linux/arch/mips/ralink/reset.c
NeilBrown 891731f6a5
MIPS: ralink: Remove ralink_halt()
ralink_halt() does nothing that machine_halt() doesn't already do, so it
adds no value.

It actually causes incorrect behaviour due to the "unreachable()" at the
end. This tells the compiler that the end of the function will never be
reached, which isn't true. The compiler responds by not adding a
'return' instruction, so control simply moves on to whatever bytes come
afterwards in memory. In my tested, that was the ralink_restart()
function. This means that an attempt to 'halt' the machine would
actually cause a reboot.

So remove ralink_halt() so that a 'halt' really does halt.

Fixes: c06e836ada ("MIPS: ralink: adds reset code")
Signed-off-by: NeilBrown <neil@brown.name>
Cc: John Crispin <john@phrozen.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.9+
Patchwork: https://patchwork.linux-mips.org/patch/18851/
Signed-off-by: James Hogan <jhogan@kernel.org>
2018-03-21 23:43:39 +00:00

107 lines
2.2 KiB
C

/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* Copyright (C) 2008-2009 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
* Copyright (C) 2013 John Crispin <john@phrozen.org>
*/
#include <linux/pm.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/reset-controller.h>
#include <asm/reboot.h>
#include <asm/mach-ralink/ralink_regs.h>
/* Reset Control */
#define SYSC_REG_RESET_CTRL 0x034
#define RSTCTL_RESET_PCI BIT(26)
#define RSTCTL_RESET_SYSTEM BIT(0)
static int ralink_assert_device(struct reset_controller_dev *rcdev,
unsigned long id)
{
u32 val;
if (id < 8)
return -1;
val = rt_sysc_r32(SYSC_REG_RESET_CTRL);
val |= BIT(id);
rt_sysc_w32(val, SYSC_REG_RESET_CTRL);
return 0;
}
static int ralink_deassert_device(struct reset_controller_dev *rcdev,
unsigned long id)
{
u32 val;
if (id < 8)
return -1;
val = rt_sysc_r32(SYSC_REG_RESET_CTRL);
val &= ~BIT(id);
rt_sysc_w32(val, SYSC_REG_RESET_CTRL);
return 0;
}
static int ralink_reset_device(struct reset_controller_dev *rcdev,
unsigned long id)
{
ralink_assert_device(rcdev, id);
return ralink_deassert_device(rcdev, id);
}
static const struct reset_control_ops reset_ops = {
.reset = ralink_reset_device,
.assert = ralink_assert_device,
.deassert = ralink_deassert_device,
};
static struct reset_controller_dev reset_dev = {
.ops = &reset_ops,
.owner = THIS_MODULE,
.nr_resets = 32,
.of_reset_n_cells = 1,
};
void ralink_rst_init(void)
{
reset_dev.of_node = of_find_compatible_node(NULL, NULL,
"ralink,rt2880-reset");
if (!reset_dev.of_node)
pr_err("Failed to find reset controller node");
else
reset_controller_register(&reset_dev);
}
static void ralink_restart(char *command)
{
if (IS_ENABLED(CONFIG_PCI)) {
rt_sysc_m32(0, RSTCTL_RESET_PCI, SYSC_REG_RESET_CTRL);
mdelay(50);
}
local_irq_disable();
rt_sysc_w32(RSTCTL_RESET_SYSTEM, SYSC_REG_RESET_CTRL);
unreachable();
}
static int __init mips_reboot_setup(void)
{
_machine_restart = ralink_restart;
return 0;
}
arch_initcall(mips_reboot_setup);