Re: [PATCH 1/5] clk: Ingenic: Adjust code to make it compatible with X1830.

From: Paul Cercueil
Date: Fri Nov 29 2019 - 06:23:56 EST

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In reply to: Zhou Yanjie: "Re: [PATCH 1/5] clk: Ingenic: Adjust code to make it compatible with X1830."
Next in thread: Zhou Yanjie: "[PATCH 2/5] dt-bindings: clock: Add X1830 bindings."
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Hi Zhou,

Le mer., nov. 27, 2019 at 11:32, Zhou Yanjie <zhouyanjie@xxxxxxxx> a écrit :
1.Adjust the PLL related code in "cgu.c" and "cgu.h" to make it
compatible with the X1830 Soc from Ingenic.
2.Adjust the code in "jz4740-cgu.c" to be compatible with the
new cgu code.
3.Adjust the code in "jz4725b-cgu.c" to be compatible with the
new cgu code.
4.Adjust the code in "jz4770-cgu.c" to be compatible with the
new cgu code.
5.Adjust the code in "jz4780-cgu.c" to be compatible with the
new cgu code.
6.Adjust the code in "x1000-cgu.c" to be compatible with the
new cgu code.

Signed-off-by: Zhou Yanjie <zhouyanjie@xxxxxxxx>
---
drivers/clk/ingenic/cgu.c | 55 +++++++++++++++++++++++++++++----------
drivers/clk/ingenic/cgu.h | 12 ++++++++-
drivers/clk/ingenic/jz4725b-cgu.c | 3 ++-
drivers/clk/ingenic/jz4740-cgu.c | 3 ++-
drivers/clk/ingenic/jz4770-cgu.c | 6 +++--
drivers/clk/ingenic/jz4780-cgu.c | 3 ++-
drivers/clk/ingenic/x1000-cgu.c | 6 +++--
7 files changed, 66 insertions(+), 22 deletions(-)

diff --git a/drivers/clk/ingenic/cgu.c b/drivers/clk/ingenic/cgu.c
index 6e96303..c3c69a8 100644
--- a/drivers/clk/ingenic/cgu.c
+++ b/drivers/clk/ingenic/cgu.c
@@ -84,7 +84,7 @@ ingenic_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
pll_info = &clk_info->pll;

spin_lock_irqsave(&cgu->lock, flags);
- ctl = readl(cgu->base + pll_info->reg);
+ ctl = readl(cgu->base + pll_info->reg[1]);

I really don't like this patch. There is no info on what reg[1] and reg[0] are. First, don't use hardcoded numbers, use macros with meaningful names. Second, why not just have two fields instead of one 2-values array? That would remove a lot of the noise.

Because the X1830's PLL has been greatly changed, the bypass control is
placed in another register, so now two registers may needed to control the
PLL.

That kind of info belongs in the commit message.

If two fields are used, all the PLL related code of jz47xx-cgu.c / x1000-cgu.c
will be more verbose. Using array methods such as:
.reg = { -1, CGU_REG_CPPCR0 },
in jz4770-cgu.c,

or :
.reg = { CGU_REG_CPPCR, CGU_REG_APLL },
in x1830-cgu.c,

can let us intuitively see that how many control registers the PLL has.
Maybe adding a corresponding comment to reg[0] and reg[1] is a better way?

I don't see how having two fields would make the code more verbose. From what I can see it would make this patch much smaller...

spin_unlock_irqrestore(&cgu->lock, flags);

m = (ctl >> pll_info->m_shift) & GENMASK(pll_info->m_bits - 1, 0);
@@ -93,8 +93,17 @@ ingenic_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
n += pll_info->n_offset;
od_enc = ctl >> pll_info->od_shift;
od_enc &= GENMASK(pll_info->od_bits - 1, 0);
- bypass = !pll_info->no_bypass_bit &&
- !!(ctl & BIT(pll_info->bypass_bit));
+
+ if (pll_info->version >= CGU_X1830) {
+ spin_lock_irqsave(&cgu->lock, flags);
+ ctl = readl(cgu->base + pll_info->reg[0]);
+ spin_unlock_irqrestore(&cgu->lock, flags);

Why the spinlock?

The original code used spinlock when reading the control register,
so when reading this new control register, I think it should also
be added with spinlock.

Well, the original code looks wrong to me. There's nothing to protect here.

Maybe @Paul Burton can shed some light?

+
+ bypass = !pll_info->no_bypass_bit &&
+ !!(ctl & BIT(pll_info->bypass_bit));
+ } else

Please comply to the kernel coding style - use brackets after the else.

My fault, I will fix this in v2.

+ bypass = !pll_info->no_bypass_bit &&
+ !!(ctl & BIT(pll_info->bypass_bit));

if (bypass)
return parent_rate;
@@ -106,7 +115,10 @@ ingenic_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
BUG_ON(od == pll_info->od_max);
od++;

- return div_u64((u64)parent_rate * m, n * od);
+ if (pll_info->version >= CGU_X1830)
+ return div_u64((u64)parent_rate * m * 2, n * od);

Where does that *2 come from?

