clk: qcom: Add support for Krait clocks

The Krait clocks are made up of a series of muxes and a divider
that choose between a fixed rate clock and dedicated HFPLLs for
each CPU. Instead of using mmio accesses to remux parents, the
Krait implementation exposes the remux control via cp15
registers. Support these clocks.

Change-Id: Ic720d45d8c78e6c5a901e58ec6fd23fa15302a21
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Taniya Das <tdas@codeaurora.org>

4 files changed, 221 insertions, 0 deletions

diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index 5aa3f8ef4a8a..792ac62fc470 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -131,3 +131,7 @@ config QCOM_HFPLL
 	  Support for the high-frequency PLLs present on MSM devices.
 	  Say Y if you want to support CPU frequency scaling on devices
 	  such as MSM8974, APQ8084, etc.
+
+config KRAIT_CLOCKS
+	bool
+	select KRAIT_L2_ACCESSORS
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index 58a6f020f4a3..d44fd9279cd4 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -8,6 +8,7 @@ clk-qcom-y += clk-rcg2.o
 clk-qcom-y += clk-branch.o
 clk-qcom-y += clk-regmap-divider.o
 clk-qcom-y += clk-regmap-mux.o
+clk-qcom-$(CONFIG_KRAIT_CLOCKS) += clk-krait.o
 clk-qcom-y += clk-hfpll.o
 clk-qcom-y += reset.o
 clk-qcom-$(CONFIG_QCOM_GDSC) += gdsc.o
diff --git a/drivers/clk/qcom/clk-krait.c b/drivers/clk/qcom/clk-krait.c
new file mode 100644
index 000000000000..84277741a9c8
--- /dev/null
+++ b/drivers/clk/qcom/clk-krait.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/spinlock.h>
+
+#include <asm/krait-l2-accessors.h>
+
+#include "clk-krait.h"
+
+/* Secondary and primary muxes share the same cp15 register */
+static DEFINE_SPINLOCK(krait_clock_reg_lock);
+
+#define LPL_SHIFT	8
+static void __krait_mux_set_sel(struct krait_mux_clk *mux, int sel)
+{
+	unsigned long flags;
+	u32 regval;
+
+	spin_lock_irqsave(&krait_clock_reg_lock, flags);
+	regval = krait_get_l2_indirect_reg(mux->offset);
+	regval &= ~(mux->mask << mux->shift);
+	regval |= (sel & mux->mask) << mux->shift;
+	if (mux->lpl) {
+		regval &= ~(mux->mask << (mux->shift + LPL_SHIFT));
+		regval |= (sel & mux->mask) << (mux->shift + LPL_SHIFT);
+	}
+	krait_set_l2_indirect_reg(mux->offset, regval);
+	spin_unlock_irqrestore(&krait_clock_reg_lock, flags);
+
+	/* Wait for switch to complete. */
+	mb();
+	udelay(1);
+}
+
+static int krait_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct krait_mux_clk *mux = to_krait_mux_clk(hw);
+	u32 sel;
+
+	sel = clk_mux_reindex(index, mux->parent_map, 0);
+	mux->en_mask = sel;
+	/* Don't touch mux if CPU is off as it won't work */
+	if (__clk_is_enabled(hw->clk))
+		__krait_mux_set_sel(mux, sel);
+	return 0;
+}
+
+static u8 krait_mux_get_parent(struct clk_hw *hw)
+{
+	struct krait_mux_clk *mux = to_krait_mux_clk(hw);
+	u32 sel;
+
+	sel = krait_get_l2_indirect_reg(mux->offset);
+	sel >>= mux->shift;
+	sel &= mux->mask;
+	mux->en_mask = sel;
+
+	return clk_mux_get_parent(hw, sel, mux->parent_map, 0);
+}
+
+static struct clk_hw *krait_mux_get_safe_parent(struct clk_hw *hw,
+						unsigned long *safe_freq)
+{
+	int i;
+	struct krait_mux_clk *mux = to_krait_mux_clk(hw);
