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[V9,2/3] PCI: tegra: Add loadable kernel module support

Message ID 1519812034-11120-3-git-send-email-mmaddireddy@nvidia.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Manikanta Maddireddy Feb. 28, 2018, 10 a.m. UTC
Implement remove callback function for Tegra PCIe driver to add
loadable kernel module support.

Per PCIe r3.0, sec 5.3.3.2.1, PCIe root port should broadcast PME_Turn_Off
message before PCIe link goes to L2. PME_Turn_Off broadcast mechanism is
implemented in AFI module. Each Tegra PCIe root port has its own
PME_Turn_Off and PME_TO_Ack bitmap in AFI_PME register, program this
register to broadcast PME_Turn_Off message.

Once PME_TO_Ack is recieved driver will turn OFF PCIe clock, power gate
PCIe partition and turn OFF regulators.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
---
V2:
* no change in this patch
V3:
* use tegra_pcie_debugfs_exit() helper function in tegra_pcie_debugfs_init()
V4:
* no change in this patch
V5:
* Decoupled from https://patchwork.ozlabs.org/patch/832053/ and
rebased on linux-next
V6:
* no change in this patch
V7:
* no change in this patch
V8:
* Added new lines around conditional blocks
V9:
* Squash PME_Turn_Off patch on top this to have single working LKM patch

 drivers/pci/host/pci-tegra.c | 103 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 100 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index e68507f658d8..60b1d5e1cfa4 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -31,10 +31,12 @@ 
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/interrupt.h>
+#include <linux/iopoll.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/module.h>
 #include <linux/msi.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
@@ -152,6 +154,8 @@ 
 #define  AFI_INTR_EN_FPCI_TIMEOUT	(1 << 7)
 #define  AFI_INTR_EN_PRSNT_SENSE	(1 << 8)
 
+#define AFI_PCIE_PME		0xf0
+
 #define AFI_PCIE_CONFIG					0x0f8
 #define  AFI_PCIE_CONFIG_PCIE_DISABLE(x)		(1 << ((x) + 1))
 #define  AFI_PCIE_CONFIG_PCIE_DISABLE_ALL		0xe
@@ -232,6 +236,8 @@ 
 #define PADS_REFCLK_CFG_PREDI_SHIFT		8  /* 11:8 */
 #define PADS_REFCLK_CFG_DRVI_SHIFT		12 /* 15:12 */
 
+#define PME_ACK_TIMEOUT 10000
+
 struct tegra_msi {
 	struct msi_controller chip;
 	DECLARE_BITMAP(used, INT_PCI_MSI_NR);
@@ -243,8 +249,16 @@  struct tegra_msi {
 };
 
 /* used to differentiate between Tegra SoC generations */
+struct tegra_pcie_port_soc {
+	struct {
+		u8 turnoff_bit;
+		u8 ack_bit;
+	} pme;
+};
+
 struct tegra_pcie_soc {
 	unsigned int num_ports;
+	const struct tegra_pcie_port_soc *ports;
 	unsigned int msi_base_shift;
 	u32 pads_pll_ctl;
 	u32 tx_ref_sel;
@@ -1357,6 +1371,32 @@  static int tegra_pcie_put_resources(struct tegra_pcie *pcie)
 	return 0;
 }
 
+static void tegra_pcie_pme_turnoff(struct tegra_pcie_port *port)
+{
+	struct tegra_pcie *pcie = port->pcie;
+	const struct tegra_pcie_soc *soc = pcie->soc;
+	int err;
+	u32 val;
+	u8 ack_bit;
+
+	val = afi_readl(pcie, AFI_PCIE_PME);
+	val |= (0x1 << soc->ports[port->index].pme.turnoff_bit);
+	afi_writel(pcie, val, AFI_PCIE_PME);
+
+	ack_bit = soc->ports[port->index].pme.ack_bit;
+	err = readl_poll_timeout(pcie->afi + AFI_PCIE_PME, val,
+				 val & (0x1 << ack_bit), 1, PME_ACK_TIMEOUT);
+	if (err)
+		dev_err(pcie->dev, "PME Ack is not received on port: %d\n",
+			port->index);
+
+	usleep_range(10000, 11000);
+
+	val = afi_readl(pcie, AFI_PCIE_PME);
+	val &= ~(0x1 << soc->ports[port->index].pme.turnoff_bit);
+	afi_writel(pcie, val, AFI_PCIE_PME);
+}
+
 static int tegra_msi_alloc(struct tegra_msi *chip)
 {
 	int msi;
@@ -2102,8 +2142,14 @@  static void tegra_pcie_disable_ports(struct tegra_pcie *pcie)
 	}
 }
 
