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);
+}