Hi Ilpo,
Thanks for the feedback.
> Subject: Re: [PATCH v4 5/6] serial: 8250_em: Use pseudo offset for UART_FCR
>
> On Fri, 17 Feb 2023, Biju Das wrote:
>
> > UART_FCR shares the same offset with UART_IIR. We cannot use UART_FCR
> > in serial8250_em_serial_in() as it overlaps with UART_IIR.
> >
> > This patch introduces a macro UART_FCR_EM with a high value to avoid
> > overlapping with existing UART_* register defines.
> >
> > This will help us to use UART_FCR_EM consistently in serial8250_em_
> > serial{_in/_out} function to read/write FCR register.
> >
> > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > Suggested-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> > ---
> > v4:
> > * New patch. Used UART_FCR_EM for read/write of FCR register.
> > ---
> > drivers/tty/serial/8250/8250_em.c | 13 ++++++++++++-
> > 1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/serial/8250/8250_em.c
> > b/drivers/tty/serial/8250/8250_em.c
> > index 499d7a8847ec..4165fd3bb17a 100644
> > --- a/drivers/tty/serial/8250/8250_em.c
> > +++ b/drivers/tty/serial/8250/8250_em.c
> > @@ -19,6 +19,13 @@
> > #define UART_DLL_EM 9
> > #define UART_DLM_EM 10
> >
> > +/*
> > + * A high value for UART_FCR_EM avoids overlapping with existing
> > +UART_*
> > + * register defines. UART_FCR_EM_HW is the real HW register offset.
> > + */
> > +#define UART_FCR_EM 0x10003
> > +#define UART_FCR_EM_HW 3
> > +
> > struct serial8250_em_priv {
> > int line;
> > };
> > @@ -29,12 +36,14 @@ static void serial8250_em_serial_out(struct uart_port
> *p, int offset, int value)
> > case UART_TX: /* TX @ 0x00 */
> > writeb(value, p->membase);
> > break;
> > - case UART_FCR: /* FCR @ 0x0c (+1) */
>
> 8250_port wants this to remain in place, I think. Otherwise it's attempts to
> set UART_FCR will end up into wrong destination.
Oops, next patch has this change.
+ case UART_FCR:
+ serial8250_em_reg_update(p, UART_FCR_EM, value);
I just need to keep UART_FCR for this patch and
remove it from "serial8250_em_serial_out_helper" on the next patch
Cheers,
Biju
>
> --
> i.
>
>
> > case UART_LCR: /* LCR @ 0x10 (+1) */
> > case UART_MCR: /* MCR @ 0x14 (+1) */
> > case UART_SCR: /* SCR @ 0x20 (+1) */
> > writel(value, p->membase + ((offset + 1) << 2));
> > break;
> > + case UART_FCR_EM:
> > + writel(value, p->membase + (UART_FCR_EM_HW << 2));
> > + break;
> > case UART_IER: /* IER @ 0x04 */
> > value &= 0x0f; /* only 4 valid bits - not Xscale */
> > fallthrough;
> > @@ -54,6 +63,8 @@ static unsigned int serial8250_em_serial_in(struct
> uart_port *p, int offset)
> > case UART_MSR: /* MSR @ 0x1c (+1) */
> > case UART_SCR: /* SCR @ 0x20 (+1) */
> > return readl(p->membase + ((offset + 1) << 2));
> > + case UART_FCR_EM:
> > + return readl(p->membase + (UART_FCR_EM_HW << 2));
> > case UART_IER: /* IER @ 0x04 */
> > case UART_IIR: /* IIR @ 0x08 */
> > case UART_DLL_EM: /* DLL @ 0x24 (+9) */
> >
