linux-kernel - [PATCH v3 1/2] soc: qcom: geni: Don't ignore clk_round_rate() errors in geni_se_clk_tbl

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Message-Id: <20180906224906.93752-1-dianders@chromium.org>
Date:   Thu,  6 Sep 2018 15:49:05 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Andy Gross <andy.gross@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     mka@...omium.org, girishm@...eaurora.org, dkota@...eaurora.org,
        evgreen@...omium.org, swboyd@...omium.org,
        Douglas Anderson <dianders@...omium.org>,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        David Brown <david.brown@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 1/2] soc: qcom: geni: Don't ignore clk_round_rate() errors in geni_se_clk_tbl_get()

The function clk_round_rate() is defined to return a "long", not an
"unsigned long".  That's because it might return a negative error
code.  Change the call in geni_se_clk_tbl_get() to check for errors.

While we're at it, get rid of a useless init of "freq".

NOTE: overall the idea that we should iterate over clk_round_rate() to
try to reconstruct a table already present in the clock driver is
questionable.  Specifically:
- This method relies on "clk_round_rate()" rounding up.
- This method only works if the table is sorted and has no duplicates.
...this patch doesn't try to fix those problems, it just makes the
error handling more correct.

Fixes: eddac5af0654 ("soc: qcom: Add GENI based QUP Wrapper driver")
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
---

Changes in v3:
- Init "freq" again since removing it was wrong (kbuild test robot).

Changes in v2:
- Get rid of unneeded init of "freq" (Matthias).
- Add Matthias tag.

 drivers/soc/qcom/qcom-geni-se.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index feed3db21c10..1b19b8428c4a 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -513,7 +513,7 @@ EXPORT_SYMBOL(geni_se_resources_on);
  */
 int geni_se_clk_tbl_get(struct geni_se *se, unsigned long **tbl)
 {
-	unsigned long freq = 0;
+	long freq = 0;
 	int i;
 
 	if (se->clk_perf_tbl) {
@@ -529,7 +529,7 @@ int geni_se_clk_tbl_get(struct geni_se *se, unsigned long **tbl)
 
 	for (i = 0; i < MAX_CLK_PERF_LEVEL; i++) {
 		freq = clk_round_rate(se->clk, freq + 1);
-		if (!freq || freq == se->clk_perf_tbl[i - 1])
+		if (freq <= 0 || freq == se->clk_perf_tbl[i - 1])
 			break;
 		se->clk_perf_tbl[i] = freq;
 	}
-- 
2.19.0.rc2.392.g5ba43deb5a-goog