Message-Id: <1548953587-12719-1-git-send-email-lsun@mellanox.com>
Date:   Thu, 31 Jan 2019 11:53:07 -0500
From:   Liming Sun <lsun@...lanox.com>
To:     Andy Shevchenko <andy@...radead.org>,
        Darren Hart <dvhart@...radead.org>,
        Vadim Pasternak <vadimp@...lanox.com>,
        David Woods <dwoods@...lanox.com>
Cc:     Liming Sun <lsun@...lanox.com>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] platform/mellanox: Add bootctl driver for Mellanox BlueField Soc

This commit adds the bootctl platform driver for Mellanox BlueField
Soc, which controls the eMMC boot partition swapping and sends SMC
calls to ATF running at exception level EL3 to program some system
register. This register is only accessible in secure code and is
used to enable the watchdog after reboot.

Below are the sequences of a typical use case.

  1. User-space tool upgrades one eMMC boot partition and requests
     the boot partition swapping;

  2. The bootctl driver handles such request and sends SMC call
     to ATF. ATF programs register BREADCRUMB0 which has value
     preserved during software reset. It also programs eMMC to
     swap the boot partition;

  3. After software reset (rebooting), ATF BL1 (BootRom) checks
     register BREADCRUMB0 to enable watchdog if configured;

  4. If booting fails, the watchdog timer will trigger rebooting.
     In such case, ATF BootRom will switch the boot partition
     to the previous one.

Reviewed-by: David Woods <dwoods@...lanox.com>
Signed-off-by: Liming Sun <lsun@...lanox.com>
---
 drivers/platform/mellanox/Kconfig         |  14 +-
 drivers/platform/mellanox/Makefile        |   1 +
 drivers/platform/mellanox/mlxbf-bootctl.c | 306 ++++++++++++++++++++++++++++++
 drivers/platform/mellanox/mlxbf-bootctl.h | 108 +++++++++++
 4 files changed, 428 insertions(+), 1 deletion(-)
 create mode 100644 drivers/platform/mellanox/mlxbf-bootctl.c
 create mode 100644 drivers/platform/mellanox/mlxbf-bootctl.h

diff --git a/drivers/platform/mellanox/Kconfig b/drivers/platform/mellanox/Kconfig
index cd8a908..e3c6a5e 100644
--- a/drivers/platform/mellanox/Kconfig
+++ b/drivers/platform/mellanox/Kconfig
@@ -5,7 +5,7 @@
 
 menuconfig MELLANOX_PLATFORM
 	bool "Platform support for Mellanox hardware"
-	depends on X86 || ARM || COMPILE_TEST
+	depends on X86 || ARM || ARM64 || COMPILE_TEST
 	---help---
 	  Say Y here to get to see options for platform support for
 	  Mellanox systems. This option alone does not add any kernel code.
@@ -34,4 +34,16 @@ config MLXREG_IO
 	  to system resets operation, system reset causes monitoring and some
 	  kinds of mux selection.
 
