Add imxrtc(4), a driver for the "secure" RTC in the Low Power Domain of the

SNVS block found on i.MX7 and i.MX8.

2 files changed, 171 insertions, 1 deletions

diff --git a/sys/dev/fdt/files.fdt b/sys/dev/fdt/files.fdt
index 8b5a1443a1b..62de92fee6b 100644
--- a/sys/dev/fdt/files.fdt
+++ b/sys/dev/fdt/files.fdt
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.63 2018/06/05 20:41:19 kettenis Exp $
+#	$OpenBSD: files.fdt,v 1.64 2018/06/16 14:11:35 kettenis Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -239,6 +239,10 @@ device	imxpd: fdt
 attach	imxpd at fdt
 file	dev/fdt/imxpd.c			imxpd
 
+device	imxrtc
+attach	imxrtc at fdt
+file	dev/fdt/imxrtc.c		imxrtc
+
 device	imxuart
 attach	imxuart at fdt
 file	dev/fdt/imxuart.c		imxuart
diff --git a/sys/dev/fdt/imxrtc.c b/sys/dev/fdt/imxrtc.c
new file mode 100644
index 00000000000..1ae4f240810
--- /dev/null
+++ b/sys/dev/fdt/imxrtc.c
@@ -0,0 +1,166 @@
+/*	$OpenBSD: imxrtc.c,v 1.1 2018/06/16 14:11:35 kettenis Exp $	*/
+/*
+ * Copyright (c) 2018 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/intr.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/clock_subr.h>
+
+extern todr_chip_handle_t todr_handle;
+
+/* Registers. */
+#define LPCR			0x38
+#define  LPCR_SRTC_ENV		(1 << 0)
+#define LPSR			0x4c
+#define LPSRTCMR		0x50
+#define LPSRTCLR		0x54
+
+#define HREAD4(sc, reg)							\
+	(regmap_read_4((sc)->sc_rm, (reg)))
+#define HWRITE4(sc, reg, val)						\
+	regmap_write_4((sc)->sc_rm, (reg), (val))
+
+struct imxrtc_softc {
+	struct device		sc_dev;
+	struct regmap		*sc_rm;
+
+	struct todr_chip_handle sc_todr;
+};
+
+int imxrtc_match(struct device *, void *, void *);
+void imxrtc_attach(struct device *, struct device *, void *);
+
+struct cfattach	imxrtc_ca = {
+	sizeof (struct imxrtc_softc), imxrtc_match, imxrtc_attach
+};
+
+struct cfdriver imxrtc_cd = {
+	NULL, "imxrtc", DV_DULL
+};
+
+int	imxrtc_gettime(struct todr_chip_handle *, struct timeval *);
+int	imxrtc_settime(struct todr_chip_handle *, struct timeval *);
+
+int
+imxrtc_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "fsl,sec-v4.0-mon-rtc-lp");
+}
+
+void
+imxrtc_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct imxrtc_softc *sc = (struct imxrtc_softc *)self;
+	struct fdt_attach_args *faa = aux;
+	uint32_t regmap;
+
+	regmap = OF_getpropint(faa->fa_node, "regmap", 0);
+	sc->sc_rm = regmap_byphandle(regmap);
+	if (sc->sc_rm == NULL) {
+		printf(": no registers\n");
+		return;
+	}
+
+	printf("\n");
+
+	sc->sc_todr.cookie = sc;
+	sc->sc_todr.todr_gettime = imxrtc_gettime;
+	sc->sc_todr.todr_settime = imxrtc_settime;
+	todr_handle = &sc->sc_todr;
+}
+
+int
+imxrtc_gettime(struct todr_chip_handle *handle, struct timeval *tv)
+{
+	struct imxrtc_softc *sc = handle->cookie;
+	uint64_t mr, lr, srtc, srtc2;
+	uint32_t cr;
+	int retries;
+	int s;
+
+	cr = HREAD4(sc, LPCR);
+	if ((cr & LPCR_SRTC_ENV) == 0)
+		return EINVAL;
+
+	/*
+	 * Read counters until we read back the same values twice.
+	 * This shouldn't take more than two attempts; throw in an
+	 * extra round just in case.
+	 */
+	s = splhigh();
+	mr = HREAD4(sc, LPSRTCMR);
+	lr = HREAD4(sc, LPSRTCLR);
+	srtc = (mr << 32) | lr;
+	for (retries = 3; retries > 0; retries--) {
+		mr = HREAD4(sc, LPSRTCMR);
+		lr = HREAD4(sc, LPSRTCLR);
+		srtc2 = (mr << 32) | lr;
+		if (srtc == srtc2)
+			break;
+		srtc = srtc2;
+	}
+	splx(s);
+	if (retries == 0)
+		return EIO;
+
+	tv->tv_sec = srtc / 32768;
+	tv->tv_usec = ((srtc % 32768) * 1000000U) / 32768U;
+	return 0;
+}
+
+int
+imxrtc_settime(struct todr_chip_handle *handle, struct timeval *tv)
+{
+	struct imxrtc_softc *sc = handle->cookie;
+	uint64_t srtc;
+	uint32_t cr;
+	int timeout;
+
+	/* Disable RTC. */
+	cr = HREAD4(sc, LPCR);
+	cr &= ~LPCR_SRTC_ENV;
+	HWRITE4(sc, LPCR, cr);
+	for (timeout = 1000000; timeout > 0; timeout--) {
+		if ((HREAD4(sc, LPCR) & LPCR_SRTC_ENV) == 0)
+			break;
+	}
+
+	srtc = tv->tv_sec * 32768 + (tv->tv_usec * 32768U / 1000000U);
+	HWRITE4(sc, LPSRTCMR, srtc >> 32);
+	HWRITE4(sc, LPSRTCLR, srtc & 0xffffffff);
+
+	/* Enable RTC. */
+	cr |= LPCR_SRTC_ENV;
+	HWRITE4(sc, LPCR, cr);
+	for (timeout = 1000000; timeout > 0; timeout--) {
+		if (HREAD4(sc, LPCR) & LPCR_SRTC_ENV)
+			break;
+	}
+
+	return 0;
+}