}
}
+static void
+serial_out_sync(struct uart_8250_port *up, int offset, int value)
+{
+ switch (up->port.iotype) {
+ case UPIO_MEM:
+ case UPIO_MEM32:
+#ifdef CONFIG_SERIAL_8250_AU1X00
+ case UPIO_AU:
+#endif
+ serial_out(up, offset, value);
+ serial_in(up, UART_LCR); /* safe, no side-effects */
+ break;
+ default:
+ serial_out(up, offset, value);
+ }
+}
+
/*
* We used to support using pause I/O for certain machines. We
* haven't supported this for a while, but just in case it's badly
#endif
serial_outp(up, UART_MCR, save_mcr);
serial8250_clear_fifos(up);
- (void)serial_in(up, UART_RX);
+ serial_in(up, UART_RX);
if (up->capabilities & UART_CAP_UUE)
serial_outp(up, UART_IER, UART_IER_UUE);
else
serial_do_unlink(i, up);
}
+/* Base timer interval for polling */
+static inline int poll_timeout(int timeout)
+{
+ return timeout > 6 ? (timeout / 2 - 2) : 1;
+}
+
/*
* This function is used to handle ports that do not have an
* interrupt. This doesn't work very well for 16450's, but gives
static void serial8250_timeout(unsigned long data)
{
struct uart_8250_port *up = (struct uart_8250_port *)data;
- unsigned int timeout;
unsigned int iir;
iir = serial_in(up, UART_IIR);
if (!(iir & UART_IIR_NO_INT))
serial8250_handle_port(up);
+ mod_timer(&up->timer, jiffies + poll_timeout(up->port.timeout));
+}
+
+static void serial8250_backup_timeout(unsigned long data)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *)data;
+ unsigned int iir, ier = 0;
+
+ /*
+ * Must disable interrupts or else we risk racing with the interrupt
+ * based handler.
+ */
+ if (is_real_interrupt(up->port.irq)) {
+ ier = serial_in(up, UART_IER);
+ serial_out(up, UART_IER, 0);
+ }
- timeout = up->port.timeout;
- timeout = timeout > 6 ? (timeout / 2 - 2) : 1;
- mod_timer(&up->timer, jiffies + timeout);
+ iir = serial_in(up, UART_IIR);
+
+ /*
+ * This should be a safe test for anyone who doesn't trust the
+ * IIR bits on their UART, but it's specifically designed for
+ * the "Diva" UART used on the management processor on many HP
+ * ia64 and parisc boxes.
+ */
+ if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
+ (!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) &&
+ (serial_in(up, UART_LSR) & UART_LSR_THRE)) {
+ iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
+ iir |= UART_IIR_THRI;
+ }
+
+ if (!(iir & UART_IIR_NO_INT))
+ serial8250_handle_port(up);
+
+ if (is_real_interrupt(up->port.irq))
+ serial_out(up, UART_IER, ier);
+
+ /* Standard timer interval plus 0.2s to keep the port running */
+ mod_timer(&up->timer, jiffies + poll_timeout(up->port.timeout) + HZ/5);
}
static unsigned int serial8250_tx_empty(struct uart_port *port)
spin_unlock_irqrestore(&up->port.lock, flags);
}
+#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
+
+/*
+ * Wait for transmitter & holding register to empty
+ */
+static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
+{
+ unsigned int status, tmout = 10000;
+
+ /* Wait up to 10ms for the character(s) to be sent. */
+ do {
+ status = serial_in(up, UART_LSR);
+
+ if (status & UART_LSR_BI)
+ up->lsr_break_flag = UART_LSR_BI;
+
+ if (--tmout == 0)
+ break;
+ udelay(1);
+ } while ((status & bits) != bits);
+
+ /* Wait up to 1s for flow control if necessary */
+ if (up->port.flags & UPF_CONS_FLOW) {
+ tmout = 1000000;
+ while (!(serial_in(up, UART_MSR) & UART_MSR_CTS) && --tmout) {
+ udelay(1);
+ touch_nmi_watchdog();
+ }
+ }
+}
+
static int serial8250_startup(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
serial_outp(up, UART_LCR, 0);
}
+ if (is_real_interrupt(up->port.irq)) {
+ /*
+ * Test for UARTs that do not reassert THRE when the
+ * transmitter is idle and the interrupt has already
+ * been cleared. Real 16550s should always reassert
+ * this interrupt whenever the transmitter is idle and
+ * the interrupt is enabled. Delays are necessary to
+ * allow register changes to become visible.
+ */
+ spin_lock_irqsave(&up->port.lock, flags);
+
+ wait_for_xmitr(up, UART_LSR_THRE);
+ serial_out_sync(up, UART_IER, UART_IER_THRI);
+ udelay(1); /* allow THRE to set */
+ serial_in(up, UART_IIR);
+ serial_out(up, UART_IER, 0);
+ serial_out_sync(up, UART_IER, UART_IER_THRI);
+ udelay(1); /* allow a working UART time to re-assert THRE */
+ iir = serial_in(up, UART_IIR);
+ serial_out(up, UART_IER, 0);
+
+ spin_unlock_irqrestore(&up->port.lock, flags);
+
+ /*
+ * If the interrupt is not reasserted, setup a timer to
+ * kick the UART on a regular basis.
+ */
+ if (iir & UART_IIR_NO_INT) {
+ pr_debug("ttyS%d - using backup timer\n", port->line);
+ up->timer.function = serial8250_backup_timeout;
+ up->timer.data = (unsigned long)up;
+ mod_timer(&up->timer, jiffies +
+ poll_timeout(up->port.timeout) + HZ/5);
+ }
+ }
+
/*
* If the "interrupt" for this port doesn't correspond with any
* hardware interrupt, we use a timer-based system. The original
* driver used to do this with IRQ0.
*/
if (!is_real_interrupt(up->port.irq)) {
- unsigned int timeout = up->port.timeout;
-
- timeout = timeout > 6 ? (timeout / 2 - 2) : 1;
-
up->timer.data = (unsigned long)up;
- mod_timer(&up->timer, jiffies + timeout);
+ mod_timer(&up->timer, jiffies + poll_timeout(up->port.timeout));
} else {
retval = serial_link_irq_chain(up);
if (retval)
*/
(void) serial_in(up, UART_RX);
- if (!is_real_interrupt(up->port.irq))
- del_timer_sync(&up->timer);
- else
+ del_timer_sync(&up->timer);
+ up->timer.function = serial8250_timeout;
+ if (is_real_interrupt(up->port.irq))
serial_unlink_irq_chain(up);
}
#ifdef CONFIG_SERIAL_8250_CONSOLE
-#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
-
-/*
- * Wait for transmitter & holding register to empty
- */
-static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
-{
- unsigned int status, tmout = 10000;
-
- /* Wait up to 10ms for the character(s) to be sent. */
- do {
- status = serial_in(up, UART_LSR);
-
- if (status & UART_LSR_BI)
- up->lsr_break_flag = UART_LSR_BI;
-
- if (--tmout == 0)
- break;
- udelay(1);
- } while ((status & bits) != bits);
-
- /* Wait up to 1s for flow control if necessary */
- if (up->port.flags & UPF_CONS_FLOW) {
- tmout = 1000000;
- while (!(serial_in(up, UART_MSR) & UART_MSR_CTS) && --tmout) {
- udelay(1);
- touch_nmi_watchdog();
- }
- }
-}
-
static void serial8250_console_putchar(struct uart_port *port, int ch)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
git.openpandora.org / pandora-kernel.git / blobdiff