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ARM: 8730/1: B15: Add suspend/resume hooks 

The Broadcom Brahma-B15 CPU readahead cache registers will be restored
to their Power-on-Reset values after a S3 suspend/resume cycles, so we
want to restore what we had enabled before.

Another thing we want to take care of is disabling the read-ahead cache
prior to suspending to avoid any sort of side effect with the spinlock
we need to grab to serialize register accesses.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Florian Fainelli 2017-12-01 01:10:12 +01:00 committed by Russell King
parent 55de88778f
commit 534f5f36a2
1 changed files with 48 additions and 0 deletions
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48
arch/arm/mm/cache-b15-rac.c
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@ -15,6 +15,7 @@
#include <linux/of_address.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/syscore_ops.h>
#include <asm/cacheflush.h>
#include <asm/hardware/cache-b15-rac.h>
@ -41,6 +42,10 @@ extern void v7_flush_kern_cache_all(void);
RACENPREF_MASK << RACENDATA_SHIFT)
#define RAC_ENABLED 0
/* Special state where we want to bypass the spinlock and call directly
* into the v7 cache maintenance operations during suspend/resume
*/
#define RAC_SUSPENDED 1
static void __iomem *b15_rac_base;
static DEFINE_SPINLOCK(rac_lock);
@ -96,6 +101,12 @@ void b15_flush_##name(void) \
unsigned int do_flush; \
u32 val = 0; \
\
if (test_bit(RAC_SUSPENDED, &b15_rac_flags)) { \
v7_flush_##name(); \
bar; \
return; \
} \
\
spin_lock(&rac_lock); \
do_flush = test_bit(RAC_ENABLED, &b15_rac_flags); \
if (do_flush) \
@ -208,6 +219,39 @@ static int b15_rac_dead_cpu(unsigned int cpu)
}
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_PM_SLEEP
static int b15_rac_suspend(void)
{
/* Suspend the read-ahead cache oeprations, forcing our cache
* implementation to fallback to the regular ARMv7 calls.
*
* We are guaranteed to be running on the boot CPU at this point and
* with every other CPU quiesced, so setting RAC_SUSPENDED is not racy
* here.
*/
rac_config0_reg = b15_rac_disable_and_flush();
set_bit(RAC_SUSPENDED, &b15_rac_flags);
return 0;
}
static void b15_rac_resume(void)
{
/* Coming out of a S3 suspend/resume cycle, the read-ahead cache
* register RAC_CONFIG0_REG will be restored to its default value, make
* sure we re-enable it and set the enable flag, we are also guaranteed
* to run on the boot CPU, so not racy again.
*/
__b15_rac_enable(rac_config0_reg);
clear_bit(RAC_SUSPENDED, &b15_rac_flags);
}
static struct syscore_ops b15_rac_syscore_ops = {
.suspend = b15_rac_suspend,
.resume = b15_rac_resume,
};
#endif
static int __init b15_rac_init(void)
{
struct device_node *dn;
@ -242,6 +286,10 @@ static int __init b15_rac_init(void)
goto out_cpu_dead;
#endif
#ifdef CONFIG_PM_SLEEP
register_syscore_ops(&b15_rac_syscore_ops);
#endif
spin_lock(&rac_lock);
reg = __raw_readl(b15_rac_base + RAC_CONFIG0_REG);
for_each_possible_cpu(cpu)