* Shilimkar, Santosh <santosh.shilimkar@xxxxxx> [100218 21:22]: > Bye the way just to add bit more clarity, this patch addresses TX > hardware restriction in the new UART IP used on omap3630 and omap4430. > First part of the fix for RX is already in mainline, > Commit: "ce13d4716a276f4331d78ba28a5093a63822ab95" > > More details on this thread are here. > http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg19447.html Thanks, I've updated the comments for this patch with the link above and added the whole series into omap for-next. Regards, Tony > > -----Original Message----- > > From: Shilimkar, Santosh > > Sent: Thursday, February 18, 2010 2:29 PM > > To: tony@xxxxxxxxxxx > > Cc: linux-omap@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Shilimkar, Santosh; Woodruff, > > Richard; Ghorai, Sukumar > > Subject: [PATCH 1/9] omap3/4: 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 | 31 ++++++++++++++++++++++++++++--- > > 1 files changed, 28 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c > > index 5f3035e..b79bc89 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> > > @@ -160,6 +161,13 @@ 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) > > { > > @@ -620,6 +628,20 @@ 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; > > @@ -721,11 +743,14 @@ 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; > > - else if ((serial_read_reg(uart->p, UART_OMAP_MVER) & 0xFF) > > - >= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV) > > + 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->p->serial_in = serial_in_override; > > + uart->p->serial_out = serial_out_override; > > + } > > } > > > > /** > > -- > > 1.6.0.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
