On Tue, Sep 11 2018 at 17:02 -0600, Matthias Kaehlcke wrote:
Hi Raju/Lina, On Fri, Jul 27, 2018 at 03:34:46PM +0530, Raju P L S S S N wrote:From: Lina Iyer <ilina@xxxxxxxxxxxxxx> Controllers may be in 'solver' state, where they could be in autonomous mode executing low power modes for their hardware and as such are not available for sending active votes. Device driver may notify RPMH API that the controller is in solver mode and when in such mode, disallow requests from platform drivers for state change using the RSC. Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx> Signed-off-by: Raju P.L.S.S.S.N <rplsssn@xxxxxxxxxxxxxx> --- drivers/soc/qcom/rpmh-internal.h | 2 ++ drivers/soc/qcom/rpmh.c | 59 ++++++++++++++++++++++++++++++++++++++++ include/soc/qcom/rpmh.h | 5 ++++ 3 files changed, 66 insertions(+) diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h index 4ff43bf..6cd2f78 100644 --- a/drivers/soc/qcom/rpmh-internal.h +++ b/drivers/soc/qcom/rpmh-internal.h @@ -72,12 +72,14 @@ struct rpmh_request { * @cache_lock: synchronize access to the cache data * @dirty: was the cache updated since flush * @batch_cache: Cache sleep and wake requests sent as batch + * @in_solver_mode: Controller is busy in solver mode */ struct rpmh_ctrlr { struct list_head cache; spinlock_t cache_lock; bool dirty; struct list_head batch_cache; + bool in_solver_mode; }; /** diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c index 2382276..0d276fd 100644 --- a/drivers/soc/qcom/rpmh.c +++ b/drivers/soc/qcom/rpmh.c @@ -5,6 +5,7 @@ #include <linux/atomic.h> #include <linux/bug.h> +#include <linux/delay.h> #include <linux/interrupt.h> #include <linux/jiffies.h> #include <linux/kernel.h> @@ -75,6 +76,50 @@ static struct rpmh_ctrlr *get_rpmh_ctrlr(const struct device *dev) return &drv->client; } +static int check_ctrlr_state(struct rpmh_ctrlr *ctrlr, enum rpmh_state state) +{ + unsigned long flags; + int ret = 0; + + /* Do not allow setting active votes when in solver mode */ + spin_lock_irqsave(&ctrlr->cache_lock, flags); + if (ctrlr->in_solver_mode && state == RPMH_ACTIVE_ONLY_STATE) + ret = -EBUSY; + spin_unlock_irqrestore(&ctrlr->cache_lock, flags); + + return ret; +} + +/** + * rpmh_mode_solver_set: Indicate that the RSC controller hardware has + * been configured to be in solver mode + * + * @dev: the device making the request + * @enable: Boolean value indicating if the controller is in solver mode. + * + * When solver mode is enabled, passthru API will not be able to send wake + * votes, just awake and active votes. + */ +int rpmh_mode_solver_set(const struct device *dev, bool enable) +{ + struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev); + unsigned long flags; + + for (;;) { + spin_lock_irqsave(&ctrlr->cache_lock, flags); + if (rpmh_rsc_ctrlr_is_idle(ctrlr_to_drv(ctrlr))) { + ctrlr->in_solver_mode = enable;As commented on '[v2,1/6] drivers: qcom: rpmh-rsc: return if the controller is idle', this seems potentially racy. _is_idle() could report the controller as idle, even though some TCSes are in use (after _is_idle() visited them). Additional locking may be needed or a comment if this situation should never happen on a sane system (I don't know enough about RPMh and its clients to judge if this is the case).
Hmm.. Forgot that we call from here. May be a lock might be helpful. -- Lina
