git: e5d63cec57a5 - stable/15 - uart: Add support for the Intel XScale controller

The branch stable/15 has been updated by bnovkov:

URL: https://cgit.FreeBSD.org/src/commit/?id=e5d63cec57a57f8403ccb09f73297877ef471175

commit e5d63cec57a57f8403ccb09f73297877ef471175
Author:     Bojan Novković <[email protected]>
AuthorDate: 2026-06-18 02:03:55 +0000
Commit:     Bojan Novković <[email protected]>
CommitDate: 2026-08-10 16:04:06 +0000

    uart: Add support for the Intel XScale controller
    
    The ns8250 driver avoids clearing IER bit 0x10 to account for the
    split "receiver time-out interrupt enable" bit, but it never sets
    it in `ier_rxbits` even though a comment in `ns8250_init` implies so.
    
    Fix this by setting `IER_RXTMOUT` if we've matched an XScale uart.
    
    Differential Revision:  https://reviews.freebsd.org/D57629
    Reviewed by:    imp
    MFC after:      2 weeks
    
    (cherry picked from commit 1665954e508f74588108e96c30b90d1a88807faa)
---
 sys/dev/uart/uart_dev_ns8250.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/dev/uart/uart_dev_ns8250.c b/sys/dev/uart/uart_dev_ns8250.c
index 6d8097db6581..ca024daa7c33 100644
--- a/sys/dev/uart/uart_dev_ns8250.c
+++ b/sys/dev/uart/uart_dev_ns8250.c
@@ -526,6 +526,7 @@ UART_ACPI_CLASS_AND_DEVICE(acpi_compat_data);
 static struct ofw_compat_data compat_data[] = {
 	{"ns16550",	(uintptr_t)&uart_ns8250_class},
 	{"ns16550a",	(uintptr_t)&uart_ns8250_class},
+	{"intel,xscale-uart",	(uintptr_t)&uart_ns8250_class},
 	{NULL,		(uintptr_t)NULL},
 };
 UART_FDT_CLASS_AND_DEVICE(compat_data);
@@ -611,6 +612,12 @@ ns8250_bus_attach(struct uart_softc *sc)
 
 	/* Get IER RX interrupt bits */
 	ivar = IER_EMSC | IER_ERLS | IER_ERXRDY;
+#ifdef FDT
+	/* Intel XScale models won't work without IER_RXTMOUT set. */
+	if (ofw_bus_is_compatible(sc->sc_dev, "intel,xscale-uart"))
+		ivar |= IER_RXTMOUT;
+#endif
+
 	resource_int_value("uart", device_get_unit(sc->sc_dev), "ier_rxbits",
 	    &ivar);
 	ns8250->ier_rxbits = (uint8_t)(ivar & 0xff);