riscv/sifive: add SiFive FU540 PRCI driver

The SiFive FU540 Power Reset Clocking Interrupt block contains a PLL
that turns the input crystal (33.3MHz) into a 1-1.5GHz clock.
This clock in turn is divided by two to produce the tlclk, which is fed
into devices such as the SPI and I2C controllers.

Register a new clock device for the PRCI so that those devices can
read the correct clock through the clk framework.

Submitted by:   kp
Sponsored by:   Axiado

3 files changed, 274 insertions, 0 deletions

diff --git a/sys/riscv/sifive/files.sifive b/sys/riscv/sifive/files.sifive
new file mode 100644
index 000000000000..f8b31fda18cc
--- /dev/null
+++ b/sys/riscv/sifive/files.sifive
@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+riscv/sifive/fu540_prci.c		standard
diff --git a/sys/riscv/sifive/fu540_prci.c b/sys/riscv/sifive/fu540_prci.c
new file mode 100644
index 000000000000..53930ae417b6
--- /dev/null
+++ b/sys/riscv/sifive/fu540_prci.c
@@ -0,0 +1,268 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2019 Axiado Corporation
+ * All rights reserved.
+ *
+ * This software was developed in part by Kristof Provost under contract for
+ * Axiado Corporation.
+ *
+ * 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/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/rman.h>
+
+#include <machine/bus.h>
+#include <machine/cpu.h>
+
+#include <dev/extres/clk/clk.h>
+
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+#include <dev/ofw/openfirm.h>
+
+static struct resource_spec prci_spec[] = {
+	{ SYS_RES_MEMORY, 0, RF_ACTIVE },
+	RESOURCE_SPEC_END
+};
+
+struct prci_softc {
+	device_t		dev;
+
+	struct mtx		mtx;
+
+	struct clkdom		*clkdom;
+	struct resource		*res;
+	bus_space_tag_t		bst;
+	bus_space_handle_t	bsh;
+};
+
+struct prci_clk_pll_sc {
+	struct prci_softc	*parent_sc;
+};
+
+#define	PRCI_LOCK(sc)			mtx_lock(&(sc)->mtx)
+#define	PRCI_UNLOCK(sc)			mtx_unlock(&(sc)->mtx)
+#define	PRCI_ASSERT_LOCKED(sc)		mtx_assert(&(sc)->mtx, MA_OWNED);
+#define	PRCI_ASSERT_UNLOCKED(sc)	mtx_assert(&(sc)->mtx, MA_NOTOWNED);
+
+#define	PRCI_COREPLL			0x4
+#define		PRCI_COREPLL_DIVR_MASK	0x3f
+#define		PRCI_COREPLL_DIVR_SHIFT	0
+#define		PRCI_COREPLL_DIVF_MASK	0x7fc0
+#define		PRCI_COREPLL_DIVF_SHIFT	6
+#define		PRCI_COREPLL_DIVQ_MASK	0x38000
+#define		PRCI_COREPLL_DIVQ_SHIFT	15
+
+#define	PRCI_READ(_sc, _reg)		\
+    bus_space_read_4((_sc)->bst, (_sc)->bsh, (_reg))
+
+static int
+prci_clk_pll_init(struct clknode *clk, device_t dev)
+{
+
+	clknode_init_parent_idx(clk, 0);
+
+	return (0);
+}
+
+static int
+prci_clk_pll_recalc(struct clknode *clk, uint64_t *freq)
+{
+	struct prci_clk_pll_sc *sc;
+	struct clknode *parent_clk;
+	uint32_t val;
+	uint64_t refclk, divf, divq, divr;
+	int err;
+
+	KASSERT(freq != NULL, ("freq cannot be NULL"));
+
+	sc = clknode_get_softc(clk);
+
+	PRCI_LOCK(sc->parent_sc);
+
+	/* Get refclock frequency. */
+	parent_clk = clknode_get_parent(clk);
+	err = clknode_get_freq(parent_clk, &refclk);
+	if (err) {
+		device_printf(sc->parent_sc->dev,
+		    "Failed to get refclk frequency\n");
+		PRCI_UNLOCK(sc->parent_sc);
+		return (err);
+	}
+
+	/* Calculate the PLL output */
+	val = PRCI_READ(sc->parent_sc, PRCI_COREPLL);
+
+	divf = (val & PRCI_COREPLL_DIVF_MASK) >> PRCI_COREPLL_DIVF_SHIFT;
+	divq = (val & PRCI_COREPLL_DIVQ_MASK) >> PRCI_COREPLL_DIVQ_SHIFT;
+	divr = (val & PRCI_COREPLL_DIVR_MASK) >> PRCI_COREPLL_DIVR_SHIFT;
+
+	*freq = refclk / (divr + 1) * (2 * (divf + 1)) / (1 << divq);
+
+	PRCI_UNLOCK(sc->parent_sc);
+
+	return (0);
