[PATCH v2 0/6] clk: renesas: r8a779[56]: Add Z and Z2 clock support

[PATCH v2 0/6] clk: renesas: r8a779[56]: Add Z and Z2 clock support

[Simon Horman]

Hi,

this patch-set adds Z and Z2 clock support.

These are dependencies for supporting CPUFreq. The remainder of that
work is being posted separately and can be found at:

https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git topic/rcar-gen3-cpufreq


A description of steps taken to lightly exercise the same feature for the
r88a7795 the above can be found at the link below. The results are the same
for the r8a7796 with the exception that it has two active CPU cores rather
than four.

http://elinux.org/Tests:R-CAR-GEN3-CPUFreq


Based on clk-renesas-for-v4.14-tag1

Changes since v1:
* Rebase
* Include r8a7795 and r8a7796 changes in same patchset

Takeshi Kihara (6):
  clk: renesas: rcar-gen3: Add Z clock divider support
  clk: renesas: rcar-gen3: Add Z2 clock divider support
  clk: renesas: r8a7795: Add Z clock
  clk: renesas: r8a7795: Add Z2 clock
  clk: renesas: r8a7796: Add Z clock
  clk: renesas: r8a7796: Add Z2 clock

 drivers/clk/renesas/r8a7795-cpg-mssr.c |   2 +
 drivers/clk/renesas/r8a7796-cpg-mssr.c |   2 +
 drivers/clk/renesas/rcar-gen3-cpg.c    | 204 +++++++++++++++++++++++++++++++++
 drivers/clk/renesas/rcar-gen3-cpg.h    |   2 +
 4 files changed, 210 insertions(+)

-- 
2.1.4

[PATCH v2 1/6] clk: renesas: rcar-gen3: Add Z clock divider support

[Simon Horman]

From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Z clock divider support for R-Car Gen3 SoC.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[simon: divide parent by 2; use bitops macros]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
v1 [Simon Horman]
* Divide parent clock by 2 to give correct rate
* Use GENMASK, FIELD_{GET,PREP}
* Correct whitespace
* Arrange local variables in reverse christmas tree order

v0 [Takeshi Kihara]
---
 drivers/clk/renesas/rcar-gen3-cpg.c | 138 ++++++++++++++++++++++++++++++++++++
 drivers/clk/renesas/rcar-gen3-cpg.h |   1 +
 2 files changed, 139 insertions(+)

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index 951105816547..f688b5f44961 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/bug.h>
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/device.h>
@@ -29,6 +30,139 @@
 #define CPG_PLL2CR		0x002c
 #define CPG_PLL4CR		0x01f4
 
