[RFC PATCH 19/25] kvx: power: scall poweroff driver

Yann Sionneau
2023-01-03T17:00:32Z

Add a driver to poweroff the Coolidge SoC
when running under Qemu, ISS or when
the debugger (jtag-runner) runs on PL0
to catch the scall.

CC: Sebastian Reichel <sre@kernel.org>
CC: linux-kernel@vger.kernel.org
CC: linux-pm@vger.kernel.org
Co-developed-by: Clement Leger <clement.leger@bootlin.com>
Signed-off-by: Clement Leger <clement.leger@bootlin.com>
Co-developed-by: Julian Vetter <jvetter@kalray.eu>
Signed-off-by: Julian Vetter <jvetter@kalray.eu>
Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
---
drivers/power/reset/kvx-scall-poweroff.c | 53 ++++++++++++++++++++++++
1 file changed, 53 insertions(+)
create mode 100644 drivers/power/reset/kvx-scall-poweroff.c

diff --git a/drivers/power/reset/kvx-scall-poweroff.c b/drivers/power/reset/kvx-scall-poweroff.c
new file mode 100644
index 000000000000..586d93fbcaed
--- /dev/null
+++ b/drivers/power/reset/kvx-scall-poweroff.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017 - 2022 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#include <linux/pm.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define SCALL_NUM_EXIT "0xfff"
+
+static void kvx_scall_poweroff(void)
+{
+ register int status asm("r0") = 0;
+
+ asm volatile ("scall " SCALL_NUM_EXIT "\n\t;;"
+ : /* out */
+ : "r"(status));
+
+ unreachable();
+}
+
+static int kvx_scall_poweroff_probe(struct platform_device *pdev)
+{
+ pm_power_off = kvx_scall_poweroff;
+
+ return 0;
+}
+
+static int kvx_scall_poweroff_remove(struct platform_device *pdev)
+{
+ if (pm_power_off == kvx_scall_poweroff)
+ pm_power_off = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id kvx_scall_poweroff_of_match[] = {
+ { .compatible = "kalray,kvx-scall-poweroff" },
+ {}
+};
+
+static struct platform_driver kvx_scall_poweroff_driver = {
+ .probe = kvx_scall_poweroff_probe,
+ .remove = kvx_scall_poweroff_remove,
+ .driver = {
+ .name = "kvx-scall-poweroff",
+ .of_match_table = kvx_scall_poweroff_of_match,
+ },
+};
+module_platform_driver(kvx_scall_poweroff_driver);
--
2.37.2