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.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Craig Tatlor <ctatlor97@gmail.com>
[sboyd@kernel.org: Move hidden config to top outside of the visible qcom
config zone so that menuconfig looks nice]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 124 insertions, 0 deletions

diff --git a/drivers/clk/qcom/clk-krait.c b/drivers/clk/qcom/clk-krait.c
new file mode 100644
index 000000000000..2e417678029f
--- /dev/null
+++ b/drivers/clk/qcom/clk-krait.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018, The Linux Foundation. All rights reserved.
+
+#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);
+}
+
+const struct clk_ops krait_mux_clk_ops = {
+	.set_parent = krait_mux_set_parent,
+	.get_parent = krait_mux_get_parent,
+	.determine_rate = __clk_mux_determine_rate_closest,
+};
+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);