+/* Z Clock
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is adjustable.  clk->rate = (parent->rate * mult / 32 ) / 2
+ * parent - fixed parent.  No clk_set_parent support
+ */
+#define CPG_FRQCRB			0x00000004
+#define CPG_FRQCRB_KICK			BIT(31)
+#define CPG_FRQCRC			0x000000e0
+#define CPG_FRQCRC_ZFC_MASK		GENMASK(12, 8)
+
+struct cpg_z_clk {
+	struct clk_hw hw;
+	void __iomem *reg;
+	void __iomem *kick_reg;
+};
+
+#define to_z_clk(_hw)	container_of(_hw, struct cpg_z_clk, hw)
+
+static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	struct cpg_z_clk *zclk = to_z_clk(hw);
+	unsigned long rate;
+	unsigned int mult;
+
+	mult = 32 - FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg));
+	/* There is a PLL post-divider of 1/2,
+	 * thus the doubling of the divisor below.
+	 */
+	rate = div_u64((u64)parent_rate * mult + 16, 32 * 2);
+	/* Round to closest value at 100MHz unit */
+	rate = 100000000 * DIV_ROUND_CLOSEST(rate, 100000000);
+
+	return rate;
+}
+
+static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long *parent_rate)
+{
+	unsigned long prate = *parent_rate;
+	unsigned int mult;
+
+	if (!prate)
+		prate = 1;
+
+	mult = div_u64((u64)rate * 32 + prate/2, prate);
+	mult = clamp(mult, 1U, 32U);
+
+	return *parent_rate / 32 * mult;
+}
+
+static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct cpg_z_clk *zclk = to_z_clk(hw);
+	unsigned int mult;
+	unsigned int i;
+	u32 val, kick;
+
+	mult = div_u64((u64)rate * 32 + parent_rate/2, parent_rate);
+	mult = clamp(mult, 1U, 32U);
+
+	if (clk_readl(zclk->kick_reg) & CPG_FRQCRB_KICK)
+		return -EBUSY;
+
+	val = clk_readl(zclk->reg) & ~CPG_FRQCRC_ZFC_MASK;
+	val |= FIELD_PREP(CPG_FRQCRC_ZFC_MASK, 32 - mult);
+	clk_writel(val, zclk->reg);
+
+	/*
+	 * Set KICK bit in FRQCRB to update hardware setting and wait for
+	 * clock change completion.
+	 */
+	kick = clk_readl(zclk->kick_reg);
+	kick |= CPG_FRQCRB_KICK;
+	clk_writel(kick, zclk->kick_reg);
+
+	/*
+	 * Note: There is no HW information about the worst case latency.
+	 *
+	 * Using experimental measurements, it seems that no more than
+	 * ~10 iterations are needed, independently of the CPU rate.
+	 * Since this value might be dependent of external xtal rate, pll1
+	 * rate or even the other emulation clocks rate, use 1000 as a
+	 * "super" safe value.
+	 */
+	for (i = 1000; i; i--) {
+		if (!(clk_readl(zclk->kick_reg) & CPG_FRQCRB_KICK))
+			return 0;
+
+		cpu_relax();
+	}
+
+	return -ETIMEDOUT;
+}
+
+static const struct clk_ops cpg_z_clk_ops = {
+	.recalc_rate = cpg_z_clk_recalc_rate,
+	.round_rate = cpg_z_clk_round_rate,
+	.set_rate = cpg_z_clk_set_rate,
+};
+
+static struct clk * __init cpg_z_clk_register(const char *name,
+					      const char *parent_name,
+					      void __iomem *reg)
+{
+	struct clk_init_data init;
+	struct cpg_z_clk *zclk;
+	struct clk *clk;
+
+	zclk = kzalloc(sizeof(*zclk), GFP_KERNEL);
+	if (!zclk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &cpg_z_clk_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	zclk->reg = reg + CPG_FRQCRC;
+	zclk->kick_reg = reg + CPG_FRQCRB;
+	zclk->hw.init = &init;
+
+	clk = clk_register(NULL, &zclk->hw);
+	if (IS_ERR(clk))
+		kfree(zclk);
+
+	return clk;
+}
 
 /*
  * SDn Clock
@@ -373,6 +507,10 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 		mult = 1;
 		break;
 
+	case CLK_TYPE_GEN3_Z:
+		return cpg_z_clk_register(core->name, __clk_get_name(parent),
+					  base);
+
 	default:
 		return ERR_PTR(-EINVAL);
 	}
diff --git a/drivers/clk/renesas/rcar-gen3-cpg.h b/drivers/clk/renesas/rcar-gen3-cpg.h
index d756ef8b78eb..89da28f6f71b 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.h
+++ b/drivers/clk/renesas/rcar-gen3-cpg.h
@@ -21,6 +21,7 @@ enum rcar_gen3_clk_types {
 	CLK_TYPE_GEN3_SD,
 	CLK_TYPE_GEN3_R,
 	CLK_TYPE_GEN3_PE,
+	CLK_TYPE_GEN3_Z,
 };
 
 #define DEF_GEN3_SD(_name, _id, _parent, _offset)	\
-- 
2.1.4

[PATCH v2 2/6] clk: renesas: rcar-gen3: Add Z2 clock divider support

[Simon Horman]

