Vikram Pandita <vikram.pandita@xxxxxx> writes: > OMAP3630 and OMAP4430 UART IP blocks have a restriction wrt RX FIFO. > Empty RX fifo read causes an abort. OMAP1/2/3 do not have this restriction. > > Overrigt the default 8250 read handler: mem_serial_in() > by a custom handler: serial_in_8250() > > serial_in_8250() makes sure that RX fifo is not read when empty, > on omap4 and 3630 silicons only > > tested on zoom3(3630) board > > Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx> > Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> > --- > v1: initial implementation > http://patchwork.kernel.org/patch/60785/ > http://patchwork.kernel.org/patch/60786/ > > v2: incorporate review comments from Alan Cox > http://patchwork.kernel.org/patch/60785/ > No 8250 driver change required now > > arch/arm/mach-omap2/serial.c | 28 ++++++++++++++++++++++++++++ > 1 files changed, 28 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c > index 2e17b57..362cb82 100644 > --- a/arch/arm/mach-omap2/serial.c > +++ b/arch/arm/mach-omap2/serial.c > @@ -71,6 +71,30 @@ struct omap_uart_state { > > static LIST_HEAD(uart_list); > > +static struct omap_uart_state omap_uart[]; > +static inline unsigned int serial_read_reg(struct plat_serial8250_port *, int); > + > +/* > + * Overrigt the default 8250 read handler: mem_serial_in() > + * Empty RX fifo read causes an abort on omap3630 and omap4 > + * This function makes sure that an empty rx fifo is not read on these silicons > + * (OMAP1/2/3 are not affected) > + */ > +static unsigned int serial_in_8250(struct uart_port *up, int offset) > +{ > + /* Do not read empty UART fifo on omap3630/44xx */ > + if ((UART_RX == offset) && > + (cpu_is_omap3630() || cpu_is_omap44xx())) { Rather than the cpu_is_* here, why not just override the function for these platforms and leave the default for 34xx/35xx. Kevin -- 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
