1 files changed, 602 insertions, 0 deletions

diff --git a/drivers/clk/baikal-t1/ccu-div.c b/drivers/clk/baikal-t1/ccu-div.c
new file mode 100644
index 000000000000..bd40f5936f08
--- /dev/null
+++ b/drivers/clk/baikal-t1/ccu-div.c
@@ -0,0 +1,602 @@
+// 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 Dividers interface driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-div: " fmt
+
+#include <linux/kernel.h>
+#include <linux/printk.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/delay.h>
+#include <linux/time64.h>
+#include <linux/debugfs.h>
+
+#include "ccu-div.h"
+
+#define CCU_DIV_CTL			0x00
+#define CCU_DIV_CTL_EN			BIT(0)
+#define CCU_DIV_CTL_RST			BIT(1)
+#define CCU_DIV_CTL_SET_CLKDIV		BIT(2)
+#define CCU_DIV_CTL_CLKDIV_FLD		4
+#define CCU_DIV_CTL_CLKDIV_MASK(_width) \
+	GENMASK((_width) + CCU_DIV_CTL_CLKDIV_FLD - 1, CCU_DIV_CTL_CLKDIV_FLD)
+#define CCU_DIV_CTL_LOCK_SHIFTED	BIT(27)
+#define CCU_DIV_CTL_LOCK_NORMAL		BIT(31)
+
+#define CCU_DIV_RST_DELAY_US		1
+#define CCU_DIV_LOCK_CHECK_RETRIES	50
+
+#define CCU_DIV_CLKDIV_MIN		0
+#define CCU_DIV_CLKDIV_MAX(_mask) \
+	((_mask) >> CCU_DIV_CTL_CLKDIV_FLD)
+
+/*
+ * Use the next two methods until there are generic field setter and
+ * getter available with non-constant mask support.
+ */
+static inline u32 ccu_div_get(u32 mask, u32 val)
+{
+	return (val & mask) >> CCU_DIV_CTL_CLKDIV_FLD;
+}
+
+static inline u32 ccu_div_prep(u32 mask, u32 val)
+{
+	return (val << CCU_DIV_CTL_CLKDIV_FLD) & mask;
+}
+
+static inline unsigned long ccu_div_lock_delay_ns(unsigned long ref_clk,
+						  unsigned long div)
+{
+	u64 ns = 4ULL * (div ?: 1) * NSEC_PER_SEC;
+
+	do_div(ns, ref_clk);
+
+	return ns;
+}
+
+static inline unsigned long ccu_div_calc_freq(unsigned long ref_clk,
+					      unsigned long div)
+{
+	return ref_clk / (div ?: 1);
+}
+
+static int ccu_div_var_update_clkdiv(struct ccu_div *div,
+				     unsigned long parent_rate,
+				     unsigned long divider)
+{
+	unsigned long nd;
+	u32 val = 0;
+	u32 lock;
+	int count;
+
+	nd = ccu_div_lock_delay_ns(parent_rate, divider);
+
+	if (div->features & CCU_DIV_LOCK_SHIFTED)
+		lock = CCU_DIV_CTL_LOCK_SHIFTED;
+	else
+		lock = CCU_DIV_CTL_LOCK_NORMAL;
+
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   CCU_DIV_CTL_SET_CLKDIV, CCU_DIV_CTL_SET_CLKDIV);
+
+	/*
+	 * Until there is nsec-version of readl_poll_timeout() is available
+	 * we have to implement the next polling loop.
