dmaengine: dmatest: Use fixed point div to calculate iops

Use fixed point division to calculate iops to prevent reporting 0 iops
when operations last for longer than a second.

Signed-off-by: Seraj Alijan <seraj.alijan@sondrel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index d192772..998344b 100644 (file)
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -177,6 +177,13 @@ MODULE_PARM_DESC(test_list, "Print current test list");
 #define PATTERN_COUNT_MASK     0x1f
 #define PATTERN_MEMSET_IDX     0x01
 
+/* Fixed point arithmetic ops */
+#define FIXPT_SHIFT            8
+#define FIXPNT_MASK            0xFF
+#define FIXPT_TO_INT(a)        ((a) >> FIXPT_SHIFT)
+#define INT_TO_FIXPT(a)        ((a) << FIXPT_SHIFT)
+#define FIXPT_GET_FRAC(a)      ((((a) & FIXPNT_MASK) * 100) >> FIXPT_SHIFT)
+
 /* poor man's completion - we want to use wait_event_freezable() on it */
 struct dmatest_done {
        bool                    done;
@@ -453,13 +460,15 @@ static unsigned long long dmatest_persec(s64 runtime, unsigned int val)
        }
 
        per_sec *= val;
+       per_sec = INT_TO_FIXPT(per_sec);
        do_div(per_sec, runtime);
+
        return per_sec;
 }
 
 static unsigned long long dmatest_KBs(s64 runtime, unsigned long long len)
 {
-       return dmatest_persec(runtime, len >> 10);
+       return FIXPT_TO_INT(dmatest_persec(runtime, len >> 10));
 }
 
 /*
@@ -500,6 +509,7 @@ static int dmatest_func(void *data)
        ktime_t                 comparetime = 0;
        s64                     runtime = 0;
        unsigned long long      total_len = 0;
+       unsigned long long      iops = 0;
        u8                      align = 0;
        bool                    is_memset = false;
        dma_addr_t              *srcs;
@@ -838,9 +848,10 @@ err_usrcs:
 err_free_coefs:
        kfree(pq_coefs);
 err_thread_type:
-       pr_info("%s: summary %u tests, %u failures %llu iops %llu KB/s (%d)\n",
+       iops = dmatest_persec(runtime, total_tests);
+       pr_info("%s: summary %u tests, %u failures %llu.%02llu iops %llu KB/s (%d)\n",
                current->comm, total_tests, failed_tests,
-               dmatest_persec(runtime, total_tests),
+               FIXPT_TO_INT(iops), FIXPT_GET_FRAC(iops),
                dmatest_KBs(runtime, total_len), ret);
 
        /* terminate all transfers on specified channels */