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Date: Mon, 18 May 2015 14:08:27 +0100
From: Punit Agrawal <punit.agrawal@....com>
To: "Suzuki K. Poulose" <suzuki.poulose@....com>
Cc: linux-arm-kernel@...ts.infradead.org,
Mark Rutland <mark.rutland@....com>,
devicetree@...r.kernel.org,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Arnd Bergmann <arnd@...db.de>, Pawel Moll <pawel.moll@....com>,
Will Deacon <will.deacon@....com>,
linux-kernel@...r.kernel.org, arm@...nel.org,
Olof Johansson <olof@...om.net>
Subject: Re: [PATCH 4/7] arm-cci: Abstract handling for CCI events
"Suzuki K. Poulose" <suzuki.poulose@....com> writes:
> From: "Suzuki K. Poulose" <suzuki.poulose@....com>
>
> Given that each CCI has different set of interfaces and
> its associated events, it is good to abstract the validation of the
> event codes to make it easier to add support for a new CCI model.
>
> This patch also abstracts the mapping of a given event to a counter,
> as there are some special counters for certain specific events.
>
> We assume that the fixed hardware counters are always at the beginning,
> so that we can use cci_model->fixed_hw_events as an upper bound to given
> idx to check if we need to program the counter for an event.
>
> Cc: Punit Agrawal <punit.agrawal@....com>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Will Deacon <will.deacon@....com>
> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@....com>
Acked-by: Punit Agrawal <punit.agrawal@....com>
> ---
> drivers/bus/arm-cci.c | 78 ++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 55 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> index 82d5681..4b9a8d3 100644
> --- a/drivers/bus/arm-cci.c
> +++ b/drivers/bus/arm-cci.c
> @@ -107,6 +107,7 @@ struct cci_pmu_hw_events {
> raw_spinlock_t pmu_lock;
> };
>
> +struct cci_pmu;
> /*
> * struct cci_pmu_model:
> * @fixed_hw_cntrs - Number of fixed event counters
> @@ -119,6 +120,8 @@ struct cci_pmu_model {
> u32 num_hw_cntrs;
> u32 cntr_size;
> struct event_range event_ranges[CCI_IF_MAX];
> + int (*validate_hw_event)(struct cci_pmu *, unsigned long);
> + int (*get_event_idx)(struct cci_pmu *, struct cci_pmu_hw_events *, unsigned long);
> };
>
> static struct cci_pmu_model cci_pmu_models[];
> @@ -189,7 +192,29 @@ enum cci400_perf_events {
> #define CCI_REV_R1_MASTER_PORT_MIN_EV 0x00
> #define CCI_REV_R1_MASTER_PORT_MAX_EV 0x11
>
> -static int pmu_validate_hw_event(struct cci_pmu *cci_pmu, unsigned long hw_event)
> +static int cci400_get_event_idx(struct cci_pmu *cci_pmu,
> + struct cci_pmu_hw_events *hw,
> + unsigned long cci_event)
> +{
> + int idx;
> +
> + /* cycles event idx is fixed */
> + if (cci_event == CCI_PMU_CYCLES) {
> + if (test_and_set_bit(CCI_PMU_CYCLE_CNTR_IDX, hw->used_mask))
> + return -EAGAIN;
> +
> + return CCI_PMU_CYCLE_CNTR_IDX;
> + }
> +
> + for (idx = CCI_PMU_CNTR0_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); ++idx)
> + if (!test_and_set_bit(idx, hw->used_mask))
> + return idx;
> +
> + /* No counters available */
> + return -EAGAIN;
> +}
> +
> +static int cci400_validate_hw_event(struct cci_pmu *cci_pmu, unsigned long hw_event)
> {
> u8 ev_source = CCI_PMU_EVENT_SOURCE(hw_event);
> u8 ev_code = CCI_PMU_EVENT_CODE(hw_event);
> @@ -198,6 +223,9 @@ static int pmu_validate_hw_event(struct cci_pmu *cci_pmu, unsigned long hw_event
> if (hw_event & ~CCI_PMU_EVENT_MASK)
> return -ENOENT;
>
> + if (hw_event == CCI_PMU_CYCLES)
> + return hw_event;
> +
> switch (ev_source) {
> case CCI_PORT_S0:
> case CCI_PORT_S1:
> @@ -289,18 +317,14 @@ static u32 pmu_get_max_counters(void)
