clk: add highbank clock support

This adds real clock support to Calxeda Highbank SOC using the common
clock infrastructure.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
[mturquette@linaro.org: fixed up invalid writes to const struct member]
Signed-off-by: Mike Turquette <mturquette@linaro.org>

2 files changed, 347 insertions, 0 deletions

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index a4d67d7a753..02ffdf647b5 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
 obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
 				   clk-mux.o clk-divider.o clk-fixed-factor.o
 # SoCs specific
+obj-$(CONFIG_ARCH_HIGHBANK)	+= clk-highbank.o
 obj-$(CONFIG_ARCH_MXS)		+= mxs/
 obj-$(CONFIG_PLAT_SPEAR)	+= spear/
 obj-$(CONFIG_ARCH_U300)		+= clk-u300.o
diff --git a/drivers/clk/clk-highbank.c b/drivers/clk/clk-highbank.c
new file mode 100644
index 00000000000..52fecadf004
--- /dev/null
+++ b/drivers/clk/clk-highbank.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright 2011-2012 Calxeda, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+extern void __iomem *sregs_base;
+
+#define HB_PLL_LOCK_500		0x20000000
+#define HB_PLL_LOCK		0x10000000
+#define HB_PLL_DIVF_SHIFT	20
+#define HB_PLL_DIVF_MASK	0x0ff00000
+#define HB_PLL_DIVQ_SHIFT	16
+#define HB_PLL_DIVQ_MASK	0x00070000
+#define HB_PLL_DIVR_SHIFT	8
+#define HB_PLL_DIVR_MASK	0x00001f00
+#define HB_PLL_RANGE_SHIFT	4
+#define HB_PLL_RANGE_MASK	0x00000070
+#define HB_PLL_BYPASS		0x00000008
+#define HB_PLL_RESET		0x00000004
+#define HB_PLL_EXT_BYPASS	0x00000002
+#define HB_PLL_EXT_ENA		0x00000001
+
+#define HB_PLL_VCO_MIN_FREQ	2133000000
+#define HB_PLL_MAX_FREQ		HB_PLL_VCO_MIN_FREQ
+#define HB_PLL_MIN_FREQ		(HB_PLL_VCO_MIN_FREQ / 64)
+
+#define HB_A9_BCLK_DIV_MASK	0x00000006
+#define HB_A9_BCLK_DIV_SHIFT	1
+#define HB_A9_PCLK_DIV		0x00000001
+
+struct hb_clk {
+        struct clk_hw	hw;
+	void __iomem	*reg;
+	char *parent_name;
+};
+#define to_hb_clk(p) container_of(p, struct hb_clk, hw)
+
+static int clk_pll_prepare(struct clk_hw *hwclk)
+	{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 reg;
+
+	reg = readl(hbclk->reg);
+	reg &= ~HB_PLL_RESET;
+	writel(reg, hbclk->reg);
+
+	while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
+		;
+	while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
+		;
+
+	return 0;
+}
+
+static void clk_pll_unprepare(struct clk_hw *hwclk)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 reg;
+
+	reg = readl(hbclk->reg);
+	reg |= HB_PLL_RESET;
+	writel(reg, hbclk->reg);
+}
+
+static int clk_pll_enable(struct clk_hw *hwclk)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 reg;
+
+	reg = readl(hbclk->reg);
+	reg |= HB_PLL_EXT_ENA;
+	writel(reg, hbclk->reg);
+
+	return 0;
+}
+
+static void clk_pll_disable(struct clk_hw *hwclk)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 reg;
+
+	reg = readl(hbclk->reg);
+	reg &= ~HB_PLL_EXT_ENA;
+	writel(reg, hbclk->reg);
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
+					 unsigned long parent_rate)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	unsigned long divf, divq, vco_freq, reg;
+
+	reg = readl(hbclk->reg);
+	if (reg & HB_PLL_EXT_BYPASS)
+		return parent_rate;
+
+	divf = (reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT;
+	divq = (reg & HB_PLL_DIVQ_MASK) >> HB_PLL_DIVQ_SHIFT;
+	vco_freq = parent_rate * (divf + 1);
+
+	return vco_freq / (1 << divq);
+}
+
+static void clk_pll_calc(unsigned long rate, unsigned long ref_freq,
+			u32 *pdivq, u32 *pdivf)
+{
+	u32 divq, divf;
+	unsigned long vco_freq;
+
+	if (rate < HB_PLL_MIN_FREQ)
+		rate = HB_PLL_MIN_FREQ;
+	if (rate > HB_PLL_MAX_FREQ)
+		rate = HB_PLL_MAX_FREQ;
+
+	for (divq = 1; divq <= 6; divq++) {
+		if ((rate * (1 << divq)) >= HB_PLL_VCO_MIN_FREQ)
+			break;
+	}
+
+	vco_freq = rate * (1 << divq);
+	divf = (vco_freq + (ref_freq / 2)) / ref_freq;
+	divf--;
+
+	*pdivq = divq;
+	*pdivf = divf;
+}
+
+static long clk_pll_round_rate(struct clk_hw *hwclk, unsigned long rate,
+			       unsigned long *parent_rate)
+{
+	u32 divq, divf;
+	unsigned long ref_freq = *parent_rate;
+
+	clk_pll_calc(rate, ref_freq, &divq, &divf);
+
+	return (ref_freq * (divf + 1)) / (1 << divq);
+}
+
+static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
+			    unsigned long parent_rate)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 divq, divf;
+	u32 reg;
+
+	clk_pll_calc(rate, parent_rate, &divq, &divf);
+
+	reg = readl(hbclk->reg);
+	if (divf != ((reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT)) {