+	 */
+	count = CCU_DIV_LOCK_CHECK_RETRIES;
+	do {
+		ndelay(nd);
+		regmap_read(div->sys_regs, div->reg_ctl, &val);
+		if (val & lock)
+			return 0;
+	} while (--count);
+
+	return -ETIMEDOUT;
+}
+
+static int ccu_div_var_enable(struct clk_hw *hw)
+{
+	struct clk_hw *parent_hw = clk_hw_get_parent(hw);
+	struct ccu_div *div = to_ccu_div(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(div->sys_regs, div->reg_ctl, &val);
+	if (val & CCU_DIV_CTL_EN)
+		return 0;
+
+	spin_lock_irqsave(&div->lock, flags);
+	ret = ccu_div_var_update_clkdiv(div, clk_hw_get_rate(parent_hw),
+					ccu_div_get(div->mask, val));
+	if (!ret)
+		regmap_update_bits(div->sys_regs, div->reg_ctl,
+				   CCU_DIV_CTL_EN, CCU_DIV_CTL_EN);
+	spin_unlock_irqrestore(&div->lock, flags);
+	if (ret)
+		pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw));
+
+	return ret;
+}
+
+static int ccu_div_gate_enable(struct clk_hw *hw)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   CCU_DIV_CTL_EN, CCU_DIV_CTL_EN);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+static void ccu_div_gate_disable(struct clk_hw *hw)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl, CCU_DIV_CTL_EN, 0);
+	spin_unlock_irqrestore(&div->lock, flags);
+}
+
+static int ccu_div_gate_is_enabled(struct clk_hw *hw)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	u32 val = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &val);
+
+	return !!(val & CCU_DIV_CTL_EN);
+}
+
+static unsigned long ccu_div_var_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long divider;
+	u32 val = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &val);
+	divider = ccu_div_get(div->mask, val);
+
+	return ccu_div_calc_freq(parent_rate, divider);
+}
+
+static inline unsigned long ccu_div_var_calc_divider(unsigned long rate,
+						     unsigned long parent_rate,
+						     unsigned int mask)
+{
+	unsigned long divider;
+
+	divider = parent_rate / rate;
+	return clamp_t(unsigned long, divider, CCU_DIV_CLKDIV_MIN,
+		       CCU_DIV_CLKDIV_MAX(mask));
+}
+
+static long ccu_div_var_round_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long *parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long divider;
+
+	divider = ccu_div_var_calc_divider(rate, *parent_rate, div->mask);
+
+	return ccu_div_calc_freq(*parent_rate, divider);
+}
+
+/*
+ * This method is used for the clock divider blocks, which support the
+ * on-the-fly rate change. So due to lacking the EN bit functionality
+ * they can't be gated before the rate adjustment.
+ */
+static int ccu_div_var_set_rate_slow(struct clk_hw *hw, unsigned long rate,
+				     unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags, divider;
+	u32 val;
+	int ret;
+
+	divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask);
+	if (divider == 1 && div->features & CCU_DIV_SKIP_ONE) {
+		divider = 0;
+	} else if (div->features & CCU_DIV_SKIP_ONE_TO_THREE) {
+		if (divider == 1 || divider == 2)
+			divider = 0;
+		else if (divider == 3)
+			divider = 4;
+	}
+
+	val = ccu_div_prep(div->mask, divider);
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, val);
+	ret = ccu_div_var_update_clkdiv(div, parent_rate, divider);
+	spin_unlock_irqrestore(&div->lock, flags);
+	if (ret)
+		pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw));
+
+	return ret;
+}
+
+/*
+ * This method is used for the clock divider blocks, which don't support
+ * the on-the-fly rate change.
+ */
+static int ccu_div_var_set_rate_fast(struct clk_hw *hw, unsigned long rate,
+				     unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags, divider = 1;
+	u32 val;
+
+	divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask);
+	val = ccu_div_prep(div->mask, divider);
+
+	/*
+	 * Also disable the clock divider block if it was enabled by default
+	 * or by the bootloader.
+	 */
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   div->mask | CCU_DIV_CTL_EN, val);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+static unsigned long ccu_div_fixed_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+
+	return ccu_div_calc_freq(parent_rate, div->divider);
+}
+
+static long ccu_div_fixed_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+
+	return ccu_div_calc_freq(*parent_rate, div->divider);
+}
+
+static int ccu_div_fixed_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	return 0;
+}
+
+int ccu_div_reset_domain(struct ccu_div *div)
+{
+	unsigned long flags;
+
+	if (!div || !(div->features & CCU_DIV_RESET_DOMAIN))
+		return -EINVAL;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   CCU_DIV_CTL_RST, CCU_DIV_CTL_RST);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	/* The next delay must be enough to cover all the resets. */
+	udelay(CCU_DIV_RST_DELAY_US);
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+struct ccu_div_dbgfs_bit {
+	struct ccu_div *div;
+	const char *name;
+	u32 mask;
+};
+
+#define CCU_DIV_DBGFS_BIT_ATTR(_name, _mask) {	\
+		.name = _name,			\
+		.mask = _mask			\
+	}
+
+static const struct ccu_div_dbgfs_bit ccu_div_bits[] = {
+	CCU_DIV_DBGFS_BIT_ATTR("div_en", CCU_DIV_CTL_EN),
+	CCU_DIV_DBGFS_BIT_ATTR("div_rst", CCU_DIV_CTL_RST),
+	CCU_DIV_DBGFS_BIT_ATTR("div_bypass", CCU_DIV_CTL_SET_CLKDIV),
+	CCU_DIV_DBGFS_BIT_ATTR("div_lock", CCU_DIV_CTL_LOCK_NORMAL)
+};
+
+#define CCU_DIV_DBGFS_BIT_NUM	ARRAY_SIZE(ccu_div_bits)
+
+/*
+ * It can be dangerous to change the Divider settings behind clock framework
+ * back, therefore we don't provide any kernel config based compile time option
+ * for this feature to enable.
