fdt: Support SCMI shared memory under reserved-memory nodes

Add a simplebus-based pseudo-bus that matches the "reserved-memory"
node in the device tree.  Update the SCMI shared memory driver so that
it can attach either as a child of mmio_sram or directly under
simplebus (via the new reserved-memory bus). Make the mmio_sram memory
resource shareable so both attachment methods can coexist when required.

MFC after:      1 week
Reviewed by:    manu

sys/conf/files

@@ -1739,6 +1739,7 @@ dev/fdt/fdt_clock_if.m		optional fdt fdt_clock
 dev/fdt/fdt_common.c		optional fdt
 dev/fdt/fdt_pinctrl.c		optional fdt fdt_pinctrl
 dev/fdt/fdt_pinctrl_if.m	optional fdt fdt_pinctrl
+dev/fdt/fdt_reserved_memory.c	optional fdt
 dev/fdt/fdt_slicer.c		optional fdt cfi | fdt mx25l | fdt n25q | fdt at45d
 dev/fdt/fdt_static_dtb.S	optional fdt fdt_dtb_static \
 	dependency	"${FDT_DTS_FILE:T:R}.dtb"

sys/dev/fdt/fdt_reserved_memory.c

@@ -0,0 +1,80 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2018 Rubicon Communications, LLC (Netgate)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+
+#include <dev/fdt/simplebus.h>
+
+#include <dev/ofw/ofw_bus.h>
+
+static int
+fdt_reserved_memory_probe(device_t dev)
+{
+	char *name;
+	phandle_t node;
+	int rv;
+
+	node = ofw_bus_get_node(dev);
+	if (node == -1)
+		return (ENXIO);
+
+	if (!OF_hasprop(node, "ranges"))
+		return (ENXIO);
+
+	rv = OF_getprop_alloc(node, "name", (void **)&name);
+	if (rv == -1)
+		return (ENXIO);
+
+	rv = strcmp(name, "reserved-memory");
+	free(name, M_OFWPROP);
+	if (rv != 0)
+		return (ENXIO);
+
+	device_set_desc(dev, "Reserved memory pseudo-bus");
+
+	return (BUS_PROBE_GENERIC);
+}
+
+static device_method_t fdt_reserved_memory_methods[] = {
+
+	/* Device interface */
+	DEVMETHOD(device_probe,		fdt_reserved_memory_probe),
+
+	DEVMETHOD_END
+};
+
+DEFINE_CLASS_1(fdt_reserved_memory, fdt_reserved_memory_driver,
+    fdt_reserved_memory_methods, 0, simplebus_driver);
+
+EARLY_DRIVER_MODULE(fdt_reserved_memory, simplebus, fdt_reserved_memory_driver,
+    0, 0, BUS_PASS_BUS);
+MODULE_VERSION(fdt_reserved_memory, 1);

sys/dev/firmware/arm/scmi_shmem.c

@@ -32,19 +32,17 @@
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
-#include <sys/cpu.h>
+#include <sys/rman.h>
 #include <sys/kernel.h>
-#include <sys/lock.h>
 #include <sys/module.h>
 
 #include <machine/atomic.h>
+#include <machine/bus.h>
 
 #include <dev/fdt/simplebus.h>
 #include <dev/fdt/fdt_common.h>
 #include <dev/ofw/ofw_bus_subr.h>
 
-#include "mmio_sram_if.h"
-
 #include "scmi_shmem.h"
 #include "scmi.h"
 
@@ -53,7 +51,7 @@
 
 struct shmem_softc {
 	device_t		dev;
-	device_t		parent;
+	struct resource		*res;
 	int			reg;
 	int			inflight;
 };
@@ -88,19 +86,16 @@ shmem_attach(device_t dev)
 {
 	struct shmem_softc *sc;
 	phandle_t node;
-	int reg;
-
-	sc = device_get_softc(dev);
-	sc->dev = dev;
-	sc->parent = device_get_parent(dev);
+	int rid;
 
 	node = ofw_bus_get_node(dev);
-	if (node == -1)
-		return (ENXIO);
+	sc = device_get_softc(dev);
+	sc->dev = dev;
 
-	OF_getencprop(node, "reg", &reg, sizeof(reg));
+	rid = 0;
+	sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
+	    RF_ACTIVE | RF_SHAREABLE);
 
-	sc->reg = reg;
 	atomic_store_rel_int(&sc->inflight, INFLIGHT_NONE);
 
 	OF_device_register_xref(OF_xref_from_node(node), dev);
@@ -111,7 +106,10 @@ shmem_attach(device_t dev)
 static int
 shmem_detach(device_t dev)
 {
+	struct shmem_softc *sc;
 
+	sc = device_get_softc(dev);
+	bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->res);
 	return (0);
 }
 
@@ -119,15 +117,9 @@ static void
 scmi_shmem_read(device_t dev, bus_size_t offset, void *buf, bus_size_t len)
 {
 	struct shmem_softc *sc;
-	uint8_t *addr;
-	int i;
 
 	sc = device_get_softc(dev);
-
-	addr = (uint8_t *)buf;
-
-	for (i = 0; i < len; i++)
-		addr[i] = MMIO_SRAM_READ_1(sc->parent, sc->reg + offset + i);
+	bus_read_region_1(sc->res, offset, buf, len);
 }
 
 static void
@@ -135,15 +127,10 @@ scmi_shmem_write(device_t dev, bus_size_t offset, const void *buf,
     bus_size_t len)
 {
 	struct shmem_softc *sc;
-	const uint8_t *addr;
-	int i;
 
 	sc = device_get_softc(dev);
-
-	addr = (const uint8_t *)buf;
-
-	for (i = 0; i < len; i++)
-		MMIO_SRAM_WRITE_1(sc->parent, sc->reg + offset + i, addr[i]);
+	sc = device_get_softc(dev);
+	bus_write_region_1(sc->res, offset, buf, len);
 }
 
 device_t
@@ -322,4 +309,6 @@ DEFINE_CLASS_1(shmem, shmem_driver, shmem_methods, sizeof(struct shmem_softc),
 
 EARLY_DRIVER_MODULE(shmem, mmio_sram, shmem_driver, 0, 0,
     BUS_PASS_INTERRUPT + BUS_PASS_ORDER_MIDDLE);
+EARLY_DRIVER_MODULE(shmem, simplebus, shmem_driver, 0, 0,
+    BUS_PASS_INTERRUPT + BUS_PASS_ORDER_MIDDLE);
 MODULE_VERSION(scmi_shmem, 1);

sys/dev/sram/mmio_sram.c

@@ -46,7 +46,7 @@
 #define	dprintf(fmt, ...)
 
 static struct resource_spec mmio_sram_spec[] = {
-	{ SYS_RES_MEMORY,	0,	RF_ACTIVE },
+	{ SYS_RES_MEMORY,	0,	RF_ACTIVE | RF_SHAREABLE},
 	{ -1, 0 }
 };