[PATCH v2 6/9] clk: msm: Add support for branches/gate clocks

Stephen Boyd
2013-10-02T19:07:17Z

drivers/clk/msm/Makefile | 1 +
drivers/clk/msm/clk-branch.c | 153 +++++++++++++++++++++++++++++++++++++++++++
drivers/clk/msm/clk-branch.h | 50 ++++++++++++++
3 files changed, 204 insertions(+)
create mode 100644 drivers/clk/msm/clk-branch.c
create mode 100644 drivers/clk/msm/clk-branch.h

diff --git a/drivers/clk/msm/Makefile b/drivers/clk/msm/Makefile
index fb78ac9..e1cee29 100644
--- a/drivers/clk/msm/Makefile
+++ b/drivers/clk/msm/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_COMMON_CLK_MSM) += clk-msm.o
clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-pll.o
clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-rcg.o
clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-rcg2.o
+clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-branch.o
diff --git a/drivers/clk/msm/clk-branch.c b/drivers/clk/msm/clk-branch.c
new file mode 100644
index 0000000..3c67b43
--- /dev/null
+++ b/drivers/clk/msm/clk-branch.c
@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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/bitops.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+
+#include "clk-branch.h"
+
+#define to_clk_branch(_hw) container_of(_hw, struct clk_branch, hw)
+
+static bool clk_branch_in_hwcg_mode(const struct clk_branch *br)
+{
+ u32 val;
+
+ if (!br->hwcg_reg)
+ return 0;
+
+ regmap_read(br->hw.regmap, br->hwcg_reg, &val);
+
+ return !!(val & BIT(br->hwcg_bit));
+}
+
+static bool clk_branch_check_halt(const struct clk_branch *br, bool enabling)
+{
+ bool invert = (br->halt_check == BRANCH_HALT_ENABLE);
+ u32 val;
+
+ regmap_read(br->hw.regmap, br->halt_reg, &val);
+
+ val &= BIT(br->halt_bit);
+ if (invert)
+ val = !val;
+
+ return !!val == !enabling;
+}
+
+#define BRANCH_CLK_OFF BIT(31)
+#define BRANCH_NOC_FSM_STATUS_SHIFT 28
+#define BRANCH_NOC_FSM_STATUS_MASK 0x7
+#define BRANCH_NOC_FSM_STATUS_ON (0x2 << BRANCH_NOC_FSM_STATUS_SHIFT)
+
+static bool clk_branch2_check_halt(const struct clk_branch *br, bool enabling)
+{
+ u32 val;
+ u32 mask;
+
+ mask = BRANCH_NOC_FSM_STATUS_MASK << BRANCH_NOC_FSM_STATUS_SHIFT;
+ mask |= BRANCH_CLK_OFF;
+
+ regmap_read(br->hw.regmap, br->halt_reg, &val);
+
+ if (enabling) {
+ val &= mask;
+ return (val & BRANCH_CLK_OFF) == 0 ||
+ val == BRANCH_NOC_FSM_STATUS_ON;
+ } else {
+ return val & BRANCH_CLK_OFF;
+ }
+}
+
+static int clk_branch_wait(const struct clk_branch *br, bool enabling,
+ bool (check_halt)(const struct clk_branch *, bool))
+{
+ bool voted = br->halt_check & BRANCH_VOTED;
+ const char *name = __clk_get_name(br->hw.clk);
+
+ /* Skip checking halt bit if the clock is in hardware gated mode */
+ if (clk_branch_in_hwcg_mode(br))
+ return 0;
+
+ if (br->halt_check == BRANCH_HALT_DELAY || (!enabling && voted)) {
+ udelay(10);
+ } else if (br->halt_check == BRANCH_HALT_ENABLE ||
+ br->halt_check == BRANCH_HALT ||
+ (enabling && voted)) {
+ int count = 200;
+
+ while (count-- > 0) {
+ if (check_halt(br, enabling))
+ return 0;
+ udelay(1);
+ }
+ WARN("%s status stuck at 'o%s'", name, enabling ? "ff" : "n");
+ return -EBUSY;
+ }
+ return 0;
+}
+
+static int clk_branch_toggle(struct clk_hw *hw, bool en,
+ bool (check_halt)(const struct clk_branch *, bool))
+{
+ struct clk_branch *br = to_clk_branch(hw);
+ int ret;
+
+ if (en) {
+ ret = clk_enable_regmap(hw);
+ if (ret)
+ return ret;
+ } else {
+ clk_disable_regmap(hw);
+ }
+
+ return clk_branch_wait(br, en, check_halt);
+}
+
+static int clk_branch_enable(struct clk_hw *hw)
+{
+ return clk_branch_toggle(hw, true, clk_branch_check_halt);
+}
+
+static void clk_branch_disable(struct clk_hw *hw)
+{
+ clk_branch_toggle(hw, false, clk_branch_check_halt);
+}
+
+const struct clk_ops clk_branch_ops = {
+ .enable = clk_branch_enable,
+ .disable = clk_branch_disable,
+ .is_enabled = clk_is_enabled_regmap,
+};
+EXPORT_SYMBOL_GPL(clk_branch_ops);
+
+static int clk_branch2_enable(struct clk_hw *hw)
+{
+ return clk_branch_toggle(hw, true, clk_branch2_check_halt);
+}
+
+static void clk_branch2_disable(struct clk_hw *hw)
+{
+ clk_branch_toggle(hw, false, clk_branch2_check_halt);
+}
+
+const struct clk_ops clk_branch2_ops = {
+ .enable = clk_branch2_enable,
+ .disable = clk_branch2_disable,
+ .is_enabled = clk_is_enabled_regmap,
+};
+EXPORT_SYMBOL_GPL(clk_branch2_ops);
diff --git a/drivers/clk/msm/clk-branch.h b/drivers/clk/msm/clk-branch.h
new file mode 100644
index 0000000..28874cf
--- /dev/null
+++ b/drivers/clk/msm/clk-branch.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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 __MSM_CLK_BRANCH_H__
+#define __MSM_CLK_BRANCH_H__
+
+#include <linux/clk-provider.h>
+
+/**
+ * struct clk_branch - gating clock with status bit and dynamic hardware gating
+ *
+ * @hwcg_reg: dynamic hardware clock gating register
+ * @hwcg_bit: ORed with @hwcg_reg to enable dynamic hardware clock gating
+ * @halt_reg: halt register
+ * @halt_bit: ANDed with @halt_reg to test for clock halted
+ * @halt_check: type of halt checking to perform
+ * @hw: handle between common and hardware-specific interfaces
+ *
+ * Clock which can gate its output.
+ */
+struct clk_branch {
+ u32 hwcg_reg;
+ u32 halt_reg;
+ u8 hwcg_bit;
+ u8 halt_bit;
+ u8 halt_check;
+#define BRANCH_VOTED BIT(7) /* Delay on disable */
+#define BRANCH_HALT 0 /* pol: 1 = halt */
+#define BRANCH_HALT_VOTED (BRANCH_HALT | BRANCH_VOTED)
+#define BRANCH_HALT_ENABLE 1 /* pol: 0 = halt */
+#define BRANCH_HALT_ENABLE_VOTED (BRANCH_HALT_ENABLE | BRANCH_VOTED)
+#define BRANCH_HALT_DELAY 2 /* No bit to check; just delay */
+
+ struct clk_hw hw;
+};
+
+extern const struct clk_ops clk_branch_ops;
+extern const struct clk_ops clk_branch2_ops;