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Subject[PATCH v9 tty-next 4/4] serial: 8250_pci1xxxx: Add power management functions to quad-uart driver
Date
pci1xxxx's quad-uart function has the capability to wake up UART
from suspend state. Enable wakeup before entering into suspend and
disable wakeup on resume.

Co-developed-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
---
Changes in v9:
- No Change

Changes in v8:
- No Change

Changes in v7:
- No Change

Changes in v6:
- No Change

Changes in v5:
- Corrected commit message

Changes in v4:
- No Change

Changes in v3:
- Handled race condition in suspend and resume callbacks

Changes in v2:
- Use DEFINE_SIMPLE_DEV_PM_OPS instead of SIMPLE_DEV_PM_OPS.
- Use pm_sleep_ptr instead of CONFIG_PM_SLEEP.
- Change the return data type of pci1xxxx_port_suspend to bool from int.
---
drivers/tty/serial/8250/8250_pci1xxxx.c | 115 ++++++++++++++++++++++++
1 file changed, 115 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
index e46c6b835a36..31790c8b6087 100644
--- a/drivers/tty/serial/8250/8250_pci1xxxx.c
+++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
@@ -211,6 +211,116 @@ static const struct serial_rs485 pci1xxxx_rs485_supported = {
/* Delay RTS before send is not supported */
};

+static bool pci1xxxx_port_suspend(int line)
+{
+ struct uart_8250_port *up = serial8250_get_port(line);
+ struct uart_port *port = &up->port;
+ struct tty_port *tport = &port->state->port;
+ unsigned long flags;
+ bool ret = false;
+ u8 wakeup_mask;
+
+ mutex_lock(&tport->mutex);
+ if (port->suspended == 0 && port->dev) {
+ wakeup_mask = readb(up->port.membase + UART_WAKE_MASK_REG);
+
+ spin_lock_irqsave(&port->lock, flags);
+ port->mctrl &= ~TIOCM_OUT2;
+ port->ops->set_mctrl(port, port->mctrl);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ ret = (wakeup_mask & UART_WAKE_SRCS) != UART_WAKE_SRCS;
+ }
+
+ writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG);
+ mutex_unlock(&tport->mutex);
+
+ return ret;
+}
+
+static void pci1xxxx_port_resume(int line)
+{
+ struct uart_8250_port *up = serial8250_get_port(line);
+ struct uart_port *port = &up->port;
+ struct tty_port *tport = &port->state->port;
+ unsigned long flags;
+
+ mutex_lock(&tport->mutex);
+ writeb(UART_BLOCK_SET_ACTIVE, port->membase + UART_ACTV_REG);
+ writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG);
+
+ if (port->suspended == 0) {
+ spin_lock_irqsave(&port->lock, flags);
+ port->mctrl |= TIOCM_OUT2;
+ port->ops->set_mctrl(port, port->mctrl);
+ spin_unlock_irqrestore(&port->lock, flags);
+ }
+ mutex_unlock(&tport->mutex);
+}
+
+static int pci1xxxx_suspend(struct device *dev)
+{
+ struct pci1xxxx_8250 *priv = dev_get_drvdata(dev);
+ struct pci_dev *pcidev = to_pci_dev(dev);
+ bool wakeup = false;
+ unsigned int data;
+ void __iomem *p;
+ int i;
+
+ for (i = 0; i < priv->nr; i++) {
+ if (priv->line[i] >= 0) {
+ serial8250_suspend_port(priv->line[i]);
+ wakeup |= pci1xxxx_port_suspend(priv->line[i]);
+ }
+ }
+
+ p = pci_ioremap_bar(pcidev, 0);
+ if (!p) {
+ dev_err(dev, "remapping of bar 0 memory failed");
+ return -ENOMEM;
+ }
+
+ data = readl(p + UART_RESET_REG);
+ writel(data | UART_RESET_D3_RESET_DISABLE, p + UART_RESET_REG);
+
+ if (wakeup)
+ writeb(UART_PCI_CTRL_D3_CLK_ENABLE, p + UART_PCI_CTRL_REG);
+
+ iounmap(p);
+ device_set_wakeup_enable(dev, true);
+ pci_wake_from_d3(pcidev, true);
+
+ return 0;
+}
+
+static int pci1xxxx_resume(struct device *dev)
+{
+ struct pci1xxxx_8250 *priv = dev_get_drvdata(dev);
+ struct pci_dev *pcidev = to_pci_dev(dev);
+ unsigned int data;
+ void __iomem *p;
+ int i;
+
+ p = pci_ioremap_bar(pcidev, 0);
+ if (!p) {
+ dev_err(dev, "remapping of bar 0 memory failed");
+ return -ENOMEM;
+ }
+
+ data = readl(p + UART_RESET_REG);
+ writel(data & ~UART_RESET_D3_RESET_DISABLE, p + UART_RESET_REG);
+ iounmap(p);
+
+ for (i = 0; i < priv->nr; i++) {
+ if (priv->line[i] >= 0) {
+ pci1xxxx_port_resume(priv->line[i]);
+ serial8250_resume_port(priv->line[i]);
+ }
+ }
+
+ return 0;
+}
+
static int pci1xxxx_setup(struct pci_dev *pdev,
struct uart_8250_port *port, int port_idx)
{
@@ -350,6 +460,8 @@ static void pci1xxxx_serial_remove(struct pci_dev *dev)
pci_iounmap(dev, priv->membase);
}

+static DEFINE_SIMPLE_DEV_PM_OPS(pci1xxxx_pm_ops, pci1xxxx_suspend, pci1xxxx_resume);
+
static const struct pci_device_id pci1xxxx_pci_tbl[] = {
{ PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_PCI11010) },
{ PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_PCI11101) },
@@ -364,6 +476,9 @@ static struct pci_driver pci1xxxx_pci_driver = {
.name = "pci1xxxx serial",
.probe = pci1xxxx_serial_probe,
.remove = pci1xxxx_serial_remove,
+ .driver = {
+ .pm = pm_sleep_ptr(&pci1xxxx_pm_ops),
+ },
.id_table = pci1xxxx_pci_tbl,
};
module_pci_driver(pci1xxxx_pci_driver);
--
2.25.1
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