1 files changed, 321 insertions, 0 deletions
diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c b/drivers/platform/mellanox/mlxbf-bootctl.c
new file mode 100644
index 000000000000..61753b648506
--- /dev/null
+++ b/drivers/platform/mellanox/mlxbf-bootctl.c
@@ -0,0 +1,321 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Mellanox boot control driver
+ *
+ * This driver provides a sysfs interface for systems management
+ * software to manage reset-time actions.
+ *
+ * Copyright (C) 2019 Mellanox Technologies
+ */
+
+#include <linux/acpi.h>
+#include <linux/arm-smccc.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "mlxbf-bootctl.h"
+
+#define MLXBF_BOOTCTL_SB_SECURE_MASK		0x03
+#define MLXBF_BOOTCTL_SB_TEST_MASK		0x0c
+
+#define MLXBF_SB_KEY_NUM			4
+
+/* UUID used to probe ATF service. */
+static const char *mlxbf_bootctl_svc_uuid_str =
+	"89c036b4-e7d7-11e6-8797-001aca00bfc4";
+
+struct mlxbf_bootctl_name {
+	u32 value;
+	const char *name;
+};
+
+static struct mlxbf_bootctl_name boot_names[] = {
+	{ MLXBF_BOOTCTL_EXTERNAL, "external" },
+	{ MLXBF_BOOTCTL_EMMC, "emmc" },
+	{ MLNX_BOOTCTL_SWAP_EMMC, "swap_emmc" },
+	{ MLXBF_BOOTCTL_EMMC_LEGACY, "emmc_legacy" },
+	{ MLXBF_BOOTCTL_NONE, "none" },
+};
+
+static const char * const mlxbf_bootctl_lifecycle_states[] = {
+	[0] = "Production",
+	[1] = "GA Secured",
+	[2] = "GA Non-Secured",
+	[3] = "RMA",
+};
+
+/* ARM SMC call which is atomic and no need for lock. */
+static int mlxbf_bootctl_smc(unsigned int smc_op, int smc_arg)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(smc_op, smc_arg, 0, 0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+/* Return the action in integer or an error code. */
+static int mlxbf_bootctl_reset_action_to_val(const char *action)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(boot_names); i++)
+		if (sysfs_streq(boot_names[i].name, action))
+			return boot_names[i].value;
+
+	return -EINVAL;
+}
+
+/* Return the action in string. */
+static const char *mlxbf_bootctl_action_to_string(int action)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(boot_names); i++)
+		if (boot_names[i].value == action)
+			return boot_names[i].name;
+
+	return "invalid action";
+}
+
+static ssize_t post_reset_wdog_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	int ret;
+
+	ret = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_POST_RESET_WDOG, 0);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t post_reset_wdog_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	unsigned long value;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &value);
+	if (ret)
+		return ret;
+
+	ret = mlxbf_bootctl_smc(MLXBF_BOOTCTL_SET_POST_RESET_WDOG, value);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t mlxbf_bootctl_show(int smc_op, char *buf)
+{
+	int action;
+
+	action = mlxbf_bootctl_smc(smc_op, 0);
+	if (action < 0)
+		return action;
+
+	return sprintf(buf, "%s\n", mlxbf_bootctl_action_to_string(action));
+}
+
+static int mlxbf_bootctl_store(int smc_op, const char *buf, size_t count)
+{
+	int ret, action;
+
+	action = mlxbf_bootctl_reset_action_to_val(buf);
+	if (action < 0)
+		return action;
+
+	ret = mlxbf_bootctl_smc(smc_op, action);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t reset_action_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	return mlxbf_bootctl_show(MLXBF_BOOTCTL_GET_RESET_ACTION, buf);
+}
+
+static ssize_t reset_action_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	return mlxbf_bootctl_store(MLXBF_BOOTCTL_SET_RESET_ACTION, buf, count);
+}
+
+static ssize_t second_reset_action_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	return mlxbf_bootctl_show(MLXBF_BOOTCTL_GET_SECOND_RESET_ACTION, buf);
+}
+
+static ssize_t second_reset_action_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	return mlxbf_bootctl_store(MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION, buf,
+				   count);
+}
+
+static ssize_t lifecycle_state_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	int lc_state;
+
+	lc_state = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS,
+				     MLXBF_BOOTCTL_FUSE_STATUS_LIFECYCLE);
+	if (lc_state < 0)
+		return lc_state;
+
+	lc_state &=
+		MLXBF_BOOTCTL_SB_TEST_MASK | MLXBF_BOOTCTL_SB_SECURE_MASK;
+
+	/*
+	 * If the test bits are set, we specify that the current state may be
+	 * due to using the test bits.
