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memory: tegra20: Protect debug code with a lock 

Simultaneous accesses to MC_STAT h/w shouldn't be allowed since one
collection process stomps on another. There is no good reason for
polling stats in parallel in practice, nevertheless let's add a
protection lock, just for consistency.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20210323210446.24867-2-digetx@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
This commit is contained in:
Dmitry Osipenko 2021-03-24 00:04:46 +03:00 committed by Krzysztof Kozlowski
parent 7ebb09db5b
commit 289471984f
1 changed files with 7 additions and 0 deletions
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7
drivers/memory/tegra/tegra20.c
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@ -5,6 +5,7 @@
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/string.h>
@ -55,6 +56,8 @@
/* we store collected statistics as a fixed point values */
#define MC_FX_FRAC_SCALE 100
static DEFINE_MUTEX(tegra20_mc_stat_lock);
struct tegra20_mc_stat_gather {
unsigned int pri_filter;
unsigned int pri_event;
@ -615,8 +618,12 @@ static int tegra20_mc_stats_show(struct seq_file *s, void *unused)
if (!stats)
return -ENOMEM;
mutex_lock(&tegra20_mc_stat_lock);
tegra20_mc_collect_stats(mc, stats);
mutex_unlock(&tegra20_mc_stat_lock);
seq_puts(s, "Memory client Events Timeout High priority Bandwidth ARB RW change Successive Page miss\n");
seq_puts(s, "-----------------------------------------------------------------------------------------------------\n");