This reads out the status of the secure boot controller and exposes it
in sysfs.
An example on a AST2600A3 QEMU model:
# grep . /sys/bus/soc/devices/soc0/*
/sys/bus/soc/devices/soc0/abr_image:0
/sys/bus/soc/devices/soc0/family:AST2600
/sys/bus/soc/devices/soc0/low_security_key:0
/sys/bus/soc/devices/soc0/machine:Rainier 2U
/sys/bus/soc/devices/soc0/otp_protected:0
/sys/bus/soc/devices/soc0/revision:A3
/sys/bus/soc/devices/soc0/secure_boot:1
/sys/bus/soc/devices/soc0/serial_number:888844441234abcd
/sys/bus/soc/devices/soc0/soc_id:05030303
/sys/bus/soc/devices/soc0/uart_boot:1
On boot the state of the system according to the secure boot controller
will be printed:
[ 0.037634] AST2600 secure boot enabled
or
[ 0.037935] AST2600 secure boot disabled
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
Reviewed-by: Ryan Chen <ryan_chen@xxxxxxxxxxxxxx>
---
drivers/soc/aspeed/aspeed-socinfo.c | 73 +++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)
diff --git a/drivers/soc/aspeed/aspeed-socinfo.c b/drivers/soc/aspeed/aspeed-socinfo.c
index 1ca140356a08..6faf2c199c90 100644
--- a/drivers/soc/aspeed/aspeed-socinfo.c
+++ b/drivers/soc/aspeed/aspeed-socinfo.c
@@ -9,6 +9,8 @@
#include <linux/slab.h>
#include <linux/sys_soc.h>
+static u32 security_status;
+
static struct {
const char *name;
const u32 id;
@@ -74,6 +76,54 @@ static const char *siliconid_to_rev(u32 siliconid)
return "??";
}
+#define SEC_STATUS 0x14
+#define ABR_IMAGE_SOURCE BIT(13)
+#define OTP_PROTECTED BIT(8)
+#define LOW_SEC_KEY BIT(7)
+#define SECURE_BOOT BIT(6)
+#define UART_BOOT BIT(5)
+
+static ssize_t abr_image_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", !!(security_status & ABR_IMAGE_SOURCE));
+}
+static DEVICE_ATTR_RO(abr_image);
+
+static ssize_t low_security_key_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", !!(security_status & LOW_SEC_KEY));
+}
+static DEVICE_ATTR_RO(low_security_key);
+
+static ssize_t otp_protected_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", !!(security_status & OTP_PROTECTED));
+}
+static DEVICE_ATTR_RO(otp_protected);
+
+static ssize_t secure_boot_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", !!(security_status & SECURE_BOOT));
+}
+static DEVICE_ATTR_RO(secure_boot);
+
+static ssize_t uart_boot_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ /* Invert the bit, as 1 is boot from SPI/eMMC */
+ return sprintf(buf, "%d\n", !(security_status & UART_BOOT));
+}
+static DEVICE_ATTR_RO(uart_boot);
+
+static struct attribute *aspeed_attrs[] = {
+ &dev_attr_abr_image.attr,
+ &dev_attr_low_security_key.attr,
+ &dev_attr_otp_protected.attr,
+ &dev_attr_secure_boot.attr,
+ &dev_attr_uart_boot.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(aspeed);
+
static int __init aspeed_socinfo_init(void)
{
struct soc_device_attribute *attrs;
@@ -81,6 +131,7 @@ static int __init aspeed_socinfo_init(void)
struct device_node *np;
void __iomem *reg;
bool has_chipid = false;
+ bool has_sbe = false;
u32 siliconid;
u32 chipid[2];
const char *machine = NULL;
@@ -109,6 +160,20 @@ static int __init aspeed_socinfo_init(void)
}
of_node_put(np);
+ /* AST2600 only */
+ np = of_find_compatible_node(NULL, NULL, "aspeed,ast2600-sbc");
+ if (of_device_is_available(np)) {
+ void *base = of_iomap(np, 0);
+ if (!base) {
+ of_node_put(np);
+ return -ENODEV;
+ }
+ security_status = readl(base + SEC_STATUS);
+ has_sbe = true;
+ iounmap(base);
+ of_node_put(np);
+ }
+
attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
if (!attrs)
return -ENODEV;
@@ -135,6 +200,9 @@ static int __init aspeed_socinfo_init(void)
attrs->serial_number = kasprintf(GFP_KERNEL, "%08x%08x",
chipid[1], chipid[0]);
+ if (has_sbe)
+ attrs->custom_attr_group = aspeed_groups[0];
+
soc_dev = soc_device_register(attrs);
if (IS_ERR(soc_dev)) {
kfree(attrs->soc_id);
@@ -148,6 +216,11 @@ static int __init aspeed_socinfo_init(void)
attrs->revision,
attrs->soc_id);
+ if (has_sbe) {
+ pr_info("AST2600 secure boot %s\n",
+ (security_status & SECURE_BOOT) ? "enabled" : "disabled");
+ }
+
return 0;
}
early_initcall(aspeed_socinfo_init);
--
2.33.0