+config MLXBF_BOOTCTL
+	tristate "Mellanox BlueField Firmware Boot Control driver"
+	depends on ARM64
+	help
+          The Mellanox BlueField firmware implements functionality to
+          request swapping the primary and alternate eMMC boot
+          partition, and to set up a watchdog that can undo that swap
+          if the system does not boot up correctly.  This driver
+          provides sysfs access to the firmware, to be used in
+          conjunction with the eMMC device driver to do any necessary
+          initial swap of the boot partition.
+
 endif # MELLANOX_PLATFORM
diff --git a/drivers/platform/mellanox/Makefile b/drivers/platform/mellanox/Makefile
index 57074d9c..76b0370 100644
--- a/drivers/platform/mellanox/Makefile
+++ b/drivers/platform/mellanox/Makefile
@@ -5,3 +5,4 @@
 #
 obj-$(CONFIG_MLXREG_HOTPLUG)	+= mlxreg-hotplug.o
 obj-$(CONFIG_MLXREG_IO) += mlxreg-io.o
+obj-$(CONFIG_MLXBF_BOOTCTL)	+= mlxbf-bootctl.o
diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c b/drivers/platform/mellanox/mlxbf-bootctl.c
new file mode 100644
index 0000000..7efa535
--- /dev/null
+++ b/drivers/platform/mellanox/mlxbf-bootctl.c
@@ -0,0 +1,306 @@
+// 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_DRIVER_NAME		"mlxbf-bootctl"
+#define MLXBF_BOOTCTL_DRIVER_DESCRIPTION	"Mellanox boot control driver"
+
+#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 * const mlxbf_bootctl_svc_uuid_str =
+	"89c036b4-e7d7-11e6-8797-001aca00bfc4";
+
+/*
+ * UUID structure used to match the returned value from ATF in
+ * four 32-bit words. No need to do endian conversion here.
+ */
+union mlxbf_bootctl_uuid {
+	guid_t guid;
+	u32 words[4];
+};
+
+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] = "soft_non_secure",
+	[1] = "secure",
+	[2] = "hard_non_secure",
+	[3] = "rma",
+};
+
+/* The SMC calls in question are atomic, so we don't have to lock here. */
+static int mlxbf_bootctl_smc_call1(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;
+}
+
+/* Syntactic sugar to avoid having to specify an unused argument. */
+#define mlxbf_bootctl_smc_call0(smc_op) mlxbf_bootctl_smc_call1(smc_op, 0)
+
+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 MLXBF_BOOTCTL_INVALID;
+}
+
+static const char *mlxbf_bootctl_reset_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 "";
+}
+
+static ssize_t post_reset_wdog_show(struct device_driver *drv, char *buf)
+{
+	return sprintf(buf, "%d\n",
+		mlxbf_bootctl_smc_call0(MLXBF_BOOTCTL_GET_POST_RESET_WDOG));
+}
+
+static ssize_t post_reset_wdog_store(struct device_driver *drv,
+				     const char *buf, size_t count)
+{
+	unsigned long watchdog;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &watchdog);
+	if (ret)
+		return ret;
+
+	ret = mlxbf_bootctl_smc_call1(MLXBF_BOOTCTL_SET_POST_RESET_WDOG,
+				      watchdog);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t reset_action_show(struct device_driver *drv, char *buf)
+{
+	int action;
+
+	action = mlxbf_bootctl_smc_call0(MLXBF_BOOTCTL_GET_RESET_ACTION);
+
+	return sprintf(buf, "%s\n",
+		       mlxbf_bootctl_reset_action_to_string(action));
+}
+
+static ssize_t reset_action_store(struct device_driver *drv,
+				  const char *buf, size_t count)
+{
+	int ret, action = mlxbf_bootctl_reset_action_to_val(buf);
+
+	if (action == MLXBF_BOOTCTL_INVALID || action == MLXBF_BOOTCTL_NONE)
+		return -EINVAL;
+
+	ret = (mlxbf_bootctl_smc_call1(MLXBF_BOOTCTL_SET_RESET_ACTION, action));
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t second_reset_action_show(struct device_driver *drv, char *buf)
+{
+	int action;
+	const char *name;
+
+	action = mlxbf_bootctl_smc_call0(MLXBF_BOOTCTL_GET_SECOND_RESET_ACTION);
+	name = mlxbf_bootctl_reset_action_to_string(action);
+
+	return sprintf(buf, "%s\n", name);
+}
+
+static ssize_t second_reset_action_store(struct device_driver *drv,
+					 const char *buf, size_t count)
+{
