4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Aaron Sierra asierra@xes-inc.com
[ Upstream commit c7e1b4059075c9e8eed101d7cc5da43e95eb5e18 ]
Exar sleep wake-up handling has been done on a per-channel basis by virtue of INT0 being accessible from each channel's address space. I believe this was initially done out of necessity, but now that Exar devices have their own driver, we can do things more efficiently by registering a dedicated INT0 handler at the PCI device level.
I see this change providing the following benefits:
1. If more than one port is active, eliminates the redundant bus cycles for reading INT0 on every interrupt. 2. This note associated with hooking in the per-channel handler in 8250_port.c is resolved: /* Fixme: probably not the best place for this */
Cc: Matt Schulte matts@commtech-fastcom.com Signed-off-by: Aaron Sierra asierra@xes-inc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_exar.c | 34 ++++++++++++++++++++++++++++++---- drivers/tty/serial/8250/8250_port.c | 26 -------------------------- 2 files changed, 30 insertions(+), 30 deletions(-)
--- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -37,6 +37,7 @@ #define PCI_DEVICE_ID_EXAR_XR17V4358 0x4358 #define PCI_DEVICE_ID_EXAR_XR17V8358 0x8358
+#define UART_EXAR_INT0 0x80 #define UART_EXAR_8XMODE 0x88 /* 8X sampling rate select */
#define UART_EXAR_FCTR 0x08 /* Feature Control Register */ @@ -124,6 +125,7 @@ struct exar8250_board { struct exar8250 { unsigned int nr; struct exar8250_board *board; + void __iomem *virt; int line[0]; };
@@ -134,12 +136,9 @@ static int default_setup(struct exar8250 const struct exar8250_board *board = priv->board; unsigned int bar = 0;
- if (!pcim_iomap_table(pcidev)[bar] && !pcim_iomap(pcidev, bar, 0)) - return -ENOMEM; - port->port.iotype = UPIO_MEM; port->port.mapbase = pci_resource_start(pcidev, bar) + offset; - port->port.membase = pcim_iomap_table(pcidev)[bar] + offset; + port->port.membase = priv->virt + offset; port->port.regshift = board->reg_shift;
return 0; @@ -423,6 +422,25 @@ static void pci_xr17v35x_exit(struct pci port->port.private_data = NULL; }
+/* + * These Exar UARTs have an extra interrupt indicator that could fire for a + * few interrupts that are not presented/cleared through IIR. One of which is + * a wakeup interrupt when coming out of sleep. These interrupts are only + * cleared by reading global INT0 or INT1 registers as interrupts are + * associated with channel 0. The INT[3:0] registers _are_ accessible from each + * channel's address space, but for the sake of bus efficiency we register a + * dedicated handler at the PCI device level to handle them. + */ +static irqreturn_t exar_misc_handler(int irq, void *data) +{ + struct exar8250 *priv = data; + + /* Clear all PCI interrupts by reading INT0. No effect on IIR */ + ioread8(priv->virt + UART_EXAR_INT0); + + return IRQ_HANDLED; +} + static int exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent) { @@ -451,6 +469,9 @@ exar_pci_probe(struct pci_dev *pcidev, c return -ENOMEM;
priv->board = board; + priv->virt = pcim_iomap(pcidev, bar, 0); + if (!priv->virt) + return -ENOMEM;
pci_set_master(pcidev);
@@ -464,6 +485,11 @@ exar_pci_probe(struct pci_dev *pcidev, c uart.port.irq = pci_irq_vector(pcidev, 0); uart.port.dev = &pcidev->dev;
+ rc = devm_request_irq(&pcidev->dev, uart.port.irq, exar_misc_handler, + IRQF_SHARED, "exar_uart", priv); + if (rc) + return rc; + for (i = 0; i < nr_ports && i < maxnr; i++) { rc = board->setup(priv, pcidev, &uart, i); if (rc) { --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -458,7 +458,6 @@ static void io_serial_out(struct uart_po }
static int serial8250_default_handle_irq(struct uart_port *port); -static int exar_handle_irq(struct uart_port *port);
static void set_io_from_upio(struct uart_port *p) { @@ -1904,26 +1903,6 @@ static int serial8250_default_handle_irq }
/* - * These Exar UARTs have an extra interrupt indicator that could - * fire for a few unimplemented interrupts. One of which is a - * wakeup event when coming out of sleep. Put this here just - * to be on the safe side that these interrupts don't go unhandled. - */ -static int exar_handle_irq(struct uart_port *port) -{ - unsigned int iir = serial_port_in(port, UART_IIR); - int ret = 0; - - if (((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X)) && - serial_port_in(port, UART_EXAR_INT0) != 0) - ret = 1; - - ret |= serial8250_handle_irq(port, iir); - - return ret; -} - -/* * Newer 16550 compatible parts such as the SC16C650 & Altera 16550 Soft IP * have a programmable TX threshold that triggers the THRE interrupt in * the IIR register. In this case, the THRE interrupt indicates the FIFO @@ -3107,11 +3086,6 @@ static void serial8250_config_port(struc if (port->type == PORT_UNKNOWN) serial8250_release_std_resource(up);
- /* Fixme: probably not the best place for this */ - if ((port->type == PORT_XR17V35X) || - (port->type == PORT_XR17D15X)) - port->handle_irq = exar_handle_irq; - register_dev_spec_attr_grp(up); up->fcr = uart_config[up->port.type].fcr; }