From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Z2 clock divider support for R-Car Gen3 SoC.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[simon: add recalc_rate() helper; use bitops macros]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
v1 [Simon Horman]
* Provide __cpg_z_clk_recalc_rate() helper
* Use GENMASK

v0 [Takeshi Kihara]
---
 drivers/clk/renesas/rcar-gen3-cpg.c | 76 ++++++++++++++++++++++++++++++++++---
 drivers/clk/renesas/rcar-gen3-cpg.h |  1 +
 2 files changed, 72 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index f688b5f44961..8f44cbf895fb 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -30,7 +30,7 @@
 #define CPG_PLL2CR		0x002c
 #define CPG_PLL4CR		0x01f4
 
-/* Z Clock
+/* Z Clock & Z2 Clock
  *
  * Traits of this clock:
  * prepare - clk_prepare only ensures that parents are prepared
@@ -42,6 +42,7 @@
 #define CPG_FRQCRB_KICK			BIT(31)
 #define CPG_FRQCRC			0x000000e0
 #define CPG_FRQCRC_ZFC_MASK		GENMASK(12, 8)
+#define CPG_FRQCRC_Z2FC_MASK		GENMASK(4, 0)
 
 struct cpg_z_clk {
 	struct clk_hw hw;
@@ -51,14 +52,13 @@ struct cpg_z_clk {
 
 #define to_z_clk(_hw)	container_of(_hw, struct cpg_z_clk, hw)
 
-static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
-					   unsigned long parent_rate)
+static unsigned long __cpg_z_clk_recalc_rate(unsigned long parent_rate,
+					     unsigned int val)
 {
-	struct cpg_z_clk *zclk = to_z_clk(hw);
 	unsigned long rate;
 	unsigned int mult;
 
-	mult = 32 - FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg));
+	mult = 32 - val;
 	/* There is a PLL post-divider of 1/2,
 	 * thus the doubling of the divisor below.
 	 */
@@ -69,6 +69,26 @@ static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
 	return rate;
 }
 
+static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	struct cpg_z_clk *zclk = to_z_clk(hw);
+	unsigned int val;
+
+	val = FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg));
+	return __cpg_z_clk_recalc_rate(parent_rate, val);
+}
+
+static unsigned long cpg_z2_clk_recalc_rate(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	struct cpg_z_clk *zclk = to_z_clk(hw);
+	unsigned int val;
+
+	val = FIELD_GET(CPG_FRQCRC_Z2FC_MASK, clk_readl(zclk->reg));
+	return __cpg_z_clk_recalc_rate(parent_rate, val);
+}
+
 static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 				 unsigned long *parent_rate)
 {
@@ -129,12 +149,25 @@ static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 	return -ETIMEDOUT;
 }
 
+static int cpg_z2_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long parent_rate)
+{
+	pr_info("Do not support Z2 clock changing\n");
+	return 0;
+}
+
 static const struct clk_ops cpg_z_clk_ops = {
 	.recalc_rate = cpg_z_clk_recalc_rate,
 	.round_rate = cpg_z_clk_round_rate,
 	.set_rate = cpg_z_clk_set_rate,
 };
 
+static const struct clk_ops cpg_z2_clk_ops = {
+	.recalc_rate = cpg_z2_clk_recalc_rate,
+	.round_rate = cpg_z_clk_round_rate,
+	.set_rate = cpg_z2_clk_set_rate,
+};
+
 static struct clk * __init cpg_z_clk_register(const char *name,
 					      const char *parent_name,
 					      void __iomem *reg)
@@ -164,6 +197,35 @@ static struct clk * __init cpg_z_clk_register(const char *name,
 	return clk;
 }
 