+ */
+#undef CCU_DIV_ALLOW_WRITE_DEBUGFS
+#ifdef CCU_DIV_ALLOW_WRITE_DEBUGFS
+
+static int ccu_div_dbgfs_bit_set(void *priv, u64 val)
+{
+	const struct ccu_div_dbgfs_bit *bit = priv;
+	struct ccu_div *div = bit->div;
+	unsigned long flags;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   bit->mask, val ? bit->mask : 0);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+static int ccu_div_dbgfs_var_clkdiv_set(void *priv, u64 val)
+{
+	struct ccu_div *div = priv;
+	unsigned long flags;
+	u32 data;
+
+	val = clamp_t(u64, val, CCU_DIV_CLKDIV_MIN,
+		      CCU_DIV_CLKDIV_MAX(div->mask));
+	data = ccu_div_prep(div->mask, val);
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, data);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+#define ccu_div_dbgfs_mode		0644
+
+#else /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */
+
+#define ccu_div_dbgfs_bit_set		NULL
+#define ccu_div_dbgfs_var_clkdiv_set	NULL
+#define ccu_div_dbgfs_mode		0444
+
+#endif /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */
+
+static int ccu_div_dbgfs_bit_get(void *priv, u64 *val)
+{
+	const struct ccu_div_dbgfs_bit *bit = priv;
+	struct ccu_div *div = bit->div;
+	u32 data = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &data);
+	*val = !!(data & bit->mask);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_bit_fops,
+	ccu_div_dbgfs_bit_get, ccu_div_dbgfs_bit_set, "%llu\n");
+
+static int ccu_div_dbgfs_var_clkdiv_get(void *priv, u64 *val)
+{
+	struct ccu_div *div = priv;
+	u32 data = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &data);
+	*val = ccu_div_get(div->mask, data);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_var_clkdiv_fops,
+	ccu_div_dbgfs_var_clkdiv_get, ccu_div_dbgfs_var_clkdiv_set, "%llu\n");
+
+static int ccu_div_dbgfs_fixed_clkdiv_get(void *priv, u64 *val)
+{
+	struct ccu_div *div = priv;
+
+	*val = div->divider;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_fixed_clkdiv_fops,
+	ccu_div_dbgfs_fixed_clkdiv_get, NULL, "%llu\n");
+
+static void ccu_div_var_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	struct ccu_div_dbgfs_bit *bits;
+	int didx, bidx, num = 2;
+	const char *name;
+
+	num += !!(div->flags & CLK_SET_RATE_GATE) +
+		!!(div->features & CCU_DIV_RESET_DOMAIN);
+
+	bits = kcalloc(num, sizeof(*bits), GFP_KERNEL);
+	if (!bits)
+		return;
+
+	for (didx = 0, bidx = 0; bidx < CCU_DIV_DBGFS_BIT_NUM; ++bidx) {
+		name = ccu_div_bits[bidx].name;
+		if (!(div->flags & CLK_SET_RATE_GATE) &&
+		    !strcmp("div_en", name)) {
+			continue;
+		}
+
+		if (!(div->features & CCU_DIV_RESET_DOMAIN) &&
+		    !strcmp("div_rst", name)) {
+			continue;
+		}
+
+		bits[didx] = ccu_div_bits[bidx];
+		bits[didx].div = div;
+
+		if (div->features & CCU_DIV_LOCK_SHIFTED &&
+		    !strcmp("div_lock", name)) {
+			bits[didx].mask = CCU_DIV_CTL_LOCK_SHIFTED;
+		}
+
+		debugfs_create_file_unsafe(bits[didx].name, ccu_div_dbgfs_mode,
+					   dentry, &bits[didx],
+					   &ccu_div_dbgfs_bit_fops);
+		++didx;
+	}
+
+	debugfs_create_file_unsafe("div_clkdiv", ccu_div_dbgfs_mode, dentry,
+				   div, &ccu_div_dbgfs_var_clkdiv_fops);
+}
+
+static void ccu_div_gate_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	struct ccu_div_dbgfs_bit *bit;
+
+	bit = kmalloc(sizeof(*bit), GFP_KERNEL);
+	if (!bit)
+		return;
+
+	*bit = ccu_div_bits[0];
+	bit->div = div;