+}
+
+static clknode_method_t prci_clk_pll_clknode_methods[] = {
+	CLKNODEMETHOD(clknode_init,		prci_clk_pll_init),
+	CLKNODEMETHOD(clknode_recalc_freq,	prci_clk_pll_recalc),
+	CLKNODEMETHOD_END
+};
+
+DEFINE_CLASS_1(prci_clk_pll_clknode, prci_clk_pll_clknode_class,
+    prci_clk_pll_clknode_methods, sizeof(struct prci_clk_pll_sc),
+    clknode_class);
+
+static int
+prci_probe(device_t dev)
+{
+
+	if (!ofw_bus_status_okay(dev))
+		return (ENXIO);
+
+	if (!ofw_bus_is_compatible(dev, "sifive,aloeprci0"))
+		return (ENXIO);
+
+	device_set_desc(dev, "SiFive FU540 Power Reset Clocking Interrupt");
+
+	return (BUS_PROBE_DEFAULT);
+}
+
+static void
+prci_pll_register(struct prci_softc *parent_sc, struct clknode_init_def *clkdef)
+{
+	struct clknode *clk;
+	struct prci_clk_pll_sc *sc;
+
+	clk = clknode_create(parent_sc->clkdom, &prci_clk_pll_clknode_class,
+	    clkdef);
+	if (clk == NULL)
+		panic("Failed to create clknode");
+
+	sc = clknode_get_softc(clk);
+	sc->parent_sc = parent_sc;
+
+	clknode_register(parent_sc->clkdom, clk);
+}
+
+static int
+prci_attach(device_t dev)
+{
+	struct clknode_init_def clkdef;
+	struct prci_softc *sc;
+	clk_t clk_parent;
+	phandle_t node;
+	int i, ncells, error;
+
+	sc = device_get_softc(dev);
+	sc->dev = dev;
+
+	mtx_init(&sc->mtx, device_get_nameunit(sc->dev), NULL, MTX_DEF);
+
+	error = bus_alloc_resources(dev, prci_spec, &sc->res);
+	if (error) {
+		device_printf(dev, "Couldn't allocate resources\n");
+		goto fail;
+	}
+	sc->bst = rman_get_bustag(sc->res);
+	sc->bsh = rman_get_bushandle(sc->res);
+
+	node = ofw_bus_get_node(dev);
+	error = ofw_bus_parse_xref_list_get_length(node, "clocks",
+	    "#clock-cells", &ncells);
+	if (error != 0 || ncells != 1) {
+		device_printf(dev, "couldn't find parent clock\n");
+		goto fail;
+	}
+
+	bzero(&clkdef, sizeof(clkdef));
+	clkdef.id = 0;
+	clkdef.name = "coreclk";
+	clkdef.parent_names = mallocarray(ncells, sizeof(char *), M_OFWPROP,
+	    M_WAITOK);
+	for (i = 0; i < ncells; i++) {
+		error = clk_get_by_ofw_index(dev, 0, i, &clk_parent);
+		if (error != 0) {
+			device_printf(dev, "cannot get clock %d\n", error);
+			goto fail1;
+		}
+		clkdef.parent_names[i] = clk_get_name(clk_parent);
+		if (bootverbose)
+			device_printf(dev, "clk parent: %s\n",
+			    clkdef.parent_names[i]);
+		clk_release(clk_parent);
+	}
+	clkdef.parent_cnt = ncells;
+
+	sc->clkdom = clkdom_create(dev);
+	if (sc->clkdom == NULL) {
+		device_printf(dev, "Couldn't create clock domain\n");
+		goto fail;
+	}
+
+	/* We can't free a clkdom, so from now on we cannot fail. */
+	prci_pll_register(sc, &clkdef);
+
+	error = clkdom_finit(sc->clkdom);
+	if (error)
+		panic("Couldn't finalise clock domain");
+
+	return (0);
+
+fail1:
+	free(clkdef.parent_names, M_OFWPROP);
+
+fail:
+	bus_release_resources(dev, prci_spec, &sc->res);
+	mtx_destroy(&sc->mtx);
+	return (error);
+}
+
+static device_method_t prci_methods[] = {
+	DEVMETHOD(device_probe,		prci_probe),
+	DEVMETHOD(device_attach,	prci_attach),
+
+	DEVMETHOD_END
+};
+
+static driver_t prci_driver = {
+	"fu540prci",
+	prci_methods,
+	sizeof(struct prci_softc)
+};
+
+static devclass_t prci_devclass;
+
+EARLY_DRIVER_MODULE(fu540prci, simplebus, prci_driver, prci_devclass, 0, 0,
+    BUS_PASS_BUS);
diff --git a/sys/riscv/sifive/std.sifive b/sys/riscv/sifive/std.sifive
new file mode 100644
index 000000000000..f1e513873425
--- /dev/null
+++ b/sys/riscv/sifive/std.sifive
@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+files		"../sifive/files.sifive"