Tony,
Can this be merged now in linux-omap ?
> -----Original Message-----
> From: Shilimkar, Santosh
> Sent: Friday, January 29, 2010 3:58 PM
> To: tony@xxxxxxxxxxx
> Cc: linux-omap@xxxxxxxxxxxxxxx; Shilimkar, Santosh; Woodruff, Richard; Ghorai, Sukumar
> Subject: [PATCH v2] OMAP: UART: fix full-fifo write abort
>
> This patch is addition to the already merged commit on non-empty
> uart fifo read abort. "ce13d4716a276f4331d78ba28a5093a63822ab95"
>
> OMAP3630 and OMAP4430 UART IP blocks have a restriction on TX FIFO
> too. If you try to write to the tx fifo when it is full, the system aborts.
>
> This can be easily reproducible by not suppressing interconnect errors or
> long duration testing where continuous prints over console from multiple
> threads. This patch is addressing the issue by ensuring that write is
> not issued while fifo is full. A timeout is added to avoid any hang
> on fifo-full for 10 mS which is unlikely case.
>
> Patch is validated on OMAP3630 and OMAP4 SDP.
>
> V2 version removed the additional 1 uS on every TX as per
> Tony's suggestion
>
> Signed-off-by: Woodruff Richard <r-woodruff2@xxxxxx>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> CC: Ghorai Sukumar <s-ghorai@xxxxxx>
> ---
> arch/arm/mach-omap2/serial.c | 30 ++++++++++++++++++++++++++++--
> 1 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
> index 8c964be..324928d 100644
> --- a/arch/arm/mach-omap2/serial.c
> +++ b/arch/arm/mach-omap2/serial.c
> @@ -23,6 +23,7 @@
> #include <linux/serial_reg.h>
> #include <linux/clk.h>
> #include <linux/io.h>
> +#include <linux/delay.h>
>
> #include <plat/common.h>
> #include <plat/board.h>
> @@ -139,6 +140,13 @@ static inline unsigned int serial_read_reg(struct plat_serial8250_port *up,
> return (unsigned int)__raw_readb(up->membase + offset);
> }
>
> +static inline void __serial_write_reg(struct uart_port *up, int offset,
> + int value)
> +{
> + offset <<= up->regshift;
> + __raw_writeb(value, up->membase + offset);
> +}
> +
> static inline void serial_write_reg(struct plat_serial8250_port *p, int offset,
> int value)
> {
> @@ -598,6 +606,20 @@ static unsigned int serial_in_override(struct uart_port *up, int offset)
> return __serial_read_reg(up, offset);
> }
>
> +static void serial_out_override(struct uart_port *up, int offset, int value)
> +{
> + unsigned int status, tmout = 10000;
> +
> + status = __serial_read_reg(up, UART_LSR);
> + while (!(status & UART_LSR_THRE)) {
> + /* Wait up to 10ms for the character(s) to be sent. */
> + if (--tmout == 0)
> + break;
> + udelay(1);
> + status = __serial_read_reg(up, UART_LSR);
> + }
> + __serial_write_reg(up, offset, value);
> +}
> void __init omap_serial_early_init(void)
> {
> int i;
> @@ -698,11 +720,15 @@ void __init omap_serial_init_port(int port)
> * omap3xxx: Never read empty UART fifo on UARTs
> * with IP rev >=0x52
> */
> - if (cpu_is_omap44xx())
> + if (cpu_is_omap44xx()) {
> uart->p->serial_in = serial_in_override;
> + uart->p->serial_out = serial_out_override;
> + }
> else if ((serial_read_reg(uart->p, UART_OMAP_MVER) & 0xFF)
> - >= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV)
> + >= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV) {
> uart->p->serial_in = serial_in_override;
> + uart->p->serial_out = serial_out_override;
> + }
> }
>
> /**
> --
> 1.6.0.4
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