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wifipineapple-openwrt/target/linux/mvebu/patches-3.10/0096-clk-mvebu-Add-Core-Div...

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From ac8294dfb4085f3193bec27673062e5ad63d770a Mon Sep 17 00:00:00 2001
From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Date: Thu, 26 Sep 2013 16:35:27 -0300
Subject: [PATCH 096/203] clk: mvebu: Add Core Divider clock
This commit introduces a new group of clocks present in Armada 370/XP
SoCs (called "Core Divider" clocks) and add a provider for them.
The only clock supported for now is the NAND clock (ndclk), but the
infrastructure to add the rest is already set.
Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
---
arch/arm/mach-mvebu/Kconfig | 1 +
drivers/clk/mvebu/Kconfig | 3 +
drivers/clk/mvebu/Makefile | 1 +
drivers/clk/mvebu/clk-corediv.c | 223 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 228 insertions(+)
create mode 100644 drivers/clk/mvebu/clk-corediv.c
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -13,6 +13,7 @@ config ARCH_MVEBU
select MVEBU_CLK_CORE
select MVEBU_CLK_CPU
select MVEBU_CLK_GATING
+ select MVEBU_CLK_COREDIV
select MVEBU_MBUS
select ZONE_DMA if ARM_LPAE
select ARCH_REQUIRE_GPIOLIB
--- a/drivers/clk/mvebu/Kconfig
+++ b/drivers/clk/mvebu/Kconfig
@@ -6,3 +6,6 @@ config MVEBU_CLK_CPU
config MVEBU_CLK_GATING
bool
+
+config MVEBU_CLK_COREDIV
+ bool
--- a/drivers/clk/mvebu/Makefile
+++ b/drivers/clk/mvebu/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_MVEBU_CLK_CORE) += clk.o clk-core.o
obj-$(CONFIG_MVEBU_CLK_CPU) += clk-cpu.o
obj-$(CONFIG_MVEBU_CLK_GATING) += clk-gating-ctrl.o
+obj-$(CONFIG_MVEBU_CLK_COREDIV) += clk-corediv.o
--- /dev/null
+++ b/drivers/clk/mvebu/clk-corediv.c
@@ -0,0 +1,223 @@
+/*
+ * MVEBU Core divider clock
+ *
+ * Copyright (C) 2013 Marvell
+ *
+ * Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk-provider.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <asm/io.h>
+
+#define CORE_CLK_DIV_RATIO_MASK 0xff
+#define CORE_CLK_DIV_RATIO_RELOAD BIT(8)
+#define CORE_CLK_DIV_ENABLE_OFFSET 24
+#define CORE_CLK_DIV_RATIO_OFFSET 0x8
+
+struct clk_corediv_desc {
+ unsigned int mask;
+ unsigned int offset;
+ unsigned int fieldbit;
+};
+
+struct clk_corediv {
+ struct clk_hw hw;
+ void __iomem *reg;
+ struct clk_corediv_desc desc;
+ spinlock_t lock;
+};
+
+static struct clk_onecell_data clk_data;
+
+static const struct clk_corediv_desc mvebu_corediv_desc[] __initconst = {
+ { .mask = 0x3f, .offset = 8, .fieldbit = 1 }, /* NAND clock */
+};
+
+#define to_corediv_clk(p) container_of(p, struct clk_corediv, hw)
+
+static int clk_corediv_is_enabled(struct clk_hw *hwclk)
+{
+ struct clk_corediv *corediv = to_corediv_clk(hwclk);
+ struct clk_corediv_desc *desc = &corediv->desc;
+ u32 enable_mask = BIT(desc->fieldbit) << CORE_CLK_DIV_ENABLE_OFFSET;
+
+ return !!(readl(corediv->reg) & enable_mask);
+}
+
+static int clk_corediv_enable(struct clk_hw *hwclk)
+{
+ struct clk_corediv *corediv = to_corediv_clk(hwclk);
+ struct clk_corediv_desc *desc = &corediv->desc;
+ unsigned long flags = 0;
+ u32 reg;
+
+ spin_lock_irqsave(&corediv->lock, flags);
+
+ reg = readl(corediv->reg);
+ reg |= (BIT(desc->fieldbit) << CORE_CLK_DIV_ENABLE_OFFSET);
+ writel(reg, corediv->reg);
+
+ spin_unlock_irqrestore(&corediv->lock, flags);
+
+ return 0;
+}
+
+static void clk_corediv_disable(struct clk_hw *hwclk)
+{
+ struct clk_corediv *corediv = to_corediv_clk(hwclk);
+ struct clk_corediv_desc *desc = &corediv->desc;
+ unsigned long flags = 0;
+ u32 reg;
+
+ spin_lock_irqsave(&corediv->lock, flags);
+
+ reg = readl(corediv->reg);
+ reg &= ~(BIT(desc->fieldbit) << CORE_CLK_DIV_ENABLE_OFFSET);
