Tony, Can this be merged now in linux-omap ? > -----Original Message----- > From: Shilimkar, Santosh > Sent: Friday, January 29, 2010 3:58 PM > To: [email protected] > Cc: [email protected]; 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 <[email protected]> > Signed-off-by: Santosh Shilimkar <[email protected]> > CC: Ghorai Sukumar <[email protected]> > --- > 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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