> static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *event)
> {
> struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
> - struct hw_perf_event *hw_event = &event->hw;
> - unsigned long cci_event = hw_event->config_base;
> + unsigned long cci_event = event->hw.config_base;
> int idx;
>
> - if (cci_event == CCI_PMU_CYCLES) {
> - if (test_and_set_bit(CCI_PMU_CYCLE_CNTR_IDX, hw->used_mask))
> - return -EAGAIN;
> + if (cci_pmu->model->get_event_idx)
> + return cci_pmu->model->get_event_idx(cci_pmu, hw, cci_event);
>
> - return CCI_PMU_CYCLE_CNTR_IDX;
> - }
> -
> - for (idx = CCI_PMU_CNTR0_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); ++idx)
> + /* Generic code to find an unused idx from the mask */
> + for(idx = 0; idx <= CCI_PMU_CNTR_LAST(cci_pmu); idx++)
> if (!test_and_set_bit(idx, hw->used_mask))
> return idx;
>
> @@ -310,19 +334,13 @@ static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *ev
>
> static int pmu_map_event(struct perf_event *event)
> {
> - int mapping;
> - unsigned long config = event->attr.config;
> + struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
>
> - if (event->attr.type < PERF_TYPE_MAX)
> + if (event->attr.type < PERF_TYPE_MAX ||
> + !cci_pmu->model->validate_hw_event)
> return -ENOENT;
>
> - if (config == CCI_PMU_CYCLES)
> - mapping = config;
> - else
> - mapping = pmu_validate_hw_event(to_cci_pmu(event->pmu),
> - config);
> -
> - return mapping;
> + return cci_pmu->model->validate_hw_event(cci_pmu, event->attr.config);
> }
>
> static int pmu_request_irq(struct cci_pmu *cci_pmu, irq_handler_t handler)
> @@ -450,7 +468,7 @@ static irqreturn_t pmu_handle_irq(int irq_num, void *dev)
> * This should work regardless of whether we have per-counter overflow
> * interrupt or a combined overflow interrupt.
> */
> - for (idx = CCI_PMU_CYCLE_CNTR_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); idx++) {
> + for (idx = 0; idx <= CCI_PMU_CNTR_LAST(cci_pmu); idx++) {
> struct perf_event *event = events->events[idx];
> struct hw_perf_event *hw_counter;
>
> @@ -538,6 +556,16 @@ static void cci_pmu_disable(struct pmu *pmu)
> raw_spin_unlock_irqrestore(&hw_events->pmu_lock, flags);
> }
>
> +/*
> + * Check if the idx represents a non-programmable counter.
> + * All the fixed event counters are mapped before the programmable
> + * counters.
> + */
> +static bool pmu_fixed_hw_idx(struct cci_pmu *cci_pmu, int idx)
> +{
> + return (idx >= 0) && (idx < cci_pmu->model->fixed_hw_cntrs);
> +}
> +
> static void cci_pmu_start(struct perf_event *event, int pmu_flags)
> {
> struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
> @@ -562,8 +590,8 @@ static void cci_pmu_start(struct perf_event *event, int pmu_flags)
>
> raw_spin_lock_irqsave(&hw_events->pmu_lock, flags);
>
> - /* Configure the event to count, unless you are counting cycles */
> - if (idx != CCI_PMU_CYCLE_CNTR_IDX)
> + /* Configure the counter unless you are counting a fixed event */
> + if (!pmu_fixed_hw_idx(cci_pmu, idx))
> pmu_set_event(cci_pmu, idx, hwc->config_base);
>
> pmu_event_set_period(event);
> @@ -907,6 +935,8 @@ static struct cci_pmu_model cci_pmu_models[] = {
> CCI_REV_R0_MASTER_PORT_MAX_EV,
> },
> },
> + .validate_hw_event = cci400_validate_hw_event,
> + .get_event_idx = cci400_get_event_idx,
> },
> [CCI_REV_R1] = {
> .name = "CCI_400_r1",
> @@ -923,6 +953,8 @@ static struct cci_pmu_model cci_pmu_models[] = {
> CCI_REV_R1_MASTER_PORT_MAX_EV,
> },
> },
> + .validate_hw_event = cci400_validate_hw_event,
> + .get_event_idx = cci400_get_event_idx,
> },
> };
--
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