diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/clk/baikal-t1/ccu-pll.c | 558 |
1 files changed, 558 insertions, 0 deletions
diff --git a/drivers/clk/baikal-t1/ccu-pll.c b/drivers/clk/baikal-t1/ccu-pll.c new file mode 100644 index 000000000..13ef28001 --- /dev/null +++ b/drivers/clk/baikal-t1/ccu-pll.c @@ -0,0 +1,558 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC + * + * Authors: + * Serge Semin <Sergey.Semin@baikalelectronics.ru> + * Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru> + * + * Baikal-T1 CCU PLL interface driver + */ + +#define pr_fmt(fmt) "bt1-ccu-pll: " fmt + +#include <linux/kernel.h> +#include <linux/printk.h> +#include <linux/limits.h> +#include <linux/bits.h> +#include <linux/bitfield.h> +#include <linux/slab.h> +#include <linux/clk-provider.h> +#include <linux/of.h> +#include <linux/spinlock.h> +#include <linux/regmap.h> +#include <linux/iopoll.h> +#include <linux/time64.h> +#include <linux/rational.h> +#include <linux/debugfs.h> + +#include "ccu-pll.h" + +#define CCU_PLL_CTL 0x000 +#define CCU_PLL_CTL_EN BIT(0) +#define CCU_PLL_CTL_RST BIT(1) +#define CCU_PLL_CTL_CLKR_FLD 2 +#define CCU_PLL_CTL_CLKR_MASK GENMASK(7, CCU_PLL_CTL_CLKR_FLD) +#define CCU_PLL_CTL_CLKF_FLD 8 +#define CCU_PLL_CTL_CLKF_MASK GENMASK(20, CCU_PLL_CTL_CLKF_FLD) +#define CCU_PLL_CTL_CLKOD_FLD 21 +#define CCU_PLL_CTL_CLKOD_MASK GENMASK(24, CCU_PLL_CTL_CLKOD_FLD) +#define CCU_PLL_CTL_BYPASS BIT(30) +#define CCU_PLL_CTL_LOCK BIT(31) +#define CCU_PLL_CTL1 0x004 +#define CCU_PLL_CTL1_BWADJ_FLD 3 +#define CCU_PLL_CTL1_BWADJ_MASK GENMASK(14, CCU_PLL_CTL1_BWADJ_FLD) + +#define CCU_PLL_LOCK_CHECK_RETRIES 50 + +#define CCU_PLL_NR_MAX \ + ((CCU_PLL_CTL_CLKR_MASK >> CCU_PLL_CTL_CLKR_FLD) + 1) +#define CCU_PLL_NF_MAX \ + ((CCU_PLL_CTL_CLKF_MASK >> (CCU_PLL_CTL_CLKF_FLD + 1)) + 1) +#define CCU_PLL_OD_MAX \ + ((CCU_PLL_CTL_CLKOD_MASK >> CCU_PLL_CTL_CLKOD_FLD) + 1) +#define CCU_PLL_NB_MAX \ + ((CCU_PLL_CTL1_BWADJ_MASK >> CCU_PLL_CTL1_BWADJ_FLD) + 1) +#define CCU_PLL_FDIV_MIN 427000UL +#define CCU_PLL_FDIV_MAX 3500000000UL +#define CCU_PLL_FOUT_MIN 200000000UL +#define CCU_PLL_FOUT_MAX 2500000000UL +#define CCU_PLL_FVCO_MIN 700000000UL +#define CCU_PLL_FVCO_MAX 3500000000UL +#define CCU_PLL_CLKOD_FACTOR 2 + +static inline unsigned long ccu_pll_lock_delay_us(unsigned long ref_clk, + unsigned long nr) +{ + u64 us = 500ULL * nr * USEC_PER_SEC; + + do_div(us, ref_clk); + + return us; +} + +static inline unsigned long ccu_pll_calc_freq(unsigned long ref_clk, + unsigned long nr, + unsigned long nf, + unsigned long od) +{ + u64 tmp = ref_clk; + + do_div(tmp, nr); + tmp *= nf; + do_div(tmp, od); + + return tmp; +} + +static int ccu_pll_reset(struct ccu_pll *pll, unsigned long ref_clk, + unsigned long nr) +{ + unsigned long ud, ut; + u32 val; + + ud = ccu_pll_lock_delay_us(ref_clk, nr); + ut = ud * CCU_PLL_LOCK_CHECK_RETRIES; + + regmap_update_bits(pll->sys_regs, pll->reg_ctl, + CCU_PLL_CTL_RST, CCU_PLL_CTL_RST); + + return regmap_read_poll_timeout_atomic(pll->sys_regs, pll->reg_ctl, val, + val & CCU_PLL_CTL_LOCK, ud, ut); +} + +static