+static struct clk * __init cpg_z2_clk_register(const char *name,
+					      const char *parent_name,
+					      void __iomem *reg)
+{
+	struct clk_init_data init;
+	struct cpg_z_clk *zclk;
+	struct clk *clk;
+
+	zclk = kzalloc(sizeof(*zclk), GFP_KERNEL);
+	if (!zclk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &cpg_z2_clk_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	zclk->reg = reg + CPG_FRQCRC;
+	zclk->kick_reg = reg + CPG_FRQCRB;
+	zclk->hw.init = &init;
+
+	clk = clk_register(NULL, &zclk->hw);
+	if (IS_ERR(clk))
+		kfree(zclk);
+
+	return clk;
+}
+
 /*
  * SDn Clock
  */
@@ -511,6 +573,10 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 		return cpg_z_clk_register(core->name, __clk_get_name(parent),
 					  base);
 
+	case CLK_TYPE_GEN3_Z2:
+		return cpg_z2_clk_register(core->name, __clk_get_name(parent),
+					   base);
+
 	default:
 		return ERR_PTR(-EINVAL);
 	}
diff --git a/drivers/clk/renesas/rcar-gen3-cpg.h b/drivers/clk/renesas/rcar-gen3-cpg.h
index 89da28f6f71b..c03fd498c96b 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.h
+++ b/drivers/clk/renesas/rcar-gen3-cpg.h
@@ -22,6 +22,7 @@ enum rcar_gen3_clk_types {
 	CLK_TYPE_GEN3_R,
 	CLK_TYPE_GEN3_PE,
 	CLK_TYPE_GEN3_Z,
+	CLK_TYPE_GEN3_Z2,
 };
 
 #define DEF_GEN3_SD(_name, _id, _parent, _offset)	\
-- 
2.1.4

[PATCH v2 3/6] clk: renesas: r8a7795: Add Z clock

[Simon Horman]

From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Z clock for R8A7795 SoC.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/clk/renesas/r8a7795-cpg-mssr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/renesas/r8a7795-cpg-mssr.c b/drivers/clk/renesas/r8a7795-cpg-mssr.c
index 762b2f8824f1..2a0546fd47dc 100644
--- a/drivers/clk/renesas/r8a7795-cpg-mssr.c
+++ b/drivers/clk/renesas/r8a7795-cpg-mssr.c
@@ -74,6 +74,7 @@ static struct cpg_core_clk r8a7795_core_clks[] __initdata = {
 	DEF_FIXED(".sdsrc",     CLK_SDSRC,         CLK_PLL1_DIV2,  2, 1),
 
 	/* Core Clock Outputs */
+	DEF_BASE("z",           R8A7795_CLK_Z,     CLK_TYPE_GEN3_Z, CLK_PLL0),
 	DEF_FIXED("ztr",        R8A7795_CLK_ZTR,   CLK_PLL1_DIV2,  6, 1),
 	DEF_FIXED("ztrd2",      R8A7795_CLK_ZTRD2, CLK_PLL1_DIV2, 12, 1),
 	DEF_FIXED("zt",         R8A7795_CLK_ZT,    CLK_PLL1_DIV2,  4, 1),
-- 
2.1.4

[PATCH v2 4/6] clk: renesas: r8a7795: Add Z2 clock

[Simon Horman]

From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Z2 clock for r8a7795 SoC.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
---
 drivers/clk/renesas/r8a7795-cpg-mssr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/renesas/r8a7795-cpg-mssr.c b/drivers/clk/renesas/r8a7795-cpg-mssr.c
index 2a0546fd47dc..1c931d8ec0cc 100644
--- a/drivers/clk/renesas/r8a7795-cpg-mssr.c
+++ b/drivers/clk/renesas/r8a7795-cpg-mssr.c
@@ -75,6 +75,7 @@ static struct cpg_core_clk r8a7795_core_clks[] __initdata = {
 
 	/* Core Clock Outputs */
 	DEF_BASE("z",           R8A7795_CLK_Z,     CLK_TYPE_GEN3_Z, CLK_PLL0),
+	DEF_BASE("z2",          R8A7795_CLK_Z2,    CLK_TYPE_GEN3_Z2, CLK_PLL2),
 	DEF_FIXED("ztr",        R8A7795_CLK_ZTR,   CLK_PLL1_DIV2,  6, 1),
 	DEF_FIXED("ztrd2",      R8A7795_CLK_ZTRD2, CLK_PLL1_DIV2, 12, 1),
 	DEF_FIXED("zt",         R8A7795_CLK_ZT,    CLK_PLL1_DIV2,  4, 1),
-- 
2.1.4