+	debugfs_create_file_unsafe(bit->name, ccu_div_dbgfs_mode, dentry, bit,
+				   &ccu_div_dbgfs_bit_fops);
+
+	debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div,
+				   &ccu_div_dbgfs_fixed_clkdiv_fops);
+}
+
+static void ccu_div_fixed_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+
+	debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div,
+				   &ccu_div_dbgfs_fixed_clkdiv_fops);
+}
+
+#else /* !CONFIG_DEBUG_FS */
+
+#define ccu_div_var_debug_init NULL
+#define ccu_div_gate_debug_init NULL
+#define ccu_div_fixed_debug_init NULL
+
+#endif /* !CONFIG_DEBUG_FS */
+
+static const struct clk_ops ccu_div_var_gate_to_set_ops = {
+	.enable = ccu_div_var_enable,
+	.disable = ccu_div_gate_disable,
+	.is_enabled = ccu_div_gate_is_enabled,
+	.recalc_rate = ccu_div_var_recalc_rate,
+	.round_rate = ccu_div_var_round_rate,
+	.set_rate = ccu_div_var_set_rate_fast,
+	.debug_init = ccu_div_var_debug_init
+};
+
+static const struct clk_ops ccu_div_var_nogate_ops = {
+	.recalc_rate = ccu_div_var_recalc_rate,
+	.round_rate = ccu_div_var_round_rate,
+	.set_rate = ccu_div_var_set_rate_slow,
+	.debug_init = ccu_div_var_debug_init
+};
+
+static const struct clk_ops ccu_div_gate_ops = {
+	.enable = ccu_div_gate_enable,
+	.disable = ccu_div_gate_disable,
+	.is_enabled = ccu_div_gate_is_enabled,
+	.recalc_rate = ccu_div_fixed_recalc_rate,
+	.round_rate = ccu_div_fixed_round_rate,
+	.set_rate = ccu_div_fixed_set_rate,
+	.debug_init = ccu_div_gate_debug_init
+};
+
+static const struct clk_ops ccu_div_fixed_ops = {
+	.recalc_rate = ccu_div_fixed_recalc_rate,
+	.round_rate = ccu_div_fixed_round_rate,
+	.set_rate = ccu_div_fixed_set_rate,
+	.debug_init = ccu_div_fixed_debug_init
+};
+
+struct ccu_div *ccu_div_hw_register(const struct ccu_div_init_data *div_init)
+{
+	struct clk_parent_data parent_data = { };
+	struct clk_init_data hw_init = { };
+	struct ccu_div *div;
+	int ret;
+
+	if (!div_init)
+		return ERR_PTR(-EINVAL);
+
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		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.
+	 */
+	div->hw.init = &hw_init;
+	div->id = div_init->id;
+	div->reg_ctl = div_init->base + CCU_DIV_CTL;
+	div->sys_regs = div_init->sys_regs;
+	div->flags = div_init->flags;
+	div->features = div_init->features;
+	spin_lock_init(&div->lock);
+
+	hw_init.name = div_init->name;
+	hw_init.flags = div_init->flags;
+
+	if (div_init->type == CCU_DIV_VAR) {
+		if (hw_init.flags & CLK_SET_RATE_GATE)
+			hw_init.ops = &ccu_div_var_gate_to_set_ops;
+		else
+			hw_init.ops = &ccu_div_var_nogate_ops;
+		div->mask = CCU_DIV_CTL_CLKDIV_MASK(div_init->width);
+	} else if (div_init->type == CCU_DIV_GATE) {
+		hw_init.ops = &ccu_div_gate_ops;
+		div->divider = div_init->divider;
+	} else if (div_init->type == CCU_DIV_FIXED) {
+		hw_init.ops = &ccu_div_fixed_ops;
+		div->divider = div_init->divider;
+	} else {
+		ret = -EINVAL;
+		goto err_free_div;
+	}
+
+	if (!div_init->parent_name) {
+		ret = -EINVAL;
+		goto err_free_div;
+	}
+	parent_data.fw_name = div_init->parent_name;
+	hw_init.parent_data = &parent_data;
+	hw_init.num_parents = 1;
+
+	ret = of_clk_hw_register(div_init->np, &div->hw);
+	if (ret)
+		goto err_free_div;
+
+	return div;
+
+err_free_div:
+	kfree(div);
+
+	return ERR_PTR(ret);
+}
+
+void ccu_div_hw_unregister(struct ccu_div *div)
+{
+	clk_hw_unregister(&div->hw);
+
+	kfree(div);
+}