| Message ID | 1430499992-47944-1-git-send-email-lina.iyer@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Fri, May 01 2015 at 11:27 -0600, Jeffrey Hugo wrote: >On 5/1/2015 11:06 AM, Lina Iyer wrote: > >>diff --git a/drivers/hwspinlock/qcom_hwspinlock.c b/drivers/hwspinlock/qcom_hwspinlock.c >>index 93b62e0..043c62c 100644 >>--- a/drivers/hwspinlock/qcom_hwspinlock.c >>+++ b/drivers/hwspinlock/qcom_hwspinlock.c >>@@ -25,16 +25,26 @@ >> >> #include "hwspinlock_internal.h" >> >>-#define QCOM_MUTEX_APPS_PROC_ID 1 >>-#define QCOM_MUTEX_NUM_LOCKS 32 >>+#define QCOM_MUTEX_APPS_PROC_ID 1 >>+#define QCOM_MUTEX_CPUIDLE_OFFSET 128 >>+#define QCOM_CPUIDLE_LOCK 7 >>+#define QCOM_MUTEX_NUM_LOCKS 32 >>+ > >This part of the diff doesn't look right. Why is it showing that >QCOM_MUTEX_APPS_PROC_ID and QCOM_MUTEX_NUM_LOCKS are deleted and added >lines? Shouldn't they be unchanged by this patch? > Sigh. I must have updated the tabs to play nice. Will fix in the next spin. Thanks for the review. --Lina >-- >Jeffrey Hugo >Qualcomm Innovation Center, Inc. >The Qualcomm Innovation Center, Inc. is a member of the Code Aurora >Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hwspinlock/qcom_hwspinlock.c b/drivers/hwspinlock/qcom_hwspinlock.c index 93b62e0..043c62c 100644 --- a/drivers/hwspinlock/qcom_hwspinlock.c +++ b/drivers/hwspinlock/qcom_hwspinlock.c @@ -25,16 +25,26 @@ #include "hwspinlock_internal.h" -#define QCOM_MUTEX_APPS_PROC_ID 1 -#define QCOM_MUTEX_NUM_LOCKS 32 +#define QCOM_MUTEX_APPS_PROC_ID 1 +#define QCOM_MUTEX_CPUIDLE_OFFSET 128 +#define QCOM_CPUIDLE_LOCK 7 +#define QCOM_MUTEX_NUM_LOCKS 32 + +static inline u32 __qcom_get_proc_id(struct hwspinlock *lock) +{ + return hwspin_lock_get_id(lock) == QCOM_CPUIDLE_LOCK ? + (QCOM_MUTEX_CPUIDLE_OFFSET + smp_processor_id()) : + QCOM_MUTEX_APPS_PROC_ID; +} static int qcom_hwspinlock_trylock(struct hwspinlock *lock) { struct regmap_field *field = lock->priv; u32 lock_owner; int ret; + u32 proc_id = __qcom_get_proc_id(lock); - ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID); + ret = regmap_field_write(field, proc_id); if (ret) return ret; @@ -42,7 +52,7 @@ static int qcom_hwspinlock_trylock(struct hwspinlock *lock) if (ret) return ret; - return lock_owner == QCOM_MUTEX_APPS_PROC_ID; + return lock_owner == proc_id; } static void qcom_hwspinlock_unlock(struct hwspinlock *lock) @@ -57,7 +67,7 @@ static void qcom_hwspinlock_unlock(struct hwspinlock *lock) return; } - if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) { + if (lock_owner != __qcom_get_proc_id(lock)) { pr_err("%s: spinlock not owned by us (actual owner is %d)\n", __func__, lock_owner); }
Hwspinlocks are widely used between processors in an SoC, and also between elevation levels within in the same processor. QCOM SoC's use hwspinlock to serialize entry into a low power mode when the context switches from Linux to secure monitor. Lock #7 has been assigned for this purpose. In order to differentiate between one cpu core holding a lock while another cpu is contending for the same lock, the proc id written into the lock is (128 + cpu id). This makes it unique value among the cpu cores and therefore when a core locks the hwspinlock, other cores would wait for the lock to be released since they would have a different proc id. This value is specific for the lock #7 only. Cc: Jeffrey Hugo <jhugo@codeaurora.org> Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com> Cc: Andy Gross <agross@codeaurora.org> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> --- drivers/hwspinlock/qcom_hwspinlock.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)