[PATCH v2 5/6] clk: renesas: r8a7796: Add Z clock

[Simon Horman]

From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Z clock for R8A7796 SoC.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/clk/renesas/r8a7796-cpg-mssr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/renesas/r8a7796-cpg-mssr.c b/drivers/clk/renesas/r8a7796-cpg-mssr.c
index e5e7fb212288..e8d5e75afc65 100644
--- a/drivers/clk/renesas/r8a7796-cpg-mssr.c
+++ b/drivers/clk/renesas/r8a7796-cpg-mssr.c
@@ -74,6 +74,7 @@ static const struct cpg_core_clk r8a7796_core_clks[] __initconst = {
 	DEF_FIXED(".sdsrc",     CLK_SDSRC,         CLK_PLL1_DIV2,  2, 1),
 
 	/* Core Clock Outputs */
+	DEF_BASE("z",           R8A7796_CLK_Z,     CLK_TYPE_GEN3_Z, CLK_PLL0),
 	DEF_FIXED("ztr",        R8A7796_CLK_ZTR,   CLK_PLL1_DIV2,  6, 1),
 	DEF_FIXED("ztrd2",      R8A7796_CLK_ZTRD2, CLK_PLL1_DIV2, 12, 1),
 	DEF_FIXED("zt",         R8A7796_CLK_ZT,    CLK_PLL1_DIV2,  4, 1),
-- 
2.1.4

[PATCH v2 6/6] clk: renesas: r8a7796: Add Z2 clock

[Simon Horman]

From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Z2 clock for R8A7796 SoC.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/clk/renesas/r8a7796-cpg-mssr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/renesas/r8a7796-cpg-mssr.c b/drivers/clk/renesas/r8a7796-cpg-mssr.c
index e8d5e75afc65..48731741b59e 100644
--- a/drivers/clk/renesas/r8a7796-cpg-mssr.c
+++ b/drivers/clk/renesas/r8a7796-cpg-mssr.c
@@ -75,6 +75,7 @@ static const struct cpg_core_clk r8a7796_core_clks[] __initconst = {
 
 	/* Core Clock Outputs */
 	DEF_BASE("z",           R8A7796_CLK_Z,     CLK_TYPE_GEN3_Z, CLK_PLL0),
+	DEF_BASE("z2",          R8A7796_CLK_Z2,    CLK_TYPE_GEN3_Z2, CLK_PLL2),
 	DEF_FIXED("ztr",        R8A7796_CLK_ZTR,   CLK_PLL1_DIV2,  6, 1),
 	DEF_FIXED("ztrd2",      R8A7796_CLK_ZTRD2, CLK_PLL1_DIV2, 12, 1),
 	DEF_FIXED("zt",         R8A7796_CLK_ZT,    CLK_PLL1_DIV2,  4, 1),
-- 
2.1.4

[PATCH v2 0/6] clk: renesas: r8a779[56]: Add Z and Z2 clock support

[Geert Uytterhoeven]

Hi Simon,

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> this patch-set adds Z and Z2 clock support.
>
> These are dependencies for supporting CPUFreq. The remainder of that
> work is being posted separately and can be found at:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git topic/rcar-gen3-cpufreq
>
> A description of steps taken to lightly exercise the same feature for the
> r88a7795 the above can be found at the link below. The results are the same
> for the r8a7796 with the exception that it has two active CPU cores rather
> than four.
>
> http://elinux.org/Tests:R-CAR-GEN3-CPUFreq

Thanks for your patches, and the wiki page!

