[PATCH v2 05/11] soc: qcom: icc-bwmon: clear all registers on init

From: Krzysztof Kozlowski
Date: Thu Jul 28 2022 - 07:38:18 EST


The hardware programming guide recommends to clear all registers on
first initialization, through separate field in BWMON_CLEAR register.

This makes sense in general but especially if driver is rebound to avoid
spurious/early interrupts.

Cc: Rajendra Nayak <quic_rjendra@xxxxxxxxxxx>
Cc: Sibi Sankar <quic_sibis@xxxxxxxxxxx>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
---
drivers/soc/qcom/icc-bwmon.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c
index a820855e85b4..d2df8feff651 100644
--- a/drivers/soc/qcom/icc-bwmon.c
+++ b/drivers/soc/qcom/icc-bwmon.c
@@ -50,6 +50,7 @@

#define BWMON_CLEAR 0x2a4
#define BWMON_CLEAR_CLEAR BIT(0)
+#define BWMON_CLEAR_CLEAR_ALL BIT(1)

#define BWMON_SAMPLE_WINDOW 0x2a8
#define BWMON_THRESHOLD_HIGH 0x2ac
@@ -127,8 +128,12 @@ struct icc_bwmon {
unsigned int current_kbps;
};

-static void bwmon_clear_counters(struct icc_bwmon *bwmon)
+static void bwmon_clear_counters(struct icc_bwmon *bwmon, bool clear_all)
{
+ unsigned int val = BWMON_CLEAR_CLEAR;
+
+ if (clear_all)
+ val |= BWMON_CLEAR_CLEAR_ALL;
/*
* Clear counters. The order and barriers are
* important. Quoting downstream Qualcomm msm-4.9 tree:
@@ -137,7 +142,7 @@ static void bwmon_clear_counters(struct icc_bwmon *bwmon)
* region. So, we need to make sure the counter clear is completed
* before we try to clear the IRQ or do any other counter operations.
*/
- writel(BWMON_CLEAR_CLEAR, bwmon->base + BWMON_CLEAR);
+ writel(val, bwmon->base + BWMON_CLEAR);
}

static void bwmon_clear_irq(struct icc_bwmon *bwmon)
@@ -208,7 +213,7 @@ static void bwmon_start(struct icc_bwmon *bwmon)
unsigned int thres_count;
int window;

- bwmon_clear_counters(bwmon);
+ bwmon_clear_counters(bwmon, true);

window = mult_frac(bwmon->data->sample_ms, HW_TIMER_HZ, MSEC_PER_SEC);
/* Maximum sampling window: 0xfffff */
@@ -304,7 +309,7 @@ static irqreturn_t bwmon_intr_thread(int irq, void *dev_id)
bwmon_set_threshold(bwmon, BWMON_THRESHOLD_HIGH, up_kbps);
bwmon_set_threshold(bwmon, BWMON_THRESHOLD_MED, down_kbps);
/* Write barriers in bwmon_clear_counters() */
- bwmon_clear_counters(bwmon);
+ bwmon_clear_counters(bwmon, false);
bwmon_clear_irq(bwmon);
bwmon_enable(bwmon, irq_enable);

--
2.34.1