diff options
Diffstat (limited to 'drivers/clk')
| -rw-r--r-- | drivers/clk/mvebu/armada-37xx-periph.c | 83 |
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, ®, &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, |