I gave it a try on R-Car H3 (ES1.0 and ES2.0) and M3-W (ES1.0), and the
off-by-two factor of the Z clock frequency is gone.
I couldn't test on R-Car H3 ES1.1. Probably it's OK, too (ES1.1 fixed the
missing PLL0/2/4 post-divider in ES1.0).

1. After boot-up, the CPU clock frequency is 1.5 GHz, and
   /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq and
   /sys/kernel/debug/clk/z/clk_rate agree. Good.

2. After switching to the conservative governor, scaling_cur_freq reports
   either a 500 MHz or 1 GHz clock rate.
   But /sys/kernel/debug/clk/z/clk_rate disagrees: it reports either a 200
   or 700 MHz clock rate.

   Ah, there's also cpuinfo_cur_freq. That value matches the Z clock.
   Interestingly, cpuinfo_cur_freq is lower than cpuinfo_min_freq?
   /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq:200000
   /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq:1500000
   /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq:500000

3. After switching back to the performance governor, scaling_cur_freq reports
   1.5 GHz again.
   But cpuinfo_cur_freq is still only 700 MHz, just like z/clk_rate.

Do you know what's wrong?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 0/6] clk: renesas: r8a779[56]: Add Z and Z2 clock support

[Simon Horman]

On Wed, Aug 23, 2017 at 05:20:55PM +0200, Geert Uytterhoeven wrote:
> Hi Simon,
> 
> On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
> <horms+renesas@verge.net.au> wrote:
> > this patch-set adds Z and Z2 clock support.
> >
> > These are dependencies for supporting CPUFreq. The remainder of that
> > work is being posted separately and can be found at:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git topic/rcar-gen3-cpufreq
> >
> > A description of steps taken to lightly exercise the same feature for the
> > r88a7795 the above can be found at the link below. The results are the same
> > for the r8a7796 with the exception that it has two active CPU cores rather
> > than four.
> >
> > http://elinux.org/Tests:R-CAR-GEN3-CPUFreq
> 
> Thanks for your patches, and the wiki page!
> 
> I gave it a try on R-Car H3 (ES1.0 and ES2.0) and M3-W (ES1.0), and the
> off-by-two factor of the Z clock frequency is gone.
> I couldn't test on R-Car H3 ES1.1. Probably it's OK, too (ES1.1 fixed the
> missing PLL0/2/4 post-divider in ES1.0).
> 
> 1. After boot-up, the CPU clock frequency is 1.5 GHz, and
>    /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq and
>    /sys/kernel/debug/clk/z/clk_rate agree. Good.
> 
> 2. After switching to the conservative governor, scaling_cur_freq reports
>    either a 500 MHz or 1 GHz clock rate.
>    But /sys/kernel/debug/clk/z/clk_rate disagrees: it reports either a 200
>    or 700 MHz clock rate.
> 
>    Ah, there's also cpuinfo_cur_freq. That value matches the Z clock.
>    Interestingly, cpuinfo_cur_freq is lower than cpuinfo_min_freq?
>    /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq:200000
>    /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq:1500000
>    /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq:500000
> 
> 3. After switching back to the performance governor, scaling_cur_freq reports
>    1.5 GHz again.
>    But cpuinfo_cur_freq is still only 700 MHz, just like z/clk_rate.
> 
> Do you know what's wrong?

Unfortunately not. I will look into this.

[PATCH v2 3/6] clk: renesas: r8a7795: Add Z clock

[Geert Uytterhoeven]

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Z clock for R8A7795 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
(queue up pending acceptance of patch 1/6)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 5/6] clk: renesas: r8a7796: Add Z clock

[Geert Uytterhoeven]

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Z clock for R8A7796 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
(queue up pending acceptance of patch 1/6)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 4/6] clk: renesas: r8a7795: Add Z2 clock

[Geert Uytterhoeven]

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Z2 clock for r8a7795 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
(queue up pending acceptance of patch 2/6)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 6/6] clk: renesas: r8a7796: Add Z2 clock

[Geert Uytterhoeven]

