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Commit c7e1b405 authored by Aaron Sierra's avatar Aaron Sierra Committed by Greg Kroah-Hartman
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tty: serial: exar: Relocate sleep wake-up handling 



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: default avatarAaron Sierra <asierra@xes-inc.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b027e229

drivers/tty/serial/8250/8250_exar.c

+30 −4
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#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 */
@@ -121,6 +122,7 @@ struct exar8250_board { 
struct exar8250 {

	unsigned int		nr;

	struct exar8250_board	*board;

	void __iomem		*virt;

	int			line[0];

};
@@ -131,12 +133,9 @@ static int default_setup(struct exar8250 *priv, struct pci_dev *pcidev, 
	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;
@@ -420,6 +419,25 @@ static void pci_xr17v35x_exit(struct pci_dev *pcidev) 
	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)

{
@@ -448,6 +466,9 @@ exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent) 
		return -ENOMEM;



	priv->board = board;

	priv->virt = pcim_iomap(pcidev, bar, 0);

	if (!priv->virt)

		return -ENOMEM;



	pci_set_master(pcidev);
@@ -461,6 +482,11 @@ exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent) 
	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) {

drivers/tty/serial/8250/8250_port.c

+0 −26
Original line number Diff line number Diff line
@@ -441,7 +441,6 @@ static void io_serial_out(struct uart_port *p, int offset, int value) 
}



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)

{
@@ -1883,26 +1882,6 @@ static int serial8250_default_handle_irq(struct uart_port *port) 
	return ret;

}



/*

 * 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
@@ -3067,11 +3046,6 @@ static void serial8250_config_port(struct uart_port *port, int flags) 
	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;

}