+		/* Need to re-lock PLL, so put it into bypass mode */
+		reg |= HB_PLL_EXT_BYPASS;
+		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
+
+		writel(reg | HB_PLL_RESET, hbclk->reg);
+		reg &= ~(HB_PLL_DIVF_MASK | HB_PLL_DIVQ_MASK);
+		reg |= (divf << HB_PLL_DIVF_SHIFT) | (divq << HB_PLL_DIVQ_SHIFT);
+		writel(reg | HB_PLL_RESET, hbclk->reg);
+		writel(reg, hbclk->reg);
+
+		while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
+			;
+		while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
+			;
+		reg |= HB_PLL_EXT_ENA;
+		reg &= ~HB_PLL_EXT_BYPASS;
+	} else {
+		reg &= ~HB_PLL_DIVQ_MASK;
+		reg |= divq << HB_PLL_DIVQ_SHIFT;
+	}
+	writel(reg, hbclk->reg);
+
+	return 0;
+}
+
+static const struct clk_ops clk_pll_ops = {
+	.prepare = clk_pll_prepare,
+	.unprepare = clk_pll_unprepare,
+	.enable = clk_pll_enable,
+	.disable = clk_pll_disable,
+	.recalc_rate = clk_pll_recalc_rate,
+	.round_rate = clk_pll_round_rate,
+	.set_rate = clk_pll_set_rate,
+};
+
+static unsigned long clk_cpu_periphclk_recalc_rate(struct clk_hw *hwclk,
+						   unsigned long parent_rate)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 div = (readl(hbclk->reg) & HB_A9_PCLK_DIV) ? 8 : 4;
+	return parent_rate / div;
+}
+
+static const struct clk_ops a9periphclk_ops = {
+	.recalc_rate = clk_cpu_periphclk_recalc_rate,
+};
+
+static unsigned long clk_cpu_a9bclk_recalc_rate(struct clk_hw *hwclk,
+						unsigned long parent_rate)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 div = (readl(hbclk->reg) & HB_A9_BCLK_DIV_MASK) >> HB_A9_BCLK_DIV_SHIFT;
+
+	return parent_rate / (div + 2);
+}
+
+static const struct clk_ops a9bclk_ops = {
+	.recalc_rate = clk_cpu_a9bclk_recalc_rate,
+};
+
+static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
+					     unsigned long parent_rate)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 div;
+
+	div = readl(hbclk->reg) & 0x1f;
+	div++;
+	div *= 2;
+
+	return parent_rate / div;
+}
+
+static long clk_periclk_round_rate(struct clk_hw *hwclk, unsigned long rate,
+				   unsigned long *parent_rate)
+{
+	u32 div;
+
+	div = *parent_rate / rate;
+	div++;
+	div &= ~0x1;
+
+	return *parent_rate / div;
+}
+
+static int clk_periclk_set_rate(struct clk_hw *hwclk, unsigned long rate,
+				unsigned long parent_rate)
+{
+	struct hb_clk *hbclk = to_hb_clk(hwclk);
+	u32 div;
+
+	div = parent_rate / rate;
+	if (div & 0x1)
+		return -EINVAL;
+
+	writel(div >> 1, hbclk->reg);
+	return 0;
+}
+
+static const struct clk_ops periclk_ops = {
+	.recalc_rate = clk_periclk_recalc_rate,
+	.round_rate = clk_periclk_round_rate,
+	.set_rate = clk_periclk_set_rate,
+};
+
+static __init struct clk *hb_clk_init(struct device_node *node, const struct clk_ops *ops)
+{
+	u32 reg;
+	struct clk *clk;
+	struct hb_clk *hb_clk;
+	const char *clk_name = node->name;
+	const char *parent_name;
+	struct clk_init_data init;
+	int rc;
+
+	rc = of_property_read_u32(node, "reg", &reg);
+	if (WARN_ON(rc))
+		return NULL;
+
+	hb_clk = kzalloc(sizeof(*hb_clk), GFP_KERNEL);
+	if (WARN_ON(!hb_clk))
+		return NULL;
+
+	hb_clk->reg = sregs_base + reg;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+
+	init.name = clk_name;
+	init.ops = ops;
+	init.flags = 0;
+	parent_name = of_clk_get_parent_name(node, 0);
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	hb_clk->hw.init = &init;
+
+	clk = clk_register(NULL, &hb_clk->hw);
+	if (WARN_ON(IS_ERR(clk))) {
+		kfree(hb_clk);
+		return NULL;
+	}
+	rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	return clk;
+}
+
+static void __init hb_pll_init(struct device_node *node)
+{
+	hb_clk_init(node, &clk_pll_ops);
+}
+
+static void __init hb_a9periph_init(struct device_node *node)
+{
+	hb_clk_init(node, &a9periphclk_ops);
+}
+
+static void __init hb_a9bus_init(struct device_node *node)
+{
+	struct clk *clk = hb_clk_init(node, &a9bclk_ops);
+	clk_prepare_enable(clk);
+}
+
+static void __init hb_emmc_init(struct device_node *node)
+{
+	hb_clk_init(node, &periclk_ops);
+}
+
+static const __initconst struct of_device_id clk_match[] = {
+	{ .compatible = "fixed-clock", .data = of_fixed_clk_setup, },
+	{ .compatible = "calxeda,hb-pll-clock", .data = hb_pll_init, },
+	{ .compatible = "calxeda,hb-a9periph-clock", .data = hb_a9periph_init, },
+	{ .compatible = "calxeda,hb-a9bus-clock", .data = hb_a9bus_init, },
+	{ .compatible = "calxeda,hb-emmc-clock", .data = hb_emmc_init, },
+	{}
+};
+
+void __init highbank_clocks_init(void)
+{
+	of_clk_init(clk_match);
+}