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Z2 clock for R8A7796 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
(queue up pending acceptance of patch 1/6)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 6/6] clk: renesas: r8a7796: Add Z2 clock

[Geert Uytterhoeven]

On Thu, Aug 24, 2017 at 1:50 PM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
> <horms+renesas@verge.net.au> wrote:
>> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>>
>> This patch adds Z2 clock for R8A7796 SoC.
>>
>> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> (queue up pending acceptance of patch 1/6)

2/6, of course.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 1/6] clk: renesas: rcar-gen3: Add Z clock divider support

[Geert Uytterhoeven]

Hi Simon,

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Z clock divider support for R-Car Gen3 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> [simon: divide parent by 2; use bitops macros]
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Thanks for this patch!

> --- a/drivers/clk/renesas/rcar-gen3-cpg.c
> +++ b/drivers/clk/renesas/rcar-gen3-cpg.c
> @@ -13,6 +13,7 @@
>   */
>
>  #include <linux/bug.h>
> +#include <linux/bitfield.h>
>  #include <linux/clk.h>
>  #include <linux/clk-provider.h>
>  #include <linux/device.h>
> @@ -29,6 +30,139 @@
>  #define CPG_PLL2CR             0x002c
>  #define CPG_PLL4CR             0x01f4
>
> +/* Z Clock

/*
 * Z Clock

> + *
> + * Traits of this clock:
> + * prepare - clk_prepare only ensures that parents are prepared
> + * enable - clk_enable only ensures that parents are enabled
> + * rate - rate is adjustable.  clk->rate = (parent->rate * mult / 32 ) / 2
> + * parent - fixed parent.  No clk_set_parent support
> + */
> +#define CPG_FRQCRB                     0x00000004
> +#define CPG_FRQCRB_KICK                        BIT(31)
> +#define CPG_FRQCRC                     0x000000e0
> +#define CPG_FRQCRC_ZFC_MASK            GENMASK(12, 8)
> +
> +struct cpg_z_clk {
> +       struct clk_hw hw;
> +       void __iomem *reg;
> +       void __iomem *kick_reg;
> +};
> +
> +#define to_z_clk(_hw)  container_of(_hw, struct cpg_z_clk, hw)
> +
> +static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
> +                                          unsigned long parent_rate)
> +{
> +       struct cpg_z_clk *zclk = to_z_clk(hw);
> +       unsigned long rate;
> +       unsigned int mult;
> +
> +       mult = 32 - FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg));
> +       /* There is a PLL post-divider of 1/2,

/*
 * There is a PLL post-divider of 1/2,

> +        * thus the doubling of the divisor below.
> +        */
> +       rate = div_u64((u64)parent_rate * mult + 16, 32 * 2);

DIV_ROUND_CLOSEST_ULL()

> +       /* Round to closest value at 100MHz unit */
> +       rate = 100000000 * DIV_ROUND_CLOSEST(rate, 100000000);

Why?

With this rounding, we can no longer distinguish between e.g.
1218750000 and 1265625000 Hz.

> +
> +       return rate;
> +}
> +
> +static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> +                                unsigned long *parent_rate)
> +{
> +       unsigned long prate = *parent_rate;
> +       unsigned int mult;
> +
> +       if (!prate)
> +               prate = 1;

Can this really happen?

> +
> +       mult = div_u64((u64)rate * 32 + prate/2, prate);

mult = DIV_ROUND_CLOSEST_ULL(rate * 32ULL, prate);

> +       mult = clamp(mult, 1U, 32U);
> +
> +       return *parent_rate / 32 * mult;

To avoid losing precision, you should do the multiplication first, using
64-bit math.