This is because the calculation method of the PLL frequency multiplication
of X1830 has changed, and a factor of 2 is added compared to the original
method (on page 381 of the X1830's PM manual).

Instead of adding a pll_info->version, add a pll_info->rate_multiplier, set it to 1 everywhere and 2 on the X1830.

Cheers,
-Paul

+ else
+ return div_u64((u64)parent_rate * m, n * od);
}

static unsigned long
@@ -139,7 +151,10 @@ ingenic_pll_calc(const struct ingenic_cgu_clk_info *clk_info,
if (pod)
*pod = od;

- return div_u64((u64)parent_rate * m, n * od);
+ if (pll_info->version >= CGU_X1830)
+ return div_u64((u64)parent_rate * m * 2, n * od);
+ else
+ return div_u64((u64)parent_rate * m, n * od);
}

static inline const struct ingenic_cgu_clk_info *to_clk_info(
@@ -183,7 +198,7 @@ ingenic_pll_set_rate(struct clk_hw *hw, unsigned long req_rate,
clk_info->name, req_rate, rate);

spin_lock_irqsave(&cgu->lock, flags);
- ctl = readl(cgu->base + pll_info->reg);
+ ctl = readl(cgu->base + pll_info->reg[1]);

ctl &= ~(GENMASK(pll_info->m_bits - 1, 0) << pll_info->m_shift);
ctl |= (m - pll_info->m_offset) << pll_info->m_shift;
@@ -194,7 +209,7 @@ ingenic_pll_set_rate(struct clk_hw *hw, unsigned long req_rate,
ctl &= ~(GENMASK(pll_info->od_bits - 1, 0) << pll_info->od_shift);
ctl |= pll_info->od_encoding[od - 1] << pll_info->od_shift;

- writel(ctl, cgu->base + pll_info->reg);
+ writel(ctl, cgu->base + pll_info->reg[1]);
spin_unlock_irqrestore(&cgu->lock, flags);

return 0;
@@ -212,16 +227,28 @@ static int ingenic_pll_enable(struct clk_hw *hw)
u32 ctl;

spin_lock_irqsave(&cgu->lock, flags);
- ctl = readl(cgu->base + pll_info->reg);

- ctl &= ~BIT(pll_info->bypass_bit);
+ if (pll_info->version >= CGU_X1830) {
+ ctl = readl(cgu->base + pll_info->reg[0]);
+
+ ctl &= ~BIT(pll_info->bypass_bit);
+
+ writel(ctl, cgu->base + pll_info->reg[0]);
+
+ ctl = readl(cgu->base + pll_info->reg[1]);
+ } else {
+ ctl = readl(cgu->base + pll_info->reg[1]);
+
+ ctl &= ~BIT(pll_info->bypass_bit);
+ }
+
ctl |= BIT(pll_info->enable_bit);

- writel(ctl, cgu->base + pll_info->reg);
+ writel(ctl, cgu->base + pll_info->reg[1]);

/* wait for the PLL to stabilise */
for (i = 0; i < timeout; i++) {
- ctl = readl(cgu->base + pll_info->reg);
+ ctl = readl(cgu->base + pll_info->reg[1]);
if (ctl & BIT(pll_info->stable_bit))
break;
mdelay(1);
@@ -245,11 +272,11 @@ static void ingenic_pll_disable(struct clk_hw *hw)
u32 ctl;

spin_lock_irqsave(&cgu->lock, flags);
- ctl = readl(cgu->base + pll_info->reg);
+ ctl = readl(cgu->base + pll_info->reg[1]);

ctl &= ~BIT(pll_info->enable_bit);

- writel(ctl, cgu->base + pll_info->reg);
+ writel(ctl, cgu->base + pll_info->reg[1]);
spin_unlock_irqrestore(&cgu->lock, flags);
}

@@ -263,7 +290,7 @@ static int ingenic_pll_is_enabled(struct clk_hw *hw)
u32 ctl;

spin_lock_irqsave(&cgu->lock, flags);
- ctl = readl(cgu->base + pll_info->reg);
+ ctl = readl(cgu->base + pll_info->reg[1]);
spin_unlock_irqrestore(&cgu->lock, flags);

