[PATCH v4] PCI: tegra: add PM-ops support
From: Vidya Sagar
Date: Mon Oct 13 2014 - 05:50:35 EST
adds support for suspend_noirq and resume_noirq hooks
of PM framework. Enables powergating of PCIe partition during
suspend.
It also separates allocation part from
tegra_pcie_enable_msi() to make a new API tegra_pcie_alloc_msi()
to avoid passing extra param in the original API
Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
---
v4:
changed type of num_ports from int to unsigned int in tegra_pcie_check_ports()
took care of indentation issues
v3:
Modified commit message according to review comments
powering off PCIe in resume if no devices are found instead of
putting the resources
removed unnecessary whitespace changes
modified tegra_pcie_check_ports to return number of ports active
v2:
separated alloc_msi from enable_msi
changed tegra_pcie_check_ports to a static function
removed irrelevant comments
NOTE:
This patch currently uses suspend_noirq, resume_noirq calls as
the PCI subsystem (in its own _noirq call) tries to save config registers
of connected PCIe devices.
In the platform that I'm working on, there is a dependency of PCIe drive's working
on I2C controller (because of the way PCIe power rails are controlled) and hence,
by the time suspend_noirq() is called, I2C would have been disabled, hence I'm not
supposed to use _noirq calls in this patch.
Here is the call flow on how PCI_PM _noirq() call is invoked
[<c02a4338>] (pci_bus_read_config_dword+0x88/0x90) from [<c02aa8a0>] (pci_save_state+0x30/0x174)
[<c02aa8a0>] (pci_save_state+0x30/0x174) from [<c02ad020>] (pci_pm_suspend_noirq+0x23c/0x258)
[<c02ad020>] (pci_pm_suspend_noirq+0x23c/0x258) from [<c03f85d0>] (dpm_run_callback+0x34/0x54)
[<c03f85d0>] (dpm_run_callback+0x34/0x54) from [<c03f8e74>] (dpm_suspend_end+0x29c/0x694)
[<c03f8e74>] (dpm_suspend_end+0x29c/0x694) from [<c0084b04>] (suspend_devices_and_enter+0x150/0x420)
[<c0084b04>] (suspend_devices_and_enter+0x150/0x420) from [<c0084fac>] (pm_suspend+0x1d8/0x2a4)
[<c0084fac>] (pm_suspend+0x1d8/0x2a4) from [<c0083b6c>] (state_store+0x74/0xc4)
[<c0083b6c>] (state_store+0x74/0xc4) from [<c026ecf0>] (kobj_attr_store+0x14/0x20)
[<c026ecf0>] (kobj_attr_store+0x14/0x20) from [<c0177334>] (sysfs_write_file+0x170/0x1a0)
[<c0177334>] (sysfs_write_file+0x170/0x1a0) from [<c0118afc>] (vfs_write+0xbc/0x198)
[<c0118afc>] (vfs_write+0xbc/0x198) from [<c0118fe8>] (SyS_write+0x5c/0x16c)
[<c0118fe8>] (SyS_write+0x5c/0x16c) from [<c000f140>] (ret_fast_syscall+0x0/0x30)
Can someone help me understand why does PCI subsystem use suspend_noirq calls
(pci_pm_suspend_noirq()) instead of normal suspend ?
drivers/pci/host/pci-tegra.c | 111 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 93 insertions(+), 18 deletions(-)
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 5ac9f06..0875a78 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -985,14 +985,21 @@ static void tegra_pcie_power_off(struct tegra_pcie *pcie)
{
int err;
- /* TODO: disable and unprepare clocks? */
-
err = phy_power_off(pcie->phy);
if (err < 0)
dev_warn(pcie->dev, "failed to power off PHY: %d\n", err);
reset_control_assert(pcie->pcie_xrst);
+
+ clk_disable_unprepare(pcie->pll_e);
+
+ if (pcie->soc_data->has_cml_clk)
+ clk_disable_unprepare(pcie->cml_clk);
+
+ clk_disable_unprepare(pcie->afi_clk);
reset_control_assert(pcie->afi_rst);
+
+ clk_disable_unprepare(pcie->pex_clk);
reset_control_assert(pcie->pex_rst);
tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);
@@ -1126,7 +1133,7 @@ static int tegra_pcie_get_resources(struct tegra_pcie *pcie)
}
err = tegra_pcie_power_on(pcie);
- if (err) {
+ if (err < 0) {
dev_err(&pdev->dev, "failed to power up: %d\n", err);
return err;
}
@@ -1329,14 +1336,11 @@ static const struct irq_domain_ops msi_domain_ops = {
.map = tegra_msi_map,
};
-static int tegra_pcie_enable_msi(struct tegra_pcie *pcie)