+	int num_parents = clk_hw_get_num_parents(hw);
+
+	i = mux->safe_sel;
+	for (i = 0; i < num_parents; i++)
+		if (mux->safe_sel == mux->parent_map[i])
+			break;
+
+	return clk_hw_get_parent_by_index(hw, i);
+}
+
+static int krait_mux_enable(struct clk_hw *hw)
+{
+	struct krait_mux_clk *mux = to_krait_mux_clk(hw);
+
+	__krait_mux_set_sel(mux, mux->en_mask);
+
+	return 0;
+}
+
+static void krait_mux_disable(struct clk_hw *hw)
+{
+	struct krait_mux_clk *mux = to_krait_mux_clk(hw);
+
+	__krait_mux_set_sel(mux, mux->safe_sel);
+}
+
+const struct clk_ops krait_mux_clk_ops = {
+	.enable = krait_mux_enable,
+	.disable = krait_mux_disable,
+	.set_parent = krait_mux_set_parent,
+	.get_parent = krait_mux_get_parent,
+	.determine_rate = __clk_mux_determine_rate_closest,
+	.get_safe_parent = krait_mux_get_safe_parent,
+};
+EXPORT_SYMBOL_GPL(krait_mux_clk_ops);
+
+/* The divider can divide by 2, 4, 6 and 8. But we only really need div-2. */
+static long krait_div2_round_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long *parent_rate)
+{
+	*parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), rate * 2);
+	return DIV_ROUND_UP(*parent_rate, 2);
+}
+
+static int krait_div2_set_rate(struct clk_hw *hw, unsigned long rate,
+			unsigned long parent_rate)
+{
+	struct krait_div2_clk *d = to_krait_div2_clk(hw);
+	unsigned long flags;
+	u32 val;
+	u32 mask = BIT(d->width) - 1;
+
+	if (d->lpl)
+		mask = mask << (d->shift + LPL_SHIFT) | mask << d->shift;
+
+	spin_lock_irqsave(&krait_clock_reg_lock, flags);
+	val = krait_get_l2_indirect_reg(d->offset);
+	val &= ~mask;
+	krait_set_l2_indirect_reg(d->offset, val);
+	spin_unlock_irqrestore(&krait_clock_reg_lock, flags);
+
+	return 0;
+}
+
+static unsigned long
+krait_div2_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	struct krait_div2_clk *d = to_krait_div2_clk(hw);
+	u32 mask = BIT(d->width) - 1;
+	u32 div;
+
+	div = krait_get_l2_indirect_reg(d->offset);
+	div >>= d->shift;
+	div &= mask;
+	div = (div + 1) * 2;
+
+	return DIV_ROUND_UP(parent_rate, div);
+}
+
+const struct clk_ops krait_div2_clk_ops = {
+	.round_rate = krait_div2_round_rate,
+	.set_rate = krait_div2_set_rate,
+	.recalc_rate = krait_div2_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(krait_div2_clk_ops);
diff --git a/drivers/clk/qcom/clk-krait.h b/drivers/clk/qcom/clk-krait.h
new file mode 100644
index 000000000000..5d0063538e5d
--- /dev/null
+++ b/drivers/clk/qcom/clk-krait.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __QCOM_CLK_KRAIT_H
+#define __QCOM_CLK_KRAIT_H
+
+#include <linux/clk-provider.h>
+
+struct krait_mux_clk {
+	unsigned int	*parent_map;
+	bool		has_safe_parent;
+	u8		safe_sel;
+	u32		offset;
+	u32		mask;
+	u32		shift;
+	u32		en_mask;
+	bool		lpl;
+
+	struct clk_hw	hw;
+};
+
+#define to_krait_mux_clk(_hw) container_of(_hw, struct krait_mux_clk, hw)
+
+extern const struct clk_ops krait_mux_clk_ops;
+
+struct krait_div2_clk {
+	u32		offset;
+	u8		width;
+	u32		shift;
+	bool		lpl;
+
+	struct clk_hw	hw;
+};
+
+#define to_krait_div2_clk(_hw) container_of(_hw, struct krait_div2_clk, hw)
+
+extern const struct clk_ops krait_div2_clk_ops;
+
+#endif