msm: msm_xo: Fix scheduling while atomic bug
clk_get_sys() can't be called in atomic context, but the msm_xo
code is calling clk_get_sys within a spin_lock_irqsave(). This
leads to scheduling while atomic bugs. Fixing this to call
clk_get_sys() in a non-atomic location is not as simple as moving
the clk_get_sys() call to somewhere else such as msm_xo_init() or
msm_xo_get() since those are called before the clock driver is
initialized.
Luckily we have moved the XO voting in the clock driver to the
RPM clock driver so we can move the msm_xo interface to a
sleepable API using mutex_lock()/mutex_unlock() and also use the
sleepable variant of msm_rpmrs_set(). This should remove the
scheduling while atomic bug and also make the XO buffer API less
invasive by spinning on the RPM to respond to RPM requests.
Change-Id: I510cb125bde84b80b562add36494b716955ed773
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/arch/arm/mach-msm/msm_xo.c b/arch/arm/mach-msm/msm_xo.c
index 86776d3..407231a 100644
--- a/arch/arm/mach-msm/msm_xo.c
+++ b/arch/arm/mach-msm/msm_xo.c
@@ -15,7 +15,7 @@
#include <linux/init.h>
#include <linux/err.h>
#include <linux/module.h>
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
#include <linux/debugfs.h>
#include <linux/list.h>
#include <linux/seq_file.h>
@@ -29,7 +29,7 @@
#include "rpm_resources.h"
-static DEFINE_SPINLOCK(msm_xo_lock);
+static DEFINE_MUTEX(msm_xo_lock);
struct msm_xo {
unsigned votes[NUM_MSM_XO_MODES];
@@ -151,13 +151,12 @@
static int msm_xo_show_voters(struct seq_file *m, void *v)
{
- unsigned long flags;
int i;
- spin_lock_irqsave(&msm_xo_lock, flags);
+ mutex_lock(&msm_xo_lock);
for (i = 0; i < ARRAY_SIZE(msm_xo_sources); i++)
msm_xo_dump_xo(m, &msm_xo_sources[i], msm_xo_to_str[i]);
- spin_unlock_irqrestore(&msm_xo_lock, flags);
+ mutex_unlock(&msm_xo_lock);
return 0;
}
@@ -221,7 +220,7 @@
*/
((msm_xo_sources[MSM_XO_CORE].mode ? 1 : 0) << 20) |
((msm_xo_sources[MSM_XO_CORE].mode ? 1 : 0) << 18);
- ret = msm_rpm_set_noirq(MSM_RPM_CTX_SET_0, &cmd, 1);
+ ret = msm_rpm_set(MSM_RPM_CTX_SET_0, &cmd, 1);
if (ret)
xo->mode = prev_vote;
@@ -281,7 +280,6 @@
int msm_xo_mode_vote(struct msm_xo_voter *xo_voter, enum msm_xo_modes mode)
{
int ret;
- unsigned long flags;
if (!xo_voter)
return 0;
@@ -289,9 +287,9 @@
if (mode >= NUM_MSM_XO_MODES || IS_ERR(xo_voter))
return -EINVAL;
- spin_lock_irqsave(&msm_xo_lock, flags);
+ mutex_lock(&msm_xo_lock);
ret = __msm_xo_mode_vote(xo_voter, mode);
- spin_unlock_irqrestore(&msm_xo_lock, flags);
+ mutex_unlock(&msm_xo_lock);
return ret;
}
@@ -310,7 +308,6 @@
struct msm_xo_voter *msm_xo_get(enum msm_xo_ids xo_id, const char *voter)
{
int ret;
- unsigned long flags;
struct msm_xo_voter *xo_voter;
if (xo_id >= NUM_MSM_XO_IDS) {
@@ -333,10 +330,10 @@
xo_voter->xo = &msm_xo_sources[xo_id];
/* Voters vote for OFF by default */
- spin_lock_irqsave(&msm_xo_lock, flags);
+ mutex_lock(&msm_xo_lock);
xo_voter->xo->votes[MSM_XO_MODE_OFF]++;
list_add(&xo_voter->list, &xo_voter->xo->voters);
- spin_unlock_irqrestore(&msm_xo_lock, flags);
+ mutex_unlock(&msm_xo_lock);
return xo_voter;
@@ -357,16 +354,14 @@
*/
void msm_xo_put(struct msm_xo_voter *xo_voter)
{
- unsigned long flags;
-
if (!xo_voter || IS_ERR(xo_voter))
return;
- spin_lock_irqsave(&msm_xo_lock, flags);
+ mutex_lock(&msm_xo_lock);
__msm_xo_mode_vote(xo_voter, MSM_XO_MODE_OFF);
xo_voter->xo->votes[MSM_XO_MODE_OFF]--;
list_del(&xo_voter->list);
- spin_unlock_irqrestore(&msm_xo_lock, flags);
+ mutex_unlock(&msm_xo_lock);
kfree(xo_voter->name);
kfree(xo_voter);