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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: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Aaron Sierra 2018-01-24 18:19:23 -06:00 committed by Greg Kroah-Hartman
parent b027e2298b
commit c7e1b40590
2 changed files with 30 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/tty/serial/8250/8250_exar.c
View File

@ -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) {

26
drivers/tty/serial/8250/8250_port.c
View File

@ -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;
}