Add aplefuse(4), a driver for the eFuses on Apple Silicon SoCs.

ok patrick@

3 files changed, 119 insertions, 2 deletions

diff --git a/sys/arch/arm64/conf/GENERIC b/sys/arch/arm64/conf/GENERIC
index d6608a85bdd..9788fcf7269 100644
--- a/sys/arch/arm64/conf/GENERIC
+++ b/sys/arch/arm64/conf/GENERIC
@@ -1,4 +1,4 @@
-# $OpenBSD: GENERIC,v 1.250 2022/12/12 19:18:25 kettenis Exp $
+# $OpenBSD: GENERIC,v 1.251 2022/12/17 11:56:44 kettenis Exp $
 #
 # GENERIC machine description file
 #
@@ -157,6 +157,7 @@ apldcms*	at apldchidev?
 wsmouse*	at apldcms? mux 0
 apldma*		at fdt?
 apldog*		at fdt? early 1
+aplefuse*	at fdt? early 1
 apliic*		at fdt?
 iic*		at apliic?
 aplintc*	at fdt? early 1
diff --git a/sys/arch/arm64/conf/files.arm64 b/sys/arch/arm64/conf/files.arm64
index f5e39dfb2b5..b30947a9e61 100644
--- a/sys/arch/arm64/conf/files.arm64
+++ b/sys/arch/arm64/conf/files.arm64
@@ -1,4 +1,4 @@
-# $OpenBSD: files.arm64,v 1.64 2022/11/21 21:48:06 kettenis Exp $
+# $OpenBSD: files.arm64,v 1.65 2022/12/17 11:56:44 kettenis Exp $
 
 maxpartitions	16
 maxusers	2 8 128
@@ -169,6 +169,10 @@ device	apldog
 attach	apldog at fdt
 file	arch/arm64/dev/apldog.c			apldog
 
+device	aplefuse
+attach	aplefuse at fdt
+file	arch/arm64/dev/aplefuse.c		aplefuse
+
 device	apliic: i2cbus
 attach	apliic at fdt
 file	arch/arm64/dev/apliic.c			apliic
diff --git a/sys/arch/arm64/dev/aplefuse.c b/sys/arch/arm64/dev/aplefuse.c
new file mode 100644
index 00000000000..53eb1e4e329
--- /dev/null
+++ b/sys/arch/arm64/dev/aplefuse.c
@@ -0,0 +1,112 @@
+/*	$OpenBSD: aplefuse.c,v 1.1 2022/12/17 11:56:44 kettenis Exp $	*/
+/*
+ * Copyright (c) 2022 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_misc.h>
+#include <dev/ofw/fdt.h>
+
+struct aplefuse_softc {
+	struct device		sc_dev;
+	bus_space_tag_t		sc_iot;
+	bus_space_handle_t	sc_ioh;
+	bus_size_t		sc_ios;
+
+	struct nvmem_device	sc_nd;
+};
+
+int	aplefuse_match(struct device *, void *, void *);
+void	aplefuse_attach(struct device *, struct device *, void *);
+
+const struct cfattach aplefuse_ca = {
+	sizeof (struct aplefuse_softc), aplefuse_match, aplefuse_attach
+};
+
+struct cfdriver aplefuse_cd = {
+	NULL, "aplefuse", DV_DULL
+};
+
+int	aplefuse_nvmem_read(void *, bus_addr_t, void *, bus_size_t);
+int	aplefuse_nvmem_write(void *, bus_addr_t, const void *, bus_size_t);
+
+int
+aplefuse_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "apple,efuses");
+}
+
+void
+aplefuse_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct aplefuse_softc *sc = (struct aplefuse_softc *)self;
+	struct fdt_attach_args *faa = aux;
+
+	if (faa->fa_nreg < 1) {
+		printf(": no registers\n");
+		return;
+	}
+
+	sc->sc_iot = faa->fa_iot;
+	if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
+	    faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
+		printf(": can't map registers\n");
+		return;
+	}
+	sc->sc_ios = faa->fa_reg[0].size;
+
+	printf("\n");
+
+	sc->sc_nd.nd_node = faa->fa_node;
+	sc->sc_nd.nd_cookie = sc;
+	sc->sc_nd.nd_read = aplefuse_nvmem_read;
+	nvmem_register(&sc->sc_nd);
+}
+
+int
+aplefuse_nvmem_read(void *cookie, bus_addr_t addr, void *data, bus_size_t size)
+{
+	struct aplefuse_softc *sc = cookie;
+	uint8_t *p = data;
+	uint32_t value;
+	uint8_t buf[4];
+	int offset;
+
+	if (addr > sc->sc_ios || size > sc->sc_ios - addr)
+		return EINVAL;
+
+	offset = addr & 0x3;
+	addr &= ~0x3;
+	while (size > 0) {
+		value = bus_space_read_4(sc->sc_iot, sc->sc_ioh, addr);
+		htolem32(buf, value);
+		memcpy(p, &buf[offset], MIN(size, 4 - offset));
+		size -= MIN(size, 4 - offset);
+		p += MIN(size, 4 - offset);
+		addr += 4;
+		offset = 0;
+	}
+
+	return 0;
+}