int ccu_pll_enable(struct clk_hw *hw) +{ + struct clk_hw *parent_hw = clk_hw_get_parent(hw); + struct ccu_pll *pll = to_ccu_pll(hw); + unsigned long flags; + u32 val = 0; + int ret; + + if (!parent_hw) { + pr_err("Can't enable '%s' with no parent", clk_hw_get_name(hw)); + return -EINVAL; + } + + regmap_read(pll->sys_regs, pll->reg_ctl, &val); + if (val & CCU_PLL_CTL_EN) + return 0; + + spin_lock_irqsave(&pll->lock, flags); + regmap_write(pll->sys_regs, pll->reg_ctl, val | CCU_PLL_CTL_EN); + ret = ccu_pll_reset(pll, clk_hw_get_rate(parent_hw), + FIELD_GET(CCU_PLL_CTL_CLKR_MASK, val) + 1); + spin_unlock_irqrestore(&pll->lock, flags); + if (ret) + pr_err("PLL '%s' reset timed out\n", clk_hw_get_name(hw)); + + return ret; +} + +static void ccu_pll_disable(struct clk_hw *hw) +{ + struct ccu_pll *pll = to_ccu_pll(hw); + unsigned long flags; + + spin_lock_irqsave(&pll->lock, flags); + regmap_update_bits(pll->sys_regs, pll->reg_ctl, CCU_PLL_CTL_EN, 0); + spin_unlock_irqrestore(&pll->lock, flags); +} + +static int ccu_pll_is_enabled(struct clk_hw *hw) +{ + struct ccu_pll *pll = to_ccu_pll(hw); + u32 val = 0; + + regmap_read(pll->sys_regs, pll->reg_ctl, &val); + + return !!(val & CCU_PLL_CTL_EN); +} + +static unsigned long ccu_pll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct ccu_pll *pll = to_ccu_pll(hw); + unsigned long nr, nf, od; + u32 val = 0; + + regmap_read(pll->sys_regs, pll->reg_ctl, &val); + nr = FIELD_GET(CCU_PLL_CTL_CLKR_MASK, val) + 1; + nf = FIELD_GET(CCU_PLL_CTL_CLKF_MASK, val) + 1; + od = FIELD_GET(CCU_PLL_CTL_CLKOD_MASK, val) + 1; + + return ccu_pll_calc_freq(parent_rate, nr, nf, od); +} + +static void ccu_pll_calc_factors(unsigned long rate, unsigned long parent_rate, + unsigned long *nr, unsigned long *nf, + unsigned long *od) +{ + unsigned long err, freq, min_err = ULONG_MAX; + unsigned long num, denom, n1, d1, nri; + unsigned long nr_max, nf_max, od_max; + + /* + * Make sure PLL is working with valid input signal (Fdiv). If + * you want to speed the function up just reduce CCU_PLL_NR_MAX. + * This will cause a worse approximation though. + */ + nri = (parent_rate / CCU_PLL_FDIV_MAX) + 1; + nr_max = min(parent_rate / CCU_PLL_FDIV_MIN, CCU_PLL_NR_MAX); + + /* + * Find a closest [nr;nf;od] vector taking into account the + * limitations like: 1) 700MHz <= Fvco <= 3.5GHz, 2) PLL Od is + * either 1 or even number within the acceptable range (alas 1s + * is also excluded by the next loop). + */ + for (; nri <= nr_max; ++nri) { + /* Use Od factor to fulfill the limitation 2). */ + num = CCU_PLL_CLKOD_FACTOR * rate; + denom = parent_rate / nri; + + /* + * Make sure Fvco is within the acceptable range to fulfill + * the condition 1). Note due to the CCU_PLL_CLKOD_FACTOR value + * the actual upper limit is also divided by that factor. + * It's not big problem for us since practically there is no + * need in clocks with that high frequency. + */ + nf_max = min(CCU_PLL_FVCO_MAX / denom, CCU_PLL_NF_MAX); + od_max = CCU_PLL_OD_MAX / CCU_PLL_CLKOD_FACTOR; + + /* + * Bypass the out-of-bound values, which can't be properly + * handled by the rational fraction approximation algorithm. + */ + if (num / denom >= nf_max) { + n1 = nf_max; + d1 = 1; + } else if (denom / num >= od_max) { + n1 = 1; + d1 = od_max; + } else { + rational_best_approximation(num, denom, nf_max, od_max, + &n1, &d1); + } + + /* Select the best approximation of the target rate. */ + freq = ccu_pll_calc_freq(parent_rate, nri, n1, d1); + err = abs((int64_t)freq - num); + if (err < min_err) { + min_err = err; + *nr = nri; + *nf = n1; + *od = CCU_PLL_CLKOD_FACTOR * d1; + } + } +} + +static long ccu_pll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + unsigned long nr = 1, nf = 1, od = 1; + + ccu_pll_calc_factors(rate, *parent_rate, &nr, &nf, &od); + + return ccu_pll_calc_freq(*parent_rate, nr, nf, od); +} + +/* + * This method is used for PLLs, which support the on-the-fly dividers + * adjustment. So there is no need in gating such clocks. + */ +static int ccu_pll_set_rate_reset(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct ccu_pll *pll = to_ccu_pll(hw); + unsigned long nr, nf, od; + unsigned long flags; + u32 mask, val; + int ret; + + ccu_pll_calc_factors(rate, parent_rate, &nr, &nf, &od); + + mask = CCU_PLL_CTL_CLKR_MASK | CCU_PLL_CTL_CLKF_MASK | + CCU_PLL_CTL_CLKOD_MASK; + val = FIELD_PREP(CCU_PLL_CTL_CLKR_MASK, nr - 1) | + FIELD_PREP(CCU_PLL_CTL_CLKF_MASK, nf - 1) | + FIELD_PREP(CCU_PLL_CTL_CLKOD_MASK, od - 1); + + spin_lock_irqsave(&pll->lock, flags); + regmap_update_bits(pll->sys_regs, pll->reg_ctl, mask, val); + ret = ccu_pll_reset(pll, parent_rate, nr); + spin_unlock_irqrestore(&pll->lock, flags); + if (ret) + pr_err("PLL '%s' reset timed out\n", clk_hw_get_name(hw)); + + return ret; +} + +/* + * This method is used for PLLs, which don't support the on-the-fly dividers + * adjustment. So the corresponding clocks are supposed to be gated first. + */ +static int ccu_pll_set_rate_norst(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct ccu_pll *pll = to_ccu_pll(hw); + unsigned long nr, nf, od; + unsigned long flags; + u32 mask, val; + + ccu_pll_calc_factors(rate, parent_rate, &nr, &nf, &od); + + /* + * Disable PLL if it was enabled by default or left enabled by the + * system bootloader. + */ + mask = CCU_PLL_CTL_CLKR_MASK | CCU_PLL_CTL_CLKF_MASK | + CCU_PLL_CTL_CLKOD_MASK | CCU_PLL_CTL_EN; + val = FIELD_PREP(CCU_PLL_CTL_CLKR_MASK, nr - 1) | + FIELD_PREP(CCU_PLL_CTL_CLKF_MASK, nf - 1) | + FIELD_PREP(CCU_PLL_CTL_CLKOD_MASK, od - 1); + + spin_lock_irqsave(&pll->lock, flags); + regmap_update_bits(pll->sys_regs, pll->reg_ctl, mask, val); + spin_unlock_irqrestore(&pll->lock, flags); + + return 0; +} + +#ifdef CONFIG_DEBUG_FS + +struct ccu_pll_dbgfs_bit { + struct ccu_pll *pll; + const char *name; + unsigned int reg; + u32 mask; +}; + +struct ccu_pll_dbgfs_fld { + struct ccu_pll *pll; + const char *name; + unsigned int reg; + unsigned int lsb; + u32 mask; + u32 min; + u32 max; +}; + +#define CCU_PLL_DBGFS_BIT_ATTR(_name, _reg, _mask) \ + { \ + .name = _name, \ + .reg = _reg, \ + .mask = _mask \ + } + +#define CCU_PLL_DBGFS_FLD_ATTR(_name, _reg, _lsb, _mask, _min, _max) \ + { \ + .name = _name, \ + .reg = _reg, \ + .lsb = _lsb, \ + .mask = _mask, \ + .min = _min, \ + .max = _max \ + } + +static const struct ccu_pll_dbgfs_bit ccu_pll_bits[] = { + CCU_PLL_DBGFS_BIT_ATTR("pll_en", CCU_PLL_CTL, CCU_PLL_CTL_EN), + CCU_PLL_DBGFS_BIT_ATTR("pll_rst", CCU_PLL_CTL, CCU_PLL_CTL_RST), + CCU_PLL_DBGFS_BIT_ATTR("pll_bypass", CCU_PLL_CTL, CCU_PLL_CTL_BYPASS), + CCU_PLL_DBGFS_BIT_ATTR("pll_lock", CCU_PLL_CTL, CCU_PLL_CTL_LOCK) +}; + +#define CCU_PLL_DBGFS_BIT_NUM ARRAY_SIZE(ccu_pll_bits) + +static const struct ccu_pll_dbgfs_fld ccu_pll_flds[] = { + CCU_PLL_DBGFS_FLD_ATTR("pll_nr", CCU_PLL_CTL, CCU_PLL_CTL_CLKR_FLD, + CCU_PLL_CTL_CLKR_MASK, 1, CCU_PLL_NR_MAX), + CCU_PLL_DBGFS_FLD_ATTR("pll_nf", CCU_PLL_CTL, CCU_PLL_CTL_CLKF_FLD, + CCU_PLL_CTL_CLKF_MASK, 1, CCU_PLL_NF_MAX), + CCU_PLL_DBGFS_FLD_ATTR("pll_od", CCU_PLL_CTL, CCU_PLL_CTL_CLKOD_FLD, + CCU_PLL_CTL_CLKOD_MASK, 1, CCU_PLL_OD_MAX), + CCU_PLL_DBGFS_FLD_ATTR("pll_nb", CCU_PLL_CTL1, CCU_PLL_CTL1_BWADJ_FLD, + CCU_PLL_CTL1_BWADJ_MASK, 1, CCU_PLL_NB_MAX) +}; + +#define CCU_PLL_DBGFS_FLD_NUM ARRAY_SIZE(ccu_pll_flds) + +/* + * It can be dangerous to change the PLL settings behind clock framework back, + * therefore we don't provide any kernel config based compile time option for + * this feature to enable. + */ +#undef CCU_PLL_ALLOW_WRITE_DEBUGFS +#ifdef CCU_PLL_ALLOW_WRITE_DEBUGFS + +static int ccu_pll_dbgfs_bit_set(void *priv, u64 val) +{ + const struct ccu_pll_dbgfs_bit *bit = priv; + struct ccu_pll *pll = bit->pll; + unsigned long flags; + + spin_lock_irqsave(&pll->lock, flags); + regmap_update_bits(pll->sys_regs, pll->reg_ctl + bit->reg, + bit->mask, val ? bit->mask : 0); + spin_unlock_irqrestore(&pll->lock, flags); + + return 0; +} + +static int ccu_pll_dbgfs_fld_set(void *priv, u64 val) +{ + struct ccu_pll_dbgfs_fld *fld = priv; + struct ccu_pll *pll = fld->pll; + unsigned long flags; + u32 data; + + val = clamp_t(u64, val, fld->min, fld->max); + data = ((val - 1) << fld->lsb) & fld->mask; + + spin_lock_irqsave(&pll->lock, flags); + regmap_update_bits(pll->sys_regs, pll->reg_ctl + fld->reg, fld->mask, + data); + spin_unlock_irqrestore(&pll->lock, flags); + + return 0; +} + +#define ccu_pll_dbgfs_mode 0644 + +#else /* !CCU_PLL_ALLOW_WRITE_DEBUGFS */ + +#define ccu_pll_dbgfs_bit_set NULL +#define ccu_pll_dbgfs_fld_set NULL +#define ccu_pll_dbgfs_mode 0444 + +#endif /* !CCU_PLL_ALLOW_WRITE_DEBUGFS */ + +static int ccu_pll_dbgfs_bit_get(void *priv, u64 *val) +{ + struct ccu_pll_dbgfs_bit *bit = priv; + struct ccu_pll *pll = bit->pll; + u32 data = 0; + + regmap_read(pll->sys_regs, pll->reg_ctl + bit->reg, &data); + *val = !!