[RFT,V2,1/8] clk: divider: add explicit big endian support

Commit Message

Jonas Gorski April 15, 2019, 10:10 a.m. UTC

Add a clock specific flag to switch register accesses to big endian, to
allow runtime configuration of big endian divider clocks.

Signed-off-by: Jonas Gorski <[e-mail]>
---
V1 -> V2:
 * switch from global to local flag

 drivers/clk/clk-divider.c    | 26 ++++++++++++++++++++++----
 include/linux/clk-provider.h |  4 ++++
 2 files changed, 26 insertions(+), 4 deletions(-)

Comments

Stephen Boyd April 17, 2019, 11:32 p.m. UTC | #1

Quoting Jonas Gorski (2019-04-15 03:10:39)
> @@ -370,7 +388,7 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
>         if (divider->flags & CLK_DIVIDER_READ_ONLY) {
>                 u32 val;
>  
> -               val = clk_readl(divider->reg) >> divider->shift;
> +               val = clk_div_readl(divider->reg) >> divider->shift;

Good deal that kbuild running sparse found that this was supposed to be
divider and not divider->reg. If you can fix that and remove the else in
all the basic type readl wrappers then this series looks good to merge
for me.

Jonas Gorski April 18, 2019, 9 a.m. UTC | #2

On Thu, 18 Apr 2019 at 01:32, Stephen Boyd <[e-mail]> wrote:
>
> Quoting Jonas Gorski (2019-04-15 03:10:39)
> > @@ -370,7 +388,7 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
> >         if (divider->flags & CLK_DIVIDER_READ_ONLY) {
> >                 u32 val;
> >
> > -               val = clk_readl(divider->reg) >> divider->shift;
> > +               val = clk_div_readl(divider->reg) >> divider->shift;
>
> Good deal that kbuild running sparse found that this was supposed to be
> divider and not divider->reg. If you can fix that and remove the else in
> all the basic type readl wrappers then this series looks good to merge
> for me.

Yeah, I'm quite glad about that. I was first confused why I didn't
catch it in my test build, but then remembered only C++ complains
about implicit void* casts (IIRC). I have it already fixed locally and
did a sparse build myself, was just waiting for at least one non-bot
comment before resending the series.


Regards
Jonas

Patch

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index e5a17265cfaf..ff791a7a5e9e 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -25,6 +25,24 @@ 
  * parent - fixed parent.  No clk_set_parent support
  */
 
+static inline u32 clk_div_readl(struct clk_divider *divider)
+{
+	if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+		return ioread32be(divider->reg);
+	else
+		return clk_readl(divider->reg);
+}
+
+static inline void clk_div_writel(struct clk_divider *divider, u32 val)
+{
+	if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+		iowrite32be(val, divider->reg);
+	else
+		clk_writel(val, divider->reg);
+}
+
+#define div_mask(width)	((1 << (width)) - 1)
+
 static unsigned int _get_table_maxdiv(const struct clk_div_table *table,
 				      u8 width)
 {
@@ -135,7 +153,7 @@  static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
 	struct clk_divider *divider = to_clk_divider(hw);
 	unsigned int val;
 
-	val = clk_readl(divider->reg) >> divider->shift;
+	val = clk_div_readl(divider) >> divider->shift;
 	val &= clk_div_mask(divider->width);
 
 	return divider_recalc_rate(hw, parent_rate, val, divider->table,
@@ -370,7 +388,7 @@  static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
 	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
 		u32 val;
 
-		val = clk_readl(divider->reg) >> divider->shift;
+		val = clk_div_readl(divider->reg) >> divider->shift;
 		val &= clk_div_mask(divider->width);
 
 		return divider_ro_round_rate(hw, rate, prate, divider->table,
@@ -420,11 +438,11 @@  static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 	if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
 		val = clk_div_mask(divider->width) << (divider->shift + 16);
 	} else {
-		val = clk_readl(divider->reg);
+		val = clk_div_readl(divider->reg);
 		val &= ~(clk_div_mask(divider->width) << divider->shift);
 	}
 	val |= (u32)value << divider->shift;
-	clk_writel(val, divider->reg);
+	clk_div_writel(divider, val);
 
 	if (divider->lock)
 		spin_unlock_irqrestore(divider->lock, flags);
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index db21437c77e2..7117b8cc0c0c 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -416,6 +416,9 @@  struct clk_div_table {
  * CLK_DIVIDER_MAX_AT_ZERO - For dividers which are like CLK_DIVIDER_ONE_BASED
  *	except when the value read from the register is zero, the divisor is
  *	2^width of the field.
+ * CLK_DIVIDER_BIG_ENDIAN - By default little endian register accesses are used
+ *	for the divider register.  Setting this flag makes the register accesses
+ *	big endian.
  */
 struct clk_divider {
 	struct clk_hw	hw;
@@ -437,6 +440,7 @@  struct clk_divider {
 #define CLK_DIVIDER_ROUND_CLOSEST	BIT(4)
 #define CLK_DIVIDER_READ_ONLY		BIT(5)
 #define CLK_DIVIDER_MAX_AT_ZERO		BIT(6)
+#define CLK_DIVIDER_BIG_ENDIAN		BIT(7)
 
 extern const struct clk_ops clk_divider_ops;
 extern const struct clk_ops clk_divider_ro_ops;