie_power_off(pcie);
 
-- 
2.17.1


  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 17:39 [PATCH V5 00/27] Enable Tegra PCIe root port features Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 01/27] soc/tegra: pmc: Export tegra_powergate_power_on() Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 02/27] PCI: tegra: Handle failure cases in tegra_pcie_power_on() Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 03/27] PCI: tegra: Rearrange Tegra PCIe driver functions Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 04/27] PCI: tegra: Mask AFI_INTR in runtime suspend Manikanta Maddireddy
2019-06-17 17:39 ` Manikanta Maddireddy [this message]
2019-06-17 17:39 ` [PATCH V5 06/27] PCI: tegra: Add PCIe Gen2 link speed support Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 07/27] PCI: tegra: Advertise PCIe Advanced Error Reporting (AER) capability Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 08/27] PCI: tegra: Program UPHY electrical settings for Tegra210 Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 09/27] PCI: tegra: Enable opportunistic UpdateFC and ACK Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 10/27] PCI: tegra: Disable AFI dynamic clock gating Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 11/27] PCI: tegra: Process pending DLL transactions before entering L1 or L2 Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 12/27] PCI: tegra: Enable PCIe xclk clock clamping Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 13/27] PCI: tegra: Increase the deskew retry time Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 14/27] PCI: tegra: Add SW fixup for RAW violations Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 15/27] PCI: tegra: Update flow control timer frequency in Tegra210 Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 16/27] PCI: tegra: Set target speed as Gen1 before starting LTSSM Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 17/27] PCI: tegra: Fix PLLE power down issue due to CLKREQ# signal Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 18/27] PCI: tegra: Program AFI_CACHE* registers only for Tegra20 Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 19/27] PCI: tegra: Change PRSNT_SENSE IRQ log to debug Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 20/27] PCI: tegra: Use legacy IRQ for port service drivers Manikanta Maddireddy
2019-06-18  5:47   ` Manikanta Maddireddy
2019-06-18 13:35     ` Lorenzo Pieralisi
2019-06-17 17:39 ` [PATCH V5 21/27] PCI: tegra: Add AFI_PEX2_CTRL reg offset as part of soc struct Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 22/27] dt-bindings: pci: tegra: Document PCIe DPD pinctrl optional prop Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 23/27] arm64: tegra: Add PEX DPD states as pinctrl properties Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 24/27] PCI: tegra: Put PEX CLK & BIAS pads in DPD mode Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 25/27] PCI: Add DT binding for "reset-gpios" property Manikanta Maddireddy
2019-06-17 17:39 ` [PATCH V5 26/27] PCI: tegra: Add support for GPIO based PERST# Manikanta Maddireddy
2019-06-18 10:51   ` Thierry Reding
2019-06-17 17:39 ` [PATCH V5 27/27] PCI: tegra: Change link retry log level to debug Manikanta Maddireddy

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