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From: Greg Kroah-Hartman on 4 Jun 2010 17:00
From: Tobias Klauser <tklauser(a)distanz.ch>

The check for the TRDY flag after writing the character is not needed.
Also do a cpu_relax() inside the loop.

Pass a struct uart_port to altera_uart_console_putc, so we do not need
to get it (and dereference pointers) for every character.

Cc: Thomas Chou <thomas(a)wytron.com.tw>
Signed-off-by: Tobias Klauser <tklauser(a)distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>
---
drivers/serial/altera_uart.c | 23 ++++++++---------------
1 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/serial/altera_uart.c b/drivers/serial/altera_uart.c
index b1609cc..7d6afc9 100644
--- a/drivers/serial/altera_uart.c
+++ b/drivers/serial/altera_uart.c
@@ -391,31 +391,24 @@ int __init early_altera_uart_setup(struct altera_uart_platform_uart *platp)
return 0;
}

-static void altera_uart_console_putc(struct console *co, const char c)
+static void altera_uart_console_putc(struct uart_port *port, const char c)
{
- struct uart_port *port = &(altera_uart_ports + co->index)->port;
- int i;
+ while (!(readl(port->membase + ALTERA_UART_STATUS_REG) &
+ ALTERA_UART_STATUS_TRDY_MSK))
+ cpu_relax();

- for (i = 0; i < 0x10000; i++) {
- if (readl(port->membase + ALTERA_UART_STATUS_REG) &
- ALTERA_UART_STATUS_TRDY_MSK)
- break;
- }
writel(c, port->membase + ALTERA_UART_TXDATA_REG);
- for (i = 0; i < 0x10000; i++) {
- if (readl(port->membase + ALTERA_UART_STATUS_REG) &
- ALTERA_UART_STATUS_TRDY_MSK)
- break;
- }
}

static void altera_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
+ struct uart_port *port = &(altera_uart_ports + co->index)->port;
+
for (; count; count--, s++) {
- altera_uart_console_putc(co, *s);
+ altera_uart_console_putc(port, *s);
if (*s == '\n')
- altera_uart_console_putc(co, '\r');
+ altera_uart_console_putc(port, '\r');
}
}

--
1.7.1

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Prev: [PATCH 05/11] TTY/n_gsm: potential double lock
Next: irq: support IRQ_NESTED_THREAD with non-threaded interrupt handlers