mirror of
https://github.com/torvalds/linux.git
synced 2024-12-29 14:21:47 +00:00
c24bfa8f21
Apparently, this code does not actually fall through to the next case
because the machine restarts before it has a chance. However, for the
sake of maintenance and readability, we better add the missing break
statement.
Addresses-Coverity-ID: 1437892 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
156 lines
3.6 KiB
C
156 lines
3.6 KiB
C
/*
|
|
* SPI slave handler controlling system state
|
|
*
|
|
* This SPI slave handler allows remote control of system reboot, power off,
|
|
* halt, and suspend.
|
|
*
|
|
* Copyright (C) 2016-2017 Glider bvba
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
* Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote
|
|
* system):
|
|
*
|
|
* # reboot='\x7c\x50'
|
|
* # poweroff='\x71\x3f'
|
|
* # halt='\x38\x76'
|
|
* # suspend='\x1b\x1b'
|
|
* # spidev_test -D /dev/spidev2.0 -p $suspend # or $reboot, $poweroff, $halt
|
|
*/
|
|
|
|
#include <linux/completion.h>
|
|
#include <linux/module.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/suspend.h>
|
|
#include <linux/spi/spi.h>
|
|
|
|
/*
|
|
* The numbers are chosen to display something human-readable on two 7-segment
|
|
* displays connected to two 74HC595 shift registers
|
|
*/
|
|
#define CMD_REBOOT 0x7c50 /* rb */
|
|
#define CMD_POWEROFF 0x713f /* OF */
|
|
#define CMD_HALT 0x3876 /* HL */
|
|
#define CMD_SUSPEND 0x1b1b /* ZZ */
|
|
|
|
struct spi_slave_system_control_priv {
|
|
struct spi_device *spi;
|
|
struct completion finished;
|
|
struct spi_transfer xfer;
|
|
struct spi_message msg;
|
|
__be16 cmd;
|
|
};
|
|
|
|
static
|
|
int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv);
|
|
|
|
static void spi_slave_system_control_complete(void *arg)
|
|
{
|
|
struct spi_slave_system_control_priv *priv = arg;
|
|
u16 cmd;
|
|
int ret;
|
|
|
|
if (priv->msg.status)
|
|
goto terminate;
|
|
|
|
cmd = be16_to_cpu(priv->cmd);
|
|
switch (cmd) {
|
|
case CMD_REBOOT:
|
|
dev_info(&priv->spi->dev, "Rebooting system...\n");
|
|
kernel_restart(NULL);
|
|
break;
|
|
|
|
case CMD_POWEROFF:
|
|
dev_info(&priv->spi->dev, "Powering off system...\n");
|
|
kernel_power_off();
|
|
break;
|
|
|
|
case CMD_HALT:
|
|
dev_info(&priv->spi->dev, "Halting system...\n");
|
|
kernel_halt();
|
|
break;
|
|
|
|
case CMD_SUSPEND:
|
|
dev_info(&priv->spi->dev, "Suspending system...\n");
|
|
pm_suspend(PM_SUSPEND_MEM);
|
|
break;
|
|
|
|
default:
|
|
dev_warn(&priv->spi->dev, "Unknown command 0x%x\n", cmd);
|
|
break;
|
|
}
|
|
|
|
ret = spi_slave_system_control_submit(priv);
|
|
if (ret)
|
|
goto terminate;
|
|
|
|
return;
|
|
|
|
terminate:
|
|
dev_info(&priv->spi->dev, "Terminating\n");
|
|
complete(&priv->finished);
|
|
}
|
|
|
|
static
|
|
int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv)
|
|
{
|
|
int ret;
|
|
|
|
spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
|
|
|
|
priv->msg.complete = spi_slave_system_control_complete;
|
|
priv->msg.context = priv;
|
|
|
|
ret = spi_async(priv->spi, &priv->msg);
|
|
if (ret)
|
|
dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int spi_slave_system_control_probe(struct spi_device *spi)
|
|
{
|
|
struct spi_slave_system_control_priv *priv;
|
|
int ret;
|
|
|
|
priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
|
|
if (!priv)
|
|
return -ENOMEM;
|
|
|
|
priv->spi = spi;
|
|
init_completion(&priv->finished);
|
|
priv->xfer.rx_buf = &priv->cmd;
|
|
priv->xfer.len = sizeof(priv->cmd);
|
|
|
|
ret = spi_slave_system_control_submit(priv);
|
|
if (ret)
|
|
return ret;
|
|
|
|
spi_set_drvdata(spi, priv);
|
|
return 0;
|
|
}
|
|
|
|
static int spi_slave_system_control_remove(struct spi_device *spi)
|
|
{
|
|
struct spi_slave_system_control_priv *priv = spi_get_drvdata(spi);
|
|
|
|
spi_slave_abort(spi);
|
|
wait_for_completion(&priv->finished);
|
|
return 0;
|
|
}
|
|
|
|
static struct spi_driver spi_slave_system_control_driver = {
|
|
.driver = {
|
|
.name = "spi-slave-system-control",
|
|
},
|
|
.probe = spi_slave_system_control_probe,
|
|
.remove = spi_slave_system_control_remove,
|
|
};
|
|
module_spi_driver(spi_slave_system_control_driver);
|
|
|
|
MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
|
|
MODULE_DESCRIPTION("SPI slave handler controlling system state");
|
|
MODULE_LICENSE("GPL v2");
|