[PATCH 09/10] PCI: tegra: Broadcast PME_turn_Off message before link goes to L2

Manikanta Maddireddy
2017-11-24T15:53:19Z

Per PCIe r3.0, sec 5.3.3.2.1, PCIe root port shoould 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.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---
drivers/pci/host/pci-tegra.c | 76 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 76 insertions(+)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 2ff1ac3aefc1..af999c650941 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -155,6 +155,8 @@
#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
@@ -315,6 +317,7 @@
#define PADS_REFCLK_CFG_DRVI_SHIFT 12 /* 15:12 */

#define LINK_RETRAIN_TIMEOUT 100000
+#define PME_ACK_TIMEOUT 10000

struct tegra_msi {
struct msi_controller chip;
@@ -1483,6 +1486,76 @@ static int tegra_pcie_put_resources(struct tegra_pcie *pcie)
return 0;
}

+static inline u32 get_pme_turnoff_bitmap(struct tegra_pcie_port *port)
+{
+ struct device *dev = port->pcie->dev;
+ struct device_node *np = dev->of_node;
+ int ret = 0;
+
+ switch (port->index) {
+ case 0:
+ ret = 0;
+ case 1:
+ ret = 8;
+ case 2:
+ if (of_device_is_compatible(np, "nvidia,tegra30-pcie"))
+ ret = 16;
+ else
+ ret = 12;
+ }
+ return ret;
+}
+
+static inline u32 get_pme_ack_bitmap(struct tegra_pcie_port *port)
+{
+ struct device *dev = port->pcie->dev;
+ struct device_node *np = dev->of_node;
+ int ret = 0;
+
+ switch (port->index) {
+ case 0:
+ ret = 5;
+ case 1:
+ ret = 10;
+ case 2:
+ if (of_device_is_compatible(np, "nvidia,tegra30-pcie"))
+ ret = 18;
+ else
+ ret = 14;
+ }
+ return ret;
+}
+
+static void tegra_pcie_pme_turnoff(struct tegra_pcie_port *port)
+{
+ struct tegra_pcie *pcie = port->pcie;
+ ktime_t deadline;
+ unsigned int data;
+
+ data = afi_readl(pcie, AFI_PCIE_PME);
+ data |= (0x1 << get_pme_turnoff_bitmap(port));
+ afi_writel(pcie, data, AFI_PCIE_PME);
+
+ deadline = ktime_add_us(ktime_get(), PME_ACK_TIMEOUT);
+ do {
+ data = afi_readl(pcie, AFI_PCIE_PME);
+ data &= (0x1 << get_pme_ack_bitmap(port));
+ udelay(1);
+ if (ktime_after(ktime_get(), deadline))
+ break;
+ } while (!data);
+
+ if (data)
+ dev_err(pcie->dev, "PME Ack is not receieved on port: %d\n",
+ port->index);
+
+ usleep_range(10000, 11000);
+
+ data = afi_readl(pcie, AFI_PCIE_PME);
+ data &= ~(0x1 << get_pme_turnoff_bitmap(port));
+ afi_writel(pcie, data, AFI_PCIE_PME);
+}
+
static int tegra_msi_alloc(struct tegra_msi *chip)
{
int msi;
@@ -2808,6 +2881,7 @@ 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, *tmp;

if (IS_ENABLED(CONFIG_DEBUG_FS))
tegra_pcie_debugfs_exit(pcie);
@@ -2815,6 +2889,8 @@ static int tegra_pcie_remove(struct platform_device *pdev)
pci_remove_root_bus(host->bus);
if (IS_ENABLED(CONFIG_PCI_MSI))
tegra_pcie_disable_msi(pcie);
+ list_for_each_entry_safe(port, tmp, &pcie->ports, list)
+ tegra_pcie_pme_turnoff(port);
tegra_pcie_disable_ports(pcie);
tegra_pcie_free_resources(pcie);
tegra_pcie_disable_controller(pcie);
--
2.1.4