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>

1 files changed, 39 insertions, 39 deletions

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index b95d17fbb8d7..aa6c3bdac040 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -176,11 +176,10 @@ clk_rcg2_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 	return calc_rate(parent_rate, m, n, mode, hid_div);
 }
 
-static long _freq_tbl_determine_rate(struct clk_hw *hw,
-		const struct freq_tbl *f, unsigned long rate,
-		unsigned long *p_rate, struct clk_hw **p_hw)
+static int _freq_tbl_determine_rate(struct clk_hw *hw,
+		const struct freq_tbl *f, struct clk_rate_request *req)
 {
-	unsigned long clk_flags;
+	unsigned long clk_flags, rate = req->rate;
 	struct clk *p;
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
 	int index;
@@ -210,19 +209,19 @@ static long _freq_tbl_determine_rate(struct clk_hw *hw,
 	} else {
 		rate =  __clk_get_rate(p);
 	}
-	*p_hw = __clk_get_hw(p);
-	*p_rate = rate;
+	req->best_parent_hw = __clk_get_hw(p);
+	req->best_parent_rate = rate;
+	req->rate = f->freq;
 
-	return f->freq;
+	return 0;
 }
 
-static long clk_rcg2_determine_rate(struct clk_hw *hw, unsigned long rate,
-		unsigned long min_rate, unsigned long max_rate,
-		unsigned long *p_rate, struct clk_hw **p)
+static int clk_rcg2_determine_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
 {
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
 
-	return _freq_tbl_determine_rate(hw, rcg->freq_tbl, rate, p_rate, p);
+	return _freq_tbl_determine_rate(hw, rcg->freq_tbl, req);
 }
 
 static int clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f)
@@ -374,35 +373,34 @@ static int clk_edp_pixel_set_rate_and_parent(struct clk_hw *hw,
 	return clk_edp_pixel_set_rate(hw, rate, parent_rate);
 }
 
-static long clk_edp_pixel_determine_rate(struct clk_hw *hw, unsigned long rate,
-				 unsigned long min_rate,
-				 unsigned long max_rate,
-				 unsigned long *p_rate, struct clk_hw **p)
+static int clk_edp_pixel_determine_rate(struct clk_hw *hw,
+					struct clk_rate_request *req)
 {
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
 	const struct freq_tbl *f = rcg->freq_tbl;
 	const struct frac_entry *frac;
 	int delta = 100000;
-	s64 src_rate = *p_rate;
 	s64 request;
 	u32 mask = BIT(rcg->hid_width) - 1;
 	u32 hid_div;
 	int index = qcom_find_src_index(hw, rcg->parent_map, f->src);
+	struct clk *p = clk_get_parent_by_index(hw->clk, index);
 
 	/* Force the correct parent */
-	*p = __clk_get_hw(clk_get_parent_by_index(hw->clk, index));
+	req->best_parent_hw = __clk_get_hw(p);
+	req->best_parent_rate = __clk_get_rate(p);
 
-	if (src_rate == 810000000)
+	if (req->best_parent_rate == 810000000)
 		frac = frac_table_810m;
 	else
 		frac = frac_table_675m;
 
 	for (; frac->num; frac++) {
-		request = rate;
+		request = req->rate;
 		request *= frac->den;
 		request = div_s64(request, frac->num);
-		if ((src_rate < (request - delta)) ||
-		    (src_rate > (request + delta)))
+		if ((req->best_parent_rate < (request - delta)) ||
+		    (req->best_parent_rate > (request + delta)))
 			continue;
 
 		regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG,
@@ -410,8 +408,10 @@ static long clk_edp_pixel_determine_rate(struct clk_hw *hw, unsigned long rate,
 		hid_div >>= CFG_SRC_DIV_SHIFT;
 		hid_div &= mask;
 
-		return calc_rate(src_rate, frac->num, frac->den, !!frac->den,
-				 hid_div);
+		req->rate = calc_rate(req->best_parent_rate,
+				      frac->num, frac->den,
+				      !!frac->den, hid_div);
+		return 0;
 	}
 
 	return -EINVAL;
@@ -428,9 +428,8 @@ const struct clk_ops clk_edp_pixel_ops = {
 };
 EXPORT_SYMBOL_GPL(clk_edp_pixel_ops);
 
-static long clk_byte_determine_rate(struct clk_hw *hw, unsigned long rate,
-			 unsigned long min_rate, unsigned long max_rate,
-			 unsigned long *p_rate, struct clk_hw **p_hw)
+static int clk_byte_determine_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
 {
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
 	const struct freq_tbl *f = rcg->freq_tbl;
@@ -439,17 +438,19 @@ static long clk_byte_determine_rate(struct clk_hw *hw, unsigned long rate,
 	u32 mask = BIT(rcg->hid_width) - 1;
 	struct clk *p;
 
-	if (rate == 0)
+	if (req->rate == 0)
 		return -EINVAL;
 
 	p = clk_get_parent_by_index(hw->clk, index);
-	*p_hw = __clk_get_hw(p);
-	*p_rate = parent_rate = __clk_round_rate(p, rate);
+	req->best_parent_hw = __clk_get_hw(p);
+	req->best_parent_rate = parent_rate = __clk_round_rate(p, req->rate);
 
-	div = DIV_ROUND_UP((2 * parent_rate), rate) - 1;
+	div = DIV_ROUND_UP((2 * parent_rate), req->rate) - 1;
 	div = min_t(u32, div, mask);
 
-	return calc_rate(parent_rate, 0, 0, 0, div);
+	req->rate = calc_rate(parent_rate, 0, 0, 0, div);
+
+	return 0;
 }
 
 static int clk_byte_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -494,10 +495,8 @@ static const struct frac_entry frac_table_pixel[] = {
 	{ }
 };
 
-static long clk_pixel_determine_rate(struct clk_hw *hw, unsigned long rate,
-				 unsigned long min_rate,
-				 unsigned long max_rate,
-				 unsigned long *p_rate, struct clk_hw **p)
+static int clk_pixel_determine_rate(struct clk_hw *hw,
+				    struct clk_rate_request *req)
 {
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
 	unsigned long request, src_rate;
@@ -507,18 +506,19 @@ static long clk_pixel_determine_rate(struct clk_hw *hw, unsigned long rate,
 	int index = qcom_find_src_index(hw, rcg->parent_map, f->src);
 	struct clk *parent = clk_get_parent_by_index(hw->clk, index);
 
-	*p = __clk_get_hw(parent);
+	req->best_parent_hw = __clk_get_hw(parent);
 
 	for (; frac->num; frac++) {
-		request = (rate * frac->den) / frac->num;
+		request = (req->rate * frac->den) / frac->num;
 
 		src_rate = __clk_round_rate(parent, request);
 		if ((src_rate < (request - delta)) ||
 			(src_rate > (request + delta)))
 			continue;
 
-		*p_rate = src_rate;
-		return (src_rate * frac->num) / frac->den;
+		req->best_parent_rate = src_rate;
+		req->rate = (src_rate * frac->num) / frac->den;
+		return 0;
 	}
 
 	return -EINVAL;