Index: sys/dev/ofw/ofw_fdt.c
===================================================================
--- sys/dev/ofw/ofw_fdt.c
+++ sys/dev/ofw/ofw_fdt.c
@@ -79,6 +79,8 @@
 static ssize_t ofw_fdt_instance_to_path(ofw_t, ihandle_t, char *, size_t);
 static ssize_t ofw_fdt_package_to_path(ofw_t, phandle_t, char *, size_t);
 static int ofw_fdt_interpret(ofw_t, const char *, int, cell_t *);
+static int ofw_fdt_model(ofw_t, char *, size_t);
+static int ofw_fdt_compatible(ofw_t, char *, size_t);
 
 static ofw_method_t ofw_fdt_methods[] = {
 	OFWMETHOD(ofw_init,			ofw_fdt_init),
@@ -95,6 +97,8 @@
 	OFWMETHOD(ofw_instance_to_path,		ofw_fdt_instance_to_path),
 	OFWMETHOD(ofw_package_to_path,		ofw_fdt_package_to_path),
 	OFWMETHOD(ofw_interpret,		ofw_fdt_interpret),
+	OFWMETHOD(ofw_model,			ofw_fdt_model),
+	OFWMETHOD(ofw_compatible,		ofw_fdt_compatible),
 	{ 0, 0 }
 };
 
@@ -105,6 +109,11 @@
 };
 OFW_DEF(ofw_fdt);
 
+#define FDT_MODEL_LEN	80
+static char model[FDT_MODEL_LEN];
+#define FDT_COMPAT_LEN	80
+static char compatible[FDT_COMPAT_LEN];
+
 static void *fdtp = NULL;
 
 static int
@@ -125,6 +134,15 @@
 	SYSCTL_ADD_PROC(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt), OID_AUTO, "dtb",
 	    CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
 	    sysctl_handle_dtb, "", "Device Tree Blob");
+
+	if (*model != '\0')
+		SYSCTL_ADD_STRING(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt),
+		OID_AUTO, "model", CTLFLAG_RD,
+		model, FDT_MODEL_LEN, "Model as given by manufacturer");
+	if (*compatible != '\0')
+		SYSCTL_ADD_STRING(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt),
+		OID_AUTO, "compatible", CTLFLAG_RD,
+	        compatible, FDT_COMPAT_LEN, "Compatibility string as given by manufacturer");
 }
 SYSINIT(dtb_oid, SI_SUB_KMEM, SI_ORDER_ANY, sysctl_register_fdt_oid, NULL);
 
@@ -132,12 +150,27 @@
 ofw_fdt_init(ofw_t ofw, void *data)
 {
 	int err;
+	phandle_t root;
 
 	/* Check FDT blob integrity */
 	if ((err = fdt_check_header(data)) != 0)
 		return (err);
 
 	fdtp = data;
+
+	bzero(model, FDT_MODEL_LEN);
+	if ((root = ofw_fdt_finddevice(NULL, "/")) != -1) {
+		if (ofw_fdt_getproplen(NULL, root, "model") > 0)
+			ofw_fdt_getprop(NULL, root, "model", model,
+			FDT_MODEL_LEN);
+	}
+	
+	bzero(compatible, FDT_COMPAT_LEN);
+	if ((root = ofw_fdt_finddevice(NULL, "/")) != -1) {
+		if (ofw_fdt_getproplen(NULL, root, "compatible") > 0)
+			ofw_fdt_getprop(NULL, root, "compatible", compatible,
+			FDT_COMPAT_LEN);
+	}
 	return (0);
 }
 
@@ -274,7 +307,6 @@
 		return (-1);
 
 	prop = fdt_getprop(fdtp, offset, propname, &len);
-
 	if (prop == NULL && strcmp(propname, "name") == 0) {
 		/* Emulate the 'name' property */
 		name = fdt_get_name(fdtp, offset, &len);
@@ -296,7 +328,6 @@
 
 	if (prop == NULL)
 		return (-1);
-
 	bcopy(prop, buf, min(len, buflen));
 
 	return (len);
@@ -407,25 +438,35 @@
 	return (-1);
 }
 
+/* Find the model string from the fdt */
+static int
+ofw_fdt_model(ofw_t ofw, char *buf, size_t buflen)
+{
+	
+	if (buf != NULL)
+		strlcpy (buf, model, buflen);
+	return (0);
+}
+
+/* Find the compatible string from the fdt */
+static int
+ofw_fdt_compatible(ofw_t ofw, char *buf, size_t buflen)
+{
+	
+	if (buf != NULL)
+		strlcpy(buf, compatible, buflen);
+	return (0);
+}
+
 #if defined(FDT_MARVELL)
 static int
 ofw_fdt_fixup(ofw_t ofw)
 {
-#define FDT_MODEL_LEN	80
-	char model[FDT_MODEL_LEN];
 	phandle_t root;
-	ssize_t len;
 	int i;
 
-	if ((root = ofw_fdt_finddevice(ofw, "/")) == -1)
-		return (ENODEV);
-
-	if ((len = ofw_fdt_getproplen(ofw, root, "model")) <= 0)
-		return (0);
-
-	bzero(model, FDT_MODEL_LEN);
-	if (ofw_fdt_getprop(ofw, root, "model", model, FDT_MODEL_LEN) <= 0)
-		return (0);
+	if (*model == '\0')
+		return (ENOENT);
 
