diff options
Diffstat (limited to 'drivers/clk/bcm/clk-kona.c')
| -rw-r--r-- | drivers/clk/bcm/clk-kona.c | 266 |
1 files changed, 256 insertions, 10 deletions
diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c index db11a87449f..95af2e665dd 100644 --- a/drivers/clk/bcm/clk-kona.c +++ b/drivers/clk/bcm/clk-kona.c @@ -16,6 +16,14 @@ #include <linux/delay.h> +/* + * "Policies" affect the frequencies of bus clocks provided by a + * CCU. (I believe these polices are named "Deep Sleep", "Economy", + * "Normal", and "Turbo".) A lower policy number has lower power + * consumption, and policy 2 is the default. + */ +#define CCU_POLICY_COUNT 4 + #define CCU_ACCESS_PASSWORD 0xA5A500 #define CLK_GATE_DELAY_LOOP 2000 @@ -207,9 +215,154 @@ __ccu_wait_bit(struct ccu_data *ccu, u32 reg_offset, u32 bit, bool want) return true; udelay(1); } + pr_warn("%s: %s/0x%04x bit %u was never %s\n", __func__, + ccu->name, reg_offset, bit, want ? "set" : "clear"); + return false; } +/* Policy operations */ + +static bool __ccu_policy_engine_start(struct ccu_data *ccu, bool sync) +{ + struct bcm_policy_ctl *control = &ccu->policy.control; + u32 offset; + u32 go_bit; + u32 mask; + bool ret; + + /* If we don't need to control policy for this CCU, we're done. */ + if (!policy_ctl_exists(control)) + return true; + + offset = control->offset; + go_bit = control->go_bit; + + /* Ensure we're not busy before we start */ + ret = __ccu_wait_bit(ccu, offset, go_bit, false); + if (!ret) { + pr_err("%s: ccu %s policy engine wouldn't go idle\n", + __func__, ccu->name); + return false; + } + + /* + * If it's a synchronous request, we'll wait for the voltage + * and frequency of the active load to stabilize before + * returning. To do this we select the active load by + * setting the ATL bit. + * + * An asynchronous request instead ramps the voltage in the + * background, and when that process stabilizes, the target + * load is copied to the active load and the CCU frequency + * is switched. We do this by selecting the target load + * (ATL bit clear) and setting the request auto-copy (AC bit + * set). + * + * Note, we do NOT read-modify-write this register. + */ + mask = (u32)1 << go_bit; + if (sync) + mask |= 1 << control->atl_bit; + else + mask |= 1 << control->ac_bit; + __ccu_write(ccu, offset, mask); + + /* Wait for indication that operation is complete. */ + ret = __ccu_wait_bit(ccu, offset, go_bit, false); + if (!ret) + pr_err("%s: ccu %s policy engine never started\n", + __func__, ccu->name); + + return ret; +} + +static bool __ccu_policy_engine_stop(struct ccu_data *ccu) +{ + struct bcm_lvm_en *enable = &ccu->policy.enable; + u32 offset; + u32 enable_bit; + bool ret; + + /* If we don't need to control policy for this CCU, we're done. */ + if (!policy_lvm_en_exists(enable)) + return true; + + /* Ensure we're not busy before we start */ + offset = enable->offset; + enable_bit = enable->bit; + ret = __ccu_wait_bit(ccu, offset, enable_bit, false); + if (!ret) { + pr_err("%s: ccu %s policy engine already stopped\n", + __func__, ccu->name); + return false; + } + + /* Now set the bit to stop the engine (NO read-modify-write) */ + __ccu_write(ccu, offset, (u32)1 << enable_bit); + + /* Wait for indication that it has stopped. */ + ret = __ccu_wait_bit(ccu, offset, enable_bit, false); + if (!ret) + pr_err("%s: ccu %s policy engine never stopped\n", + __func__, ccu->name); + + return ret; +} + +/* + * A CCU has four operating conditions ("policies"), and some clocks + * can be disabled or enabled based on which policy is currently in + * effect. Such clocks have a bit in a "policy mask" register for + * each policy indicating whether the clock is enabled for that + * policy or not. The bit position for a clock is the same for all + * four registers, and the 32-bit registers are at consecutive + * addresses. + */ +static bool policy_init(struct ccu_data *ccu, struct bcm_clk_policy *policy) +{ + u32 offset; + u32 mask; + int i; + bool ret; + + if (!policy_exists(policy)) + return true; + + /* + * We need to stop the CCU policy engine to allow update + * of our policy bits. + */ + if (!