From 86c6868161803323de7c25bdf9749efd2f5e2dfc Mon Sep 17 00:00:00 2001
From: Kyle Evans <kevans@FreeBSD.org>
Date: Sun, 7 Jan 2018 03:31:55 +0000
Subject: [PATCH] aw_sid: Add method for reading keys via prctl registers

Technically supported on the later SoCs, this will only really be used to
add support for the H3 sid. The H3 has a silicon bug that manifests itself
by returning garbled rootkeys unless first read via the prctl registers.
---
 sys/arm/allwinner/aw_sid.c | 48 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/sys/arm/allwinner/aw_sid.c b/sys/arm/allwinner/aw_sid.c
index ecc12567bb1..6bae8e6d55a 100644
--- a/sys/arm/allwinner/aw_sid.c
+++ b/sys/arm/allwinner/aw_sid.c
@@ -39,6 +39,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/bus.h>
 #include <sys/rman.h>
 #include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
 #include <sys/module.h>
 #include <sys/sysctl.h>
 #include <machine/bus.h>
@@ -48,6 +50,16 @@ __FBSDID("$FreeBSD$");
 
 #include <arm/allwinner/aw_sid.h>
 
+/* efuse registers */
+#define	SID_PRCTL		0x40
+#define	 SID_PRCTL_OFFSET_MASK	0xff
+#define	 SID_PRCTL_OFFSET(n)	(((n) & SID_PRCTL_OFFSET_MASK) << 16)
+#define	 SID_PRCTL_LOCK		(0xac << 8)
+#define	 SID_PRCTL_READ		(0x01 << 1)
+#define	 SID_PRCTL_WRITE	(0x01 << 0)
+#define	SID_PRKEY		0x50
+#define	SID_RDKEY		0x60
+
 #define	SID_SRAM		0x200
 #define	SID_THERMAL_CALIB0	(SID_SRAM + 0x34)
 #define	SID_THERMAL_CALIB1	(SID_SRAM + 0x38)
@@ -56,6 +68,7 @@ __FBSDID("$FreeBSD$");
 
 struct aw_sid_conf {
 	bus_size_t	rootkey_offset;
+	bool		has_prctl;
 	bool		has_thermal;
 };
 
@@ -69,11 +82,13 @@ static const struct aw_sid_conf a20_conf = {
 
 static const struct aw_sid_conf a64_conf = {
 	.rootkey_offset = SID_SRAM,
+	.has_prctl = true,
 	.has_thermal = true,
 };
 
 static const struct aw_sid_conf a83t_conf = {
 	.rootkey_offset = SID_SRAM,
+	.has_prctl = true,
 	.has_thermal = true,
 };
 
@@ -88,6 +103,7 @@ static struct ofw_compat_data compat_data[] = {
 struct aw_sid_softc {
 	struct resource		*res;
 	struct aw_sid_conf	*sid_conf;
+	struct mtx		prctl_mtx;
 };
 
 static struct aw_sid_softc *aw_sid_sc;
@@ -105,6 +121,35 @@ enum sid_keys {
 #define	WR4(sc, reg, val)	bus_write_4((sc)->res, (reg), (val))
 
 static int aw_sid_sysctl(SYSCTL_HANDLER_ARGS);
+static int aw_sid_prctl_read(device_t dev, bus_size_t offset, uint32_t *val);
+
+
+/*
+ * offset here is offset into efuse space, rather than offset into sid register
+ * space. This form of read is only an option for newer SoC: A83t, H3, A64
+ */
+static int
+aw_sid_prctl_read(device_t dev, bus_size_t offset, uint32_t *val)
+{
+	struct aw_sid_softc *sc;
+	uint32_t readval;
+
+	sc = device_get_softc(dev);
+	if (!sc->sid_conf->has_prctl)
+		return (1);
+
+	mtx_lock(&sc->prctl_mtx);
+	readval = SID_PRCTL_OFFSET(offset) | SID_PRCTL_LOCK | SID_PRCTL_READ;
+	WR4(sc, SID_PRCTL, readval);
+	/* Read bit will be cleared once read has concluded */
+	while (RD4(sc, SID_PRCTL) & SID_PRCTL_READ)
+		continue;
+	readval = RD4(sc, SID_RDKEY);
+	mtx_unlock(&sc->prctl_mtx);
+	*val = readval;
+
+	return (0);
+}
 
 static int
 aw_sid_probe(device_t dev)
@@ -131,8 +176,9 @@ aw_sid_attach(device_t dev)
 		return (ENXIO);
 	}
 
-	aw_sid_sc = sc;
+	mtx_init(&sc->prctl_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
 	sc->sid_conf = (struct aw_sid_conf *)ofw_bus_search_compatible(dev, compat_data)->ocd_data;
+	aw_sid_sc = sc;
 
 	SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
 	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
-- 
2.45.0