[PATCH v2] soc: rockchip: avoid infinite loop for power domain

From: Caesar Wang
Date: Wed Oct 12 2016 - 14:34:55 EST


In some cases, we have met the infinite loop in
rockchip_pmu_set_idle_request() or rockchip_do_pmu_set_power_domain().

As the crosbug.com/p/57351 reported, the boot hangs right after this
[1.629163] bootconsole [uart8250] disabled
[1.639286] [drm:drm_core_init] Initialized drm 1.1.0 20060810
[1.645926] [drm:drm_get_platform_dev] Initialized vgem 1.0.0 20120112..
[1.654558] iommu: Adding device ff8f0000.vop to group 0
[1.660569] iommu: Adding device ff900000.vop to group 1
<hang>

This patch adds the error message and timeout to avoid infinite loop if
it fails to get the ack.

Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
---

Changes in v2:
- As the Tomasz & Heiko feedback on http://crosreview.com/395589:
* Also, need the timeout for rockchip_do_set_power_domain.
* s/target_on/is_on, s/target_idle/is_idle.
* unsigned int instear of u32.

drivers/soc/rockchip/pm_domains.c | 48 +++++++++++++++++++++++++++++++++------
1 file changed, 41 insertions(+), 7 deletions(-)

diff --git a/drivers/soc/rockchip/pm_domains.c b/drivers/soc/rockchip/pm_domains.c
index 7acd151..260fbcc 100644
--- a/drivers/soc/rockchip/pm_domains.c
+++ b/drivers/soc/rockchip/pm_domains.c
@@ -9,6 +9,7 @@
*/

#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/err.h>
#include <linux/pm_clock.h>
#include <linux/pm_domain.h>
@@ -105,12 +106,24 @@ static bool rockchip_pmu_domain_is_idle(struct rockchip_pm_domain *pd)
return (val & pd_info->idle_mask) == pd_info->idle_mask;
}

+static unsigned int rockchip_pmu_read_ack(struct rockchip_pmu *pmu)
+{
+ unsigned int val;
+
+ regmap_read(pmu->regmap, pmu->info->ack_offset, &val);
+ return val;
+}
+
static int rockchip_pmu_set_idle_request(struct rockchip_pm_domain *pd,
bool idle)
{
const struct rockchip_domain_info *pd_info = pd->info;
+ struct generic_pm_domain *genpd = &pd->genpd;
struct rockchip_pmu *pmu = pd->pmu;
unsigned int val;
+ unsigned int target_ack;
+ bool is_idle;
+ int ret;

if (pd_info->req_mask == 0)
return 0;
@@ -120,12 +133,26 @@ static int rockchip_pmu_set_idle_request(struct rockchip_pm_domain *pd,

dsb(sy);

- do {
- regmap_read(pmu->regmap, pmu->info->ack_offset, &val);
- } while ((val & pd_info->ack_mask) != (idle ? pd_info->ack_mask : 0));
+ /* Wait util idle_ack = 1 */
+ target_ack = idle ? pd_info->ack_mask : 0;
+ ret = readx_poll_timeout_atomic(rockchip_pmu_read_ack, pmu, val,
+ (val & pd_info->ack_mask) == target_ack,
+ 0, 10000);
+ if (ret) {
+ dev_err(pmu->dev,
+ "failed to get ack on domain '%s', val=0x%x\n",
+ genpd->name, val);
+ return ret;
+ }

- while (rockchip_pmu_domain_is_idle(pd) != idle)
- cpu_relax();
+ ret = readx_poll_timeout_atomic(rockchip_pmu_domain_is_idle, pd,
+ is_idle, is_idle == idle, 0, 10000);
+ if (ret) {
+ dev_err(pmu->dev,
+ "failed to set idle on domain '%s', val=%d\n",
+ genpd->name, is_idle);
+ return ret;
+ }

return 0;
}
@@ -198,6 +225,8 @@ static void rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,
bool on)
{
struct rockchip_pmu *pmu = pd->pmu;
+ struct generic_pm_domain *genpd = &pd->genpd;
+ bool is_on;

if (pd->info->pwr_mask == 0)
return;
@@ -207,8 +236,13 @@ static void rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,

dsb(sy);

- while (rockchip_pmu_domain_is_on(pd) != on)
- cpu_relax();
+ if (readx_poll_timeout_atomic(rockchip_pmu_domain_is_on, pd, is_on,
+ is_on == on, 0, 10000)) {
+ dev_err(pmu->dev,
+ "failed to set domain '%s', val=%d\n",
+ genpd->name, is_on);
+ return;
+ }
}

static int rockchip_pd_power(struct rockchip_pm_domain *pd, bool power_on)
--
1.9.1