+static const struct tegra_pcie_port_soc tegra20_pcie_ports[] = {
+	{ .pme.turnoff_bit = 0, .pme.ack_bit =  5 },
+	{ .pme.turnoff_bit = 8, .pme.ack_bit = 10 },
+};
+
 static const struct tegra_pcie_soc tegra20_pcie = {
 	.num_ports = 2,
+	.ports = tegra20_pcie_ports,
 	.msi_base_shift = 0,
 	.pads_pll_ctl = PADS_PLL_CTL_TEGRA20,
 	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_DIV10,
@@ -2117,8 +2163,15 @@  static const struct tegra_pcie_soc tegra20_pcie = {
 	.program_uphy = true,
 };
 
+static const struct tegra_pcie_port_soc tegra30_pcie_ports[] = {
+	{ .pme.turnoff_bit =  0, .pme.ack_bit =  5 },
+	{ .pme.turnoff_bit =  8, .pme.ack_bit = 10 },
+	{ .pme.turnoff_bit = 16, .pme.ack_bit = 18 },
+};
+
 static const struct tegra_pcie_soc tegra30_pcie = {
 	.num_ports = 3,
+	.ports = tegra30_pcie_ports,
 	.msi_base_shift = 8,
 	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
 	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
@@ -2135,6 +2188,7 @@  static const struct tegra_pcie_soc tegra30_pcie = {
 
 static const struct tegra_pcie_soc tegra124_pcie = {
 	.num_ports = 2,
+	.ports = tegra20_pcie_ports,
 	.msi_base_shift = 8,
 	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
 	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
@@ -2150,6 +2204,7 @@  static const struct tegra_pcie_soc tegra124_pcie = {
 
 static const struct tegra_pcie_soc tegra210_pcie = {
 	.num_ports = 2,
+	.ports = tegra20_pcie_ports,
 	.msi_base_shift = 8,
 	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
 	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
@@ -2163,8 +2218,15 @@  static const struct tegra_pcie_soc tegra210_pcie = {
 	.program_uphy = true,
 };
 
+static const struct tegra_pcie_port_soc tegra186_pcie_ports[] = {
+	{ .pme.turnoff_bit =  0, .pme.ack_bit =  5 },
+	{ .pme.turnoff_bit =  8, .pme.ack_bit = 10 },
+	{ .pme.turnoff_bit = 12, .pme.ack_bit = 14 },
+};
+
 static const struct tegra_pcie_soc tegra186_pcie = {
 	.num_ports = 3,
+	.ports = tegra186_pcie_ports,
 	.msi_base_shift = 8,
 	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
 	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
@@ -2276,6 +2338,12 @@  static const struct file_operations tegra_pcie_ports_ops = {
 	.release = seq_release,
 };
 
+static void tegra_pcie_debugfs_exit(struct tegra_pcie *pcie)
+{
+	debugfs_remove_recursive(pcie->debugfs);
+	pcie->debugfs = NULL;
+}
+
 static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
 {
 	struct dentry *file;
@@ -2292,8 +2360,7 @@  static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
 	return 0;
 
 remove:
-	debugfs_remove_recursive(pcie->debugfs);
-	pcie->debugfs = NULL;
+	tegra_pcie_debugfs_exit(pcie);
 	return -ENOMEM;
 }
 
@@ -2311,6 +2378,7 @@  static int tegra_pcie_probe(struct platform_device *pdev)
 
 	pcie = pci_host_bridge_priv(host);
 	host->sysdata = pcie;
+	platform_set_drvdata(pdev, pcie);
 
 	pcie->soc = of_device_get_match_data(dev);
 	INIT_LIST_HEAD(&pcie->ports);
@@ -2388,6 +2456,33 @@  static int tegra_pcie_probe(struct platform_device *pdev)
 	return err;
 }
 
+static int tegra_pcie_remove(struct platform_device *pdev)
+{
+	struct tegra_pcie *pcie = platform_get_drvdata(pdev);
+	struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
+	struct tegra_pcie_port *port;
+
+	if (IS_ENABLED(CONFIG_DEBUG_FS))
+		tegra_pcie_debugfs_exit(pcie);
+
+	pci_stop_root_bus(host->bus);
+	pci_remove_root_bus(host->bus);
+
+	list_for_each_entry(port, &pcie->ports, list)
+		tegra_pcie_pme_turnoff(port);
+
+	tegra_pcie_disable_ports(pcie);
+
+	if (IS_ENABLED(CONFIG_PCI_MSI))
+		tegra_pcie_disable_msi(pcie);
+
+	tegra_pcie_free_resources(pcie);
+	tegra_pcie_disable_controller(pcie);
+	tegra_pcie_put_resources(pcie);
+
+	return 0;
+}
+
 static struct platform_driver tegra_pcie_driver = {
 	.driver = {
 		.name = "tegra-pcie",
@@ -2395,5 +2490,7 @@  static struct platform_driver tegra_pcie_driver = {
 		.suppress_bind_attrs = true,
 	},
 	.probe = tegra_pcie_probe,
+	.remove = tegra_pcie_remove,
 };
-builtin_platform_driver(tegra_pcie_driver);
+module_platform_driver(tegra_pcie_driver);
+MODULE_LICENSE("GPL");