return !!(ctl & BIT(pll_info->enable_bit));
diff --git a/drivers/clk/ingenic/cgu.h b/drivers/clk/ingenic/cgu.h
index 0dc8004..5f87be4 100644
--- a/drivers/clk/ingenic/cgu.h
+++ b/drivers/clk/ingenic/cgu.h
@@ -42,8 +42,18 @@
* @stable_bit: the index of the stable bit in the PLL control register
* @no_bypass_bit: if set, the PLL has no bypass functionality
*/
+enum ingenic_cgu_version {
+ CGU_JZ4740,
+ CGU_JZ4725B,
+ CGU_JZ4770,
+ CGU_JZ4780,
+ CGU_X1000,
+ CGU_X1830,
+};
+
struct ingenic_cgu_pll_info {
- unsigned reg;
+ enum ingenic_cgu_version version;
+ unsigned reg[2];
const s8 *od_encoding;
u8 m_shift, m_bits, m_offset;
u8 n_shift, n_bits, n_offset;
diff --git a/drivers/clk/ingenic/jz4725b-cgu.c b/drivers/clk/ingenic/jz4725b-cgu.c
index a3b4635..6da7b41 100644
--- a/drivers/clk/ingenic/jz4725b-cgu.c
+++ b/drivers/clk/ingenic/jz4725b-cgu.c
@@ -53,7 +53,8 @@ static const struct ingenic_cgu_clk_info jz4725b_cgu_clocks[] = {
"pll", CGU_CLK_PLL,
.parents = { JZ4725B_CLK_EXT, -1, -1, -1 },
.pll = {
- .reg = CGU_REG_CPPCR,
+ .version = CGU_JZ4725B,
+ .reg = { -1, CGU_REG_CPPCR },
.m_shift = 23,
.m_bits = 9,
.m_offset = 2,
diff --git a/drivers/clk/ingenic/jz4740-cgu.c b/drivers/clk/ingenic/jz4740-cgu.c
index 4f0e92c..3cf800d 100644
--- a/drivers/clk/ingenic/jz4740-cgu.c
+++ b/drivers/clk/ingenic/jz4740-cgu.c
@@ -68,7 +68,8 @@ static const struct ingenic_cgu_clk_info jz4740_cgu_clocks[] = {
"pll", CGU_CLK_PLL,
.parents = { JZ4740_CLK_EXT, -1, -1, -1 },
.pll = {
- .reg = CGU_REG_CPPCR,
+ .version = CGU_JZ4740,
+ .reg = { -1, CGU_REG_CPPCR },
.m_shift = 23,
.m_bits = 9,
.m_offset = 2,
diff --git a/drivers/clk/ingenic/jz4770-cgu.c b/drivers/clk/ingenic/jz4770-cgu.c
index 956dd65..a62dfb1 100644
--- a/drivers/clk/ingenic/jz4770-cgu.c
+++ b/drivers/clk/ingenic/jz4770-cgu.c
@@ -101,7 +101,8 @@ static const struct ingenic_cgu_clk_info jz4770_cgu_clocks[] = {
"pll0", CGU_CLK_PLL,
.parents = { JZ4770_CLK_EXT },
.pll = {
- .reg = CGU_REG_CPPCR0,
+ .version = CGU_JZ4770,
+ .reg = { -1, CGU_REG_CPPCR0 },
.m_shift = 24,
.m_bits = 7,
.m_offset = 1,
@@ -123,7 +124,8 @@ static const struct ingenic_cgu_clk_info jz4770_cgu_clocks[] = {
"pll1", CGU_CLK_PLL,
.parents = { JZ4770_CLK_EXT },
.pll = {
- .reg = CGU_REG_CPPCR1,
+ .version = CGU_JZ4770,
+ .reg = { -1, CGU_REG_CPPCR1 },
.m_shift = 24,
.m_bits = 7,
.m_offset = 1,
diff --git a/drivers/clk/ingenic/jz4780-cgu.c b/drivers/clk/ingenic/jz4780-cgu.c
index ea905ff..59356d1b 100644
--- a/drivers/clk/ingenic/jz4780-cgu.c
+++ b/drivers/clk/ingenic/jz4780-cgu.c
@@ -220,7 +220,8 @@ static const struct ingenic_cgu_clk_info jz4780_cgu_clocks[] = {
/* PLLs */

#define DEF_PLL(name) { \
- .reg = CGU_REG_ ## name, \
+ .version = CGU_JZ4780, \
+ .reg = { -1, CGU_REG_ ## name }, \
.m_shift = 19, \
.m_bits = 13, \
.m_offset = 1, \
diff --git a/drivers/clk/ingenic/x1000-cgu.c b/drivers/clk/ingenic/x1000-cgu.c
index b22d87b..7179b9f 100644
--- a/drivers/clk/ingenic/x1000-cgu.c
+++ b/drivers/clk/ingenic/x1000-cgu.c
@@ -57,7 +57,8 @@ static const struct ingenic_cgu_clk_info x1000_cgu_clocks[] = {
"apll", CGU_CLK_PLL,
.parents = { X1000_CLK_EXCLK, -1, -1, -1 },
.pll = {
- .reg = CGU_REG_APLL,
+ .version = CGU_X1000,
+ .reg = { -1, CGU_REG_APLL },
.m_shift = 24,
.m_bits = 7,
.m_offset = 1,
@@ -78,7 +79,8 @@ static const struct ingenic_cgu_clk_info x1000_cgu_clocks[] = {
"mpll", CGU_CLK_PLL,
.parents = { X1000_CLK_EXCLK, -1, -1, -1 },
.pll = {
- .reg = CGU_REG_MPLL,
+ .version = CGU_X1000,
+ .reg = { -1, CGU_REG_MPLL },
.m_shift = 24,
.m_bits = 7,
.m_offset = 1,
--
2.7.4

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In reply to: Zhou Yanjie: "Re: [PATCH 1/5] clk: Ingenic: Adjust code to make it compatible with X1830."
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