 	/*
 	 * Search fixup table and call handler if appropriate.
Index: sys/dev/ofw/ofw_if.m
===================================================================
--- sys/dev/ofw/ofw_if.m
+++ sys/dev/ofw/ofw_if.m
@@ -247,6 +247,30 @@
 	cell_t		*_returns;
 };
 
+/**
+ * @brief return model name
+ *
+ * @param _model	Buffer for model
+ * @param _size		Size of buffer
+ */
+METHOD int model {
+	ofw_t		_ofw;
+	char		*_model;
+	size_t		_size;
+};
+
+/**
+ * @brief return compatible string
+ *
+ * @param _compatible	Buffer for compatible
+ * @param _size		Size of buffer
+ */
+METHOD int compatible {
+	ofw_t		_ofw;
+	char		*_compatible;
+	size_t		_size;
+};
+
 # Device I/O Functions (optional)
 
 /**
Index: sys/dev/ofw/openfirm.h
===================================================================
--- sys/dev/ofw/openfirm.h
+++ sys/dev/ofw/openfirm.h
@@ -174,6 +174,8 @@
 
 /* User interface functions */
 int		OF_interpret(const char *cmd, int nreturns, ...);
+int		OF_model(char *buf, size_t len);
+int		OF_compatible(char *buf, size_t len);
 
 /*
  * Decode the Nth register property of the given device node and create a bus
Index: sys/dev/ofw/openfirm.c
===================================================================
--- sys/dev/ofw/openfirm.c
+++ sys/dev/ofw/openfirm.c
@@ -846,3 +846,26 @@
 	for (;;)			/* just in case */
 		;
 }
+
+/* Return model from fdt. */
+int
+OF_model(char *buf, size_t len)
+{
+	
+	if (ofw_def_impl == NULL)
+		return (0);
+
+	return(OFW_MODEL(ofw_obj, buf, len));
+}
+
+/* Return compatible from fdt. */
+int
+OF_compatible(char *buf, size_t len)
+{
+	
+	if (ofw_def_impl == NULL)
+		return (0);
+
+	return(OFW_COMPATIBLE(ofw_obj, buf, len));
+}
+
Index: sys/dev/uart/uart_dev_mu.c
===================================================================
--- sys/dev/uart/uart_dev_mu.c
+++ sys/dev/uart/uart_dev_mu.c
@@ -140,7 +140,11 @@
 static void uart_mu_putc(struct uart_bas *bas, int);
 static int uart_mu_rxready(struct uart_bas *bas);
 static int uart_mu_getc(struct uart_bas *bas, struct mtx *);
+static int cpu_clock(void);
 
+#define RPI2_AND_3_CORE_CLOCK	250000000
+#define RPI4_CORE_CLOCK		500000000
+
 static struct uart_ops uart_mu_ops = {
 	.probe = uart_mu_probe,
 	.init = uart_mu_init,
@@ -157,12 +161,6 @@
 	return (0);
 }
 
-/* 
- * According to the docs, the cpu clock is locked to 250Mhz when
- * the micro-uart is used 
- */
-#define CPU_CLOCK	250000000
-
 static void
 uart_mu_param(struct uart_bas *bas, int baudrate, int databits, int stopbits,
     int parity)
@@ -193,10 +191,7 @@
 
 	/* See 2.2.1 BCM2835-ARM-Peripherals baudrate */
 	if (baudrate != 0) {
-		baud = CPU_CLOCK / (8 * baudrate);
-		/* XXX	
-		 *  baud = cpu_clock() / (8 * baudrate);
-		 */
+		baud = cpu_clock() / (8 * baudrate);
 		__uart_setreg(bas, AUX_MU_BAUD_REG, ((uint32_t)(baud & 0xFFFF)));
 	}
 	
@@ -518,4 +513,30 @@
 	__uart_setreg(bas, AUX_MU_CNTL_REG, CNTL_RXENAB|CNTL_TXENAB);
 	__uart_setreg(bas, AUX_MU_IER_REG, psc->aux_ier);
 	uart_unlock(sc->sc_hwmtx);
+}
+
+/* 
+ * From www.raspberrypi.org/documentation/configuration/uart.md
+ *
+ * "The baud rate of the mini UART is linked to the core frequency of
+ *  the VPU on the VC4 GPU. This means that, as the VPU frequency governor
+ *  varies the core frequency, the baud rate of the mini UART also changes"
+ * 
+ * Since this is rather unusable for a uart the core frequency is locked
+ * if this uart is enabled in the config. Unfortantely it is locked
+ * to 250Mhz on Rpi2 and Rpi3 but 500Mhz on Rpi4 so this driver needs
+ * to determine which is needed. This is one approach, another approach
+ * might be to query bcm2835_cpufreq.c directly.
+ */
+
+
+static int
+cpu_clock(void)
+{
+  	char model[40];
+
+	OF_model(model, sizeof(model));
+	if (strncmp(model, "Raspberry Pi 4", 14) == 0)
+		return (RPI4_CORE_CLOCK);
+	return (RPI2_AND_3_CORE_CLOCK);
 }