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Subject[PATCH v2 1/2] clk: tegra: Don't enable already enabled PLLs
Date
Initially Common Clock Framework isn't aware of the clock-enable status,
this results in enabling of clocks that were enabled by bootloader. This
is not a big deal for a regular clock-gates, but for PLL's it may have
some unpleasant consequences. Thus re-enabling PLLX (the main CPU parent
clock) may result in extra long period of PLL re-locking.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---

Changelog:

v2: No change.

drivers/clk/tegra/clk-pll.c | 50 +++++++++++++++++++++++++++----------
1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
index 830d1c87fa7c..ddb431247f08 100644
--- a/drivers/clk/tegra/clk-pll.c
+++ b/drivers/clk/tegra/clk-pll.c
@@ -444,6 +444,9 @@ static int clk_pll_enable(struct clk_hw *hw)
unsigned long flags = 0;
int ret;

+ if (clk_pll_is_enabled(hw))
+ return 0;
+
if (pll->lock)
spin_lock_irqsave(pll->lock, flags);

@@ -939,11 +942,16 @@ static int clk_plle_training(struct tegra_clk_pll *pll)
static int clk_plle_enable(struct clk_hw *hw)
{
struct tegra_clk_pll *pll = to_clk_pll(hw);
- unsigned long input_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
struct tegra_clk_pll_freq_table sel;
+ unsigned long input_rate;
u32 val;
int err;

+ if (clk_pll_is_enabled(hw))
+ return 0;
+
+ input_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
+
if (_get_table_rate(hw, &sel, pll->params->fixed_rate, input_rate))
return -EINVAL;

@@ -1354,6 +1362,9 @@ static int clk_pllc_enable(struct clk_hw *hw)
int ret;
unsigned long flags = 0;

+ if (clk_pll_is_enabled(hw))
+ return 0;
+
if (pll->lock)
spin_lock_irqsave(pll->lock, flags);

@@ -1566,7 +1577,12 @@ static int clk_plle_tegra114_enable(struct clk_hw *hw)
u32 val;
int ret;
unsigned long flags = 0;
- unsigned long input_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
+ unsigned long input_rate;
+
+ if (clk_pll_is_enabled(hw))
+ return 0;
+
+ input_rate = clk_hw_get_rate(clk_hw_get_parent(hw));

if (_get_table_rate(hw, &sel, pll->params->fixed_rate, input_rate))
return -EINVAL;
@@ -1703,6 +1719,9 @@ static int clk_pllu_tegra114_enable(struct clk_hw *hw)
return -EINVAL;
}

+ if (clk_pll_is_enabled(hw))
+ return 0;
+
input_rate = clk_hw_get_rate(__clk_get_hw(osc));

if (pll->lock)
@@ -2378,6 +2397,16 @@ struct clk *tegra_clk_register_pllre_tegra210(const char *name,
return clk;
}

+static int clk_plle_tegra210_is_enabled(struct clk_hw *hw)
+{
+ struct tegra_clk_pll *pll = to_clk_pll(hw);
+ u32 val;
+
+ val = pll_readl_base(pll);
+
+ return val & PLLE_BASE_ENABLE ? 1 : 0;
+}
+
static int clk_plle_tegra210_enable(struct clk_hw *hw)
{
struct tegra_clk_pll *pll = to_clk_pll(hw);
@@ -2385,7 +2414,12 @@ static int clk_plle_tegra210_enable(struct clk_hw *hw)
u32 val;
int ret = 0;
unsigned long flags = 0;
- unsigned long input_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
+ unsigned long input_rate;
+
+ if (clk_plle_tegra210_is_enabled(hw))
+ return 0;
+
+ input_rate = clk_hw_get_rate(clk_hw_get_parent(hw));

if (_get_table_rate(hw, &sel, pll->params->fixed_rate, input_rate))
return -EINVAL;
@@ -2496,16 +2530,6 @@ static void clk_plle_tegra210_disable(struct clk_hw *hw)
spin_unlock_irqrestore(pll->lock, flags);
}

-static int clk_plle_tegra210_is_enabled(struct clk_hw *hw)
-{
- struct tegra_clk_pll *pll = to_clk_pll(hw);
- u32 val;
-
- val = pll_readl_base(pll);
-
- return val & PLLE_BASE_ENABLE ? 1 : 0;
-}
-
static const struct clk_ops tegra_clk_plle_tegra210_ops = {
.is_enabled = clk_plle_tegra210_is_enabled,
.enable = clk_plle_tegra210_enable,
--
2.18.0
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