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-rw-r--r--drivers/clk/baikal-t1/ccu-pll.c558
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 0000000000..13ef280014
--- /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);
+}