+	int ret, action = mlxbf_bootctl_reset_action_to_val(buf);
+
+	if (action < 0)
+		return action;
+
+	ret = mlxbf_bootctl_smc_call1(MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION,
+				      action);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t lifecycle_state_show(struct device_driver *drv, char *buf)
+{
+	int lc_state;
+
+	lc_state = mlxbf_bootctl_smc_call1(
+					   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_driver *drv, char *buf)
+{
+	int sb_key_state = mlxbf_bootctl_smc_call1(
+				MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS,
+				MLXBF_BOOTCTL_FUSE_STATUS_KEYS);
+	int upper_key_used = 0;
+	int buf_len = 0;
+	const char *status;
+	int key;
+
+	if (sb_key_state < 0)
+		return sb_key_state;
+
+	for (key = MLXBF_SB_KEY_NUM - 1; key >= 0; key--) {
+		int burnt = sb_key_state & (1 << key);
+		int valid = sb_key_state &
+			      (1 << (key + MLXBF_SB_KEY_NUM));
+
+		buf_len += sprintf(buf + buf_len, "Ver%d:", key);
+		if (upper_key_used) {
+			if (burnt)
+				status = valid ? "Used" : "Wasted";
+			else
+				status = valid ? "Invalid" : "Skipped";
+		} else {
+			if (burnt) {
+				status = valid ? "In use" : "Burn incomplete";
+				if (valid)
+					upper_key_used = 1;
+			} else
+				status = valid ? "Invalid" : "Free";
+		}
+		buf_len += sprintf(buf + buf_len, status);
+		if (key != 0)
+			buf_len += sprintf(buf + buf_len, "; ");
+	}
+
+	return buf_len;
+}
+
+static DRIVER_ATTR_RW(post_reset_wdog);
+static DRIVER_ATTR_RW(reset_action);
+static DRIVER_ATTR_RW(second_reset_action);
+static DRIVER_ATTR_RO(lifecycle_state);
+static DRIVER_ATTR_RO(secure_boot_fuse_state);
+
+static struct attribute *mlxbf_bootctl_dev_attrs[] = {
+	&driver_attr_post_reset_wdog.attr,
+	&driver_attr_reset_action.attr,
+	&driver_attr_second_reset_action.attr,
+	&driver_attr_lifecycle_state.attr,
+	&driver_attr_secure_boot_fuse_state.attr,
+	NULL
+};
+
+static struct attribute_group mlxbf_bootctl_attr_group = {
+	.attrs = mlxbf_bootctl_dev_attrs
+};
+
+static const struct attribute_group *mlxbf_bootctl_attr_groups[] = {
+	&mlxbf_bootctl_attr_group,
+	NULL
+};
+
+static const struct acpi_device_id mlxbf_bootctl_acpi_ids[] = {
+	{"MLNXBF04", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(acpi, mlxbf_bootctl_acpi_ids);
+
+static int mlxbf_bootctl_probe(struct platform_device *pdev)
+{
+	struct arm_smccc_res res;
+	union mlxbf_bootctl_uuid uuid;
+
+	/* 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, &uuid.guid);
+	if (res.a0 != uuid.words[0] || res.a1 != uuid.words[1] ||
+	    res.a2 != uuid.words[2] || res.a3 != uuid.words[3])
+		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.
+	 */
+	if (mlxbf_bootctl_smc_call1(MLXBF_BOOTCTL_SET_RESET_ACTION,
+				    MLXBF_BOOTCTL_EMMC) < 0)
+		dev_err(&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_DRIVER_NAME,
+		.groups = mlxbf_bootctl_attr_groups,
+		.acpi_match_table = ACPI_PTR(mlxbf_bootctl_acpi_ids),
+	}
+};
+
+module_platform_driver(mlxbf_bootctl_driver);
+
+MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
+MODULE_AUTHOR("Mellanox Technologies");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/mellanox/mlxbf-bootctl.h b/drivers/platform/mellanox/mlxbf-bootctl.h
new file mode 100644
index 0000000..5ca19db
--- /dev/null
+++ b/drivers/platform/mellanox/mlxbf-bootctl.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2019, Mellanox Technologies. All rights reserved.
+ */
+
+#ifndef __MLXBF_BOOTCTL_H__
+#define __MLXBF_BOOTCTL_H__
+
+/*
+ * Request that the on-chip watchdog be enabled, or disabled, after
+ * the next chip soft reset. This call does not affect the current
+ * status of the on-chip watchdog. If non-zero, the argument
+ * specifies the watchdog interval in seconds. If zero, the watchdog
+ * will not be enabled after the next soft reset. Non-zero errors are
+ * returned as documented below.
+ */
+#define MLXBF_BOOTCTL_SET_POST_RESET_WDOG	0x82000000
+
+/*