__ccu_policy_engine_stop(ccu)) { + pr_err("%s: unable to stop CCU %s policy engine\n", + __func__, ccu->name); + return false; + } + + /* + * For now, if a clock defines its policy bit we just mark + * it "enabled" for all four policies. + */ + offset = policy->offset; + mask = (u32)1 << policy->bit; + for (i = 0; i < CCU_POLICY_COUNT; i++) { + u32 reg_val; + + reg_val = __ccu_read(ccu, offset); + reg_val |= mask; + __ccu_write(ccu, offset, reg_val); + offset += sizeof(u32); + } + + /* We're done updating; fire up the policy engine again. */ + ret = __ccu_policy_engine_start(ccu, true); + if (!ret) + pr_err("%s: unable to restart CCU %s policy engine\n", + __func__, ccu->name); + + return ret; +} + /* Gate operations */ /* Determine whether a clock is gated. CCU lock must be held. */ @@ -374,6 +527,35 @@ static int clk_gate(struct ccu_data *ccu, const char *name, return -EIO; } +/* Hysteresis operations */ + +/* + * If a clock gate requires a turn-off delay it will have + * "hysteresis" register bits defined. The first, if set, enables + * the delay; and if enabled, the second bit determines whether the + * delay is "low" or "high" (1 means high). For now, if it's + * defined for a clock, we set it. + */ +static bool hyst_init(struct ccu_data *ccu, struct bcm_clk_hyst *hyst) +{ + u32 offset; + u32 reg_val; + u32 mask; + + if (!hyst_exists(hyst)) + return true; + + offset = hyst->offset; + mask = (u32)1 << hyst->en_bit; + mask |= (u32)1 << hyst->val_bit; + + reg_val = __ccu_read(ccu, offset); + reg_val |= mask; + __ccu_write(ccu, offset, reg_val); + + return true; +} + /* Trigger operations */ /* @@ -806,7 +988,7 @@ static int kona_peri_clk_enable(struct clk_hw *hw) struct kona_clk *bcm_clk = to_kona_clk(hw); struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate; - return clk_gate(bcm_clk->ccu, bcm_clk->name, gate, true); + return clk_gate(bcm_clk->ccu, bcm_clk->init_data.name, gate, true); } static void kona_peri_clk_disable(struct clk_hw *hw) @@ -814,7 +996,7 @@ static void kona_peri_clk_disable(struct clk_hw *hw) struct kona_clk *bcm_clk = to_kona_clk(hw); struct bcm_clk_gate *gate = &bcm_clk->u.peri->gate; - (void)clk_gate(bcm_clk->ccu, bcm_clk->name, gate, false); + (void)clk_gate(bcm_clk->ccu, bcm_clk->init_data.name, gate, false); } static int kona_peri_clk_is_enabled(struct clk_hw *hw) @@ -849,6 +1031,58 @@ static long kona_peri_clk_round_rate(struct clk_hw *hw, unsigned long rate, rate ? rate : 1, *parent_rate, NULL); } +static long kona_peri_clk_determine_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, struct clk **best_parent) +{ + struct kona_clk *bcm_clk = to_kona_clk(hw); + struct clk *clk = hw->clk; + struct clk *current_parent; + unsigned long parent_rate; + unsigned long best_delta; + unsigned long best_rate; + u32 parent_count; + u32 which; + + /* + * If there is no other parent to choose, use the current one. + * Note: We don't honor (or use) CLK_SET_RATE_NO_REPARENT. + */ + WARN_ON_ONCE(bcm_clk->init_data.flags & CLK_SET_RATE_NO_REPARENT); + parent_count = (u32)bcm_clk->init_data.num_parents; + if (parent_count < 2) + return kona_peri_clk_round_rate(hw, rate, best_parent_rate); + + /* Unless we can do better, stick with current parent */ + current_parent = clk_get_parent(clk); + parent_rate = __clk_get_rate(current_parent); + best_rate = kona_peri_clk_round_rate(hw, rate, &parent_rate); + best_delta = abs(best_rate - rate); + + /* Check whether any other parent clock can produce a better result */ + for (which = 0; which < parent_count; which++) { + struct clk *parent = clk_get_parent_by_index(clk, which); + unsigned long delta; + unsigned long other_rate; + + BUG_ON(!parent); + if (parent == current_parent) + continue; + + /* We don't support CLK_SET_RATE_PARENT */ + parent_rate = __clk_get_rate(parent); + other_rate = kona_peri_clk_round_rate(hw, rate, &parent_rate); + delta = abs(other_rate - rate); + if (delta < best_delta) { + best_delta = delta; + best_rate = other_rate; + *best_parent = parent; + *best_parent_rate = parent_rate; + } + } + + return best_rate; +} + static int kona_peri_clk_set_parent(struct clk_hw *hw, u8 index) { struct kona_clk *bcm_clk = to_kona_clk(hw); @@ -872,12 +1106,13 @@ static int kona_peri_clk_set_parent(struct clk_hw *hw, u8 index) ret = selector_write(bcm_clk->ccu, &data->gate, sel, trig, index); if (ret == -ENXIO) { - pr_err("%s: gating failure for %s\n", __func__, bcm_clk->name); + pr_err("%s: gating failure for %s\n", __func__, + bcm_clk->init_data.name); ret = -EIO; /* Don't proliferate weird errors */ } else if (ret == -EIO) { pr_err("%s: %strigger failed for %s\n", __func__, trig == &data->pre_trig ? "pre-" : "", - bcm_clk->name); + bcm_clk->init_data.name); } return ret; @@ -936,10 +1171,12 @@ static int kona_peri_clk_set_rate(struct clk_hw *hw, unsigned long rate, ret = divider_write(bcm_clk->ccu, &data->gate, &data->div, &data->trig, scaled_div); if (ret == -ENXIO) { - pr_err("%s: gating failure for %s\n", __func__, bcm_clk->name); + pr_err("%s: gating failure for %s\n", __func__, + bcm_clk->init_data.name); ret = -EIO; /* Don't proliferate weird errors */ } else if (ret == -EIO) { - pr_err("%s: trigger failed for %s\n", __func__, bcm_clk->name); + pr_err("%s: trigger failed for %s\n", __func__, + bcm_clk->init_data.name); } return ret; @@ -950,7 +1187,7 @@ struct clk_ops kona_peri_clk_ops = { .disable = kona_peri_clk_disable, .is_enabled = kona_peri_clk_is_enabled, .recalc_rate = kona_peri_clk_recalc_rate, - .round_rate = kona_peri_clk_round_rate, + .determine_rate = kona_peri_clk_determine_rate, .set_parent = kona_peri_clk_set_parent, .get_parent = kona_peri_clk_get_parent, .set_rate = kona_peri_clk_set_rate, @@ -961,15 +1198,24 @@ static bool __peri_clk_init(struct kona_clk *bcm_clk) { struct ccu_data *ccu = bcm_clk->ccu; struct peri_clk_data *peri = bcm_clk->u.peri; - const char *name = bcm_clk->name; + const char *name = bcm_clk->init_data.name; struct bcm_clk_trig *trig; BUG_ON(bcm_clk->type != bcm_clk_peri); + if (!policy_init(ccu, &peri->policy)) { + pr_err("%s: error initializing policy for %s\n", + __func__, name); + return false; + } if (!gate_init(ccu, &peri->gate)) { pr_err("%s: error initializing gate for %s\n", __func__, name); return false; } + if (!hyst_init(ccu, &peri->hyst)) { + pr_err("%s: error initializing hyst for %s\n", __func__, name); + return false; + } if (!div_init(ccu, &peri->gate, &peri->div, &peri->trig)) { pr_err("%s: error initializing divider for %s\n", __func__, name); @@ -1014,13 +1260,13 @@ bool __init kona_ccu_init(struct ccu_data *ccu) { unsigned long flags; unsigned int which; - struct clk **clks = ccu->data.clks; + struct clk **clks = ccu->clk_data.clks; bool success = true; flags = ccu_lock(ccu); __ccu_write_enable(ccu); - for (which = 0; which < ccu->data.clk_num; which++) { + for (which = 0; which < ccu->clk_data.clk_num; which++) { struct kona_clk *bcm_clk; if (!clks[which]) |