firmware: xilinx: Add sysfs to set shutdown scope

The Linux shutdown functionality implemented via PSCI system_off does
not include an option to set a scope, i.e. which parts of the system to
shut down.

This patch creates sysfs that allows to set the shutdown scope for the
next shutdown request. When the next shutdown is performed, the platform
specific portion of PSCI-system_off can use the chosen shutdown scope.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Stefan Krsmanovic <stefan.krsmanovic@aggios.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Link: https://lore.kernel.org/r/1587761887-4279-25-git-send-email-jolly.shah@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 97 insertions, 1 deletions

diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 9ba376cfc81f..8d3661877670 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -888,6 +888,102 @@ int zynqmp_pm_system_shutdown(const u32 type, const u32 subtype)
 				   0, 0, NULL);
 }
 
+/**
+ * struct zynqmp_pm_shutdown_scope - Struct for shutdown scope
+ * @subtype:	Shutdown subtype
+ * @name:	Matching string for scope argument
+ *
+ * This struct encapsulates mapping between shutdown scope ID and string.
+ */
+struct zynqmp_pm_shutdown_scope {
+	const enum zynqmp_pm_shutdown_subtype subtype;
+	const char *name;
+};
+
+static struct zynqmp_pm_shutdown_scope shutdown_scopes[] = {
+	[ZYNQMP_PM_SHUTDOWN_SUBTYPE_SUBSYSTEM] = {
+		.subtype = ZYNQMP_PM_SHUTDOWN_SUBTYPE_SUBSYSTEM,
+		.name = "subsystem",
+	},
+	[ZYNQMP_PM_SHUTDOWN_SUBTYPE_PS_ONLY] = {
+		.subtype = ZYNQMP_PM_SHUTDOWN_SUBTYPE_PS_ONLY,
+		.name = "ps_only",
+	},
+	[ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM] = {
+		.subtype = ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM,
+		.name = "system",
+	},
+};
+
+static struct zynqmp_pm_shutdown_scope *selected_scope =
+		&shutdown_scopes[ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM];
+
+/**
+ * zynqmp_pm_is_shutdown_scope_valid - Check if shutdown scope string is valid
+ * @scope_string:	Shutdown scope string
+ *
+ * Return:		Return pointer to matching shutdown scope struct from
+ *			array of available options in system if string is valid,
+ *			otherwise returns NULL.
+ */
+static struct zynqmp_pm_shutdown_scope*
+		zynqmp_pm_is_shutdown_scope_valid(const char *scope_string)
+{
+	int count;
+
+	for (count = 0; count < ARRAY_SIZE(shutdown_scopes); count++)
+		if (sysfs_streq(scope_string, shutdown_scopes[count].name))
+			return &shutdown_scopes[count];
+
+	return NULL;
+}
+
+static ssize_t shutdown_scope_show(struct device *device,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(shutdown_scopes); i++) {
+		if (&shutdown_scopes[i] == selected_scope) {
+			strcat(buf, "[");
+			strcat(buf, shutdown_scopes[i].name);
+			strcat(buf, "]");
+		} else {
+			strcat(buf, shutdown_scopes[i].name);
+		}
+		strcat(buf, " ");
+	}
+	strcat(buf, "\n");
+
+	return strlen(buf);
+}
+
+static ssize_t shutdown_scope_store(struct device *device,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	int ret;
+	struct zynqmp_pm_shutdown_scope *scope;
+
+	scope = zynqmp_pm_is_shutdown_scope_valid(buf);
+	if (!scope)
+		return -EINVAL;
+
+	ret = zynqmp_pm_system_shutdown(ZYNQMP_PM_SHUTDOWN_TYPE_SETSCOPE_ONLY,
+					scope->subtype);
+	if (ret) {
+		pr_err("unable to set shutdown scope %s\n", buf);
+		return ret;
+	}
+
+	selected_scope = scope;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(shutdown_scope);
+
 static ssize_t ggs_show(struct device *device,
 			struct device_attribute *attr,
 			char *buf,
@@ -923,7 +1019,6 @@ static ssize_t ggs_store(struct device *device,
 	ret = zynqmp_pm_write_ggs(reg, value);
 	if (ret)
 		count = -EFAULT;
-
 err:
 	return count;
 }
@@ -1047,6 +1142,7 @@ static struct attribute *zynqmp_firmware_attrs[] = {
 	&dev_attr_pggs1.attr,
 	&dev_attr_pggs2.attr,
 	&dev_attr_pggs3.attr,
+	&dev_attr_shutdown_scope.attr,
 	NULL,
 };