+ writel(reg, corediv->reg);
+
+ spin_unlock_irqrestore(&corediv->lock, flags);
+}
+
+static unsigned long clk_corediv_recalc_rate(struct clk_hw *hwclk,
+ unsigned long parent_rate)
+{
+ struct clk_corediv *corediv = to_corediv_clk(hwclk);
+ struct clk_corediv_desc *desc = &corediv->desc;
+ u32 reg, div;
+
+ reg = readl(corediv->reg + CORE_CLK_DIV_RATIO_OFFSET);
+ div = (reg >> desc->offset) & desc->mask;
+ return parent_rate / div;
+}
+
+static long clk_corediv_round_rate(struct clk_hw *hwclk, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ /* Valid ratio are 1:4, 1:5, 1:6 and 1:8 */
+ u32 div;
+
+ div = *parent_rate / rate;
+ if (div < 4)
+ div = 4;
+ else if (div > 6)
+ div = 8;
+
+ return *parent_rate / div;
+}
+
+static int clk_corediv_set_rate(struct clk_hw *hwclk, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_corediv *corediv = to_corediv_clk(hwclk);
+ struct clk_corediv_desc *desc = &corediv->desc;
+ unsigned long flags = 0;
+ u32 reg, div;
+
+ div = parent_rate / rate;
+
+ spin_lock_irqsave(&corediv->lock, flags);
+
+ /* Write new divider to the divider ratio register */
+ reg = readl(corediv->reg + CORE_CLK_DIV_RATIO_OFFSET);
+ reg &= ~(desc->mask << desc->offset);
+ reg |= (div & desc->mask) << desc->offset;
+ writel(reg, corediv->reg + CORE_CLK_DIV_RATIO_OFFSET);
+
+ /* Set reload-force for this clock */
+ reg = readl(corediv->reg) | BIT(desc->fieldbit);
+ writel(reg, corediv->reg);
+
+ /* Now trigger the clock update */
+ reg = readl(corediv->reg) | CORE_CLK_DIV_RATIO_RELOAD;
+ writel(reg, corediv->reg);
+
+ /*
+ * Wait for clocks to settle down, and then clear all the
+ * ratios request and the reload request.
+ */
+ udelay(1000);
+ reg &= ~(CORE_CLK_DIV_RATIO_MASK | CORE_CLK_DIV_RATIO_RELOAD);
+ writel(reg, corediv->reg);
+ udelay(1000);
+
+ spin_unlock_irqrestore(&corediv->lock, flags);
+
+ return 0;
+}
+
+static const struct clk_ops corediv_ops = {
+ .enable = clk_corediv_enable,
+ .disable = clk_corediv_disable,
+ .is_enabled = clk_corediv_is_enabled,
+ .recalc_rate = clk_corediv_recalc_rate,
+ .round_rate = clk_corediv_round_rate,
+ .set_rate = clk_corediv_set_rate,
+};
+
+static void __init mvebu_corediv_clk_init(struct device_node *node)
+{
+ struct clk_init_data init;
+ struct clk_corediv *corediv;
+ struct clk **clks;
+ void __iomem *base;
+ const char *parent_name;
+ const char *clk_name;
+ int i;
+
+ base = of_iomap(node, 0);
+ if (WARN_ON(!base))
+ return;
+
+ parent_name = of_clk_get_parent_name(node, 0);
+
+ clk_data.clk_num = ARRAY_SIZE(mvebu_corediv_desc);
+
+ /* clks holds the clock array */
+ clks = kcalloc(clk_data.clk_num, sizeof(struct clk *),
+ GFP_KERNEL);
+ if (WARN_ON(!clks))
+ goto err_unmap;
+ /* corediv holds the clock specific array */
+ corediv = kcalloc(clk_data.clk_num, sizeof(struct clk_corediv),
+ GFP_KERNEL);
+ if (WARN_ON(!corediv))
+ goto err_free_clks;
+
+ spin_lock_init(&corediv->lock);
+
+ for (i = 0; i < clk_data.clk_num; i++) {
+ of_property_read_string_index(node, "clock-output-names",
+ i, &clk_name);
+ init.num_parents = 1;
+ init.parent_names = &parent_name;
+ init.name = clk_name;
+ init.ops = &corediv_ops;
+ init.flags = 0;
+
+ corediv[i].desc = mvebu_corediv_desc[i];
+ corediv[i].reg = base;
+ corediv[i].hw.init = &init;
+
+ clks[i] = clk_register(NULL, &corediv[i].hw);
+ WARN_ON(IS_ERR(clks[i]));
+ }
+
+ clk_data.clks = clks;
+ of_clk_add_provider(node, of_clk_src_onecell_get, &clk_data);
+ return;
+
+err_free_clks:
+ kfree(clks);
+err_unmap:
+ iounmap(base);
+}
+CLK_OF_DECLARE(mvebu_corediv_clk, "marvell,armada-370-corediv-clock",
+ mvebu_corediv_clk_init);
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