+ * Query the status which has been requested for the on-chip watchdog
+ * after the next chip soft reset. Returns the interval as set by
+ * MLXBF_BOOTCTL_SET_POST_RESET_WDOG.
+ */
+#define MLXBF_BOOTCTL_GET_POST_RESET_WDOG	0x82000001
+
+/*
+ * Request that a specific boot action be taken at the next soft
+ * reset. By default, the boot action is set by external chip pins,
+ * which are sampled on hard reset. Note that the boot action
+ * requested by this call will persist on subsequent resets unless
+ * this service, or the MLNX_SET_SECOND_RESET_ACTION service, is
+ * invoked. See below for the available MLNX_BOOT_xxx parameter
+ * values. Non-zero errors are returned as documented below.
+ */
+#define MLXBF_BOOTCTL_SET_RESET_ACTION		0x82000002
+
+/*
+ * Return the specific boot action which will be taken at the next
+ * soft reset. Returns the reset action (see below for the parameter
+ * values for MLXBF_BOOTCTL_SET_RESET_ACTION).
+ */
+#define MLXBF_BOOTCTL_GET_RESET_ACTION		0x82000003
+
+/*
+ * Request that a specific boot action be taken at the soft reset
+ * after the next soft reset. For a specified valid boot mode, the
+ * effect of this call is identical to that of invoking
+ * MLXBF_BOOTCTL_SET_RESET_ACTION after the next chip soft reset; in
+ * particular, after that reset, the action for the now next reset can
+ * be queried with MLXBF_BOOTCTL_GET_RESET_ACTION and modified with
+ * MLXBF_BOOTCTL_SET_RESET_ACTION. You may also specify the parameter as
+ * MLNX_BOOT_NONE, which is equivalent to specifying that no call to
+ * MLXBF_BOOTCTL_SET_RESET_ACTION be taken after the next chip soft reset.
+ * This call does not affect the action to be taken at the next soft
+ * reset. Non-zero errors are returned as documented below.
+ */
+#define MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION	0x82000004
+
+/*
+ * Return the specific boot action which will be taken at the soft
+ * reset after the next soft reset; this will be one of the valid
+ * actions for MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION.
+ */
+#define MLXBF_BOOTCTL_GET_SECOND_RESET_ACTION	0x82000005
+
+/*
+ * Return the fuse status of the current chip. The caller should specify
+ * with the second argument if the state of the lifecycle fuses or the
+ * version of secure boot fuse keys left should be returned.
+ */
+#define MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS	0x82000006
+
+/*
+ * Reset eMMC by programming the RST_N register.
+ */
+#define MLXBF_BOOTCTL_SET_EMMC_RST_N		0x82000007
+
+#define MLXBF_BOOTCTL_GET_DIMM_INFO		0x82000008
+
+/* SMC function IDs for SiP Service queries */
+#define MLXBF_BOOTCTL_SIP_SVC_CALL_COUNT	0x8200ff00
+#define MLXBF_BOOTCTL_SIP_SVC_UID		0x8200ff01
+#define MLXBF_BOOTCTL_SIP_SVC_VERSION		0x8200ff03
+
+/* ARM Standard Service Calls version numbers */
+#define MLXBF_BOOTCTL_SVC_VERSION_MAJOR		0x0
+#define MLXBF_BOOTCTL_SVC_VERSION_MINOR		0x2
+
+/* Number of svc calls defined. */
+#define MLXBF_BOOTCTL_NUM_SVC_CALLS 12
+
+/* Valid reset actions for MLXBF_BOOTCTL_SET_RESET_ACTION. */
+#define MLXBF_BOOTCTL_EXTERNAL	0 /* Not boot from eMMC */
+#define MLXBF_BOOTCTL_EMMC	1 /* From primary eMMC boot partition */
+#define MLNX_BOOTCTL_SWAP_EMMC	2 /* Swap eMMC boot partitions and reboot */
+#define MLXBF_BOOTCTL_EMMC_LEGACY	3 /* From primary eMMC in legacy mode */
+
+/* Valid arguments for requesting the fuse status. */
+#define MLXBF_BOOTCTL_FUSE_STATUS_LIFECYCLE	0 /* Return lifecycle status. */
+#define MLXBF_BOOTCTL_FUSE_STATUS_KEYS	1 /* Return secure boot key status */
+
+/* Additional value to disable the MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION. */
+#define MLXBF_BOOTCTL_NONE	0x7fffffff /* Don't change next boot action */
+
+/* Invalid mode */
+#define MLXBF_BOOTCTL_INVALID	0xffffffff
+
+#endif /* __MLXBF_BOOTCTL_H__ */
-- 
1.8.3.1

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