Commit 28947198 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Krzysztof Kozlowski
Browse files

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: default avatarDmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20210323210446.24867-2-digetx@gmail.com


Signed-off-by: default avatarKrzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
parent 7ebb09db

drivers/memory/tegra/tegra20.c

+7 −0
Original line number Diff line number Diff line
@@ -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");