Add amlsm(4), a driver for the "secure monitor" firmware interface.

For now, this driver fetches the "chip id" and feeds this as entropy
to the kernel's random subsystem.

2 files changed, 122 insertions, 1 deletions

diff --git a/sys/dev/fdt/amlsm.c b/sys/dev/fdt/amlsm.c
new file mode 100644
index 00000000000..af237545346
--- /dev/null
+++ b/sys/dev/fdt/amlsm.c
@@ -0,0 +1,117 @@
+/*	$OpenBSD: amlsm.c,v 1.1 2020/01/14 20:43:20 kettenis Exp $	*/
+/*
+ * Copyright (c) 2020 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 <sys/timeout.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/fdt.h>
+#include <dev/ofw/ofw_misc.h>
+#include <dev/rndvar.h>
+
+extern register_t smc_call(register_t, register_t, register_t, register_t);
+
+/* Calls */
+#define AML_SM_GET_SHARE_MEM_INPUT_BASE		0x82000020
+#define AML_SM_GET_SHARE_MEM_OUTPUT_BASE	0x82000021
+#define AML_SM_EFUSE_READ			0x82000030
+#define AML_SM_EFUSE_USER_MAX			0x82000033
+#define AML_SM_JTAG_ON				0x82000040
+#define AML_SM_JTAG_OFF				0x82000041
+#define AML_SM_GET_CHIP_ID			0x82000044
+
+struct aml_cpu_info {
+	uint32_t	version;
+	uint32_t	chip_id[4];
+};
+
+struct amlsm_softc {
+	struct device		sc_dev;
+	bus_space_tag_t		sc_iot;
+	bus_space_handle_t	sc_in_ioh;
+	bus_space_handle_t	sc_out_ioh;
+};
+
+int	amlsm_match(struct device *, void *, void *);
+void	amlsm_attach(struct device *, struct device *, void *);
+
+struct cfattach	amlsm_ca = {
+	sizeof (struct amlsm_softc), amlsm_match, amlsm_attach
+};
+
+struct cfdriver amlsm_cd = {
+	NULL, "amlsm", DV_DULL
+};
+
+int
+amlsm_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "amlogic,meson-gxbb-sm");
+}
+
+void
+amlsm_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct amlsm_softc *sc = (struct amlsm_softc *)self;
+	struct fdt_attach_args *faa = aux;
+	struct aml_cpu_info *info;
+	bus_addr_t addr;
+	int32_t ret;
+	int i;
+
+	sc->sc_iot = faa->fa_iot;
+
+	addr = smc_call(AML_SM_GET_SHARE_MEM_INPUT_BASE, 0, 0, 0);
+	if (addr == (bus_addr_t)-1 ||
+	    bus_space_map(sc->sc_iot, addr, PAGE_SIZE,
+	    BUS_SPACE_MAP_CACHEABLE, &sc->sc_in_ioh)) {
+		printf(": can't map shared memory\n");
+		return;
+	}
+	addr = smc_call(AML_SM_GET_SHARE_MEM_OUTPUT_BASE, 0, 0, 0);
+	if (addr == (bus_addr_t)-1 ||
+	    bus_space_map(sc->sc_iot, addr, PAGE_SIZE,
+	    BUS_SPACE_MAP_CACHEABLE, &sc->sc_out_ioh)) {
+		bus_space_unmap(sc->sc_iot, sc->sc_in_ioh, PAGE_SIZE);
+		printf(": can't map shared memory\n");
+		return;
+	}
+
+	/*
+	 * Version 2 gives us a 16-byte chip ID.  If that fails, fall
+	 * back on version 0/1 which gives us a 12-byte chipt ID.
+	 */
+	info = bus_space_vaddr(sc->sc_iot, sc->sc_out_ioh);
+	memset(info, 0, sizeof(struct aml_cpu_info));
+	ret = smc_call(AML_SM_GET_CHIP_ID, 2, 0, 0);
+	if (ret == -1)
+		ret = smc_call(AML_SM_GET_CHIP_ID, 0, 0, 0);
+
+	printf(": ver %u\n", info->version);
+	
+	if (ret != -1) {
+		for (i = 0; i < nitems(info->chip_id); i++)
+			enqueue_randomness(info->chip_id[i]);
+	}
+}
diff --git a/sys/dev/fdt/files.fdt b/sys/dev/fdt/files.fdt
index 76e494f7032..2967ec5767f 100644
--- a/sys/dev/fdt/files.fdt
+++ b/sys/dev/fdt/files.fdt
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.107 2020/01/14 16:56:32 kettenis Exp $
+#	$OpenBSD: files.fdt,v 1.108 2020/01/14 20:43:20 kettenis Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -188,6 +188,10 @@ device	amlrng
 attach	amlrng at fdt
 file	dev/fdt/amlrng.c		amlrng
 
+device	amlsm
+attach	amlsm at fdt
+file	dev/fdt/amlsm.c			amlsm
+
 device	amltemp
 attach	amltemp at fdt
 file	dev/fdt/amltemp.c		amltemp