On Wed, Aug 17, 2016 at 04:05:05PM +0200, Mark Kettenis wrote:
> > Date: Wed, 17 Aug 2016 15:36:21 +0200
> > From: Marcus Glocker <[email protected]>
> >
> > Enables FIFO for Synopsis DesignWare APB UART.
> >
> > ok?
>
> Apparently the FIFO is optional. There is a register that tells you
> whether it is enabled or not. Not sure we'll ever encounter an
> implementation that has that option turned off. But we probably
> should check to be sure.
Ok. This updated diff tries to find out about FIFO support by reading
the CPR registers FIFO_MODE field. If it contains zero, no FIFO
support, otherwise it conains the supported FIFO depth.
Unfortunately on my allwinner,sun5i-r8 it returns zero which suprises
me a bit. Therefore it would be interessting if it could be tested on
other sunxi boards as well to see whether it returns non-zero there and
hence you should find a com-line showing the FIFO size.
Thanks.
Index: com_fdt.c
===================================================================
RCS file: /cvs/src/sys/arch/armv7/dev/com_fdt.c,v
retrieving revision 1.6
diff -u -p -r1.6 com_fdt.c
--- com_fdt.c 17 Aug 2016 13:44:48 -0000 1.6
+++ com_fdt.c 18 Aug 2016 09:36:05 -0000
@@ -38,6 +38,8 @@
#include <dev/ofw/ofw_pinctrl.h>
#define com_usr 31 /* Synopsys DesignWare UART */
+#define com_cpr 61 /* Component Parameter Register */
+#define CPR_MASK_FIFO(val) ((val >> 16) & 0x00ff) /* CPR FIFO_MODE */
int com_fdt_match(struct device *, void *, void *);
void com_fdt_attach(struct device *, struct device *, void *);
@@ -98,6 +100,7 @@ com_fdt_attach(struct device *parent, st
struct fdt_attach_args *faa = aux;
int (*intr)(void *) = comintr;
int node;
+ uint32_t reg;
if (faa->fa_nreg < 1)
return;
@@ -115,11 +118,6 @@ com_fdt_attach(struct device *parent, st
sc->sc.sc_frequency = 48000000;
sc->sc.sc_uarttype = COM_UART_TI16750;
- if (OF_is_compatible(faa->fa_node, "snps,dw-apb-uart")) {
- sc->sc.sc_uarttype = COM_UART_16550;
- intr = com_fdt_intr_designware;
- }
-
if ((node = OF_finddevice("/")) != 0 &&
(OF_is_compatible(node, "allwinner,sun4i-a10") ||
OF_is_compatible(node, "allwinner,sun5i-a10s") ||
@@ -136,6 +134,15 @@ com_fdt_attach(struct device *parent, st
faa->fa_reg[0].size, 0, &sc->sc.sc_ioh)) {
printf("%s: bus_space_map failed\n", __func__);
return;
+ }
+
+ if (OF_is_compatible(faa->fa_node, "snps,dw-apb-uart")) {
+ reg = bus_space_read_4(sc->sc.sc_iot, sc->sc.sc_ioh, com_cpr);
+ if (CPR_MASK_FIFO(reg) > 0)
+ sc->sc.sc_uarttype = COM_UART_16550A;
+ else
+ sc->sc.sc_uarttype = COM_UART_16550;
+ intr = com_fdt_intr_designware;
}
pinctrl_byname(faa->fa_node, "default");