(data & bit->mask); + + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(ccu_pll_dbgfs_bit_fops, + ccu_pll_dbgfs_bit_get, ccu_pll_dbgfs_bit_set, "%llu\n"); + +static int ccu_pll_dbgfs_fld_get(void *priv, u64 *val) +{ + struct ccu_pll_dbgfs_fld *fld = priv; + struct ccu_pll *pll = fld->pll; + u32 data = 0; + + regmap_read(pll->sys_regs, pll->reg_ctl + fld->reg, &data); + *val = ((data & fld->mask) >> fld->lsb) + 1; + + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(ccu_pll_dbgfs_fld_fops, + ccu_pll_dbgfs_fld_get, ccu_pll_dbgfs_fld_set, "%llu\n"); + +static void ccu_pll_debug_init(struct clk_hw *hw, struct dentry *dentry) +{ + struct ccu_pll *pll = to_ccu_pll(hw); + struct ccu_pll_dbgfs_bit *bits; + struct ccu_pll_dbgfs_fld *flds; + int idx; + + bits = kcalloc(CCU_PLL_DBGFS_BIT_NUM, sizeof(*bits), GFP_KERNEL); + if (!bits) + return; + + for (idx = 0; idx < CCU_PLL_DBGFS_BIT_NUM; ++idx) { + bits[idx] = ccu_pll_bits[idx]; + bits[idx].pll = pll; + + debugfs_create_file_unsafe(bits[idx].name, ccu_pll_dbgfs_mode, + dentry, &bits[idx], + &ccu_pll_dbgfs_bit_fops); + } + + flds = kcalloc(CCU_PLL_DBGFS_FLD_NUM, sizeof(*flds), GFP_KERNEL); + if (!flds) + return; + + for (idx = 0; idx < CCU_PLL_DBGFS_FLD_NUM; ++idx) { + flds[idx] = ccu_pll_flds[idx]; + flds[idx].pll = pll; + + debugfs_create_file_unsafe(flds[idx].name, ccu_pll_dbgfs_mode, + dentry, &flds[idx], + &ccu_pll_dbgfs_fld_fops); + } +} + +#else /* !CONFIG_DEBUG_FS */ + +#define ccu_pll_debug_init NULL + +#endif /* !CONFIG_DEBUG_FS */ + +static const struct clk_ops ccu_pll_gate_to_set_ops = { + .enable = ccu_pll_enable, + .disable = ccu_pll_disable, + .is_enabled = ccu_pll_is_enabled, + .recalc_rate = ccu_pll_recalc_rate, + .round_rate = ccu_pll_round_rate, + .set_rate = ccu_pll_set_rate_norst, + .debug_init = ccu_pll_debug_init +}; + +static const struct clk_ops ccu_pll_straight_set_ops = { + .enable = ccu_pll_enable, + .disable = ccu_pll_disable, + .is_enabled = ccu_pll_is_enabled, + .recalc_rate = ccu_pll_recalc_rate, + .round_rate = ccu_pll_round_rate, + .set_rate = ccu_pll_set_rate_reset, + .debug_init = ccu_pll_debug_init +}; + +struct ccu_pll *ccu_pll_hw_register(const struct ccu_pll_init_data *pll_init) +{ + struct clk_parent_data parent_data = { }; + struct clk_init_data hw_init = { }; + struct ccu_pll *pll; + int ret; + + if (!pll_init) + return ERR_PTR(-EINVAL); + + pll = kzalloc(sizeof(*pll), GFP_KERNEL); + if (!pll) + return ERR_PTR(-ENOMEM); + + /* + * Note since Baikal-T1 System Controller registers are MMIO-backed + * we won't check the regmap IO operations return status, because it + * must be zero anyway. + */ + pll->hw.init = &hw_init; + pll->reg_ctl = pll_init->base + CCU_PLL_CTL; + pll->reg_ctl1 = pll_init->base + CCU_PLL_CTL1; + pll->sys_regs = pll_init->sys_regs; + pll->id = pll_init->id; + spin_lock_init(&pll->lock); + + hw_init.name = pll_init->name; + hw_init.flags = pll_init->flags; + + if (hw_init.flags & CLK_SET_RATE_GATE) + hw_init.ops = &ccu_pll_gate_to_set_ops; + else + hw_init.ops = &ccu_pll_straight_set_ops; + + if (!pll_init->parent_name) { + ret = -EINVAL; + goto err_free_pll; + } + parent_data.fw_name = pll_init->parent_name; + hw_init.parent_data = &parent_data; + hw_init.num_parents = 1; + + ret = of_clk_hw_register(pll_init->np, &pll->hw); + if (ret) + goto err_free_pll; + + return pll; + +err_free_pll: + kfree(pll); + + return ERR_PTR(ret); +} + +void ccu_pll_hw_unregister(struct ccu_pll *pll) +{ + clk_hw_unregister(&pll->hw); + + kfree(pll); +} |