+	 */
+	if (lc_state & MLXBF_BOOTCTL_SB_TEST_MASK) {
+		lc_state &= MLXBF_BOOTCTL_SB_SECURE_MASK;
+
+		return sprintf(buf, "%s(test)\n",
+			       mlxbf_bootctl_lifecycle_states[lc_state]);
+	}
+
+	return sprintf(buf, "%s\n", mlxbf_bootctl_lifecycle_states[lc_state]);
+}
+
+static ssize_t secure_boot_fuse_state_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	int burnt, valid, key, key_state, buf_len = 0, upper_key_used = 0;
+	const char *status;
+
+	key_state = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS,
+				      MLXBF_BOOTCTL_FUSE_STATUS_KEYS);
+	if (key_state < 0)
+		return key_state;
+
+	/*
+	 * key_state contains the bits for 4 Key versions, loaded from eFuses
+	 * after a hard reset. Lower 4 bits are a thermometer code indicating
+	 * key programming has started for key n (0000 = none, 0001 = version 0,
+	 * 0011 = version 1, 0111 = version 2, 1111 = version 3). Upper 4 bits
+	 * are a thermometer code indicating key programming has completed for
+	 * key n (same encodings as the start bits). This allows for detection
+	 * of an interruption in the progamming process which has left the key
+	 * partially programmed (and thus invalid). The process is to burn the
+	 * eFuse for the new key start bit, burn the key eFuses, then burn the
+	 * eFuse for the new key complete bit.
+	 *
+	 * For example 0000_0000: no key valid, 0001_0001: key version 0 valid,
+	 * 0011_0011: key 1 version valid, 0011_0111: key version 2 started
+	 * programming but did not complete, etc. The most recent key for which
+	 * both start and complete bit is set is loaded. On soft reset, this
+	 * register is not modified.
+	 */
+	for (key = MLXBF_SB_KEY_NUM - 1; key >= 0; key--) {
+		burnt = key_state & BIT(key);
+		valid = key_state & BIT(key + MLXBF_SB_KEY_NUM);
+
+		if (burnt && valid)
+			upper_key_used = 1;
+
+		if (upper_key_used) {
+			if (burnt)
+				status = valid ? "Used" : "Wasted";
+			else
+				status = valid ? "Invalid" : "Skipped";
+		} else {
+			if (burnt)
+				status = valid ? "InUse" : "Incomplete";
+			else
+				status = valid ? "Invalid" : "Free";
+		}
+		buf_len += sprintf(buf + buf_len, "%d:%s ", key, status);
+	}
+	buf_len += sprintf(buf + buf_len, "\n");
+
+	return buf_len;
+}
+
+static DEVICE_ATTR_RW(post_reset_wdog);
+static DEVICE_ATTR_RW(reset_action);
+static DEVICE_ATTR_RW(second_reset_action);
+static DEVICE_ATTR_RO(lifecycle_state);
+static DEVICE_ATTR_RO(secure_boot_fuse_state);
+
+static struct attribute *mlxbf_bootctl_attrs[] = {
+	&dev_attr_post_reset_wdog.attr,
+	&dev_attr_reset_action.attr,
+	&dev_attr_second_reset_action.attr,
+	&dev_attr_lifecycle_state.attr,
+	&dev_attr_secure_boot_fuse_state.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(mlxbf_bootctl);
+
+static const struct acpi_device_id mlxbf_bootctl_acpi_ids[] = {
+	{"MLNXBF04", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(acpi, mlxbf_bootctl_acpi_ids);
+
+static bool mlxbf_bootctl_guid_match(const guid_t *guid,
+				     const struct arm_smccc_res *res)
+{
+	guid_t id = GUID_INIT(res->a0, res->a1, res->a1 >> 16,
+			      res->a2, res->a2 >> 8, res->a2 >> 16,
+			      res->a2 >> 24, res->a3, res->a3 >> 8,
+			      res->a3 >> 16, res->a3 >> 24);
+
+	return guid_equal(guid, &id);
+}
+
+static int mlxbf_bootctl_probe(struct platform_device *pdev)
+{
+	struct arm_smccc_res res = { 0 };
+	guid_t guid;
+	int ret;
+
+	/* Ensure we have the UUID we expect for this service. */
+	arm_smccc_smc(MLXBF_BOOTCTL_SIP_SVC_UID, 0, 0, 0, 0, 0, 0, 0, &res);
+	guid_parse(mlxbf_bootctl_svc_uuid_str, &guid);
+	if (!mlxbf_bootctl_guid_match(&guid, &res))
+		return -ENODEV;
+
+	/*
+	 * When watchdog is used, it sets boot mode to MLXBF_BOOTCTL_SWAP_EMMC
+	 * in case of boot failures. However it doesn't clear the state if there
+	 * is no failure. Restore the default boot mode here to avoid any
+	 * unnecessary boot partition swapping.
+	 */
+	ret = mlxbf_bootctl_smc(MLXBF_BOOTCTL_SET_RESET_ACTION,
+				MLXBF_BOOTCTL_EMMC);
+	if (ret < 0)
+		dev_warn(&pdev->dev, "Unable to reset the EMMC boot mode\n");
+
+	return 0;
+}
+
+static struct platform_driver mlxbf_bootctl_driver = {
+	.probe = mlxbf_bootctl_probe,
+	.driver = {
+		.name = "mlxbf-bootctl",
+		.groups = mlxbf_bootctl_groups,
+		.acpi_match_table = mlxbf_bootctl_acpi_ids,
+	}
+};
+
+module_platform_driver(mlxbf_bootctl_driver);
+
+MODULE_DESCRIPTION("Mellanox boot control driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Mellanox Technologies");