clk: change clk_ops' ->determine_rate() prototype

Clock rates are stored in an unsigned long field, but ->determine_rate()
(which returns a rounded rate from a requested one) returns a long
value (errors are reported using negative error codes), which can lead
to long overflow if the clock rate exceed 2Ghz.

Change ->determine_rate() prototype to return 0 or an error code, and pass
a pointer to a clk_rate_request structure containing the expected target
rate and the rate constraints imposed by clk users.

The clk_rate_request structure might be extended in the future to contain
other kind of constraints like the rounding policy, the maximum clock
inaccuracy or other things that are not yet supported by the CCF
(power consumption constraints ?).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
CC: Jonathan Corbet <corbet@lwn.net>
CC: Tony Lindgren <tony@atomide.com>
CC: Ralf Baechle <ralf@linux-mips.org>
CC: "Emilio López" <emilio@elopez.com.ar>
CC: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
CC: Peter De Schrijver <pdeschrijver@nvidia.com>
CC: Prashant Gaikwad <pgaikwad@nvidia.com>
CC: Stephen Warren <swarren@wwwdotorg.org>
CC: Thierry Reding <thierry.reding@gmail.com>
CC: Alexandre Courbot <gnurou@gmail.com>
CC: linux-doc@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-omap@vger.kernel.org
CC: linux-mips@linux-mips.org
CC: linux-tegra@vger.kernel.org
[sboyd@codeaurora.org: Fix parent dereference problem in
__clk_determine_rate()]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
[sboyd@codeaurora.org: Folded in fix from Heiko for fixed-rate
clocks without parents or a rate determining op]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

3 files changed, 29 insertions, 33 deletions

diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
index 8c20190a3e9f..7a485870991d 100644
--- a/drivers/clk/sunxi/clk-factors.c
+++ b/drivers/clk/sunxi/clk-factors.c
@@ -79,11 +79,8 @@ static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate,
 	return rate;
 }
 
-static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate,
-				       unsigned long min_rate,
-				       unsigned long max_rate,
-				       unsigned long *best_parent_rate,
-				       struct clk_hw **best_parent_p)
+static int clk_factors_determine_rate(struct clk_hw *hw,
+				      struct clk_rate_request *req)
 {
 	struct clk *clk = hw->clk, *parent, *best_parent = NULL;
 	int i, num_parents;
@@ -96,13 +93,14 @@ static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate,
 		if (!parent)
 			continue;
 		if (__clk_get_flags(clk) & CLK_SET_RATE_PARENT)
-			parent_rate = __clk_round_rate(parent, rate);
+			parent_rate = __clk_round_rate(parent, req->rate);
 		else
 			parent_rate = __clk_get_rate(parent);
 
-		child_rate = clk_factors_round_rate(hw, rate, &parent_rate);
+		child_rate = clk_factors_round_rate(hw, req->rate,
+						    &parent_rate);
 
-		if (child_rate <= rate && child_rate > best_child_rate) {
+		if (child_rate <= req->rate && child_rate > best_child_rate) {
 			best_parent = parent;
 			best = parent_rate;
 			best_child_rate = child_rate;
@@ -110,10 +108,11 @@ static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate,
 	}
 
 	if (best_parent)
-		*best_parent_p = __clk_get_hw(best_parent);
-	*best_parent_rate = best;
+		req->best_parent_hw = __clk_get_hw(best_parent);
+	req->best_parent_rate = best;
+	req->rate = best_child_rate;
 
-	return best_child_rate;
+	return 0;
 }
 
 static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
diff --git a/drivers/clk/sunxi/clk-sun6i-ar100.c b/drivers/clk/sunxi/clk-sun6i-ar100.c
index 63cf149195ae..d70c1ea345db 100644
--- a/drivers/clk/sunxi/clk-sun6i-ar100.c
+++ b/drivers/clk/sunxi/clk-sun6i-ar100.c
@@ -44,17 +44,14 @@ static unsigned long ar100_recalc_rate(struct clk_hw *hw,
 	return (parent_rate >> shift) / (div + 1);
 }
 