+static int tegra_pcie_alloc_msi(struct tegra_pcie *pcie)
{
struct platform_device *pdev = to_platform_device(pcie->dev);
- const struct tegra_pcie_soc_data *soc = pcie->soc_data;
struct tegra_msi *msi = &pcie->msi;
- unsigned long base;
int err;
- u32 reg;
mutex_init(&msi->lock);
@@ -1368,6 +1372,21 @@ static int tegra_pcie_enable_msi(struct tegra_pcie *pcie)
/* setup AFI/FPCI range */
msi->pages = __get_free_pages(GFP_KERNEL, 0);
+
+ return 0;
+
+err:
+ irq_domain_remove(msi->domain);
+ return err;
+}
+
+static void tegra_pcie_enable_msi(struct tegra_pcie *pcie)
+{
+ const struct tegra_pcie_soc_data *soc = pcie->soc_data;
+ struct tegra_msi *msi = &pcie->msi;
+ unsigned long base;
+ u32 reg;
+
base = virt_to_phys((void *)msi->pages);
afi_writel(pcie, base >> soc->msi_base_shift, AFI_MSI_FPCI_BAR_ST);
@@ -1389,12 +1408,6 @@ static int tegra_pcie_enable_msi(struct tegra_pcie *pcie)
reg = afi_readl(pcie, AFI_INTR_MASK);
reg |= AFI_INTR_MASK_MSI_MASK;
afi_writel(pcie, reg, AFI_INTR_MASK);
-
- return 0;
-
-err:
- irq_domain_remove(msi->domain);
- return err;
}
static int tegra_pcie_disable_msi(struct tegra_pcie *pcie)
@@ -1765,10 +1778,10 @@ retry:
return false;
}
-static int tegra_pcie_enable(struct tegra_pcie *pcie)
+static int tegra_pcie_check_ports(struct tegra_pcie *pcie)
{
struct tegra_pcie_port *port, *tmp;
- struct hw_pci hw;
+ unsigned int num_ports = 0;
list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
dev_info(pcie->dev, "probing port %u, using %u lanes\n",
@@ -1776,8 +1789,10 @@ static int tegra_pcie_enable(struct tegra_pcie *pcie)
tegra_pcie_port_enable(port);
- if (tegra_pcie_port_check_link(port))
+ if (tegra_pcie_port_check_link(port)) {
+ num_ports++;
continue;
+ }
dev_info(pcie->dev, "link %u down, ignoring\n", port->index);
@@ -1785,6 +1800,16 @@ static int tegra_pcie_enable(struct tegra_pcie *pcie)
tegra_pcie_port_free(port);
}
+ return num_ports;
+}
+
+static int tegra_pcie_enable(struct tegra_pcie *pcie)
+{
+ struct hw_pci hw;
+
+ if (!tegra_pcie_check_ports(pcie))
+ return -ENODEV;
+
memset(&hw, 0, sizeof(hw));
hw.nr_controllers = 1;
@@ -2000,13 +2025,15 @@ static int tegra_pcie_probe(struct platform_device *pdev)
tegra_pcie_setup_translations(pcie);
if (IS_ENABLED(CONFIG_PCI_MSI)) {
- err = tegra_pcie_enable_msi(pcie);
+ err = tegra_pcie_alloc_msi(pcie);
if (err < 0) {
dev_err(&pdev->dev,
- "failed to enable MSI support: %d\n",
+ "failed to allocate MSI resources: %d\n",
err);
goto put_resources;
}
+
+ tegra_pcie_enable_msi(pcie);
}
err = tegra_pcie_enable(pcie);
@@ -2062,10 +2089,58 @@ static int tegra_pcie_remove(struct platform_device *pdev)
return 0;
}
+#ifdef CONFIG_PM
+static int tegra_pcie_suspend_noirq(struct device *dev)
+{
+ struct tegra_pcie *pcie = dev_get_drvdata(dev);
+
+ tegra_pcie_power_off(pcie);
+
+ return 0;
+}
+
+static int tegra_pcie_resume_noirq(struct device *dev)
+{
+ struct tegra_pcie *pcie = dev_get_drvdata(dev);
+ int err;
+
+ err = tegra_pcie_power_on(pcie);
+ if (err < 0) {
+ dev_err(dev, "failed to power on: %d\n", err);
+ return err;
+ }
+
+ err = tegra_pcie_enable_controller(pcie);
+ if (err < 0)
+ goto poweroff;
+
+ tegra_pcie_setup_translations(pcie);
+
+ tegra_pcie_enable_msi(pcie);
+
+ if (!tegra_pcie_check_ports(pcie))
+ goto poweroff;
+
+ return 0;
+
+poweroff:
+ tegra_pcie_power_off(pcie);
+ return err;
+}
+
+static const struct dev_pm_ops tegra_pcie_pm_ops = {
+ .suspend_noirq = tegra_pcie_suspend_noirq,
+ .resume_noirq = tegra_pcie_resume_noirq,
+};
+#else
+#define tegra_pcie_pm_ops NULL
+#endif /* CONFIG_PM */
+
static struct platform_driver tegra_pcie_driver = {
.driver = {
.name = "tegra-pcie",
.owner = THIS_MODULE,
+ .pm = &tegra_pcie_pm_ops,
.of_match_table = tegra_pcie_of_match,
},
.probe = tegra_pcie_probe,
--
1.8.1.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/