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-rw-r--r--drivers/clk/mvebu/armada-37xx-periph.c83
1 files changed, 45 insertions, 38 deletions
diff --git a/drivers/clk/mvebu/armada-37xx-periph.c b/drivers/clk/mvebu/armada-37xx-periph.c
index f5746f9ea929..32ac6b6b7530 100644
--- a/drivers/clk/mvebu/armada-37xx-periph.c
+++ b/drivers/clk/mvebu/armada-37xx-periph.c
@@ -84,6 +84,7 @@ struct clk_pm_cpu {
void __iomem *reg_div;
u8 shift_div;
struct regmap *nb_pm_base;
+ unsigned long l1_expiration;
};
#define to_clk_double_div(_hw) container_of(_hw, struct clk_double_div, hw)
@@ -440,33 +441,6 @@ static u8 clk_pm_cpu_get_parent(struct clk_hw *hw)
return val;
}
-static int clk_pm_cpu_set_parent(struct clk_hw *hw, u8 index)
-{
- struct clk_pm_cpu *pm_cpu = to_clk_pm_cpu(hw);
- struct regmap *base = pm_cpu->nb_pm_base;
- int load_level;
-
- /*
- * We set the clock parent only if the DVFS is available but
- * not enabled.
- */
- if (IS_ERR(base) || armada_3700_pm_dvfs_is_enabled(base))
- return -EINVAL;
-
- /* Set the parent clock for all the load level */
- for (load_level = 0; load_level < LOAD_LEVEL_NR; load_level++) {
- unsigned int reg, mask, val,
- offset = ARMADA_37XX_NB_TBG_SEL_OFF;
-
- armada_3700_pm_dvfs_update_regs(load_level, &reg, &offset);
-
- val = index << offset;
- mask = ARMADA_37XX_NB_TBG_SEL_MASK << offset;
- regmap_update_bits(base, reg, mask, val);
- }
- return 0;
-}
-
static unsigned long clk_pm_cpu_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
@@ -514,8 +488,10 @@ static long clk_pm_cpu_round_rate(struct clk_hw *hw, unsigned long rate,
}
/*
- * Switching the CPU from the L2 or L3 frequencies (300 and 200 Mhz
- * respectively) to L0 frequency (1.2 Ghz) requires a significant
+ * Workaround when base CPU frequnecy is 1000 or 1200 MHz
+ *
+ * Switching the CPU from the L2 or L3 frequencies (250/300 or 200 MHz
+ * respectively) to L0 frequency (1/1.2 GHz) requires a significant
* amount of time to let VDD stabilize to the appropriate
* voltage. This amount of time is large enough that it cannot be
* covered by the hardware countdown register. Due to this, the CPU
@@ -525,26 +501,56 @@ static long clk_pm_cpu_round_rate(struct clk_hw *hw, unsigned long rate,
* To work around this problem, we prevent switching directly from the
* L2/L3 frequencies to the L0 frequency, and instead switch to the L1
* frequency in-between. The sequence therefore becomes:
- * 1. First switch from L2/L3(200/300MHz) to L1(600MHZ)
+ * 1. First switch from L2/L3 (200/250/300 MHz) to L1 (500/600 MHz)
* 2. Sleep 20ms for stabling VDD voltage
- * 3. Then switch from L1(600MHZ) to L0(1200Mhz).
+ * 3. Then switch from L1 (500/600 MHz) to L0 (1000/1200 MHz).
*/
-static void clk_pm_cpu_set_rate_wa(unsigned long rate, struct regmap *base)
+static void clk_pm_cpu_set_rate_wa(struct clk_pm_cpu *pm_cpu,
+ unsigned int new_level, unsigned long rate,
+ struct regmap *base)
{
unsigned int cur_level;
- if (rate != 1200 * 1000 * 1000)
- return;
-
regmap_read(base, ARMADA_37XX_NB_CPU_LOAD, &cur_level);
cur_level &= ARMADA_37XX_NB_CPU_LOAD_MASK;
- if (cur_level <= ARMADA_37XX_DVFS_LOAD_1)
+
+ if (cur_level == new_level)
+ return;
+
+ /*
+ * System wants to go to L1 on its own. If we are going from L2/L3,
+ * remember when 20ms will expire. If from L0, set the value so that
+ * next switch to L0 won't have to wait.
+ */
+ if (new_level == ARMADA_37XX_DVFS_LOAD_1) {
+ if (cur_level == ARMADA_37XX_DVFS_LOAD_0)
+ pm_cpu->l1_expiration = jiffies;
+ else
+ pm_cpu->l1_expiration = jiffies + msecs_to_jiffies(20);
return;
+ }
+
+ /*
+ * If we are setting to L2/L3, just invalidate L1 expiration time,
+ * sleeping is not needed.
+ */
+ if (rate < 1000*1000*1000)
+ goto invalidate_l1_exp;
+
+ /*
+ * We are going to L0 with rate >= 1GHz. Check whether we have been at
+ * L1 for long enough time. If not, go to L1 for 20ms.
+ */
+ if (pm_cpu->l1_expiration && jiffies >= pm_cpu->l1_expiration)
+ goto invalidate_l1_exp;
regmap_update_bits(base, ARMADA_37XX_NB_CPU_LOAD,
ARMADA_37XX_NB_CPU_LOAD_MASK,
ARMADA_37XX_DVFS_LOAD_1);
msleep(20);
+
+invalidate_l1_exp:
+ pm_cpu->l1_expiration = 0;
}
static int clk_pm_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -578,7 +584,9 @@ static int clk_pm_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
reg = ARMADA_37XX_NB_CPU_LOAD;
mask = ARMADA_37XX_NB_CPU_LOAD_MASK;
- clk_pm_cpu_set_rate_wa(rate, base);
+ /* Apply workaround when base CPU frequency is 1000 or 1200 MHz */
+ if (parent_rate >= 1000*1000*1000)
+ clk_pm_cpu_set_rate_wa(pm_cpu, load_level, rate, base);
regmap_update_bits(base, reg, mask, load_level);
@@ -592,7 +600,6 @@ static int clk_pm_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
static const struct clk_ops clk_pm_cpu_ops = {
.get_parent = clk_pm_cpu_get_parent,
- .set_parent = clk_pm_cpu_set_parent,
.round_rate = clk_pm_cpu_round_rate,
.set_rate = clk_pm_cpu_set_rate,
.recalc_rate = clk_pm_cpu_recalc_rate,