clk: msm: clock-osm: register cycle counter callbacks with scheduler

Implement clk_osm_get_cpu_cycle_counter() which returns the
running cycle counter value. Register these two functions with
a scheduler-provided callback to allow the scheduler to estimate
CPU frequency without notification. Lastly, setup the cycle
counter to be increased on every rising edge of the XO clock
for improved accuracy.

Change-Id: Ie0f60ca79efc05901a88da13f7a6476f390518a5
CRs-Fixed: 988356
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>

diff --git a/drivers/clk/msm/clock-osm.c b/drivers/clk/msm/clock-osm.c
index d05516b..f3c9ff7 100644 (file)
--- a/drivers/clk/msm/clock-osm.c
+++ b/drivers/clk/msm/clock-osm.c
@@ -33,6 +33,7 @@
 #include <linux/interrupt.h>
 #include <linux/regulator/driver.h>
 #include <linux/uaccess.h>
+#include <linux/sched.h>
 
 #include <soc/qcom/scm.h>
 #include <soc/qcom/clock-pll.h>
@@ -104,6 +105,7 @@ enum clk_osm_trace_packet_id {
 #define OSM_CORE_TABLE_SIZE 8192
 #define OSM_REG_SIZE 32
 
+#define OSM_CYCLE_COUNTER_USE_XO_EDGE_EN BIT(8)
 #define PLL_MODE               0x0
 #define PLL_L_VAL              0x4
 #define PLL_USER_CTRL          0xC
@@ -286,16 +288,18 @@ struct clk_osm {
        struct platform_device *vdd_dev;
        void *vbases[NUM_BASES];
        unsigned long pbases[NUM_BASES];
-       u32 cpu_reg_mask;
+       spinlock_t lock;
 
+       u32 cpu_reg_mask;
        u32 num_entries;
        u32 cluster_num;
        u32 irq;
        u32 apm_crossover_vc;
-
        u32 cycle_counter_reads;
        u32 cycle_counter_delay;
        u32 cycle_counter_factor;
+       u64 total_cycle_counter;
+       u32 prev_cycle_counter;
        u32 l_val_base;
        u32 apcs_itm_present;
        u32 apcs_cfg_rcgr;
@@ -1478,8 +1482,10 @@ static void clk_osm_setup_cycle_counters(struct clk_osm *c)
        val |= BIT(0);
        /* Setup OSM clock to XO ratio */
        do_div(ratio, c->xo_clk_rate);
-       val |= BVAL(5, 1, ratio - 1);
+       val |= BVAL(5, 1, ratio - 1) | OSM_CYCLE_COUNTER_USE_XO_EDGE_EN;
        clk_osm_write_reg(c, val, OSM_CYCLE_COUNTER_CTRL_REG);
+       c->total_cycle_counter = 0;
+       c->prev_cycle_counter = 0;
        pr_debug("OSM to XO clock ratio: %d\n", ratio);
 }
 
@@ -1854,6 +1860,38 @@ fail:
        return NULL;
 }
 
+static u64 clk_osm_get_cpu_cycle_counter(int cpu)
+{
+       struct clk_osm *c;
+       u32 val;
+       unsigned long flags;
+
+       if (logical_cpu_to_clk(cpu) == &pwrcl_clk.c)
+               c = &pwrcl_clk;
+       else if (logical_cpu_to_clk(cpu) == &perfcl_clk.c)
+               c = &perfcl_clk;
+       else {
+               pr_err("no clock device for CPU=%d\n", cpu);
+               return 0;
+       }
+
+       spin_lock_irqsave(&c->lock, flags);
+       val = clk_osm_read_reg(c, OSM_CYCLE_COUNTER_STATUS_REG);
+
+       if (val < c->prev_cycle_counter) {
+               /* Handle counter overflow */
+               c->total_cycle_counter += UINT_MAX -
+                       c->prev_cycle_counter + val;
+               c->prev_cycle_counter = val;
+       } else {
+               c->total_cycle_counter += val - c->prev_cycle_counter;
+               c->prev_cycle_counter = val;
+       }
+       spin_unlock_irqrestore(&c->lock, flags);
+
+       return c->total_cycle_counter;
+}
+
 static void populate_opp_table(struct platform_device *pdev)
 {
        int cpu;
@@ -2213,6 +2251,9 @@ static int cpu_clock_osm_driver_probe(struct platform_device *pdev)
        char perfclspeedbinstr[] = "qcom,perfcl-speedbin0-v0";
        char pwrclspeedbinstr[] = "qcom,pwrcl-speedbin0-v0";
        int rc, cpu;
+       struct cpu_cycle_counter_cb cb = {
+               .get_cpu_cycle_counter = clk_osm_get_cpu_cycle_counter,
+       };
 
        rc = clk_osm_resources_init(pdev);
        if (rc) {
@@ -2344,6 +2385,9 @@ static int cpu_clock_osm_driver_probe(struct platform_device *pdev)
                clk_osm_setup_cluster_pll(&perfcl_clk);
        }
 
+       spin_lock_init(&pwrcl_clk.lock);
+       spin_lock_init(&perfcl_clk.lock);
+
        rc = of_msm_clock_register(pdev->dev.of_node, cpu_clocks_osm,
                                   ARRAY_SIZE(cpu_clocks_osm));
        if (rc) {
@@ -2404,6 +2448,8 @@ static int cpu_clock_osm_driver_probe(struct platform_device *pdev)
 
        of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
 
+       register_cpu_cycle_counter_cb(&cb);
+
        pr_info("OSM driver inited\n");
        put_online_cpus();