-static long ar100_determine_rate(struct clk_hw *hw, unsigned long rate,
-				 unsigned long min_rate,
-				 unsigned long max_rate,
-				 unsigned long *best_parent_rate,
-				 struct clk_hw **best_parent_clk)
+static int ar100_determine_rate(struct clk_hw *hw,
+				struct clk_rate_request *req)
 {
 	int nparents = __clk_get_num_parents(hw->clk);
 	long best_rate = -EINVAL;
 	int i;
 
-	*best_parent_clk = NULL;
+	req->best_parent_hw = NULL;
 
 	for (i = 0; i < nparents; i++) {
 		unsigned long parent_rate;
@@ -65,7 +62,7 @@ static long ar100_determine_rate(struct clk_hw *hw, unsigned long rate,
 
 		parent = clk_get_parent_by_index(hw->clk, i);
 		parent_rate = __clk_get_rate(parent);
-		div = DIV_ROUND_UP(parent_rate, rate);
+		div = DIV_ROUND_UP(parent_rate, req->rate);
 
 		/*
 		 * The AR100 clk contains 2 divisors:
@@ -101,14 +98,16 @@ static long ar100_determine_rate(struct clk_hw *hw, unsigned long rate,
 			continue;
 
 		tmp_rate = (parent_rate >> shift) / div;
-		if (!*best_parent_clk || tmp_rate > best_rate) {
-			*best_parent_clk = __clk_get_hw(parent);
-			*best_parent_rate = parent_rate;
+		if (!req->best_parent_hw || tmp_rate > best_rate) {
+			req->best_parent_hw = __clk_get_hw(parent);
+			req->best_parent_rate = parent_rate;
 			best_rate = tmp_rate;
 		}
 	}
 
-	return best_rate;
+	req->rate = best_rate;
+
+	return 0;
 }
 
 static int ar100_set_parent(struct clk_hw *hw, u8 index)
diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
index 9a82f17d2d73..d0f72a151bf1 100644
--- a/drivers/clk/sunxi/clk-sunxi.c
+++ b/drivers/clk/sunxi/clk-sunxi.c
@@ -118,11 +118,8 @@ static long sun6i_ahb1_clk_round(unsigned long rate, u8 *divp, u8 *pre_divp,
 	return (parent_rate / calcm) >> calcp;
 }
 
-static long sun6i_ahb1_clk_determine_rate(struct clk_hw *hw, unsigned long rate,
-					  unsigned long min_rate,
-					  unsigned long max_rate,
-					  unsigned long *best_parent_rate,
-					  struct clk_hw **best_parent_clk)
+static int sun6i_ahb1_clk_determine_rate(struct clk_hw *hw,
+					 struct clk_rate_request *req)
 {
 	struct clk *clk = hw->clk, *parent, *best_parent = NULL;
 	int i, num_parents;
@@ -135,14 +132,14 @@ static long sun6i_ahb1_clk_determine_rate(struct clk_hw *hw, unsigned long rate,
 		if (!parent)
 			continue;
 		if (__clk_get_flags(clk) & CLK_SET_RATE_PARENT)
-			parent_rate = __clk_round_rate(parent, rate);
+			parent_rate = __clk_round_rate(parent, req->rate);
 		else
 			parent_rate = __clk_get_rate(parent);
 
-		child_rate = sun6i_ahb1_clk_round(rate, NULL, NULL, i,
+		child_rate = sun6i_ahb1_clk_round(req->rate, NULL, NULL, i,
 						  parent_rate);
 
-		if (child_rate <= rate && child_rate > best_child_rate) {
+		if (child_rate <= req->rate && child_rate > best_child_rate) {
 			best_parent = parent;
 			best = parent_rate;
 			best_child_rate = child_rate;
@@ -150,10 +147,11 @@ static long sun6i_ahb1_clk_determine_rate(struct clk_hw *hw, unsigned long rate,
 	}
 
 	if (best_parent)
-		*best_parent_clk = __clk_get_hw(best_parent);
-	*best_parent_rate = best;
+		req->best_parent_hw = __clk_get_hw(best_parent);
+	req->best_parent_rate = best;
+	req->rate = best_child_rate;
 
-	return best_child_rate;
+	return 0;
 }
 
 static int sun6i_ahb1_clk_set_rate(struct clk_hw *hw, unsigned long rate,