> +}
> +
> +static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> +                             unsigned long parent_rate)
> +{
> +       struct cpg_z_clk *zclk = to_z_clk(hw);
> +       unsigned int mult;
> +       unsigned int i;
> +       u32 val, kick;
> +
> +       mult = div_u64((u64)rate * 32 + parent_rate/2, parent_rate);

DIV_ROUND_CLOSEST_ULL()

> +       /*
> +        * Note: There is no HW information about the worst case latency.
> +        *
> +        * Using experimental measurements, it seems that no more than
> +        * ~10 iterations are needed, independently of the CPU rate.
> +        * Since this value might be dependent of external xtal rate, pll1
> +        * rate or even the other emulation clocks rate, use 1000 as a

another emulated clock rate?
(Yeah, copied from Gen2 ;-)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH v2 2/6] clk: renesas: rcar-gen3: Add Z2 clock divider support

[Geert Uytterhoeven]

Hi Simon,

On Mon, Aug 21, 2017 at 3:01 PM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Z2 clock divider support for R-Car Gen3 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> [simon: add recalc_rate() helper; use bitops macros]
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Thanks for this patch!

> --- a/drivers/clk/renesas/rcar-gen3-cpg.c
> +++ b/drivers/clk/renesas/rcar-gen3-cpg.c

> @@ -69,6 +69,26 @@ static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
>         return rate;
>  }
>
> +static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
> +                                          unsigned long parent_rate)
> +{
> +       struct cpg_z_clk *zclk = to_z_clk(hw);
> +       unsigned int val;
> +
> +       val = FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg));
> +       return __cpg_z_clk_recalc_rate(parent_rate, val);
> +}
> +
> +static unsigned long cpg_z2_clk_recalc_rate(struct clk_hw *hw,
> +                                          unsigned long parent_rate)
> +{
> +       struct cpg_z_clk *zclk = to_z_clk(hw);
> +       unsigned int val;
> +
> +       val = FIELD_GET(CPG_FRQCRC_Z2FC_MASK, clk_readl(zclk->reg));
> +       return __cpg_z_clk_recalc_rate(parent_rate, val);
> +}
> +
>  static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate,
>                                  unsigned long *parent_rate)
>  {
> @@ -129,12 +149,25 @@ static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
>         return -ETIMEDOUT;
>  }
>
> +static int cpg_z2_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> +                             unsigned long parent_rate)
> +{
> +       pr_info("Do not support Z2 clock changing\n");

Oops?
This can be handled like the Z clock, can't it?
If not, please ignore some of my comments below.

> +       return 0;
> +}
> +
>  static const struct clk_ops cpg_z_clk_ops = {
>         .recalc_rate = cpg_z_clk_recalc_rate,
>         .round_rate = cpg_z_clk_round_rate,
>         .set_rate = cpg_z_clk_set_rate,
>  };
>
> +static const struct clk_ops cpg_z2_clk_ops = {
> +       .recalc_rate = cpg_z2_clk_recalc_rate,
> +       .round_rate = cpg_z_clk_round_rate,
> +       .set_rate = cpg_z2_clk_set_rate,
> +};

Apart from the field mask, above ops are identical.
What about storing the field mask in struct cpg_z_clk instead, so the ops
can be unified?
They can even be reused for the ZR (Cortex-R7) clock, which uses yet
another field mask in the same register.

The field mask can be obtained from the r8a7795_core_clks[] table,
cfr. the offset for SD clocks used by DEF_GEN3_SD().
With a new DEF_GEN3_Z() macro, we can use a single CLK_TYPE_GEN3_Z
type for all 3 clocks.

> @@ -164,6 +197,35 @@ static struct clk * __init cpg_z_clk_register(const char *name,
>         return clk;
>  }
>
> +static struct clk * __init cpg_z2_clk_register(const char *name,
> +                                             const char *parent_name,
> +                                             void __iomem *reg)
> +{

> +       init.ops = &cpg_z2_clk_ops;

This is the only difference in this function, compared to cpg_z_clk_register()
(assumed you pass the field mask to this function).

> +       zclk->reg = reg + CPG_FRQCRC;
> +       zclk->kick_reg = reg + CPG_FRQCRB;

Given the same registers are used for Z and Z2 (and ZR), what about just
storing the base address (reg) here?
And the field mask, of course.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds